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Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
1
Air pollution trends over Indian megacities and their local-to-global 1
implications 2
B.R. Gurjar 3
Department of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee, 4
Uttarakhand 247667, India 5
Khaiwal Ravindra* 6
School of Public Health, Postgraduate Institute of Medical Education and Research 7
(PGIMER), Chandigarh 160012, India 8
Ajay Singh Nagpure 9
Hubert H. Humphrey School of Public Affairs, University of Minnesota, Minneapolis, MN 10
55455, United States 11
12
ABSTRACT 13
More than half of the world’s population lives in urban areas. It is estimated that by 2030 14
there will be 41 megacities and most of them will be located in developing countries. The 15
megacities in India (Delhi, Mumbai, and Kolkata) collectively have >46 million 16
inhabitants. Increasing population and prosperity results in rapid growth of the already 17
large consumption of energy and other resources, which contributes to air pollution, 18
among other problems. Megacity pollution outflow plumes contain high levels of criteria 19
pollutants (e.g. Particulate matter, SO2, NOx), greenhouse gases, ozone precursors and 20
aerosols; which can affect the atmosphere not only on a local scale but also on regional 21
and global scales. In the current study, emissions and concentration trends of criteria and 22
other air pollutants ( polycyclic aromatic hydrocarbons, carbon monoxide and greenhouse 23
gases) were examined in the three Indian megacities using data available from various 24
journal articles, reports and online sources. Further, various policies and control strategies 25
adopted by government are also discussed to improve air quality. Decreasing trends of 26
SO2 have been observed for all three megacities due to decrease in the sulphur content in 27
coal and diesel. Whereas, increasing trend for NOx has been found in the three megacities 28
due to increase in number of vehicles registered and high flash point of CNG engines 29
which leads to high NOx emission. In terms of SPM and PM10, highest emissions have 30
been found at Kolkata whereas highest ambient concentrations at Delhi. For Mumbai and 31
Kolkata fluctuating trends of SPM concentrations were observed between 1991 to 1998 32
and stable afterwards till 2005, whereas for Delhi, fluctuating trend was observed for the 33
entire study period. 34
35
36
Keywords: Megacities, criteria pollutants, methane, carbon dioxide, PAHs, CNG, air 37
quality management 38
39
*Corresponding author: Sc hool of Public Health, Post Graduate Institute of Medical Edu cation40
and Research (PGIMER), Chandigarh, India 160012. E‐mail: Khaiwal@yahoo.com, Tel.:41
+911722755262;fax:+911722744401.42
43
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
2
CONTENTS 44
45
Abstract 46
47
1. Introduction 48
49
2. Brief details of Indian megacities 50
2.1 Delhi 51
2.2 Mumbai 52
2.3 Kolkata 53
54
3. Emission from Indian urban centers 55
3.1 Emission from major sources 56
3.2 Mitigation policies and strategies 57
58
4. Trends and status of air pollutants over Indian megacities 59
4.1Criteria pollutants 60 4.1 Sulfur dioxide 61 4.2 Nitrogen dioxide 62 4.3 Particulate matter 63
4.2 Polycyclic aromatic hydrocarbons 64
4.3 City specific studies of selected pollutants 65 4.3.1 Carbon monoxide (CO) 66 4.3.2 Greenhouse gases (N2O, CH4) 67
68
5. Health Effect of Air Pollution 69
70
6. Inferences of current study and world megacities 71
6.1 Concentration trends and status 72
6.2 Megacities as emission source in the region 73
6.3 Megacities and their role in climate change 74
6.4 Air quality management in megacities 75
76
Acknowledgement 77
References78
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
3
1. Introduction 79
80
The urban population of the world has been increasing rapidly during the past few 81
decades. While in the 1950s approximately 18% of world’s population was living in urban 82
areas, this figure had reached to 50% by the year 2001. Further, world population is 83
expected to increase from 7.0 billion to 9.3 billion from 2011 to 2050 and urban areas of 84
the world are expected to absorb all the population growth expected over this period (UN, 85
2012). The United Nations defines a megacity as a metropolitan area with a total 86
population equal to or more than ten million people. World Urbanization Prospects (UN, 87
2012) estimates that in 2011, around 10% was living in megacities and it is expected to 88
be 14% in 2025, whereas Sokhi and Kitwiroon (2008) proposed 30% increase by 2020. 89
Due to the large population density, megacities face tremendous pressure not only on basic 90
urban infrastructure/civic facilities but also on environment and human health (Wenzel et 91
al, 2007; Gurjar et al., 2010). In a study by Gurjar et al. (2008), a multi-pollutant index 92
(MPI) was developed which revealed that out of 18 megacities worldwide, only 5 were 93
classified as having ‘fair’ air quality whereas 13 had ‘poor’ air quality. Of 18 megacities 94
considered Delhi was ranked 7 in terms of air quality with MPI of 0.92 followed by 95
(Kolkata 9th, MPI-0.59) and (Mumbai 11th, MPI- 0.39). Poor air quality of Delhi is mainly 96
due to high particulate matter concentrations (Gurjar et al., 2008). Recent Global Burden 97
of Diseases indicated that increasing air pollution in megacities and other parts of the 98
country is responsible for over 650,000 premature deaths every year in India, making it 99
5th leading cause of premature mortality and there is six fold increase since 2000 (100,000 100
premature deaths). Further 31.4 million healthy life years are lost due to poor health, 101
disability or early death disability adjusted life years, DALYs (Lancet, 2012). 102
103
The large consumption of energy in various forms (e.g. fossil fuels and biofuels) 104
contributes to high levels of air pollution in megacities (Butler et al., 2008, Ravindra et al., 105
2015). Megacity plumes contain large amounts of different pollutants including 106
greenhouse gases, ozone precursors and aerosols; therefore, they affect atmospheric 107
chemistry and act as an emission source (hot spot) to the entire the region (Molina and 108
Molina et al., 2004, 2010; Kanakidou et al., 2011). Since the lifetimes of air pollutants 109
may be prolonged due to the high concentrations in megacity plumes, they can travel 110
across and even between continents and contribute to air pollution at a global scale, with 111
potential associated socio-economic and political impacts (Krass, 2007, Ravindra et al., 112
2015). Hence, there is need to understand the sources, concentration trends, transformation 113
and health risks of urban pollutants including their role in global climate change. 114
115
Along with economical growth, the urban population of India has also rapidly increased 116
during the last century. The urban fraction of the population in India has increased from 117
17% in 1951 to 31% in 2011. Interestingly out of 31%, about 13% of urban population (48 118
million and around 4% of total population) lives in the three megacities Delhi, Mumbai 119
and Kolkata. Figure 1 depicts the geographical locations of these three megacities, where 120
as Figure 2 shows the decadal population growth trend in India and its megacities. 121
122
Several studies have been carried out and published by different researchers on emissions 123
and air quality in megacities of India. Number of such publications is increasing because 124
of the increased interest of scientific community in megacities air quality related problems. 125
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
4
There are several studies, which focus on targeted pollutants and their sources in a 126
particular area of a megacity but there is a need to critically review and analyze the current 127
state of understanding of air pollution problems in Indian megacities as a whole. 128
129
To identify the research needs and data gap, the present study appraises the sources, 130
concentration trends and emissions over Indian megacities. Furthermore the study also 131
highlights the implication of policies and strategies to reduce the air pollution such as 132
introduction of compressed natural gas (CNG), improvement in fuel quality and vehicle 133
technologies, shifting of industries. The assessment is exercised using scientific data 134
available in various journal articles, reports and online sources. The review also aim to aid 135
researchers and policy makers to identify similarities and peculiarities of Indian megacities 136
in terms of causes and effects of air pollution problem so that effective air quality 137
strategies can be planned and executed in other megacities throughout the world. 138
139
2. Brief details of Indian megacities 140
2.1 Delhi: 141
Delhi is one of the largest megacities of South Asia and the political capital of India. It is 142
located between 28o 24’ 17” N to 28o 53’ 00” N latitude and 76 o
50’ 24” E to 77 o
20’ 143
37”E longitude at an elevation of 216 m above mean sea level (MSL). Delhi lies almost 144
entirely in the Gangetic plains with Great Indian Desert (Thar Desert) of Rajasthan state to 145
the west, central hot plains to the south and hilly regions to the north and east. The river 146
Yamuna forms the eastern boundary of the megacity. It has a semi-arid climate, with long 147
summers (early April to October), the monsoon season in between and notorious winters 148
(October and peaks in January) with heavy fog (Mohan and Payra, 2009). The wind is 149
westerly towards the Bay of Bengal most of the year, except in the monsoon months 150
(June–September) when the direction is reversed. 151
152
According to census 2011, Delhi has a population of 16.31 million, with a population 153
density of 11320 km-2 (Census of India, 2011). Major causes of air pollution in Delhi had 154
been large number of industries, power plants, and dense vehicular population. For 155
example, from 1971 to 2011, the road length in Delhi increased from 8,380 to 31969 km 156
(3.8 times); whereas the number of registered vehicles increased from 0.18 to 7.43 million 157
(20 times) leading to enhanced air pollution (Gurjar and Lelieveld, 2005, DSA, 2012 158
Nagpure et al., 2016). 159
160
According to a local survey, 30% of Delhi’s population was found suffering from 161
respiratory disorders due to air pollution and the number of cases found were almost 12 162
times higher than the national average (Kandlikar and Ramachandran, 2000) and poor air 163
quality was held responsible for about 18,600 premature deaths per year (TERI, 2001a). 164
Similarly recent study (Nagpure et al., 2014) suggested that air pollution related mortality 165
increased twice between 1991 and 2010 in Delhi. 166
167
2.2 Mumbai: 168
Mumbai (known as Bombay until 1996), is the sixth largest metropolitan region in the 169
world and financial capital of India. It is located between 18° 56' N latitude and 72° 51' E 170
longitude at the Arabian Sea with an average elevation from 10 m to 15 m from the MSL. 171
The total area covered by the Mumbai Metropolitan Region (MMR) is 4,355 km2, 172
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
5
including 468 km2 area of Greater Mumbai and rest of Mumbai (3887 km2). The climate of 173
Mumbai is tropical moist, with temperature ranging between 16oC and 33oC. The average 174
annual precipitation is 2,078 mm with maximum rainfall during July. The pollution load, 175
its atmospheric transport and chemistry is considerably affected by the wind direction, 176
which can bring in cleaner marine air from the west or polluted air from the eastern 177
industrial belt. The post-monsoon and winter months have a high frequency of calm 178
periods with stagnant conditions leading to air pollution build-up (Venkataraman et al., 179
2001). 180
181
Mumbai’s industrial and commercial growth has been accompanied by a rapid increase in 182
population from 0.9 million in 1901 to 18.41 million in 2011. According to Census (2011), 183
Mumbai had a population density of 19652 km-2. Expansion of industries, increased 184
foundry production and a 103% increase in vehicles has led to severe air pollution 185
problem in Mumbai. According to recent study by Lelieveld et al., 2015, , air pollution 186
results in about 10200 premature deaths in year 2010. It is interesting to know that this 187
figure was 2800 in year 1995 (URBAIR, 1996), 188
189
2.3 Kolkata: 190
Kolkata is also known as ‘City of Joy’ though it is one of the most polluted megacities of 191
the world. It is located between 22o32’N latitude and 88o20’ E longitude in north-eastern 192
India in the Ganges Delta near the Bay of Bengal, at an average elevation of 1.5 m to 9 m 193
above MSL. Kolkata has a humid tropical climate with hot and dry summers (February to 194
April), the monsoon from May to October and moderate winters (November to January). 195
The mean monthly temperature ranges from 12.6°C in the winter to 35.6°C in summer 196
months (Karar and Gupta, 2006). Rains brought by the Bay of Bengal branch of South-197
West monsoon lash the city between June and September, supplying it with an annual 198
rainfall of 1,582 mm. Daily average wind speeds range from 0.5 to 10.0 kmh-1. 199
200
Kolkata has 14.11 million habitants with a population density of7480 km-² (Census, 2011). 201
Rapid and unplanned urbanization, uncontrolled vehicular density, badly maintained 202
roads, low turnover of old vehicles play a significant role in degrading the air quality of 203
Kolkata. The study conducted by Lelieveld et al., 2015 estimated that air pollution is 204
responsible for 13500 deaths in Kolkata in year 2010. 205
206
3. Quality Control/ Quality Assurance of data used in the study 207
208
Data used in the present study has been taken from published articles and reports issued 209
from various organizations like Central Pollution Control Board (CPCB), National 210
Environmental Engineering Research Institute (NEERI), Tata Energy Research Institute 211
(TERI), Asian Development Bank, World Bank and World Health Organization (WHO). 212
CPCB has a QA/QC programme to ensure the quality of measured data which includes 213
calibration and maintenance of instruments, training programmes and guidelines for 214
ambient air quality monitoring and evaluation of monitoring stations. The current study 215
focuses only on three megacities in India which have high population density and 216
considered to be severely polluted. 217
218
4. Emissions from Indian urban centers 219
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
6
4.1 Emissions from major sources 220
Air pollution is commonly perceived as an urban problem especially in megacities, which 221
are associated with rapid industrial and population growth. CPCB has identified 43 222
industrial areas to be critically polluted based on Comprehensive Environment Pollution 223
Index (CEPI) (CPCB, 2000). Currently, in India, air pollution is widespread in urban areas 224
where vehicles are the major contributor followed by industries and thermal power plants 225
(TERI, 2001b; Kaushik et al., 2006). Further, fossils fuel combustion in various activities 226
is also one of the major sources of air pollution. Burning of biomass for residential energy 227
and seasonal burning crop residue significantly affect the urban air quality. 228
229
India has made rapid strides in industrialization, and is among the ten most industrialized 230
nations of the world. The Central Pollution Control Board (CPCB) has identified 231
seventeen categories of drastically polluting industries (large and medium scale) in India. 232
The list includes- integrated iron and steel, thermal power plants, copper/zinc/ aluminum 233
smelters, cement, oil refineries, petrochemicals, pesticides and fertilizer units. Since 1950-234
51, the electricity generation capacity in India has multiplied 55 times from a meager 1.7 235
thousand mega watt (MW) to 93.3 thousand MW (MoEF, 2000). Thermal power plant 236
constitutes about 74% of the total installed power generation capacity in India. The Energy 237
and Resources Institute (TERI) has estimated that total estimated pollution load of 238
suspended particulate matter (SPM), SO2 and NOx from thermal power sector has 239
increased 50 times from 1947 to 1997 (i.e. 300 Tg to 15000 Tg). In 1997, SPM claimed 240
the largest share (86%) of the total pollution load from thermal power sector. It is also 241
estimated that SPM emission from 7 critical industries (e.g. iron and steel, cement, sugar, 242
fertilizers, paper and paper board, copper and aluminum) has increased from 200 Tg in 243
1947 to 3000 Tg in 1997 (TERI, 2001b). 244
245
Thermal power plants are major users of coal in India, accounting for more than 25% of 246
total emissions from 1973 to 1997. Similarly petroleum sector accounts for more than 40% 247
of total emission during 1973-1997 (Mukhopadhyay and Forssell, 2005).Among all 248
sources, coal combustion is the major source of SPM, CO2 and NOx emissions whereas oil 249
combustions are responsible for SO2 emission. Industries like iron and steel smelting, and 250
the production of basic metals, metal products and machinery, fertilizer, other metallic 251
product and cement are the other important sources of SO2 and NOx in India. 252
253
The recent data shows that in India the number of motor vehicles has increased from 0.3 254
million in 1951 to 159.5 million in 2012 (Government of India, 2015).Out of these, 32% 255
are concentrated in 23 metropolitan cities. For instance, Delhi itself accounts for about 256
8% of the total registered vehicles and the number is more in comparison to the other 257
metro and megacities (e.g. Mumbai, Kolkata, and Chennai) taken together (TERI, 2001b). 258
Pachauri and Sridharan (1998) estimated that the total pollution load from the 259
transportation sector in India increased 68 times from 1947 (150 Tg) to 1997 (10300 Tg). 260
During this period, CO emissions made up the largest share (43%) of total pollutants from 261
the transport sector, followed by NOx (30%), HC (20%), SPM (5%), and SO2 (2%). 262
According to CPCB (2000) twelve major metropolitan cities in India annually produce 263
0.35 Gg of NOx, 1.91 Gg of CO and 0.67 Gg of VOC from vehicles alone (TERI, 2001b). 264
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
7
The amount of vehicular pollutants emitted is highest in Delhi followed by Mumbai, 265
Bangalore, Kolkata and Ahmedabad. 266
The ambient concentration levels of CO, SO2 and NOx have been observed far beyond the 267
safe limits prescribed by WHO (Mukhopadhyay and Forssell, 2005; Kaushik et al., 2006). 268
Indoor particulate matter on its own or in combination with SO2 causing at least 400,000 269
to 550, 000 premature deaths and 4-5 million new cases of chronic bronchitis each year in 270
India (Smith, 2000) and this number will rise significantly if the effects of outdoor air 271
pollution will also be considered. Increasing concentrations of SPM, SO2, NOx and other 272
pollutants adversely affect plant growth and cause various diseases like chlorosis and 273
necrosis (Shukla et al., 2008,). Furthermore, these pollutants also affect the built 274
environment due to their corrosive nature. As reported by Sindhwani & Goyal, 2014, the 275
numbers of vehicles (4, 3 and 2- wheelers) in Delhi and emissions of various air 276
pollutants from transport sector are presented in Figure S1-S5 for the years 2000 to 2010. 277
278
4.2 Mitigation policies and strategies 279
The Indian government has formulated legislation, policies and programmes for protecting 280
the environment, for instance, Air (Prevention and control of pollution) Act, 1981 and 281
Environment (Protection) Act, 1986 (TERI, 2001a). CPCB has adopted National Air 282
Quality Programme (NAMP) building a network of monitoring air quality monitoring 283
stations for measuring four criteria pollutants: SO2, NOx, SPM and RSPM in 26 states and 284
4 union territories. The number of monitoring stations has increased from just 7 in 1982 to 285
342 in 2012,, and is still expanding. Government has launched National Air Quality Index 286
as a measurement index consisting information of 8 pollutants into a single number for 287
public awareness of levels of air pollution parameters. Policies and measures taken for the 288
various sectors are described below. 289
290 4.2.1 Industries: Industrial emissions are regulated under Environment Protection Act, 291
1986 which involves installation of pollution control equipments to meet the emission 292
guidelines. CPCB has identified 24 critically polluted areas and action plans have been 293
formulated to improve air quality of these areas. For coal power plants located more than 294
1000 km from the pit head, ash content of the coal used has to be below 34%. 295
Environmental clearance from Ministry of Environment and Forest (MoEF) has been 296
made mandatory for establishment of development projects (29 categories) which involves 297
conducting Environmental Impact Assessment (EIA) study, public hearing and submitting 298
environmental statement. Moreover, other measured such as reduction in the sulfur 299
contents of the coal, relocation of industries (i.e. displacement of industries from inner 300
parts of city to outer areas), use of clean fuel [e.g. use of less ash and sulfur content coal, 301
liquid petroleum gas (LPG) and application of air pollution control devices have been 302
taken.For reducing dust emissions from stone crushers, use of enclosed structures and 303
water spraying system have been adopted. 304
305 4.2.2. Transport: Various measures have been taken by government to reduce vehicular 306
emissions such as introduction of cleaner fuels (e.g. unleaded gasoline, ultra-low sulfur 307
diesel, CNG, LPG), improved engine technologies, introduction of Bharat Norms 308
(equivalent to Euro norms), alternate public transport (Delhi metro rail) to trim down the 309
growing energy demand and emissions. A series of stricter norms for vehicular emission 310
reduction (Bharat Stage I-IV) have been adopted by Ministry of Road Transport and 311
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
8
Highways since 2000. Bharat Stage IV equivalent to EURO IV norms for all new vehicles 312
except two and three wheelers have been adopted from 2010 in 13 mega cities which 313
includes Delhi, Mumbai and Kolkata, and proposed to be effective in entire country from 314
2017. For two and three wheeled vehicles, Bharat Stage III norms were adopted in 2010. 315
For two wheeled vehicles, Bharat stage IV was adopted in April, 2016. Further, the 316
government has proposed to step up to Bharat Stage V and VI by April, 2020. 317
318
Leaded gasoline was phased out from entire country from early 1990s till 2000, and 319
Benzene concentration in gasoline was regulated to 3% in all India while there were no 320
specifications before 1996. Regulation for Sulphur content in diesel was 0.50% in 1996 321
and was reduced to 0.25% in 1998, 0.05% in 2005 and 0.005% in 2010. In Kolkata, 3-322
wheelers fuel has been switched to LPG from May, 2005 whereas in Delhi and Mumbai, 323
CNG is made mandatory for 3-wheelers and buses. Delhi government launched odd-even 324
scheme by allowing private diesel and petrol driven cars to run on alternate days based on 325
license plate number. According to Delhi government officials, the 15 day trial resulted in 326
reduction of maximum PM2.5 concentration from 600µg.m-3 (observed in previous month) 327
to 400µg.m-3 (observed during the implementation period). However, Council on Energy 328
Environment and Water (CEEW) suggested that there was not enough evidence to 329
conclude the improvement in air quality. 330
331
4.2.3. Biomass burning: Biomass burning is a major contributor to particulate matter 332
concentrations. Nagpure et al., 2015 showed that open burning of municipal solid waste 333
(MSW) could amount to 2-3% of total generated MSW in Delhi. To reduce the emission 334
of harmful pollutants and health impacts from burning of wood, agriculture waste and 335
animal residue, government has put emphasis on improved cook stoves. Ministry of New 336
and Renewable Energy has launched National Biomass Cook stoves Programme in 2009 337
for development and promotion of improved cook stoves. Deployment of improved 338
chulhas under pilot schemes at government schools and communities showed significant 339
reduction in emissions and fuel consumption. Moreover, Rs 131 crores has been allotted in 340
union budget 2015-2016 for promotion of improved cookstoves and solar cookers (NBCP, 341
MNRE). 342
Recently, MoEF has issued various directions to reduce air pollution from biomass 343
burning and non-exhaust sources such as mechanized sweeping of roads to reduce 344
resuspended road dust, water sprinkling and covering of construction sites by municipal 345
corporations, strict action against burning of agriculture/municipal waste in open 346
environment and elimination of use of kerosene for cooking (MoEF, 2015). 347
348
5. Trends and status of air pollutants over Indian megacities 349
Thermal power plants, transport, industries, agriculture and solid waste disposal are some 350
of the major emission sources in Indian megacities. Several emission inventories exist for 351
Delhi, whereas only few studies are available for Mumbai and Kolkata; but the existing 352
inventories focus on a particular emission source (especially transport) or a particular 353
problem (e.g. criteria air pollutants) and only for a particular year. Moreover, the 354
emissions factors of various sources in India have not been well developed, which could 355
severely affect the estimated emission inventories of air pollutants. Various sources and 356
emission load for SO2, NOx and particulate matter are depicted in Table 1 a, b, & c at 357
different sites. 358
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
9
359
360
5.1 Criteria pollutants 361
5.1.1 Sulfur dioxide (SO2) 362 5.1.1.1Delhi: Delhi was among the top five SO2 emitting megacities in the early nineties 363
and the transport sector was the prime source (Garg et al. 2001). In the last decade, 364
industries and power plants emerged as major sources of SO2 (Auto Fuel Policy Report. 365
2002, Gurjar et al. 2004). Gurjar et al. (2004) concluded that 68% of emissions were from 366
thermal power plants (TPP) during 1990 to 2000, whereas Goyal and Sidhartha (2002) 367
estimated that TPP, industries, and vehicles emitted 56.8%, 38.4%, 4.8% of SO2 368
respectively (Figure S6). According to Auto Fuel Policy Report, (2002) industrial sector 369
was the prime contributor (between 84-92%) followed by transport (5-12%) and the 370
domestic sector (0-4%) from 1994 to 1998. The recent study by Guttikunda et al., (2013) 371
suggested that for SO2 emissions the accountability of industrial sectors was highest (97%) 372
among all other sectors, its shows the impact of different policy interventions for SO2 373
reductions in Delhi. 374
375
According to Guttikunda et al. (2003), during the time period of 1990 to 2000, Delhi was 376
the second largest SO2 contributor among the megacities in India (Figure S7). Gurjar et al. 377
(2004) have demarcated an inter-annual variability in the emission trend ranging between 378
90 and 113 Gg during 1991 to 2000. Whereas Bose (1996) estimated that the total SO2
379
emission in Delhi was 45 Gg in 1990 and grew to 81 Gg by 1995 according to estimations 380
made by Bose (1996). Out of that, the transport sector alone contributed 2.27 Gg during 381
1990 and diesel vehicles emerged as the prime emitter among other vehicles (Bose, 1996). 382
However, Garg et al., (2001) also reported that the estimated emissions of SO2 (in terms of 383
per Km2) decreased from 48 to 47 Mg between years 1990 to 1995. Similarly in 2010 384
Guttikunda et al., (2013) estimated about 37.40 Gg of SO2 of emissions from all sectors in 385
Delhi. 386
387
388
A declining trend was also noticed during 1996 to 1998, which might be because of the 389
introduction of low-sulfur diesel (1996) and low plant load factors (1998). For example, 390
the introduction of low-sulfur diesel resulted in declining emissions (39 Gg in 1995 to 23 391
Gg in 1996) from the transport sector. Nevertheless, the increasing number of vehicles in 392
Delhi partly offset this measure and emission from the transport sector had almost reached 393
the level of 1990 by the year 2000 (Gurjar et al., 2004). 394
395
CNG implementation took place between 2000 and 2003 in Delhi and has largely 396
influenced the declining SO2 emission from the transport sector which could also be seen 397
in the concentration trend (Figure 3) as also endorsed by Goyal and Sidhartha (2003), 398
Ravindra et al. (2006), Reynolds and Kandlikar (2008), Kandlikar (2007). Nagpure et al., 399
2016. According to Ravindra et al. (2003) around 50% reduction was observed in SO2
400
emissions between 1998 and 2003.CPCB data shows that the annual average SO2
401
concentration was 25 µgm-3 in 1995, which gradually decreased to 4 µgm-3 by 2012 402
(CPCB, 2015). This reflects the influence of various pollution reduction policies 403
implemented by the government such as relocation and shutting down of hazardous 404
industries resulted in significant reduction in pollution levels in the last decades (Figure 4). 405
Goyal and Sidhartha (2002) have linked the variation in seasonal concentration of SO2
406
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
10
with meteorological parameters (e.g. wind direction, inversion layer etc.). Higher 407
concentrations observed were associated with the wind from WNW–NW. Further, 408
relatively low concentrations observed from June to September were stated to be due to 409
the washout of pollutants, which can be up to 40% (Ravindra et al., 2003). The observed 410
seasonal concentration profile was highest in winter > post-monsoon > pre-monsoon > 411
monsoon. During the last decade, however, the observed concentrations at all monitoring 412
stations (CPCB, 2008) were always below the standard limits of SO2 prescribed by Indian 413
National Ambient Air Quality Standard (NAAQS) and also by other agencies e.g. WHO 414
and USEPA (Table 3). The reduction in SO2 levels can also be attributed to scavenging by 415
atmospheric dust due to its alkaline nature (Kulshrestha and Sharma,2014; Kulsrestha et 416
al., 2003; Kulsrestha and Sharma 2015). 417
418 5.1.1.2 Mumbai: Mumbai was found as the foremost emitter of SO2 among all the 419
megacities studied by Guttikunda et al. (2003), while Bhanarkar et al. (2005) concluded 420
the same in terms of emission per unit area. Industries stood as the prime contributor 421
source in Mumbai (URBAIR, 1997; Auto Fuel Policy Report, 2002; Bhanarkar et al., 422
2005). As per Auto Fuel Policy Report (2002), 82-98% of emissions were from industrial 423
sources during 1992-1995 followed by 2-4% from transport and 0-16% from other 424
sources. Guttikunda et al. (2001) estimated that industrial sources were responsible for 425
70% of SO2 emission in Mumbai. Details of sectoral contributions to annual emissions of 426
SO2 and also NO
x and SPM are given in Figure 5 for the period 1992-93 (URBAIR 427
(1997). 428
429
During the year 2000 Mumbai had significantly enhanced SO2 emissions in comparison to 430
other South and Southeast Asian megacities with exceeding annual emissions of 200 431
Gg(Guttikunda et al., 2001). It was estimated that from 2001 to 2002, total estimated SO2
432
emissions from all industrial sources including power plant were 55 Gg. Previous 433
estimates of SO2 emissions from industrial sources in Mumbai was 0.38 Gg for 1987 434
(Arndt et al., 1997), 131 Gg for 1990 (Guttikunda et al., 2001), 66 Gg for 1992 (URBAIR, 435
1997) and 57.50 Gg as reported in the study conducted under Metropolitan Environment 436
Improvement Programme (MEIP) in 1993. During 1992-1993, URBAIR estimated that 437
industries were the major source of SO2 (39 Gg) in Mumbai followed by power plants (26 438
Gg), marine dock (9.5 Gg) and transport sector (3.55 Gg) . In 2010 the SO2 emissions 439
from all sectors became 56.48Gg (Figure 3), however industrial sources remained the 440
major source of SO2 (CPCB,2010). 441
442
It has been estimated for megacity Mumbai that annual SO2 emissions from all sources are 443
55 Gg during the year 2010 (Bhanarkar et al., 2005). Based on the Guttikunda et al.(2003) 444
study we have plotted emission from all sources for the period 1990 to 2000 for all three 445
Indian megacities (Figure S7). It shows that during 1990 to 2000, megacity Mumbai was 446
the largest SO2 emitter with annual emissions almost three to four times more in 447
comparison to Delhi and Kolkata. 448
449
On the basis of CPCB data we have observed that highest concentration of SO2 was in 450
1994 (34 µgm-3) whereas the least was in year 2012 (4 µgm-3). Figure 3 shows the 451
gradually declining concentration trend of SO2. However, between 1992 and 1994, the 452
concentration has increased because of growing emissions from power plants and the 453
transport sector. From 1995-2012 a decline is observed in SO2 concentrations, which 454
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
11
might be due to the implementation of various norms and measures –like the use of coal 455
with reduced sulfur content, stricter emission norms for various industries and 456
implementation of clean fuel (e.g. low sulfur diesel and CNG) in the transport sector of 457
Mumbai. Since the last decade, the ambient concentration of SO2 did not surpass the 458
standard limit set by NAAQS, India. 459
460 5.1.1.3 Kolkata: Very few studies are available about the SO2 emissions from Kolkata. A 461
study conducted by NEERI during 1977 to 1980 projected that the main sources of SO2
462
Kolkata are industries and power plants. During 1977-78, the annual emission from 463
industrial sector was 16 Gg and thermal power plants alone accounted for 34% of this 464
emission. According to NEERI, the annual emissions were stable from 1980 to 2000 (25 465
Gg). The bus and truck population increased by 78% between 1980 and 1989, which could 466
be linked to the emissions from diesel vehicles (ESS/NEERI).In the year 2003, 10 Gg of 467
SO2 was emitted from four coal based power plants located within Kolkata(ADB, 2005). 468
According to Nagpure et al., (2010) in 2010 transport sector is responsible for about 20 Gg 469
of SO2 emissions, Figure 6 shows the contributions of different categories of vehicle in 470
Kolkata. 471
472
Garg et al. (2001) estimated that SO2 emissions were 0.2Gg and 0.17 Gg/Km2, 473
respectively for 1990 and 1995. The annual SO2 emission in Kolkata from all sources 474
were 20.6 Gg(1975), 24.4 Gg(1980), 39.1 (1990) and 64.6 Gg in 2000 as reported by 475
Guttikunda et al. (2003). Furthermore, the study estimated that in 2010 the annual 476
emission of SO2 will become 200.7 Gg followed by 310.6 Gg in 2020. Per meter square 477
deposition of sulfur in Kolkata was 0.2, 0.3, and 0.6 g in 1975, 1980 and 1990 478
respectively; however, it was twofold (1.1 g) in 2000. 479
480
Figure 3 illustrates that there are large variations in ambient SO
2 concentration before 481
1999 (with two peaks during 1994 and 1999 and sharp dip in 1996) in Kolkata. This could 482
reflect the unavailability of appropriate monitoring data and use of high sulfur diesel as 483
fuel, older vehicles, and unavailability of clean coal. However, there is a declining trend 484
since 1999, which demonstrates the effects of various policies and measures implemented 485
to enhance air quality in megacity Kolkata. Highest concentrations of SO2 (49 µgm-3) were 486
observed in 1994 and the lowest (9 µgm-3) in 2004 and 2005. As the available 487
concentration data from CPCB is only for three monitoring stations in Kolkata, annual 488
average concentrations may not be representing Kolkata as a whole. 489
490
5.1.2 Oxides of nitrogen (NOx) 491 5.1.2.1 Delhi: The Auto Fuel Policy Report (2002) states that the total NOx emission from 492
various sources ranges from 66 to 74% (transport sector),13 to 29% (industrial sector), and 493
1 to 2% (domestic and other sources). According to Gurjar et al., (2004), NOx emission 494
trend showed a steep rise from 94 Gg in 1990 to 161 Gg in 2000; with highest emission 495
contribution from the transport sector. CPCB (1995) also shows that almost 50% of NOx 496
emissions are from vehicular activity, followed by domestic activities, industries, and 497
power plants. Per day emission of 0.11 Gg was estimated by Auto Fuel Policy (2002)for 498
Delhi. Annual NOx emissions from gasoline consumption have increased from 3.5 Gg to 499
4.5 Gg during 1990-91 to 1995-96, whereas from diesel they grew from 8 Gg in 1990-91 500
to12.8 Gg in 1995-96 (Sharma et al., 2002a). The study also estimated that per capita NOx 501
emission in Delhi has also increased from 1.3 Kg (1990) to 1.56 Kg (1995) with 18.5% 502
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
12
growth. Interestingly, per capita emission of NOx at national level was quite a bit less in 503
comparison to Delhi (e.g., 0.32 Kg in 1990 and 0.43 Kg in 1995). According to Xie and 504
Shah (2002), diesel driven buses/trucks and light duty gasoline vehicles (LDGV) were the 505
major source of NOx in Delhi during 1999-2001 whereas the smallest contribution was 506
from two and three wheelers. This scenario have been changed in recent year (2012) 507
according to Nagpure et al.,2016 (Figure 6) Bus population emerged as highest contributor 508
(41%) for NOx emissions followed by LCVs (19%), HCVs (17%) and car (13%) out of 509
total 105 Gg transport emissions 510
511
Several studies have observed an increasing trend in ambient air concentration of NOx in 512
Delhi (Ravindra et al., 2006;Kandlikar, 2007; Reynolds and Kandlikar, 2008). The 513
explanation for increasing NOx concentrations in Delhi seems to be related with the annual 514
increase in total number of vehicles and with higher flash-point (ignition) of CNG (540oC) 515
as compared to that of diesel (232-282oC). At such a high temperature, more nitrogen from 516
the air compresses and reacts with oxygen in the combustion chamber of CNG driven 517
vehicles and thus produces more NOx (Ravindraet al., 2006). Increasing use of Liquid 518
Petroleum Gas (LPG) in the domestic sector is another important factor responsible for 519
NOx emissions in Delhi (Kadian et al., 2007). Inefficient burning of LPG emits more NOx 520
in comparison to the traditional (e.g. wood, cow dung etc.) fuels (Mohan et al., 2007). 521
Figure 3 shows that in Delhi, the concentration of NOx gradually increased by 164%, i.e., 522
from 22 µgm-3 in 1991 to 58 µgm-3 in 2012. Kandlikar (2007) suggested that the switch to 523
CNG was responsible for the increase, however Ravindra et al. (2006) also relates it with 524
the increasing number of vehicles and their poor maintenance. 525
526
After 2001 the concentration trend shows significant increases and the levels reached to 527
the NAAQS standard limits for residential areas. However, after 2003, NOx annual 528
average concentration surpassed the standard limit given by WHO and NAAQS (annual 529
average concentration= 40 µgm-3) and reached the highest level (58 µgm-3) in 2012. This 530
causes alarm in relation to the health effects and also raises the need to understand the 531
reactivity of NOx and VOCs species which are responsible to produce ozone in the 532
presence of sunlight (Sillman, 1999). It is possible to identify two regimes with different 533
ozone-NOx-VOC sensitivity. In the NO
x-sensitive regime (with relatively low NOx and 534
high VOC), ozone increases with increasing NOx and changes little in response to 535
increasing VOC. In the NOx-saturated or VOC-sensitive regime ozone decreases with 536
increasing NOx and increases with increasing VOC (Singh et al., 2014; Genga et al., 537
2008). 538
539 5.1.2.2 Mumbai: The World Bank estimated that during 1992-93, the annual NOx 540
emission was 37 Gg and transport sector was identified as the major contributor, 541
accounting 52% of the emission in Mumbai (URBAIR, 1997). However, Auto Fuel Policy 542
Report (2002) estimates that 60% of NOx emission comes from the transport sector, 543
whereas remaining 40% is contributed by industrial sector. In 1973, thermal power plants 544
were the main industrial source, followed by chemical plants (NEERI, 1991a). A detailed 545
vehicle emission inventory by NEERI (1991a) indicates that the predominant source was 546
diesel vehicles (mainly trucks). 547
548
Based on the TERI (2002) and CPCB (2008) reports, the present study estimates 549
emissions from the transportation sector according to the vehicle population and ambient 550
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
13
air concentration from 1996 to 2005 as shown in Figure 7. The total annual NOx emission 551
from all sources was 53 Gg in 2000-01 as estimated by TERI (2002). The transport sector 552
accounted for 16.33 Gg in 1993, which increased to 27.72 Gg in 2005. Further, it is 553
projected that by 2010 it will be around 30Gg. With 79 Gg of emissions in 2007 about 554
32% of growth have been observed in NOx emission from 2000-01 when comparing TERI 555
results with CPCB (2010) study (Figure 5). Figure 7 also shows that the ambient 556
concentration declined in the last decade, which might be partly due to an insufficient 557
number of monitoring stations not representing the complete Mumbai region. It is 558
discernible from Figure 7 that the NOx concentration trend was overall declining from 559
1999 to 2002; and was highest in 1996 (34 µgm-3) and lowest in 2002 (17 µgm-3). The 560
reason behind the decreasing trend may be implementation of various pollution norms 561
(phase out of old vehicles, adopting EURO norms etc). However, since 2002 the trend 562
shows slight increment and that can be accounted for by the CNG implementation. The 563
NOx levels are lower in Mumbai than Delhi as the public is more dependent on mass 564
transport (local trains, buses etc.) than personal vehicles as in case of Delhi. 565
566 5.1.2.3. Kolkata: Kolkata is one of the largest NOx emitting urban center in India and 567
major sources includes vehicles, emissions from local industries(including power 568
generating plants) and the burning of fossil fuels (Mondal et al., 2000). Estimates show 569
that in 1970 industry was the major source of NOx (69%). NOx emissions from industrial 570
plants had increased to over 11Gg/yr by 1980 (NEERI 1991a).From 1970 to 1990 the 571
estimated annual NOx emission has increased from 1.82 Gg to 25.55 Gg from transport 572
sector. Further it shows a stable trend and it was projected that there will be no significant 573
increase before 2000. However, in the recent year transport has become the predominant 574
source of NOx and the main vehicular sources of NOx are diesel-driven trucks and buses. 575
Interestingly, diesel vehicles account only for10% of the total motor vehicle population 576
but they are responsible for almost 90% of NOx emissions. A report by ADB (2005) also 577
suggests that within the vehicle fleet the principal source (~54%) of NOx was the buses 578
used for public transport. Recently Nagpure et al., (2010) suggested that transport sector is 579
responsible for about 79 Gg in year 2010 where HCVs are responsible for most of the 580
NOx emissions (50%) followed by bus (23%) and LCVs (15%). 581
582
There was only a slight increase (from 113 to 115 Gg/Km2) in NOx emission from 1990 583
to1995 (Garg et al., 2001); whereas the per capita emission rose from 0.25 Kg in 1990 to 584
0.27 Kg in 1995 (Sharma et al., 2002a). Percentage increase in NOx in terms of per capita 585
emission is less compared to the national per capita emission trend.Sharma et al. (2002b) 586
estimated the NOx emissions from mobile sources on the basis of fuel consumption by 587
using the IPCC-96 methodologies. The emissions from gasoline consuming vehicles were 588
0.3 Gg in 1990-91 and increased to 0.4 Gg in 1995-96, while the emissions from diesel 589
were 2.6 Gg and 3.2 Gg over the same period. Another study carried out by Asian 590
Development Bank (ADB, 2005) estimated that in 2003 the total annual emission of NOx 591
from mobile source was 93.85 Gg; whereas from power plants it was 32.23 Gg. Further, a 592
model based study [using Kolkata Air Pollution Potential Reductions Model (KAPPER)] 593
has estimated that the annual emission of NOx from all sources was 131 Gg in 2003 and 594
increased to173 Gg in 2008. The model predicted that the annual emission will rise to 241 595
Gg in the year 2014. As per the ADB (2005) the mobile NOx emission contributed about 596
96 Gg in 2003 and 113 Gg in 2007; which is expected to be 174 Gg in 2014. 597
598
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
14
The average ambient NOx concentration data of Kolkata suggests a quite different scenario 599
in comparison to other megacities (Figure 3). As illustrated in Figure 3 the ambient 600
concentration of NOx was fairly constant from 1992 to 2000 followed by an increase till 601
2002 and a decline between 2002- 2005. The highest concentration of NOx (82 µgm-3) was 602
observed in 2002 and the lowest (28 µgm-3) in 1992.Possible causes for the declining trend 603
between 2002 and 2005 might be the phasing out of older vehicles. But uncertainty in the 604
above data cannot be neglected due to the small number of air quality monitoring stations 605
in Kolkata. Mondal et al. (2000) monitored ground-level concentrations of NOx at 19 606
important traffic intersections within Kolkata and noticed a seasonal variation pattern. 607
They observed a maximum average concentration (222 µgm-3) during winter and a 608
minimum (55 µgm-3) during peak monsoon. The annual average concentration of NOx at 609
traffic intersections in Kolkata was 152 µgm-3 which is close to the permissible level (150 610
µgm-3) recommended by WHO. During festival periods the concentration of NOx at traffic 611
intersections was found less than during other days (118µgm-3) because of reduced 612
vehicles. In general, the pollutant concentration was highest during winter (January) and 613
lowest during the peak monsoon period, i.e. later-half of August. In 2005, West Bengal 614
Pollution Control Board recommended that three and four wheel vehicles including buses 615
should be converted to cleaner fuels such as LPG and CNG, as happened in Delhi and 616
Mumbai during 2001-2003. 617
618
5.1.3 Particulate matter 619 5.1.3.1 Delhi: In terms of SPM, Delhi appears to be the most polluted city in the world. 620
The ambient concentrations of SPM and PM10 in Delhi are found to exceed the NAAQS 621
since last decade. The main sources of SPM and PM10 are small scale industries, domestic 622
coal burning, thermal power plants, transportation, and biomass burning (cow dung, crop 623
residue), construction sites and natural sources such as resuspended soil dust and road 624
dust. Some studies estimated that 80% of Delhi’s PM10 emissions result from industrial 625
sources (including power plants) and only about 15% are from automotive traffic (Gurjar 626
et al.,2004; Reddy and Venkataraman, 2002). Among all the industries, power plants were 627
the largest contributors to SPM emissions and increased from 131 Gg in 1990 to 150 Gg in 628
2000. Transport contributed about 19% to SPM emission in the year 2000 and its emission 629
doubled from 15 Gg in 1990 to 28 Gg in 2000 (Gurjar et al., 2004). As demonstrate in 630
Figure 6, diesel driven vehicles contribute the major fraction of PM among all vehicle 631
categories (Nagpure et al., 2016). Out of total 5.39 Gg PM emissions from transport 632
sectors diesel driven heavy commercial vehicles account 44% in Delhi during 2012 633
(Nagpure et al., 2012). The total emission of SPM in 1995 was 149 Gg (Goyal and 634
Sidhartha, 2002) and may increase by 16% by the year 2021 (Kadian et al., 2007). The 635
Auto Fuel Policy Report (2002) suggests that PM emissions range between 16% - 74% 636
from industrial sector, 3% - 22% from transport sector and 2% - 4% domestic sector, 637
respectively (Table 4). The recent study conducted by Guttikunda et al., (2011) indicated 638
that among all anthropogenic sources road dust, power plants , transport and municipal 639
solid waste (MSW) burning share highest percentage 59% (35 Gg), 12% (7.33 Gg), 8% 640
(4.99 Gg) and 8% (4.90 Gg) respectively in year 2010. 641
642
It is interesting to note that open burning of MSW emerge one of the major contributors of 643
PM2.5 and PM10 emissions especially in cities of developing countries (Guttikunda et al., 644
2014; Wiedinmyer et al., 2014.). CPCB in a study on emission inventory of Indian 645
megacities found that open MSW burning may be the source of up to 5% to 11% of all 646
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
15
direct PM emissions (CPCB, 2010). A recent study on spatial and temporal pattern of open 647
MSW-burning by Nagpure et al., 2015 found that Delhi burns about 190-246 Tons of 648
garbage every day. Despites these anthropogenic sources natural source like dust from 649
Thar Desert of neighboring Rajasthan state (Ravindra et al., 2003) contributes significant 650
amount of particulate matter to Delhi’s local air. According to Ravindra et al. (2006), 651
strong winds from the W–NW carry particulates from the Thar Desert of Rajasthan to 652
Delhi and lead to increased SPM concentrations. 653
654
Delhi’s annual average concentration of PM10 is highest among major Asian cities (HEI, 655
2004). However, no definite trend was observed since last decade for SPM (Ravindra et 656
al., 2006; CPCB, 2007). Figures 8 illustrates that SPM and PM10 concentrations in Delhi 657
were always about three to four times higher than the Indian standard for residential areas. 658
The government of Delhi and the Supreme Court of India has introduced various policy 659
measures to reduce PM emissions (e.g. implementation of CNG, less ash content coal in 660
power plants etc.). To reduce SO2 and PM emissions the Delhi government launched the 661
CNG implementation program in 2001.From 2000 to 2003 a 3% reduction was noticed, 662
whereas PM10 levels were 7% lower during the same period (Ravindra et al., 2006). 663
However, an increasing trend in SPM concentrations is observed after 2005 (Figure 8) as a 664
continuous increase in total vehicular population overshadows the positive impact of 665
CNG. Thus, it can be inferred that CNG conversion has had no significant impact on 666
particulate pollutants in Delhi (Ravindra et al., 2006; Kandlikar, 2007). 667
668 5.1.3.2Mumbai: During the last decade Mumbai was amongst the three cities in the world 669
having the highest level of SPM (World Development Report, 1992). In 1992–1993 it was 670
estimated that annual SPM and PM10 emissions in Mumbai were about 32 and 16 Gg 671
respectively (URBAIR, 1996). In case of PM10, major contributions originate from 672
vehicular exhaust plus re-suspension from roads (39%), non-combustion industrial sources 673
such as stone crushing, construction, refuse-burning (26%), industrial oil-burning (18%) 674
and domestic/commercial fuel burning e.g., wood, kerosene, liquefied petroleum gas 675
(14%) (Larssen et al., 1997). According to the World Bank (1997), the estimated total 676
annual emissions PM10 from vehicle exhaust in Greater Mumbai for the year 1992 and 677
1993 were 3.7Gg/year. Other contributions by various sources (Figure 5) for the same year 678
were the suspension of road dust (10 Gg), power plants (2.6 Gg) and industrial processes 679
(6 Gg). This study suggest that transportation, especially motor vehicles, account for 680
approximately 35% of particulate emissions in Greater Mumbai. Total PM emissions 681
estimated for 2001 was 16.6 Gg (NEERI, 2004). Out of the total annual particulate 682
emissions, industries account for 9.96 Gg (60%), vehicles- 1.83 Gg (11%), area sources- 4 683
Gg (24%), building construction (3%) and construction dust- 0.33Gg (2%) respectively 684
(NEERI, 2004; Bhanarkar et al., 2005) (Figure 8). In another similar study, the highest PM 685
emission was estimated from industries (54%) followed by area source 31%, vehicles 686
10%, and construction 5%, during 2002 (Kumar and Joseph, 2006). Further, MEIP (1993) 687
reported that industrial processes account for 66%, fuel burning- 27% and power plants- 688
7% of the total industrial PM emissions. In 1992, the contribution of power plant to the 689
industrial PM emissions was 45% (excluding stone crushers); whereas in 2001 it reduced 690
to 30% (Bhanarkar et al., 2005). According to earlier studies carried out in 1990, PM 691
emissions from power plants, industries and stone crushers were 1.50, 1.81 and 6 Gg, 692
respectively (URBAIR, 1997). World Bank (1997) suggests that motor vehicles accounts 693
for approximately 35% of particulate emissions in Greater Mumbai. On the other hand, 694
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
16
Auto fuel policy report (2002) concluded that PM emission contribution from transport 695
sector was 0 to 16%, from industrial sector 34 to 96% and from domestic and other 696
sources 53 to 56%. Amongst the industries, thermal power plants (TPP) were a major 697
source of emissions in the region contributing 19% tos PM in 2001 (Bhanarkar et al., 698
2005). In 2002, despite strong traffic and other sources in Mumbai; PM emissions were 699
dominated by the industrial sector (kumar and joseph, 2006). Further, it was also estimated 700
that out of total annual emission (9.8 Gg), chemicals and petrochemicals accounted: 701
32.7%, food: 0.6%, textiles: 4.9%, pharmaceuticals:0.4%, stone crushers: 36.9%, power 702
plant: 18.9% and others: 5.6%. Similar to Delhi, the recent study done by CPCB (2010) 703
suggests that road dust suspension due to vehicular activities (8 Gg, 30%), power plants (6 704
Gg, 21%), solid waste burning (4 Gg, 14%) and construction activities (2 Gg, 9%) are the 705
biggest contributors for most of the PM emissions in Mumbai (Figure 5). 706
707
The ambient concentration of SPM in developed countries is generally less than or about 708
100 µgm-3 (Mage et al., 1996; Harrison et al., 2008), whereas in India it prevails with an 709
annual average of 200-500 µgm-3 for an urban environment like Mumbai (URBAIR, 710
1994). SPM concentration data for two residential sites (Bandra and Kalbadevi) and one 711
industrial site (Parel) in Mumbai were taken from CPCB for the time period of 1991 to 712
2005. The average concentration trend of SPM was almost constant between 1998 and 713
2005; however a spike was observed during 1993 and 1997(Figure 3). From 1991 to 2005 714
the maximum ambient air concentration of SPM was observed in 1993 (313 µgm-3) and 715
the minimum in 1996 (213 µgm-3). According to the NEERI study, SPM concentrations in 716
Mumbai during early 1970s were 380 µgm-3and remain almost constant until 1987 (385 717
μgm-3)as reported by NEERI, 1991a. Although industries contribute a significant fraction 718
of PM emissions road dust and vehicular emissions were identified as the main sources for 719
SPM concentrations (Kumar et al., 2001).Based on the 24 hour average SPM 720
concentration, it was estimated that out of the total fraction 41% is contributed by road 721
dust, 15% from vehicular emissions, 15% from marine aerosols, 6% from coal 722
combustion, 6% from metal industries and 17% remains as unexplained contributions 723
(Kumar et al. 2004). 724
725
Kumar and Joseph (2006) observed that the PM2.5 concentration in Mumbai during 2001-726
2002 was highest in winter (89 μgm-3), followed by autumn (64 μgm-3), spring (36 μgm-3) 727
and summer (21 μgm-3). During winter, PM2.5 levels exceeded the prescribed USEPA 728
standard of 65 μgm-3 (24 hourly).The average ratio of PM2.5 to PM10 was 0.68 and 0.70 in 729
the atmosphere of Mumbai. The mean PM10 ambient concentration during the monsoon 730
season was 80% lower than the non-monsoon season (Kumar and Joseph, 2006). 731
Furthermore, it was also observed that the monsoon season is significantly associated with 732
decreased PM10 and lead (Pb) levels in the atmosphere. In general, monthly mean SPM 733
concentrations in Mumbai are also considerably reduced during the monsoon (June to 734
October) period. 735
736
Vehicular traffic contributes about 24% to PM10 emissions in Greater Mumbai. In a 737
separate study by MUTO, 2002, the annual average PM10 concentrations were found 738
varying from 221 to 520 µg.m-3 at traffic intersections. The highest PM10 value (533 μgm-
739
3) was recorded in March, at Andheri west and lowest in August 2000 at Mahim (116 740
µgm-3). These values are well above the PM10 standards for residential and industrial 741
areas. PM10 levels are predicted to decrease in the Island City and increase in Eastern and 742
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
17
Western Suburbs of Mumbai till year 2011. All predicted PM10 levels are estimated to 743
exceed the NAAQS, as improved fuel and other measures may not affect PM10 emissions 744
substantially. 745
746 5.1.3.3 Kolkata: Due to the high SPM and PM10 levels, Kolkata is placed one of among 747
the most polluted cities of the world (Chakraborty and Bhattacharya, 2004). The Asian 748
Development Bank (ADB, 2005) study found that the total annual PM10 emission in 749
Kolkata was 76 Gg during 2003 with major contributions by road dust (61%) followed by 750
vehicles (21%), industries and power plants (9%) and other sources 9% (such as biomass 751
burning, railway, domestic cooking light distillate oil burning, coal fuel kilns in brick 752
industry).Whereas a study by Chakraborty and Bhattacharya (2004) reports that 50% of 753
the total SPM comes from the transport sector and 48% from industries in Kolkata. Per 754
capita emission of PM in Kolkata in 1990 was 0.28 kg and increased to 0.33 kg in 1995 755
indicating a 19% growth (Sharma et al., 2002a). 756
757
Industrial sources were the major SPM contributor in 1990 . The high level of coal use by 758
Kolkata industry, particularly in thermal power plants, results in higher PM emissions and 759
ambient concentrations. There are four coal-fired power generating plants in Kolkata 760
which are the largest industrial point sources within the urban area. It was estimated that in 761
2003 the coal fired power plants emitted 4.1 Gg SPM, 0.94 Gg PM10 and 0.24 Gg PM2.5
762
(ADB, 2005). Sharma et al (2000b) estimated that the particulate matter emission from 763
gasoline consumption was 0.06 Gg in 1990-91 and increased to 0.08Gg in 1995-96; while 764
emission from diesel consumption were 0.6 and 0.7 Gg for 1990-91 and 1995-96. 765
766
In 2003, the PM10 emission from dust sources was 46.61 Gg, vehicle: 16.37 Gg, industry 767
and power plants: 6.55 Gg; and other area sources: 6.79 Gg respectively (ADB, 2005). 768
Among all vehicle categories, diesel driven vehicles contributed most (88%). Other area 769
sources like biomass burning, railway, domestic cooking, light distillate oil burning, coal 770
fuel kilns in brick industry emitted 4.45 Gg, 164 Gg, 1.23 Gg, 0.82 Gg, 1.19 Gg PM10 771
during 2003.According to model based predictions carried out in ADB (2005), vehicular 772
PM10 annual emissions are expected to grow from 16.4 to 30.4 Gg per year (80% increase) 773
over the period of 2004-2014. Collectively, PM10 emissions from vehicles, road dust, other 774
area sources and industry may increase from an estimated 76.3 to 139 Gg per year at the 775
projected growth rates if significant efforts have not been made to reduce emissions and 776
improve air quality. By assuming a proportional increase in PM10 by 2003 air quality was 777
expected to degrade from an estimated 7 µgm-3 to 107 µgm-3 annual averages (ADB, 778
2005). The study done by Nagpure et al., 2010, suggested that transport sector is 779
responsible for about 8 Gg of PM emissions in year 2010, and similar to Delhi heavy 780
commercial vehicles are biggest source (29%) of PM emissions in Kolkata, followed by 781
two wheeler and three wheeler (Figure 6). 782
783
Annual SPM emission data from 1992 to 2012 for Kolkata was obtained from CPCB 784
website for two residential (Lal-Bazar and Mandevitle Garden) and one industrial site 785
(Cossipore). For the period between 1992 and 2012, the average highest concentration of 786
SPM was 498 µgm-3 in 1996; whereas least was 225 µgm-3 in 2008. SPM concentration in 787
Kolkata showed no clear trend from 1992 to 1996,but declined in 1997, followed by an 788
almost stable concentration up to 2005 (Figure 3). In Kolkata, despite the decreasing SPM 789
concentration trend, both WHO guidelines and NAAQS were greatly exceeded for years 790
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
18
between 1992 and 2005. Karar and Gupta (2006) found that vehicular traffic and cluster of 791
industries are mainly responsible for the high concentration of SPM in Kolkata. They also 792
observed seasonal variations in SPM concentration during 2003-2004; for instance, 793
particulate matter was highest in winter, followed by summer, and least in monsoon 794
season due to rain washout. 795
796
In 2002, Ghose et al. (2004) observed that at various traffic inter sections in Kolkata the 797
mean SPM concentration ranged between 739.3 µgm-3 ±20% and PM
10 concentration 798
varied from 286.5 µgm-3to 421.4 µgm-3. Das et al. (2006) found that the average 24 hour 799
concentration of PM10 in Kolkata was 304 μg/m3, which is 3 times more than the Indian 800
NAAQS. It appears that the higher PM10 concentration was due to fine fraction (PM2.5) 801
released in greater quantity by vehicular exhaust. Field observations verify that PM2.5 802
constituted more than 59% of PM10 and whereas PM10-PM2.5 fractions constituted 41% of 803
PM10 in Kolkata. Also, the correlation between PM10 and PM2.5 was found higher as PM2.5 804
comprised major proportion of PM10 fractions contributed by vehicular emissions (Das et 805
al., 2006). 806
807
The meteorological parameters such as ambient temperature, relative humidity; wind 808
speed and rainfall influenced the seasonal variation of pollutants concentration. Higher 809
levels of pollutants in winter could be attributed to stable atmospheric conditions. Several 810
studies reported the large regional scale air pollutants in megacities were influenced by 811
meteorological conditions which determined the formation mechanisms and seasonal 812
variations of ozone (O3) and PM (Jiang et al., 2012; Liu et al., 2007, 2010; Song et al., 813
2008; Tang et al., 2004; Tie et al., 2006; Wang et al., 2011; Xing et al., 2011). The 814
observed values for PM2.5, and PM10 reported in other megacities are comparable 815
including the emission loads of pollutants of Indian megacities as depicted in Table 2. 816
The trend of the high concentration of pollutants were observed during the winter season 817
due to high burning of fossil fuel and agricultural waste materials, whereas the low 818
concentration was observed during the monsoon season due to the wet scrubbing and 819
absence of combustion (wood burning) sources in megacities (Awasthi et al., 2011; 820
Srimuruganandam, & Shiva Nagendra, 2011). Kumar et al., (2014) reported the higher PM 821
levels in winter are expected and can be attributed to more stable atmospheric conditions 822
(leading to poor dispersion of pollutants) and lower rainfall (resulting in less washing out 823
of particles). Winter season was also characterized by scarce rainfall, low humidity, arid 824
soil conditions and inversion conditions (Tiwari et al., 2013). These conditions were 825
favorable for the buildup of fine aerosols from local anthropogenic sources which lead to 826
higher concentrations of pollutants especially for particulate matter (PM10 & PM2.5) during 827
winter season. On the other hand, the monsoon season was characterized by high relative 828
humidity and rainfall, which cause wash out of particulate matter (Tiwari et al., 2012). 829
Hence, low concentrations were observed during the monsoon season. 830
831
5.1.3.4 Trends of SO2, NOx and PM10 in other Indian cities 832
833
According to CPCB, SO2 levels were below the NAAQS standard at all the monitoring 834
stations under NAMP programme during 2005. NO2 levels exceeded NAAQS at five 835
monitoring stations among which one was located in Delhi and two at Howrah, West 836
Bengal. On the other hand, RSPM levels exceeded the NAAQS standard at 39 monitoring 837
stations in industrial areas and 107 stations in residential areas (CPCB, 2006-07). In 2010, 838
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
19
air quality level of 35 metropolitan cities were analyzed with data collected from 144 839
monitoring stations and it was estimated that based on annual average concentration, no 840
city exceeded the NAAQS limit for SO2, 5 cities for NO2 whereas 32 cities for PM10 . In 841
2012, same analyses was performed for 46 cities having population more than one million 842
with data collected from 182 monitoring stations in residential, industrial, rural and 843
commercial areas covering 14 states and 1 union territory. It was estimated that in terms of 844
annual average concentration, only 1 city exceeded the NAAQS for SO2, 6 cities for NO2 845
whereas 34 cities exceeded the NAAQS limit for PM10 concentrations. 846
847
According to CPCB 2012 report, average annual mean concentration of SO2 from 848
measurements at 372 stations across the country under National Ambient Monitoring 849
Programme, has decreased from 15 μg/m3 in 2001 to 10 μg/m3 in 2012, which is much 850
below the national ambient standard of 50 μg/m3. This is due to the use of low sulphur 851
content coal in thermal power plants and gasoline in vehicles. In case of NO2, 852
concentration has fluctuated between 25-28 μg/m3 from 2000 to 2009, and a declining 853
pattern was during 2009-2012. This may be due to implementation of stricter norms for 854
vehicle technology since 2000. On the other hand, RSPM concentration has fluctuated 855
between 100-120 μg/m3 during 2000 to 2012 with declining trend observed between 2004-856
2007 and increasing trend from 2007-2012. High RSPM concentrations upto 2 times the 857
national standard may be due to increase in the number of vehicles, biomass burning and 858
resuspension of dust. In 1996, Government of Delhi has relocated the industrial units in 859
residential areas to industrial/conforming areas in the vicinity of Delhi (DSIIDC, Govt. of 860
NCT of Delhi). Also, In Kolkata, tanneries were directed to relocate 15 km away from the 861
city by Supreme Court of India in 1996 (Supreme Court of India, 1996), and 433 out of 862
550 tanneries have been relocated in 2007. According to a report by CSE, 26 cities have 863
been identified as most critically polluted which includes Ghaziabad (located on the 864
border of Delhi) and Delhi having RSPM levels over three times the standard limits. In a 865
study by Ravindra et al., 2015, high RSPM concentrations ranging from 125-150 μg/m3 in 866
areas surrounding Mumbai and 75-100 μg/m3 in areas surrounding Kolkata during the pre-867
monsoon season during 2012. This suggests that emissions from megacities may be 868
increasing the total air pollution emissions in the adjacent areas. 869 870
5.2 Polycyclic Aromatic Hydrocarbons (PAH) 871
872
PAHs are a group of 100 different chemical compounds consisting of two to seven fused 873
aromatic rings. It accounts for carcinogenic and pro-mutagenic effects on animal and 874
human (Ravindra et al., 2001). Some of PAHs are semi-volatile in nature and can exist in 875
particulate and vapour phase while the rest exist mostly in particle phase. In the present 876
study only particulate phase PAHs are included. Also, a list of 16 priority PAHs as per 877
United States Environmental Protection Agency is listed in Table (supplementary). 878
Industries, transport, power plants, refineries are the major sources of PAHs in most of the 879
urban areas of developed countries (Ravindra et al., 2006b; 2008). However, in India, 880
combustion of cooking fuel (e.g., wood, coal, dung, kerosene) could also contribute as a 881
major source of PAH (Ravindra et al., 2008). 882
883
In a recent review Singh et al. (2010) summarized that emissions of particulate bound 884
PAHs from major Indian cities varies from 23-190 ng/m3 for gasoline, 369-1067 ng/m3 for 885
diesel, 20.8-100.8 ng/m3 from petroleum refinery, and 12.7-206.4 μg/m3 from biomass 886
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
20
burning. However, these specific emissions may differ depending on anthropogenic 887
activities associated to that particular city or location. A comparative analysis of PAH 888
concentration in Indian urban areas shows 10 to 50 time higher levels than reported 889
internationally and specially in Europe (Ravindra et al., 2001, 2008). Table 5 summaries 890
the available studies on PAHs concentration in Delhi, Mumbai and Kolkata. 891
892 5.2.1 Delhi: According to Shankar (1990), concentration of eight PAHs compounds in 893
megacity Delhi ranged between 150–1800 ngm-3 during 1990 with a mean value of 406 894
ngm-3. CPCB (2003) reported total annual average PAHs (particulate phase) 895
concentrations of 38.2 ngm-3 for 1997 and 22.3 ngm-3 for 2000 in Delhi. In 2001-2002, 896
Sharma et al. (2003) found average concentration for seven PAHs between 35.82 and 897
162.76 ngm-3. Ravindra et al. (2006a) observed that during 2003, PAH concentration at 898
residential and traffic site were 4.5 ± 2.0 ngm-3 and 11.5 ± 3.3 ngm-3 respectively. Sharma 899
et al. (2007) have observed total PAHs concentration 668 ± 399 ngm-3to 672 ± 388 ngm-3 900
for the years 2002 and 2003 respectively. 901 902
Seasonal average concentrations of PAH were found to be maximum in winter and 903
minimum during the monsoon in Delhi (Ravindra et al., 2006a; Sharma et al., 2007). 904
According to Ravindra et al., (2006a) PAH concentration decreased around 50% after the 905
implementation of CNG. Further they suggest that diesel and gasoline driven vehicles are 906
principal sources in all seasons with coal and wood combustion in winter. Interestingly, 907
the PAH concentration were reported relatively high during nights and found to be 908
associated with the movement of heavy diesel vehicles (trucks, trolley etc.) during night 909
time (Ravindra et al., 2006a). These vehicles are not allowed to enter in Delhi during most 910
of the day time. 911
912
5.2.2 Mumbai: It was observed by Kulkarni and Venkataraman (2000) that during 1996 913
(winter season) total PAH concentrations in industrial and residential areas were 38.8 and 914
24.5 ngm-3 respectively; with individual PAH species concentrations ranging from 1 ngm-3
915
to 13 ngm-3. In 2001, total PAHs concentration varied from 4.1 ngm-3to 34.4 ngm-3 (Sahu 916
et al.,2004) and recently Puranik (2008) observed PAH levels between 18.3 to 66.6 ngm-3. 917
These concentrations are at the lower end of range of reported PAH concentrations to 918
other Indian cities as shown in Table 5 or compared to Singh et al. (2010). Kulkarni and 919
Venkataraman (2000) quoted that automobile emissions are the likely primary contributors 920
followed by some additional local sources i.e. cooking fuel combustion or industrial oil 921
burning. 922 923 5.2.3 Kolkata: According to Chattopadhyay et al. (1998) the average PAH concentration 924
during 1993 and 1994 was 77 ngm-3. Recently Rao et al., (2008) suggested that average 925
concentration of PAH in megacity Kolkata was 969 ngm-3 which was quite higher in 926
comparison to Delhi and Mumbai. Further, maximum PAH concentration was observed in 927
winter season while minimum in monsoon. Karar and Gupta, (2006) found major PAH 928
compound in the particulate fraction, Fluoranthene (B[b]F) with 0.03 µgm
-3 at the 929
residential site and 0.02 µgm-3 at the industrial site. 930
931
5.3City specific studies of selected pollutants 932
5.3.1 Carbonmonoxide (CO) 933
Carbon monoxide. CO is one of the significant sources of motor vehicle exhausts in 934
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
21
megacities of the developing countries (Kumar et al., 2008; Mayer 1999). Traffic sources 935
are one of the major source of CO émission (Ravindra et al, 2006) and estimated 86% in 936
Delhi during 1990 to 2000 (Gurjar et al. 2004). According to CPCB (2010) study megacity 937
Mumbai is responsible for about 72.5 Gg of CO from all sectors in year 2007, as per their 938
estimation area sources shares largest accountability for CO emissions in Mumbai 939
followed by transport and industrial sectors (Figure 5). Similar to Mumbai, another study 940
indicate that Delhi all sectors are responsible for about 574 Gg of CO emissions, where 941
transport is the biggest contributor, sharing about 73% of total emissions. As shown in 942
Figure 6, Nagpure et al., 2016 indicated that cars and two wheelers are the largest source 943
of CO emissions in Delhi. There are few studies are available for CO emission in Kolkata 944
for all sectors. Study done by Nagpure et al., 2010 suggests that transport sector is 945
responsible for about 111 Gg of CO emission in Kolkata, where two wheelers and cars 946
sharing highest accountability (Figure 6). India, one of the fast developing countries of 947
the world, has registered a sharp increase in vehicular pollution, particularly, in the urban 948
area (CPCB 1999). Kumar et al., (2008) reported that the CO levels were the least at 949
Palode (0.026 ppm), followed by Thiruvananthapuram (winter 0.352 ppm, summer 0.108 950
ppm and wet months 0.032 ppm), New Delhi (1.38 ppm) and Jaduguda (0.462 ppm). A 951
declining trend was observed for CO ambient concentrations between 2000 and 2006 952
(Figure 9). From 1996 to 2000, the concentration of CO in Delhi atmosphere varied for 953
different years. No particular trend in CO concentration was observed in the above period 954
and it was in its highest level. The ambient CO concentration in Delhi shows higher values 955
than the NAAQM standard for residential area (2000 µgm-3). Available data of CO is from 956
hot-spot air quality monitoring station (i.e. ITO intersection) in Delhi, which is a high 957
traffic area. Decreasing CO trends show that the CO levels are decreasing gradually in 958
Delhi. As discussed before since 1998 to 2002, Delhi launched a major initiative to 959
improve air quality, which included, phasing out of old vehicles, less lead in gasoline, 960
EURO II norms and switching all public transport and private taxi and three-wheeler 961
services from diesel to CNG along with other policies. Thus, the observed recent trends in 962
CO likely relate to the changes in Delhi’s vehicular traffic emissions influenced by 963
implementation of various policy measures. The comparison of annual average 964
concentration before and after the implementation of CNG i.e. from 1998 to 2003, shows 965
~50% reduction in CO concentration (Ravindra et al. 2006). 966
967
5.3.2 Greenhouse gases 968
India figures among the top 10 contributors to greenhouse gas emissions, although the 969
current gross emissions per capita in India are only one-sixth of the world average (ADB, 970
1994). The increasing interest in quantification of greenhouse gas emissions comes as a 971
result of growing public awareness of global warming. Many global metropolitan cities 972
and organizations are estimating their greenhouse gas emissions and developing strategies 973
to reduce their emissions. As per Intergovernmental Panel on Climate Change (IPCC), 974
carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydro fluorocarbons (HFCs), 975
per fluorocarbons (PFCs) and sulfur hexafluoride (SF6) are the major greenhouse gases. 976
Among the GHG’s, carbon dioxide is the most dominant gas causing global warming 977
which accounts for nearly 77% of global total CO2 equivalent greenhouse gas (GHG) 978
emissions (IPCC 2007).India is third biggest greenhouse gas emitter contributing about 979
5.3% of the total global emissions. Major cities in India are witnessing rapid urbanization 980
(Sridevi et al., 2014). In the major cities transportation sector is one of the major 981
anthropogenic contributors of greenhouse gases (Mitra and Sharma, 2004). Emission of 982
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
22
CO2 has been increased by 46% during 2001-2009, while an earlier study showed a 983
growth of 65% during the 1990-91 to 1999-2000 (Sharma & Pundir, 2008). During the 984
2001-2009 from the transports sector in Delhi was the major responsible to emission of 985
CO2 (Singh et. al., 2011). The national emissions of GHGs have been estimated two times 986
by Indian Network of Climate Change Assessment (INCCA) in 1994 and 2007, and the 987
results were also communicated to UNFCC. In 1994, net GHG emissions in India were 988
1228.54 million tons of CO2 equivalent which increased to 1727.71 million tons in 2007. 989
The major contributors were energy, agriculture and waste sources. The per capita 990
emissions in 1994 were 1.5 tons which increased to 1.5 tons in 2007. Also, significant 991
annual growth in terms of total GHG emissions was observed in electricity generation 992
(5.6%), cement (6%) and waste (7.3%). CO2 emissions in India have increased from 794 993
million tons of CO2 equivalent in 1994 to 1221.76 million tons in 2007 (INCCA, 2010). 994
995
In the developing megacities, such as Delhi, Mumbai and Kolkata, the sources of air 996
pollutants and greenhouse gases (GHGs) are dominated by the vehicle emissions, whereas 997
in the developing megacities, biomass burning from agriculture waste and forest fires are 998
also important sources to local air pollution. 999 1000 5.3.2.1 Nitrous oxide (N2O): N2O is also one of the important pollutants in megacity 1001
Delhi. Agricultural sector contributes approximately 50% of N2O emissions (Gurjar et al., 1002
2004). Gurjar et al., (2004) also estimated that emissions of N2O varied between 1.4 Gg 1003
and 1.7 Gg in the megacity during 1991 to 2000. Manure management, agricultural soils, 1004
fertilizers and transport are some of the main N2O contributing sources. N2O emissions 1005
decreased since 1996, which is related to the reduced animal sludge application as 1006
fertilizer, followed by a slight increase in emissions from 1998 due to increasing animals 1007
and associated manure management. In 1994, N2O emissions in India were 0.178 million 1008
tons of CO2 equivalent which was 4.4% of total GHG emissions, whereas in 2007 1009
emissions increased to 0.24 million tons with contribution to total emissions decreasing to 1010
3.9% (INCCA, 2010). 1011
1012 5.3.2.2 Methane (CH4): The estimated emission of CH4 from anthropogenic sources in 1013
India was 13 Tgy-1(Varshney and Padhy, 1999). In Delhi, per capita emission in 1990 was 1014
23 Kg, which was 1.8 Kg less than the national per capita emission level of 21.2 Kg 1015
(Sharma, et al., 2002b). The average ambient CH4 concentration in Delhi was 4121 ppbv, 1016
varying between 1703 and 9492 ppbv during 1994 and 1995 (Padhy and Varshney, 2000). 1017
Solid waste disposal was one of the main sources of CH4 emission (about 80%) during 1018
1991 to 2000 (Gurjar et al., 2004). Delhi produces huge quantity of solid waste, about 6 1019
Gg per day and about 880 Gg of biodegradable waste per annum (Padhy and Varshney, 1020
2000). It is reported that 1016 Kg of waste in a landfill emits approximately 25 ±30 m3 of 1021
CH4 (Vanni and Esposito, 1982). Delhi having six landfill sites may emit about 8.76 Gg 1022
CH4. Sewage treatment plants, wetlands, paddy fields, livestock, burning of garbage, 1023
vehicle (e.g. exhaust, lockage), coal, oil and gas combustion, are additional possible 1024
sources of CH4 in Delhi, which respectively emits 2.97 Gg, 2.93 Gg, 2.32 Gg, 2.18 Gg, 9 1025
Gg, and 0.07 Gg of CH4 annually as shown in Figure10 (Padhy and Varshney, 2000). 1026
Gurjar et al. (2004) found that CH4 emissions over Delhi have increased by about 40% i.e. 1027
from 133 Gg in 1990 to 192 Gg in 2000.Mor et al. (2006) reported that landfill CH4 1028
emission constitute major fraction of it and contributed up to 50 Gg in 2001. According to 1029
INCCA report in 2010, total CH4 emissions in India were 18 million tons of CO2 1030
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
23
equivalent which increased to 20.56 million tons in 2007 (INCCA, 2010). 1031
1032
6. Health Effect of Air Pollution: 1033
WHO reported that in 2012 around 7 million people died prematurely due to exposure to 1034
indoor and outdoor air pollution and this account for one in eight of total global deaths. 1035
This confirms that air pollution is now the world’s largest single environmental health risk 1036
(WHO, 2014). Global Burden of Disease (GBD, 2013) reported that India accounts for 1037
19% of the world’s premature deaths in 2013 and also reported that about 620,000 1038
premature deaths occur in India from air pollution-related diseases each year. This is up 1039
from 100,000 in 2000—a six-fold increase (The Lancet, 2015). According to WHO report, 1040
(WHO,2009) in India, 488,200 people dies prematurely every year as result of indoor air 1041
pollution, whereas 119,900 dies prematurely every year as result of outdoor air pollution. 1042
Earlier studied reported about 40,000 Indians are dying early every year because of air 1043
pollution, which include; 7500 in Delhi, 5700 in Mumbai and 4500 in Kolkata (Brandon 1044
and Homman, 1995) 1045
1046
Incidence of respiratory diseases in Delhi is 12 times the national average, and 30% of 1047
Delhi’s population suffers from respiratory disorders. The largest impact of particulates on 1048
daily deaths in Delhi occurs in the age group of 15–44 years (Cropper et al., 1997), an age 1049
group that may spend most time outdoors. A recent World Bank study shows that a 10% 1050
reduction in PM10 in Delhi might result in 1000 fewer deaths each year (World Bank, 1051
2003). 1052
1053
The study conducted by WHO in 1985 on 'human exposure to respirable particles' 1054
indicates that ambient concentration and exposure to PM10 in Mumbai in 1982 were much 1055
higher than the WHO air quality guidelines (MUTP, 2002). Almost 97% of the Mumbai 1056
population lives in areas where WHO AQG for PM10 is exceeded 1057
(http://www.aespl.co.in/URBAIR.pdf). Also, according to World Bank (1997), ambient air 1058
concentrations of SPM have crossed the allowable limits creating health problems to the 1059
Mumbai. After 1987, the annual average SPM reduced to 242 μgm-3 in 1991; and 1060
remained almost constant after 2005. 1061
1062
It has been reported that more than 10,000 premature deaths occurred in Kolkata in 1995 1063
due to SPM (Kazimuddin and Banerjee, 2000). During 1970’s and 80’s, annual mean and 1064
98 percentile concentrations at all monitoring stations in Kolkata greatly exceed both 1065
WHO guidelines and Indian Ambient Air Quality Standards. For example, the overall 1066
average concentration in 1987 was 557 μgm-3, over six times the maximum WHO annual 1067
guideline (60-90 μgm-3). The annual 98 percentile concentration of the Cossipore 1068
industrial monitoring site reached 1,680 μgm-3 in 1987, 14 times the WHO daily guideline 1069
and the second highest ever in Kolkata, indicating that episodes of short duration also 1070
constitute a problem. 1071 1072
Gurjar and Nagpure (2015) found that excess number of total premature mortality, 1073
respirtaory mortalitlity , cradio vasculor mortality and hospital admission COPD in Delhi, 1074
Mumbai and Kolkata incresed twice between 1991 and 2008 (Figure 11). As per their 1075
study air pollution is resposible about 7913 incidents/year, 6421 incidents/year and 6950 1076
incidents/year premature mortalities in Delhi, Mumbai and Kolkata respectvely in year in 1077
1991. These numbers wentup to 16290 incidents/year, 9802 incidents/year and 6479 1078
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
24
incidents/year in year 2008 for all three cities. Similar kinds of growth have been observed 1079
for respirtaory mortality, cradio vasculor mortality and hospital admission COPD in all 1080
three cities between 1991 and 2008. 1081
1082
1083
7. Inferences of current study and world megacities 1084
7.1 Concentration trends and status: SO2 emission in Mumbai has been found highest 1085
followed by Delhi and Kolkata. It has been observed that during the last decade industries 1086
and power plants were be to the prime SO2 sources in all three megacities and contribute. 1087
Interestingly, emissions from transport sector have reduced 4 to 5 times after the 1088
implementation of various policy norms and are well below the NAAQM standard except 1089
at few locations. 1090
1091
Transport sector is the predominating source of NOx in all the megacities contributing 1092
approximately 50 to 70 % of total emissionsr. Among all vehicles, diesel driven motor 1093
vehicles seem to be the prime contributor. Following the transport sector, industries 1094
ranked as the second largest source (10 to 30%) of NOx. The trends from three megacities 1095
shows that NOx emission has increased, which seems to be related with the increasing 1096
vehicle number and high flash-point (540 oC) in CNG engine. Concentration trend of NOx 1097
shows that ambient concentration in megacity Delhi increased after 2001. The trend of 1098
NOx level in Mumbai shows declining from 1999 to 2002 and an increasing trend since 1099
2000. But concentration trend for Kolkata showed sharp increase during 2000 to 2002, 1100
followed by significant decreasing trend afterwards. 1101
1102
In terms of SPM and PM10 emissions, Kolkata is the highest emitter followed by Mumbai 1103
and Delhi. However, ambient SPM concentration in megacity Delhi was highest followed 1104
by Kolkata and Mumbai respectively due to peculiar topography of Delhi where 1105
windblown dust contributes significantly in SPM. SPM concentrations have showed a 1106
similar trend in all the megacities since 1997. Among anthropogenic sources, industries 1107
and power plants account for significant portion of SPM and PM10 emissions (i.e. 20-80%) 1108
in all three megacities. Recent studies have found that even road dust and particle re-1109
suspension are important sources of above mentioned emissions. Gupta et al (2010) 1110
analyzed the trend of PM10 concentration was observed decrease in these metrocities. They 1111
also relate this decrease associated with changes in fuel quality, better vehicle 1112
technologies, improved industrial fuel mix, shifting of industries outside the city limits. 1113
1114
. It is difficult to conclude about the comparative concentration trends of PAH due to 1115
inconsistencies in the availability of data. However, it could be concluded that the 1116
implementation of CNG have decreased the PAH concentration up to 50% in Delhi 1117
(Ravindra et al., 2006). Further it has been noticed that PAH concentration could also 1118
increase as CNG is mainly introduced in megacities but not in the surrounding 1119
region/cities or states. As there seems to be significant differences in the concentration 1120
levels reported by individual studies, there is a need to carry out proper emission inventory 1121
and setup for regular monitoring of PAH and other toxic organics. 1122
1123
Details about concentration and trends of CO and green house gases (N2O, CH4, CO2) 1124
were mainly available for Delhi. Agriculture (50%) and solid waste (80%) sector emerged 1125
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
25
as predominant source for N2O and CH4 respectively. Transport sector was prime culprit 1126
for CO emission (86%) in megacity Delhi. A declining trend was observed for CO 1127
ambient concentrations between 2000 and 2006. 1128
1129
It could be observed that megacities differ in pollution load of various pollutants such as 1130
SPM concentration tends to be very high in the large cities of Asia (Laakso et al., 2006; 1131
Hopke et al., 2010), while European and American megacities could suffer from the 1132
product of secondary aerosols (Molina and Molina, 2004; Gros et al., 2007; Butler et al., 1133
2008; Kanakidou et al., 2011). There is a need to study how increasing NOx levels over 1134
Indian megacities could enhance the atmospheric reactivity (e.g. with ozone and other 1135
pollutants), which could form more toxic products. Further particular industry (such as 1136
thermal power plant in Delhi) in a megacity also contributes to poor air quality. 1137
1138
7.2 Megacities as emission source in the region: The buildup of anthropogenic 1139
pollutants in a megacity and resultant chemistry promote them to act as hot spot in the 1140
region. Both horizontal and vertical transport contribute to pollutant export, and the 1141
overall degree of export is strongly governed by the lifetimes of pollutants (Lawrence et 1142
al., 2007). This could also influence the air quality of cities or region near by a megacity. 1143
Guttikunda et al (2005) reports that Asian megacities have less than 2% of the land cover 1144
but provide habitat for more than 30% of population. Asian megacities produce on an 1145
average of 15% of the anthropogenic trace gas and aerosol emissions affecting all or 1146
portion of the region surrounding them. 1147
1148
Lawrence et al. (2007) have reported that long-range near surface pollutant export is 1149
generally strongest in the middle and high latitudes, especially for source locations in 1150
Eurasia, for which 17–34% of a tracer with a 10-day lifetime is exported beyond 1000 km 1151
and still remains below 1 km altitude. Further, the study highlight that pollutant export to 1152
the upper troposphere is greatest in the tropics, due to transport by deep convection, and 1153
for six source locations, more than 50% of the total mass of the 10-day lifetime tracer is 1154
found above 5 km altitude. 1155
1156
7.3. Global implications of megacity emissions 1157
1158
Degrading air quality in megacities due to rapid population growth and industrialization 1159
not only causes local problems such as health effects and visibility reduction but also has 1160
global effects such as global warming, effecting earth’s radiation budget and cloud 1161
properties. Recent studies have shown that air pollution is transported by long transport 1162
across continents resulting in the formation Atmospheric Brown Clouds (ABCs) 1163
constituting of fine particles (Chandrappa and Kulshrestha, 2015). ABCs absorbs as well 1164
as reflects sunlight leading to surface dimming, and also effects cloud precipitation. ABCs 1165
are concentrated over megacities and it shown that surface cooling may have masked 47% 1166
of warming by GHGs (Ramanathan and Feng, 2009). SO2 and NO2 in the atmosphere 1167
have been shown to form acid rain (Stern et al., 1984). Oxidation of NOx in the 1168
atmosphere results in the formation of Ozone by photochemical reaction (Finlayson et al., 1169
1977). Finlayson et al., 1983 has also shown that NO2 reacts with NaCl sea salt resulting in 1170
the formation of Cl and OH radicals which initiate photochemical reactions in the 1171
atmosphere. Ramanathan and Carmichael, 2008 have reported Black Carbon (BC), a 1172
major constituent of PM as the second largest contributor in global warming. BC may also 1173
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
26
be transported over long range distances and contribute in the formation of ABCs. SO2 1174
results in the formation of sulphate aerosol through atmospheric oxidation which scatters 1175
sunlight and effects earth’s radiation budget. 1176
7.4. Megacities and their role in climate change: As discussed above megacities act as 1177
sources of aerosols and trace gases, which can be important in determining the radiative 1178
balance of the atmosphere on urban, regional, and global scales (Gaffney et al., 2004). In a 1179
recent review Gaffney and Marley (2009) studied the emissions from the combustion of 1180
fossil fuels and biofuels and their impacts on air quality and climate. Primary aerosols 1181
emission from megacities includes carbonaceous compounds or soot [which primarily 1182
consists of elemental carbon (EC) and various organic compounds], wind-blown dust and 1183
soils, and sea-salt particles. Bencs et al. (2008) have shown how various particle and 1184
gaseous species can react to form secondary aerosols such as the oxidation of sulfur 1185
dioxide to form sulfuric acid aerosol, subsequent reactions of sulfuric acid aerosol with 1186
ammonia to form ammonium sulfates, and the reaction of ammonia with nitric acid to 1187
form particulate ammonium nitrate. Gaffney and Marley (2009) also show the examples of 1188
monoterpenes and sesquiterpenes reaction with ozone and other oxidants to form 1189
secondary organic aerosols. 1190
1191
7.5. Air quality management in megacities: Throughout the world, several cities have 1192
implemented the air quality improvement and management plan but with increasing in 1193
population and vehicular number build consistent pressure to manage air quality. 1194
However, effect of various policy norms and measures could well be seen in the 1195
concentration trend of various pollutants over Indian megacities but some abruptness in 1196
the trend has also been observed specifically in case of Kolkata. However, this abrupt 1197
behavior could be related to local meteorology and other environmental factors. The 1198
current study urges to have more air quality measuring networks and regular monitoring to 1199
have better understanding of concentration trends, emissions and for source 1200
apportionment. Further pollutant specific norms need to be implemented and sector 1201
specific detailed study is required to be carried out in order to bridge the gaps in the 1202
understanding of emissions and air quality status in megacities in India. 1203
1204
However, several studies indicate that it could be difficult to meet required air quality 1205
standard at traffic intersections and near major road networks. There is lack of effective 1206
data specially in developing world. This requires developing an effective air quality 1207
monitoring networks and common models to predict air pollution levels. Jain and Khare 1208
(2008) stress out for an effective and efficient air quality management plan including the 1209
major key player and stakeholders. Gurjar et al. (2008) also developed a MPI having 1210
combined level of SPM, SO2, and NO2 in view of the WHO guidelines for air quality. 1211
These approaches are useful to evaluate atmospheric emissions and urban air quality in 1212
megacities. Further developing index can also help monitor air quality changes over time, 1213
and relate these to other indices that provide information about the often rapidly changing 1214
state of megacities (Gurjar et al., 2008). 1215
1216
1217
Acknowledgements: Authors would like to thank the Dr. T.M. Butler, Dr. M.G. 1218
Lawrence from Institute for Advanced Sustainability Studies e.V., Berliner Strasse 130, D-1219
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
27
14467 Potsdam, Germany and Dr. J. Lelieveld from Atmospheric Chemistry Division, 1220
Max Planck Institute for Chemistry, P.O. Box 3060, D-55020 Mainz, Germany for their 1221
scientific discussion and useful suggestions. 1222
Support for this study was provided by the Max Planck Society, Germany, and Max 1223
Planck Institute for Chemistry, Mainz, Germany, through the Max Planck Partner Group 1224
for Megacities & Global Change, IIT Roorkee, India. This study is also linked to FP7 1225
European projects MEAGAPOLI (http://megapoli.dmi.dk/) and TRANSPHORM 1226
(http://www.transphorm.eu/). 1227
RK also would like to thank Department of Health Research (DHR), Indian Council of 1228
Medical Research (ICMR), Ministry of Health and Family Welfare, for providing the 1229
Fellowship Training Programme in Environmental Health under Human Resource 1230
Development Health Research Scheme. 1231
1232
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
28
References 1233
ADB (Asian Development Bank and the Clean Air Initiative for Asian Cities (CAI-Asia)), 1234
2006. Country Synthesis Report on Urban Air Quality Management. Discussion 1235
Draft, December 2006. 1236
ADB (Asian Development Bank), 2005. Strengthening Environmental Management at the 1237
State level Cluster) Component E-Strengthening Environmental Management at 1238
Waste Bengal Pollution Control Board. Final Report, Volume V-Air Quality 1239
Management, November 2005. 1240
Arndt, R.L., Carmichael, G.R., Streets, P.G., Bhatti, N., 1997. Sulphur dioxide emissions 1241
and sectoral contribution to sulphur deposition in Asia. Atmospheric Environment 1242
31, 1553–1582. 1243
Awasthi, A., Agarwal, R., Mittal, S.K., Singh, N., Singh, K., Gupta, P.K., 2011. Study of 1244
size and mass distribution of particulate matter due to crop residue burning with 1245
seasonal variation in rural area of Punjab, India. J. Environ. Monit. 13, 1073–1081. 1246
Bencs, L., Ravindra, K., de Hoog, J., Rasoazanany, E.O., Deutsch, F., Bleux, N., 1247
Berghmans, P., Roekens, E., Krata, A., Van Grieken, R., 2008.Mass and ionic 1248
composition of atmospheric fine particles over Belgium and their relation with 1249
gaseous air pollutants.Journal of Environmental Monitoring 10, 1148e1157. 1250
Bhanarkar, A.D., Rao, P.S., Gajghate, D.G., Nema P., 2005. Inventory, of SO2, PM and 1251
toxic metals emissions from industrial sources in Greater Mumbai, 1252
India.Atmospheric Environment 39, 3851–3864. 1253
Bose, R.K., 1996. Energy demand and environmental implications in urban transport—1254
Case of Delhi. Atmospheric Environment 30(3), 403–412. 1255
Butler, T.M., Lawrence, M.G., Gurjar, B.R., van Aardenne, J., Schultz, M., Lelieveld, J. 1256
2008. The representation of emissions from megacities in global emission 1257
inventories. Atmospheric Environment 42 (4), pp. 703-719 1258
Brandon, C., Homman, K., 1995. The cost of inaction: valuing the economic-wide cast of 1259
environmental degradation in India. Asia Environment Division, World Bank, 17 1260
October 1995. 1261
Chakraborti, D, 1993. Calcutta environmental profile: air pollution. In Managing Urban 1262
Environment in India: Towards an Agenda for Action. ed. K C Sivaramakrishnan, 1263
Vol. 3. The Times Research Foundation, Calcutta. 1264
Chakraborty, D., Bhattacharya , P., 2004. Air Quality Management Strategy for Kolkata 1265
City under India Canada Environment Facility Project – A Case Study.West 1266
Bengal Pollution Control Board.http://www.cleanairnet.org/baq2004/1527/articles-1267
59332_bhattacharya.pdf. 1268
Chattopadhyay, G., Samanta, G., Chatterjee, S., Chakraborti, D., 1998. Determination of 1269
particulate phase polycyclic aromatic hydrocarbons in ambient air of Calcutta for 1270
three years during winter. Environ. Technol. 19, 873–882. 1271
Chow J.C., Watson J.G., Shah J.J., Kiang C.S., Loh C., Lev-On M., Lents J.M., (...), 1272
Molina L.T. Megacities and atmospheric pollution. (2004) Journal of the Air and 1273
Waste Management Association, 54 (10), pp. 1226-1235. 1274
CPCB, 1999, Status of Air Quality in National Capital Region, Central Pollution Control 1275
Board, Ministry of Environment and Forests, Government of India CPCB, 1999. 1276
Air Quality at Major Traffic Intersections of Delhi, Central Pollution Control 1277
Board, Ministry of Environment and Forests, Government of India 1278
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
29
CPCB (Central Pollution Control Board), 2001. Air Quality in Delhi (1989–2000). 1279
NAAQMS/17/2000–2001. CPCB, Delhi -32, India. 1280
CPCB, 2003. Polycyclic Aromatic Hydrocarbons (PAHs) in Air and Their Effects on 1281
Human Health. November 2003, Central Pollution Control Board, Delhi-32, 1282
India.Available at http://www.cpcb.delhi.nic.in/ph/ch81103.htm. 1283
CPCB, 2009. Comprehensive Environmental Assessment of Industrial Clusters. 1284
December, 2009. Available at: 1285
http://cpcb.nic.in/divisionsofheadoffice/ess/NewItem_152_Final-Book_2.pdf. 1286
CPCB, 2010 Air Quality Monitoring, Emission Inventory and Source Apportionment 1287
Study for Indian Cities; Central Pollution Control Board, Government of India: 1288
New Delhi, India.Cropper, M.L., Simon, N.B., Alberini, A., Sharma, P.K., 1997. 1289
The health effects of air pollution in Delhi, India. A policy research working 1290
paper by The World Bank, PRD Working Mayer, M., Wang, C., Webster, M., 1291
Prinn, R.G., 2000, Linking local air pollution to global chemistry and climate. 1292
Journal of Geophysical Research 105, 22869–22896. Paper #1860. Available at 1293
URL: http://www.worldbank. org/nipr/work_paper/1860/index.htm. 1294
CPCB, 2010. National Ambient Air Quality Status and Trends-2010, January 2012, 1295
Central Pollution Control Board, Delhi-32, India. 1296
CPCB, 2012. National Ambient Air Quality Status and Trends-2012, August 2014, Central 1297
Pollution Control Board, Delhi-32, India. 1298
CSE report, 2013. http://www.downtoearth.org.in/news/air-pollution-killing-620000-1299
indians-every-year-global-burden-of-disease-report--40316 1300
CSE Webnet- India Environment Portal. Available at: 1301
http://www.indiaenvironmentportal.org.in/content/29350/kolkata-tanners-unhappy-1302
with-new-relocation-site/. 1303
CSE (2013).“Burden of Disease: Outdoor Air Pollution among Top Killers” Centre for Science 1304
and Environment. Dialogue Workshop, New Delhi, February 13, 2013. 1305
Das, M., Maiti, S. K., Mukhopadhyay, U., 2006. Distribution of PM
2.5 and PM10-2.5 in 1306
PM10 Fraction in Ambient Air Due to Vehicular Pollution in Kolkata Megacity. 1307
Environmental Monitoring and Assessment 122: 111–123. 1308
Dey, S., Di Girolamo, L., van Donkelaar, A., Tripathi, S.N., Gupta, T., Mohan, M., 2012. 1309
Variability of outdoor fine particulate (PM2.5) concentration in the Indian 1310
subcontinent: a remote sensing approach. Remote Sens. Environ. 127, 153–161. 1311
http://dx.doi.org/10.1016/j.rse.2012.08.021. 1312
D'Angiola A., Dawidowski L.E., Gomez D.R., Osses M. On-road traffic emissions in a 1313
megacity (2010) Atmospheric Environment, 44 (4), pp. 483-493. 1314
DSA (Delhi Statistical Abstract), 2006. Directorate of Economics and Statistics 1315
Government of National Capital Territory of Delhi. 1316
DSA (Delhi Statistical Abstract), 2012. Directorate of Economics and Statistics 1317
Government of National Capital Territory of Delhi. 1318
DSIIDC (Delhi State Industrial and Infrastructure Development Corporation)- Relocation 1319
of Industries. Available at: http://dsiidc.org/cms/relocation-industry. 1320
Finlayson-Pitts, Barbara J.; Pitts, James N., Jr., 1977. Advances in Environmental Science 1321
and Technology, 7, 75-162 CODEN: AESTC9; ISSN: 0065-2563. 1322
Finlayson-Pitts, B. J., 1983. "Reaction of NO2 with NaCl and atmospheric implications of 1323
NOCl formation.": 676-677. 1324
Finlayson-Pitts, B.J., Pitts Jr., J.N., 1986. Atmospheric Chemistry: Fundamentals and 1325
Experimental Techniques. Wiley-Interscience, New York. 1326
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
30
Garg, A., Shukla, P.R., Bhattacharya, S., Dadhwal, V.K., 2001. Sub-region (district) and 1327
sector level SO2 and NOx emissions for India: assessment of inventories and 1328
mitigation flexibility. Atmospheric Environment 35 703-713. 1329
Gaffney, J.S., Marley, N.A. 2004 Megacities as sources of black carbon. Bulletin of the 1330
American Meteorological Society, pp. 6545-6549 1331
Gaffney J.S., Marley N.A. The impacts of combustion emissions on air quality and climate 1332
- From coal to biofuels and beyond (2009) Atmospheric Environment, 43 (1), pp. 1333
23-36. 1334
Ghose M. K., Paulb, R., Banerjee, S.K., 2004. Assessment of the impacts of vehicular 1335
emissions on urban air quality and its management in Indian context: the case of 1336
Kolkata (Calcutta). Environmental Science and Policy 7 345–351. 1337
Genga, F., Tieb, X., , , Xua, J., Zhoua, G., Penga, Li, Gaoa, W., Tanga, Xu, Zhaoc, C., 1338
2008.Characterizations of ozone, NOx, and VOCs measured in Shanghai, China. 1339
Atmospheric Environment Volume 42, Issue 29, September 2008, Pages 6873–1340
6883 1341
Goyal, P., Sidhartha, 2002.Effect of winds on SO2 and SPM concentrations in 1342
Delhi.Atmospheric Environment 36, 2925-2930. 1343
Goyal, P., Sidhartha, 2003. Present scenario of air quality in Delhi: a case study of CNG 1344
implementation. Atmospheric Environment 37, 5423-5431. 1345
Gros V., Sciare J., Yu T. Air-quality measurements in megacities: Focus on gaseous 1346
organic and particulate pollutants and comparison between two contrasted cities, 1347
Paris and Beijing . (2007) ComptesRendus - Geoscience, 339 (11-12), pp. 764-774. 1348
Gurjar, B.R., Jain, A., Sharma, A., Agarwal, A., Gupta, P., Nagpure, A.S., Lelieveld, J. 1349
2010. Human health risks in megacities due to air pollution. Atmospheric 1350
Environment 44 (36), pp. 4606-4613 1351
Gurjar B.R., Butler T.M., Lawrence M.G., Lelieveld J. Evaluation of emissions and air 1352
quality in megacities. (2008) Atmospheric Environment, 42 (7), pp. 1593-1606. 1353
Guttikunda S.K., Tang Y., Carmichael G.R., Kurata G., Pan L., Streets D.G., Woo J.-H., 1354
(...), Fried A. Impacts of Asian megacity emissions on regional air quality during 1355
spring 2001. (2005) Journal of Geophysical Research D: Atmospheres, 110 (20), 1356
art. no. D20301, pp. 1-18. 1357
Gurjar, B.R., van Aardenne, J.A., Lelieveld, J., Mohan, M., 2004. Emission estimates and 1358
trends(1990-2000) for megacity Delhi and implications. Atmospheric Environment 1359
38, 5663-5681. 1360
Gurjar, B.R., Lelieveld, J., 2005. New Directions: Megacities and global change, 1361
Atmospheric Environment 39, 391–393. 1362
Gurjar, B. R., & Nagpure, A. S. 2015. Indian megacities as localities of environmental 1363
vulnerability from air quality perspective. Journal of Smart Cities, 1(1). 1364
Guttikunda, S., G. Calori, F. Velay-Lasry, R. Ngo, 2011. Air Quality Forecasting 1365
System for Cities: Modeling Architecture for Delhi, Simple Interactive Models 1366
for Better Air Quality. SIM-Air Working Paper Series 36. Delhi, Urban Emission 1367
Info, 2011.Guttikunda, S. K., Carmichael, G. R., Calori, G., Eck, C., Woo, Jung-1368
Hun., 2003. The contribution of megacities to regional sulfur pollution in Asia. 1369
Atmospheric Environment 37, 11–22. 1370
Guttikunda,S.K., Thongboonchoo, N., Arndt, R.L., Calori, 1371
G.,Carmichael,G.R.,treet,D.G.,2001. Sulphur deposition in Asia: seasonal 1372
behaviour and contributions from various energy sectors. Water,Air and Soil 1373
Pollution 131, 383–406. 1374
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
31
Guttikunda, S. K.; Goel, R.; Pant, P., 2014. Nature of air pollution, emission sources, and 1375
management in the Indian cities. Atmospheri Environment 95, 501−510.Halsall, 1376
C.J., Coleman, P.J., Davis, B.J., Burnett, V., Waterhouse, K.S., Harding-Jones, P., 1377
Jones, K.D., 1994. Polycyclic aromatic hydrocarbons in UK urban 1378
air.Environmental Science Technology 28, 2380–2386. 1379
Harrison, R.M., Stedman, J., Derwent, D.: New direction: why are PM10 concentrations in 1380
Europe not falling? Atmos. Environ. 42, 603-606 (2008). 1381
Hopke P.K., Cohen D.D., Begum B.A., Biswas S.K., Ni B., Pandit G.G., Santoso M., (...), 1382
Markowicz A. Urban air quality in the Asian region. (2008) Science of the Total 1383
Environment, 404 (1), pp. 103-112. 1384
INCCA (Indian Network for Climate Change Assessment), 2010. India: Greenhouse Gas 1385
Emissions 2007, Ministry of Environment and Forests, Government of India. 1386
Jain, S., Khare, M. 2008 Urban air quality in mega cities: A case study of Delhi City 1387
using vulnerability analysis. Environmental Monitoring and Assessment 136 (1-3), 1388
pp. 257-265 1389
Jiang, F., Liu, Q., Huang, X., Wang, T., Zhuang, B., Xie, M., 2012. Regional modeling of 1390
secondary organic aerosol over China using WRF/Chem. Journal of Aerosol 1391
Science 43, 57-73. 1392
Kadian, R., Dahiya, R.P., Garg, H.P., 2007. Energy-related emissions and mitigation 1393
opportunities from the household sector in Delhi.Energy Policy 35, 6195–6211. 1394
Kandlikar , M.., Ramachandran, G., 2000. The causes and consequences of particulate air 1395
pollution in urban India a synthesis of the science, Annual Review of Energy and 1396 the Environment25, pp. 629–684. 1397
Kandlikar, M., 2007. Air pollution at a hotspot location in Delhi: Detecting trends, 1398
seasonal cycles and oscillations. Atmospheric Environment 41, 5934–5947. 1399
Kansal, A, Khare, M, Sharma, C.S., 2011. Air quality modelling study to analyse the 1400
impact of the World Bank emission guidelines for thermal power plants in Delhi. 1401
Atmos Pollut Res.;2:99–105. doi: 10.5094/APR.2011.012 1402
Karar, K., Gupta, A.K., 2006. Seasonal variations and chemical characterization of 1403
ambient RSPM at residential and industrial sites of an urban region of Kolkata 1404
(Calcutta), India.Atmospheric Research 81, 36– 53. 1405
Kathuria, V., 2004. Impact of CNG on vehicular pollution in Delhi: a note. Transportation 1406
Research Part D-Transport andEnvironment 9 (5), 409–417. 1407
Kaushik, C.P., Ravindra, K., Yadav, K., Mehta, S., Haritash, A.K., 2006. Assessment of 1408
ambient air quality in urban centres of Haryana (India) in relation to different 1409
anthropogenic activities and health risks. Environmental Monitoring and 1410
Assessment 122, 27-40. 1411
Khillare P.S., Agarwal T., Shridhar V 2008. Impact of CNG implementation on PAHs 1412
concentration in the ambient air of Delhi: A comparative assessment of pre- and 1413
post-CNG scenario. Environmental Monitoring and Assessment, 147 (1-3), pp. 1414
223-233. 1415
Kraas F. Megacities and global change: Key priorities. (2007) Geographical Journal, 173 1416
(1), pp. 79-82. 1417
Kanakidou, M., Mihalopoulos, N., Kindap, T., Im, U., Vrekoussis, M., Gerasopoulos, E., 1418
Dermitzaki, E., (...), Moubasher, H. 2011. Megacities as hot spots of air pollution 1419
in the East Mediterranean. Atmospheric Environment, Article in Press 1420
Kazimuddin, A., Banerjee, L., 2000. Fighting For Air.Down to Earth, July 31. 1421
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
32
Kulkarni, P., Venkataraman, C., 2000. Atmospheric polycyclic aromatic hydrocarbons in 1422
Mumbai, India.Atmospheric Environment. 34, 2785-2790. 1423
Kumar, A., Srivastava, D., Agrawa, M., Goel A., 2014.Snapshot of PM Loads Evaluated 1424
at Major Road and Railway Intersections in an Urban Locality, International 1425
Journal of Environmental Protection, Jan. 2014, Vol. 4 Iss. 1, PP. 23-29. 1426
Kumar, G. M., Sampath, S., Jeena, V.S., Anjali, R., 2008. Carbon Monoxide Pollution 1427
Levels at Environmentally Different Sites, J. Ind. Geophys. Vol.12, No.1, pp.31-40 1428
Kumar, R., Joseph, A. E., 2006. Air Pollution Concentrations of PM2.5, RSPM and NO2 at 1429
Ambient and Kerbsite and Their Correlation in Metro City – Mumbai. 1430
Environmental Monitoring and Assessment 119: 191–199. 1431
Kumar, S., Gaikwad, S.A., Shekdar, A.V., Kshirsagar, P.S., Singh, R.N., 2004.Estimation 1432
method for national methane emission from solid waste landfills.Atmospheric 1433
Environment 38, 3481–3487. 1434
Kumar, S., Mondal, A.N., Gaikwad, S.A., Devotta, S., Singh, R.N., 2004. Qualitative 1435
assessment of methane emission inventory from municipal solid waste disposal 1436
sites: a case study, Atmospheric Environment 38, 4921–4929. 1437
Kumar, V., Patil, R.S., Nambi, K.S.V., 2001. Source apportionment of suspended 1438
particulate matter at two traffic junctions in Mumbai, India.Atmospheric 1439
Environment 35, 4245–4251. 1440
Kulshrestha, M.J.; Kulshrestha, U.C.; Parashar, D.C.; Vairamani, M., 2003. Estimation of 1441
SO4 contribution by dry deposition of SO2 onto the dust particles in India... 1442
Atmospheric Environment 37 (22), 3057-3063. 1443
Kulshrestha, U.; Sharma, D., 2015. Importance of atmospheric dust in India: Future scope 1444
of research. J. Indian Geophysical Union, 19, 2, 205-209. 1445
Larssen, S., Gram, F., Hagen, L.O., Jansen, H., Oltshoorn, X., Aundhe, R.V., Joglekar, U., 1446
1997.Greater Mumbai report. In: Shah, J.J., Nagpal, T. (Eds.), URBAIR: Urban 1447
Air Quality Management Strategy in Asia. The International Bank of 1448
Reconstruction and Development/The World Bank, Washington DC. 1449
Laakso L., Koponen I.K., Monkkonen P., Kulmala M., Kerminen V.-M., Wehner B., 1450
Wiedensohler A., (...), Hu M. Aerosol particles in the developing world; A 1451
comparison between New Delhi in India and Beijing in China. (2006) Water, Air, 1452
and Soil Pollution, 173 (1-4), pp. 5-20. 1453
The Lancet, Outdoor air pollution among top global health risks in 2010, 13 December 1454
2012, Health EffectsInstitute, http://www.healtheffects.org/International/GBD-1455
Press-Release.pdf 1456
The Lancet, Global, regional, and national age–sex specific c all-cause and cause-specific 1457
mortality for 240 causes of death, 1990–2013: a systematic analysis for the Global 1458
Burden of Disease Study 2013, 385: 117–71 1459
http://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(14)61682-2.pdf 1460
Lawrence M.G., Butler T.M., Steinkamp J., Gurjar B.R., Lelieveld J.Regional pollution 1461
potentials of megacities and other major population centers (2007) 1462
AtmosphericChemistry and Physics, 7 (14), pp. 3969-3987. 1463
Liu, L., Sundet, J.K., Liu, Y., Berntsen, T.K., Isaksen, I.S., 2007. A study of tropospheric 1464
ozone over China with a 3-D global CTM model. Terrestrial, Atmospheric and 1465
Oceanic Sciences 18, 515e545. 1466
Mayer, H., 1999. Air pollution in cities, Atmospheric Environment, 33, .4029-4037 1467
MEIP, 1993. Study on environmental management strategy and action plan for BMR April 1468
1993. AIC and Coopers and Lybrand,Project under MEIP. 1469
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
33
Mitra, A.P., Sharma, Subodh, K., Bhattacharya, S., Garg, A., Devotta, S., Sen, Kalyan, 1470
(Eds.), 2004. “Climate Change and India: Uncertainty Reduction in GHG 1471
Inventories”. Universities Press (India) Pvt. Ltd., Hyderabad. 1472
MoEF (Ministry of Environment and Forest) 1997. White paper on pollution in Delhi with 1473
an action plan New Delhi: 67pp. 1474
MoEF (Ministry of Environment and Forest) 2015. Government Issues Directions for 1475
Pollution Control and Improving Ambient Air Quality in Delhi and NCR. 1476
http://pib.nic.in/newsite/PrintRelease.aspx?relid=134044 1477
Mohan, M., Dagar, L., Gurjar, B. R., 2007. Preparation and Validation of Gridded 1478
Emission Inventory of Criteria Air Pollutants and Identification of Emission 1479
Hotspots for Megacity Delhi. Environmental Monitoring Assessment 130:323–1480
339. 1481
Mohan, M., Payra, S. 2009. Influence of aerosol spectrum and air pollutants on fog 1482
formation in urban environment of megacity Delhi, India. .Environmental 1483
Monitoring and Assessment 151 (1-4), pp. 265-277 1484
Mondal, R. , Sen, G.K. , Chatterjee, M., Sen, B.K., Sen, S., 2000. Short Communication 1485
Ground-level concentration of nitrogen oxides (NOx) at some traffic intersection 1486
points in Calcutta. Atmospheric Environment, 34 629-633. 1487
Molina, M.J., Molina, L.T. 2004 Megacities and atmospheric pollution. Journal of the Air 1488
and Waste Management Association 54 (6), pp. 644-680. 1489
Molina L.T., Madronich S., Gaffney J.S., Apel E., De Foy B., Fast J., Ferrare R., (...), 1490
Zavala M. An overview of the MILAGRO 2006 Campaign: Mexico City emissions 1491
and their transport and transformation (2010) Atmospheric Chemistry and Physics, 1492
10 (18), pp. 8697-8760. 1493
Mor S., Ravindra K., De Visscher A., Dahiya R.P., Chandra A. 2006. Municipal solid 1494
waste characterization and its assessment for potential methane generation: A case 1495
study. Science of the Total Environment, 371, 1-10. 1496
Mukhopadhyay, K., Forssell, O., 2005. An empirical investigation of air pollution from 1497
fossil fuel combustion and its impact on health in India during1973–1974 to 1996–1498
1997.Ecological Economics 55, 235– 250. 1499
MUTP (Mumbai Urban Transport Project), 2002.Consolidated Environmental 1500
Assessment, Executive Summaries, JUNE 2002, Mumbai Metropolitan Region 1501
Development 1502
Authority.http://www.wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/21503
002/07/27/000094946_02070204293357/Rendered/INDEX/multi0page.txt. 1504
Nagpure, A. S., Gurjar, B. R., & Martel, J. C. ,2014. Human health risks in national capital 1505
territory of Delhi due to air pollution. Atmospheric Pollution Research, 5. 1506
Nagpure, A. S., Ramaswami, A., & Russell, A. ,2015. Characterizing the Spatial and 1507
Temporal Patterns of Open Burning of Municipal Solid Waste (MSW) in Indian 1508
Cities. Environmental science & technology, 49(21), 12904-12912. 1509
National Biomass Cookstoves Programme (NBCP), Ministry of New and Renewable 1510
Energy, Government of India. Available at: 1511
http://mnre.gov.in/schemes/decentralized-systems/national-biomass-cookstoves-1512
initiative/ 1513
NEERI 1991a.Air pollution aspects of three Indian megacities. Volume III: Calcutta, 1514
National Environmental Engineering Research Institute,Nagpur. 1515
NEERI, 2004.Particulate Matter Reduction Action Plan for Greater Mumbai 1516
Region.NEERI, Nagpur, India. 1517
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
34
Pachauri, R.K., Sridharan, P.V. 1998. Looking Back to Think Ahead: growth with 1518
resource enhancement of environment and nature. New Delhi: Tata Energy 1519
Research Institute. 346 pp. 1520
Padhy, K., P., Varshney, C.K., 2000. Ambient methane levels in Delhi. Chemosphere - 1521
Global Change Science 2 185-190. 1522
Pandey, J. S., Kumar, R, Devotta, S., 2005. Health risks of NO2, SPM and SO2 in Delhi 1523
(India). Atmospheric Environment 39, 6868–6874. 1524
Pandit, G.G., Sharma, S., Mohan Rao, A.M., Krishnamoorthy, T.M., 1525
1996.Chromatographic methods for the estimation of polycyclic aromatic 1526
hydrocarbons in atmospheric particulates. Proceedings of the 5th National 1527
Symposium on Environment, Nagpur, pp. 133-136. 1528
Panther, B.C., Hooper, M.A., Tapper, N.J., 1999.A comparison of air particulate matter 1529
and associated polycyclic aromatic hydrocarbons in some tropical and temperature 1530
urban environments.Atmospheric Environment 33, 4087–4099. 1531
Park, S.S., Kim, Y.J., Kang, C.H., 2002. Atmospheric polycyclic aromatic hydrocarbons 1532
in Seoul, Korea. Atmos. Environ. 36, 2917–2924. 1533
Puranik, V. D., 2008. Dry Deposition of Polycyclic Aromatic Hydrocarbons Associated 1534
with Atmospheric Particulate Matters in an Urban Site, Mumbai, India. Aerosol 1535
and Air Quality Research, Vol. x, No. x, pp. xxx-xxx. 1536
Rao. P. S., Ansari, M. F., Pipalatkar, P., Kumar, A., Nema, P., Devotta, S., 2008. 1537
Measurement of particulatephasepolycyclicaromatichydrocarbon (PAHs) around a 1538
petroleumrefinery. Environmental Monitoring Assessment 137:387–392. 1539
Ramanathan, V., & Carmichael, G., 2008. Global and regional climate changes due to 1540
black carbon. Nature Geoscience, 1(4), 221-227. 1541
Ramanathan, V.; Feng, Y., 2009. Air pollution, greenhouse gases and climate change: 1542
Global and regional perspectives. Atmospheric Environment 43 (1): 37-50. 1543
Ravindra, K., Bencs, L., Wauters, E., de Hoog, J., Deutsch, F., Roekens, E., Bleux, N., 1544
Bergmans, P., Van Grieken, R., 2006b. Seasonal and site specific variation in 1545
vapor and aerosol phase PAHs over Flanders (Belgium) and their relation with 1546
anthropogenic activities. Atmospheric Environment 40, 771–785. 1547
Ravindra, K., Wauters, E., Tyagi, S.K., Mor, S., Van Grieken, R., 2006a. Assessment of 1548
air quality after the implementation of CNG as fuel in public transport in Delhi, 1549
India.Environmental Monitoring and Assessment 115, 405–417. 1550
Ravindra, K., , Mor, S., Ameena, Kamyotra, J.S., Kaushik C.P., 2003. Variation in spatial 1551
pattern of various air pollutants before and during initial rain of monsoon. 1552
Environmental Monitoring and Assessment 87, 145-153. 1553
Ravindra, K., Mittal, A.K., Van Grieken, R., 2001.Health risk assessment of urban 1554
suspended particulate matter with special reference to polycyclic aromatic 1555
hydrocarbons: A review. Reviews on Environmental Health 16, 169-189. 1556
Ravindra, K., R.S. Sokhi, Van Grieken, R., 2008. Atmospheric Polycyclic Aromatic 1557
Hydrocarbons: Source attribution, emission factors and regulation. Atmospheric 1558
Environment 42:2895-2921. 1559
Ravindra, K., Sidhu, M.K., Mor, S., John, S., and Pyne, S., 2015. Air pollution in India: 1560
Bridging the Gap between Science and Policy. Journal of Hazardous, Toxic, and 1561
Radioactive Waste, A4015003. DOI: 10.1061/(ASCE)HZ.2153-5515.0000303. 1562
Reddy, M. S., Venkataraman, C., 2002. Inventory of aerosol and sulphur dioxide 1563
emissions from India Part II- biomass combustion. Atmospheric Environment 36 1564
(4), 677–697. 1565
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
35
Reynolds, C., Kandlikar, M., 2008.Climate Impacts of Air Quality Policy: Switching to a 1566
Natural Gas-Fueled Public Transportation System in New Delhi. Environmental 1567
Science and Technology 42 (16), 5860–5865. 1568
Sahu, S. K., Pandit, G. G, Sadasivan, S,. 2004. Precipitation scavenging of polycyclic 1569
aromatic hydrocarbons in Mumbai, India. The Science of the Total Environment 1570
318 245–249. 1571
Sindhwani, R., Goyal, P., 2014. Assessment of traffic–generated gaseous and particulate 1572
matter emissions and trends over Delhi (2000–2010). Atmospheric Pollution 1573
Research 5 (2014) 438-446. 1574
1575
Singh, D.P., Gadi, R., Mandal, T.K. 2010 Emissions of polycyclic aromatic hydrocarbons 1576
in the atmosphere: an Indian perspective. Human and Ecological Risk Assessment 1577
16 (5), pp. 1145-1168 1578
Singh, B.P., Kumar, A., Deepak S., Punia, M., Kumar K., Jain, V.K., 2014. An 1579
assessment of ozone levels, UV radiation and their occupational health hazard 1580
estimation during photocopying operation, Journal of Hazardous Materials 275 1581
(2014) 55–62 1582
Singh, D.P., Gadi R., Mandal T. K., 2011. Characterization of particulate-bound 1583
polycyclic aromatic hydrocarbons and trace metals composition of urban air 1584
in Delhi, India, Atmospheric Environment 45 7653-7663 1585
Singh, R., & Sharma, C., 2011. Assessment of emissions from transport sector in Delhi, 1586
Journal of Scientific & Industrial research Vol. 71, pp 155-160. 1587
Sillman, S., 1999. The relation between ozone, NOx and hydrocarbons in urban and 1588
polluted rural environments, Atmospheric Environment, 33, 1821–1845. 1589
1590
Shankar, R.V., 1990. Characterization of atmospheric polynuclear aromatic hydrocarbons 1591
with special reference to automobile exhaust. Ph.D. Thesis. Jawaharlal Nehru 1592
University, New Delhi, India. 1593
Sharma, C., Dasgupta, A. ,Mitra, A.P. , 2002b. Inventory of GHGs and Other Urban 1594
Pollutants from Transport Sector In Delhi and Calcutta, Proceedings of IGES/APN 1595
Mega-City Project. 1596
Sharma, C., Dasgupta A., Mitra, A.P., 2002a.Future Scenarios of Inventories of GHGs 1597
and Urban Pollutants From Delhi and Calcutta, Proceedings of IGES/APN Mega-1598
City Project, 23-25 January 2002 (Rihga Royal Hotel Kokura, Kitakyushu Japan). 1599
Sharma, C., & Pundir, R., 2008. Inventory of green house gases and other polltants from 1600
Transport sector: Delhi, Indian Journal of health Sci Engine, 5, 117-124 1601
Sharma, D. N., Sawant, A. A., Uma, R., Cocker, D. R., 2003. Preliminary chemical 1602
characterization of particle-phase organic compounds in New Delhi, India, 1603
Atmospheric Environment 37 4317–4323. 1604
Sharma, D.; Kulshrestha, U., 2014 Spatial and Temporal Patterns of Air Pollutants in 1605
Rural and Urban Areas of India. Environmental Pollution 1606
10.1016/j.envpol.2014.08.026. 1607
Sharma, H., Jain, V.K., Khan, Z. H., 2007. Characterization and source identification of 1608
polycyclic aromatic hydrocarbons (PAHs) in the urban environment of Delhi, 1609
Chemosphere 66 302–310. 1610
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
36
Shukla S. K., Nagpure A. S., Kumar, V., Baby S., Shrivastava P., Singh D., Shukla R. N., 1611
2008. Impact of dust emission on plant vegetation in the vicinity of cement plant. 1612
Environmental Engineering and Management Journal, Vol.7, No.1, 31-35. 1613
Smith, K.R., 2000. National burden of disease in India from indoor air 1614
pollution.ProcNatlAcadSci U S A. 97(24): 13286–13293. 1615
Sridevi, H., Shreejith, K., Ramachandra, T. V., 2014.Comparative analysis of greenhouse 1616
gas emissions from major cities of India, International Journal of Renewable 1617
Energy and Environmental Engineering ISSN 2348-0157, Vol. 02, No. 01. 1618
Srimuruganandam, B., & Shiva Nagendra, S.M., 2011. Characteristics of particulate 1619
matter and heterogeneous traffic in the urban area of India. Atmos Environ. vol. 1620
45, iss. 18, pp. 3091-3102. 1621
Song, C.H., Park, M.E., Lee, K.H., Ahn, H.J., Lee, Y., Kim, J.Y., Han, K.M., Kim, J., 1622
Ghim, Y.S., Kim, Y.J., 2008. An investigation into seasonal and regional aerosol 1623
characteristics in East Asia using model-predicted and remotely-sensed aerosol 1624
properties. Atmospheric Chemistry and Physics 8, 6627e6654. 1625
Sokhi, R.S., Kitwiroon, N., 2008. Air pollution in urban areas.In World Atlas of 1626
Atmospheric Pollution Sokhi, R.S. (Editor). Anthem Press, London, UK. 1627
Stern, A. C., Boubel, R. W. and Turner, D. B., 1984. Fundamental of Air Pollution, 2nd 1628
Edition, Academic Press, 1629
Inc.http://judis.nic.in/SupremeCourt/imgs1.aspx?filename=15202 1630
Tang, Y.H., Carmichael, G.R., Seinfeld, J.H., Dabdub, D., Weber, R.J., Huebert, B., 1631
Clarke, A.D., Guazzotti, S.A., Sodeman, D.A., Prather, K.A., Uno, I., Woo, J.H., 1632
Yienger, J.J., Streets, D.G., Quinn, P.K., Johnson, J.E., Song, C.H., Grassian, V.H., 1633
Sandu, A., Talbot, R.W., Dibb, J.E., 2004. Three-dimensional simulations of 1634
inorganic aerosol distributions in east Asia during spring 2001. Journal of 1635
Geophysical Research-Atmospheres 109. 1636
TERI (Tata Energy Research Institute) 2002. Pricing and Infrastructure Costing for Supply 1637
and Distribution of CNG and ULSD to the Transport Sector in Mumbai, India.75-1638
77. 1639
TERI (The Energy and Resources Institute) 2001a.State of Environment Report for Delhi 1640
2001. Report No. 2000EE65, Supported by the Department of Environment, 1641
Government of National Capital Territory, Delhi.,TERI, New Delhi. 1642
TERI (The Energy and Resources Institute), 2001b. India state of the environment, 1643
Sponsor: United Nations Environment Programme. 1644
http://www.teriin.org/projects/ES/ ES1999EE45.pdf. 1645
Tie, X.X., Brasseur, G.P., Zhao, C.S., Granier, C., Massie, S., Qin, Y., Wang, P.C., Wang, 1646
G.L., Yang, P.C., Richter, A., 2006. Chemical characterization of air pollution in 1647
Eastern China and the Eastern United States. Atmospheric Environment 40, 2607-1648
2625. 1649
Tiwari, S., Payra, S.,Mohan, M., Verma, S., Bisht, D.S., 2011. Visibility degradation 1650
during foggy period due to anthropogenic urban aerosol at Delhi, India.Atmos. 1651
Pollut. Res 2, 116–120. 1652
Tiwari, S., Srivastava, A.K., Bisht, D.S., Parmita, P. B., Srivastava, M. K., Attri, S.D., 1653
2013. Diurnal and seasonal variations of black carbon and PM2.5 over New 1654
Delhi, India: Influence of meteorology, Atmospheric Research 125–126, 1655
50–62. 1656
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
37
UNDP (United Nation Development Programme) 2006. Hazard profiles of Indian districts, 1657
National Capacity Building Project in Disaster Management. UNDP, 2006. 1658
URBAIR, 1994. Bombay city specific report, Prepared under MEIP programme, by 1659
Steiner, L., Frederick, G., Leif, O.H. Norwegian Institute for Air Research, 1660
Norway, Huib, J.,Xander, O., Institute for Environmental Studies, Amsterdam, The 1661
Netherlands. 1662
URBAIR, 1996. Urban Air Quality Management Strategy in Asia Greater Mumbai Report, 1663
World Bank Technical Paper No 381. 1664
URBAIR, 1997. In: Shah Jitendra, J.,Nagpal, T. (Eds.), Urban Air Quality Management in 1665
Asia, Greater Mumbai Report. World Bank Technical Paper No. 381,Washing ton, 1666
DC. 1667
UN [United Nations Population Division] (2012) World urbanization prospects: the 2011 1668
revision. United Nations Population Division, New York, 50 pp 1669
http://esa.un.org/unup/pdf/WUP2011_Highlights.pdf 1670
Vanni, A., Esposito, A., 1982. Landfill gas recovery: state of the art in Italy, a feasibility 1671
study for one of the biggest Italian landfills. In: Proceedings of the Conference on 1672
Resources Recov. Solid Wastes, 10-12 May, Miami Beach, FL, New York, pp. 1673
417-424. 1674
Varshney, C.K., Padhy, P.K., 1999. Emission of total volatile organic compounds from 1675
anthropogenic sources in India. Journal of Industrial Ecology 2 (4), 93-105. 1676
Venkataraman, C., Sinha, P., Bammi, S., 2001. Sulphate aerosol size distributions at 1677
Mumbai, India, during the INDOEX-FFP (1998).Atmospheric Environment 35, 1678
2647-2655. 1679
Wang, Y., Zhang, Y., Hao, J., Luo, M., 2011. Seasonal and spatial variability of surface 1680
ozone over China: contributions from background and domestic pollution. Atmospheric 1681
Chemistry and Physics 11, 3511-3525. 1682
Wenzel, F., Bendimerad, F., Sinha, R., 2007. Megacities – mega risks. Nat Hazards 1683
42:481–491 DOI 10.1007/s11069-006-9073-2. 1684
Wiedinmyer, C., Yokelson, R. J., Gullett, B. K., 2014. Global Emissions of Trace Gases, 1685
Particulate Matter, and Hazardous Air Pollutants from Open Burning of Domestic 1686
Waste. Environmental Science and Technology, 48 (16), 9523−9530.WHO, 2006. 1687
WHO Air Quality Guidelines for Particulate Matter, Ozone, Nitrogen Dioxide and 1688
Sulfur Dioxide: Global Update 2005 (Summary of risk assessment). WHO/SDE/ 1689
PHE/OEH/06.02. 1690
WHO, 2014. WHO Air Quality Guidelines 1691
http://www.who.int/mediacentre/news/releases/2014/air-pollution/en/ 1692
WHO, 2009. WHO Air Quality Guidelines 1693
http://www.who.int/quantifying_ehimpacts/national/countryprofile/india.pdf?ua=1 1694
World Bank (1997). Urban air quality management strategy in Asia—greater Mumbai 1695
report. In: Shah JJ, Nagpal T (eds) World Bank Technical Paper No. 381. 1696
World Bank, 2003.Economic Valuation of the Health Benefits of Reduction in Air 1697
Pollution.http://www.worldbank.org/sarurbanair. 1698
Xie, J., Shah, J., 2002. Reducing Transport Air Pollution: The Case of Two-Stroke Engine 1699
Vehicles in Asian Cities. The World Bank, International Conference on 1700
Sustainable Transport and Clean Air, Jakarta, 29-31 May, 2000. 1701
Xing, J., Wang, S.X., Chatani, S., Zhang, C.Y., Wei, W., Hao, J.M., Klimont, Z., Cofala, 1702
J., Amann, M., 2011. Projections of air pollutant emissions and its impacts on 1703
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
38
regional air quality in China in 2020. Atmospheric Chemistry and Physics 11, 1704
3119-3136. 1705
Nagpure, A. S., Gurjar, B. R., Kumar, V., & Kumar, P. 2016. Estimation of exhaust and 1706
non-exhaust gaseous, particulate matter and air toxics emissions from on-road 1707
vehicles in Delhi. Atmospheric Environment, 127, 118-124. 1708
Government of India 2015, Government of India open source data. 1709
CPCB (Central Pollution Control Board),2015. Environmental Data Bank (CPCB), 1710
www.databank-cpcb.nic.in/ 1711
Nagpure, A. K., Gurjar, B. R., Sahni, N., & Kumar, P. 2010. Pollutant emissions from 1712
road vehicles in megacity Kolkata, India: past and present trends. Indian Journal of 1713
Air Pollution Control, 10(2), 18-30. 1714
Lelieveld, J., Evans, J. S., Fnais, M., Giannadaki, D., & Pozzer, A. 2015. The contribution 1715
of outdoor air pollution sources to premature mortality on a global scale. Nature, 1716
525(7569), 367-371. 1717
Guttikunda, S. K., & Calori, G. 2013. A GIS based emissions inventory at 1 km× 1 km 1718
spatial resolution for air pollution analysis in Delhi, India. Atmospheric 1719
Environment, 67, 101-111. 1720
1721
1722
1723
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
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Figure 1: Map of India showing the geographic location of three megacities 1726
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Figure 2: Decadal population growth in India and its megacities 1734
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Figure 3: Annual average concentration of SO2, NOx and SPM in Delhi, Mumbai and 1741
Kolkata from 1991 to 2012 1742
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Figure 4: SO2 concentration trend in Industrial Area and number of industries in Delhi 1746
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Figure 5: Total annual emissions (Gg) in Mumbai, in year 2007 (CPCB, 2010) 1750
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Figure 6: Contribution of Vehicle category in CO2 NOx,, PM and CO emission in (a)
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Delhi (2012) and (b) Kolkata (2010) and. (LCV- Light Commercial Vehicle; HCV:
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Heavy Commercial Vehicles, source: Nagpure et al., 2010, 2016)
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Figure 7: Comparison of vehicle population growth, emission and ambient concentration
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of NO
x
in Mumbai during 1996-2005. (Data source: Based on TERI,2002, cleanairnet.org
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a
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Figure 8: CNG vehicle population and SPM/PM10 concentration (µgm-3) trends in Delhi 1767
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Figure 9: Annual average concentration (µgm-3) of CO in Delhi 1773
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350000
400000
450000
500000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
SPM/PM 10 (µg/m3
No of CNG Vehicles
No of CNG Vehicles SPM PM 10
0
1000
2000
3000
4000
5000
6000
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Concentration(μg/m3)
Year
CO
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
45
1775
1776
1777
Figure 10: Contribution (%) of various sources in CH4 emission in Delhi (Source: 1778
Padhy and Varshney, 2000) 1779
1780
1781
7.57 7.50
5.94
55.74
23.08
0.18
Sewagetreatment
plants
wetlands
paddyfields
livestock
burningofgarbage
0
5000
10000
15000
20000
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
ExcessNumberofCases
Delhi Mumbai Kolkata
(a)
0
500
1000
1500
2000
2500
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
ExcessNumberofCases
Delhi Mumbai Kolkata
(b)
0
1000
2000
3000
4000
5000
6000
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
ExcessNumberofCases
Delhi Mumbai Kolkata
(c)
0
5000
10000
15000
20000
25000
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
ExcessNumberofCases
Delhi Mumbai Kolkata
(d)
Citation: Gurjar, B.R., Ravindra, K. and Nagpure, A.S., 2016. Air pollution trends over Indian
megacities and their local-to-global implications. Atmospheric Environment, 142, pp.475-495.
46
Figure 11: Excess number of cases of (a) total mortality (b) respiratory mortality (c) 1782
cardiovascular mortality (d) hospital admission COPD in the mega-cities Delhi, Mumbai and 1783
Kolkata (Source: Gurjar and Nagpure, 2015) 1784
1785
1786
