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RISK OF CUMULATING EFFECTS OF AIR POLLUTION SOURCES – A CASE
STUDY
Sorin ANGHEL1
Abstract
Compliance with current regulations of atmospheric pollutant emissions, (as well as in the case of other
environmental factors), requires an assessment of the pollution produced by the sources generating such
pollutants. Usually, it is estimated (by calculation or measurements) emissions and immissions generated
by a source, depending on the nature and the emission rate of pollutants, as well on the atmospheric
conditions. Even in the case of one source, emissions and immissions are within the imposed limits, it is
possible that, if an area contains several such sources, their cumulative effect would lead to overcome
these limitations, situation that must be considered in the case of the evaluation of pollution in a studied
area. Such a situation is the subject of this case study.
Keywords and phrases: sources of air pollutants, pollution assessment, cumulative effects.
1. Introduction
In the zone of Domneşti village, one of the economic activities which have escalated in
the last years is the production of stove plates (tiles). The production process generates,
especially by the operation of baking tiles, air emissions, mainly particulates, as a result of
burning wood fuel. In this area there are over a hundred burning terracotta kilns, whose
operation, especially if simultaneous, raises the issue of air pollution with particulate matter.
Calculations and measurements made in this case have shown the fact that by cumulating, the
effects of particulate pollution generated by the baking kilns must be taken into account.
2. Estimation of particulate pollution by the baking of tile kilns in Domneşti area
I have chosen for this application an area (600 x 800 m2) in Domneşti village, Argeş
County, where are located 5 baking terracotta tiles kilns, shown in Figure 1.
Fig.1. Location of five kilns in the studied area (Source: Google Maps)
1 Associate Professor PhD, Faculty of Sciences, Pitesti University, Romania, sangpit@yahoo.com .
Referring to the operation of baking tiles kilns I used the following typical data:
- a kiln works with wood fuel (about 2800 kg), the burning process lasting about 100
hours;
- combustion products are evacuated on a brick stack, having the side of the rectangular
section 30 cm and a height between 5 and 6 m above the ground.
Based on these data the following calculations can be made: Fuel consumption is M =
28 kg / h. Using information provided by the normative AP 42, US Environmental Protection
Agency2, for burning wood fuel, I used the emission factor F (g / kg) – the amount of pollutant
emitted per fuel unit of mass. Knowing the fuel consumption, the emission rate (amount of
pollutant emitted per unit of time) can be determinate using the relation R(gpollutant/h) =
F(gpollutant/kgfuel) x M(kgfuel/h). For main pollutants emitted, the results are presented in the
following table:
Table 1 - emission factors and emission rates of pollutants emitted from wood combustion.
Pollutant Emission factors F (g/kg) Emission rate R (g/h)
Pariculates PM10 1,2 33,6
CO 0,7 19,6
SO20,037 1,04
VOCtot 0,1 2,8
NOx1 28
I chose, for the performed application, particulate matter PM10 in suspension, typical
pollutant emitted by terracotta baking kilns. As air normative3 consider the emissions of
particulate for 24 hours averaging time and dust emission rate is calculated for an averaging
time of 30 minutes, I used a scaling factor equal to 0,4, linking these emissions 4. Thus, I
considered the particulate emission rate of 33.6 x 0.4: 3.6 = 3.73 mg / s.
Running SCREEN calculation software, under the condition of the considered
evacuation stack (H = 6.1 m - considering the pollutant plume height, L = 0.3 m, Hreceptor = 1.5
m - height of breath), stable atmosphere D class (without atmospheric turbulences generating
the dispersion of pollutants on a large area, with lower values at various points than in the case
of unstable atmosphere), location in rural area, I obtained the maximum value of particulate
immission 14.3 μg/m3, at 78 m distance from the stack base (compliance with O.M. no.
592/2002, which provides a limit of 50 μg / m3) as shown in the listing below:
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
pulberi
SIMPLE TERRAIN INPUTS:
SOURCE TYPE = POINT
EMISSION RATE (G/S) = .3700E-02
SOURCE HEIGHT (M) = 6.10
LENGTH OF SIDE (M) = .30
RECEPTOR HEIGHT (M) = 1.50
2 www.epa.gov/Emissions Factors & AP 42, Compilation of Air Pollutant Emission Factors
3 O. M. Nr. 592/2002 pentru aprobarea Normativului privind stabilirea valorilor limită, a valorilor de prag şi a criteriilor
şi metodelor de evaluare a dioxidului de sulf, dioxidului de azot şi oxizilor de azot, pulberilor în suspensie (PM10 şi
PM2,5), plumbului, benzenului, monoxidului de carbon şi ozonului în aerul înconjurător. ( Ministerial Order No. 592/
2002 for the approval of the Normative regarding limit values, threshold values, criteria and evaluation methods of
sulfur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter in suspension (PM10 and PM2.5), lead,
benzene, carbon monoxide and ozone in ambient air).
4 www.wikipedia.org/w/index.php?title=Flue_gas_stacks
IOPT (1=URB,2=RUR) = 2
BUOY. FLUX = .00 M**4/S**3; MOM. FLUX = .00 M**4/S**2.
*** STABILITY CLASS 4 ONLY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
**********************************
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
------- ---------- ---- ----- ----- ------ ------ ------ ------ ----
20. .8793E-01 4 1.0 1.0 320.0 6.1 1.9 1.1 NO
100. 13.46 4 1.0 1.0 320.0 6.1 8.2 4.7 NO
MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 20. M:
78. 14.35 4 1.0 1.0 320.0 6.1 6.6 3.8 NO
In order to achieve a 2D dispersion curve (planar iso-concentration curves), whereas
SCREEN 3.0 software does not have this option, I used the facilities of MATHCAD 7.0 software,
as follows:
- I covered an area of 320 x 320 m around the stack base with a grid of 40 m step,
obtaining a matrix whose elements are plotted as concentration values at different distances
from the stack;
- Using the discrete distance option of SCREEN software, I calculated the particulate
concentrations at considered distances around the stack.
The considered matrix and the dispersion curves are plotted in Figure 2.
Fig.2. Dispersion curves for a single stack and the matrix to obtain them
In order to estimate particulate immissions produced by a single kiln operating, I
overlapped the considered dispersion curves over the map area, obtaining the representation
shown in Figure 3.
Fig.3. Particulate dispersion produced by a single kiln operating
As about cumulating the immissions of all five kiln sources, I regarded a grid to fill the
entire surface area, with 50 m step. I obtained a [8 x 6] matrix whose elements were calculated
by summing in every considered point, the concentration values produced by each of the
emission sources. The cumulative immission matrix leads, using MATHCAD software, to the
cumulative iso - concentration curves; by overlapping them over the map area, I have achieved
the representation shown in Figure 4. In order to overlay the graphic elements, I also used
PAINT graphic software facilities.
It can be observed that, in the case of all five simultaneous tile kilns operation,
concentrations exceed on a significant area, which includes the five kilns, the limit value of 50
μg/m3 required by O.M. 592/2002.
Fig.4. Cumulative dispersion in the case of simultaneous operation of all kilns
3. Conclusions
The presented case study highlights the importance of cumulating effects of the pollution
produced by several sources. The cumulative effect has been also revealed by dust
measurements made by different environment companies in the studied area. For the issuance
of the environmental license, estimations are usually made for the separate operation of a
pollution source, without taking especially into account the cumulative effects with other nearby
sources. That is the reason why, in the places with clusters of tile kilns from Domneşti, Argeş
Regional Environmental Protection Agency imposed a program for their alternating operation.
References
1. U.S. ENVIRONMENTAL PROTECTION AGENCY, Office of Air and Radiation, Office of Air
Quality Planning and Standards 1991, SCREEN Model User's Guide
2. Beychok, Milton R. (2005). Fundamentals Of Stack Gas Dispersion (4th Edition ed.). author-
published
3. www.epa.gov/Emissions Factors & AP 42, Compilation of Air Pollutant Emission Factors
4. Ordinul 135/2010 privind aprobarea Metodologiei de aplicare a evaluării impactului asupra
mediului pentru proiecte publice şi private emis de Ministerul Mediului şi Pădurilor, Ministerul Agriculturii
şi Dezvoltării Rurale, Ministerul Administraţiei şi Internelor, Ministerul Dezvoltării Regionale şi Turismului
şi publicat în Monitorul Oficial 274 din 27 aprilie 2010.
5. http://www.epa.gov/air/airpollutants.html
6. BREF: Draft reference document on best available techniques in the ceramic manufacturing
industry, june 2005, European Comission
7. *** S.C. TEMPUS EDIT S.R.L. Piteşti, Environmental Assessement Studies, Environmental
Audits for clay plates production in Domneşti area.