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Indonesian active volcanoes The distribution of the 126 active volcanoes across the archipelago of Indonesia, including 120 aerial and six known submarine edifices (not shown on the map). 77 are classified as Type-A (red triangles), 29 as type-B (yellow squares) and 20 as type-C (green circles) The volcanoes visited in this work are highlighted in red-bold-italic.
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Indonesia hosts the largest number of active volcanoes, several of which are renowned for climate-changing historical eruptions. This pedigree might suggest a substantial fraction of global volcanic sulfur emissions from Indonesia and are intrinsically driven by sulfur-rich magmas. However, a paucity of observations has hampered evaluation of these...
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... Any chemical, physical, or biological material that modifies the intrinsic characteristics of the atmosphere is considered an air pollutant [4]. One of the major atmospheric pollutants is sulphur dioxide (SO 2 ), emitted from the combustion of sulphur-containing fuels [5,6], and from volcanic activities [7]. Other pollutants that may also be of environmental concern include particulate matter (PM) and volatile organic compounds (VOCs) [8]. ...
Air pollution control is a safe method for achieving a sustainable environment and can be accomplished by adequately monitoring pollutants that pose significant environmental risks. The combustion of sulfur-containing petroleum products has been a major concern for several decades. Therefore, this study was aimed at determining sulfur levels in refined petroleum products such as Premium Motor Spirit (PMS), Automotive Gas Oil (AGO), and Dual-Purpose Kerosene (DPK). It also investigated the air quality implications of sulfur levels and estimated the contribution of the refinery’s products to sulfur dioxide air emission. Fuel samples were collected from the Warri Refining and Petrochemical Company (WRPC) in Nigeria and analyzed using Ultraviolet-visible spectrophotometer (UV-Vis) and Energy-Dispersive X-ray Fluorescence (EDXRF). Sulfur levels were determined at 425 nm wavelength, and sulfur dioxide air emission were estimated for seven consecutive years from 2010 to 2016 using the emission factor approach. The densities of PMS, AGO, and DPK were 0.77 kg/l, 0.832 kg/l, and 0.82 kg/l respectively. The levels of sulfur in PMS, AGO, and DPK were 2.007 x 10<sup>-4</sup> %, 6.970 x 10<sup>-5</sup> wt%, and 4.233 x 10<sup>-5</sup> wt% respectively from UV-Vis technique and 0.016, 0.087 and 0.029% respectively for EDXRF technique were found below the sulfur limit of 0.015 %, 0.005 % and 0.015 % for PMS, AGO and DPK respectively specified by Standard Organization of Nigeria (SON) specifications of 0.1, 0.5 and 0.15wt% for PMS, AGO and DPK respectively. The annual sulfur dioxide emissions were obtained for seven consecutive years from 2010 to 2016. The results from UV-VIS were observed to have the highest SO<sub>2</sub> emission of 0.1718 tons for PMS in 2011, 0.2593 tons in 2010 for AGO, and 0.0974 tons for DPK in 2010, while the lowest emission was observed to be 0.029 tons for PMS in 2015, 0.0362 tons in 2015 for AGO and 0.0181 tons for DPK also in 2015. The results from EDXRF technique were observed to have the highest SO<sub>2</sub> emission of 13.6939 tons for PMS in 2012, 323.6881 tons for AGO in 2010, and 66.7147 tons for DPK also in 2010, while the lowest emissions for PMS, AGO and DPK were all observed in 2015 to be 2.3122, 45.1872, and 12.4182 tons respectively. The study concluded that the refinery complied with the set requirements.
... One of the major pollutants in the atmosphere is Sulfur Dioxide (SO 2 ). The sources of atmospheric SO 2 can be anthropogenic and natural activities such as fuel combustion (Akimoto & Narita, 1994) and volcanic activities (Bani et al., 2022). In general, the formation of SO 2 in the combustion process follows the following reaction: S (s) + O2 (g) → SO2 (g) (1) ...
Various techniques to measure SO2 concentration based on Differential Optical Absorption Spectroscopy (DOAS) have been widely developed and applied for various measurements. However, most of the applications are still relatively expensive. Some efforts have been made to reduce the cost by using Ultraviolet Light Emitting Diodes (LEDs) as light sources, showing promising results. Further reductions can be possibly made by providing an alternative to replace high spectral resolution spectrometers widely used in DOAS applications since those spectrometers are commercially expensive. This paper studies the feasibility of a DOAS instrument using a low-cost spectrometer and UV-LEDs as light sources. The resolution of the spectrometer is 0.7 nm. With this resolution, it is expected that the instrument hardly captures narrow band structures of SO2 optical absorption in the spectral range between 280 nm and 320 nm when measuring SO2 gas concentration lower than the limits of SO2 emissions regulated by the Indonesian government. To compensate for this drawback, narrow and broad bands of optical absorption structures are considered in the data analysis to achieve a detection limit far below the regulated limits. To capture the broadband structures, four UV-LEDs are used to cover spectral absorption from 250 nm to 320 nm. The instrument was calibrated using eight different standard concentrations of SO2. The correlation between the readings and the standard concentrations is high, indicated by the Pearson correlation coefficient of 0.9999. It was also found that the lowest concentration the instrument can distinguish from blank samples or the Limit of Detection is 16 ppm. However, the instrument can precisely measure concentrations higher than or equal to 25 ppm with a standard deviation of less than 10% of the mean concentration measured from five measurements. This is far below the required legal limits, below 229 ppm. After the calibration, the DOAS instrument was used to measure SO2 sampled from the emission of burning coals. To compare, a commercial SO2 sensor was used to measure the same gas. The results indicate that the difference in the readings between the two instruments is around 6% of the concentration.
... Orellano et al. [16] have shown that SO 2 has a negative effect on mortality even at low concentrations. The emission of plumes with high SO 2 concentrations, resulting from processes such as coal and fuel combustions and sulfide oxide refining, is a characteristic of industrial areas [18,19], and the burning of biomass and volcanic eruptions are natural sources of SO 2 (e.g., [20]). Anthropogenic sources of SO 2 also include ship emissions (e.g., [21][22][23]). ...
The main goal of this paper is to study pollution during sea breeze days in the Split town center, which is placed near the industrial area with three cement plants and one asbestos cement plant, as well as a harbor with high traffic, and investigate the sources of pollution with SO2 and its relation to atmospheric parameters using stepwise multiple linear regression (MLR). The hourly temperature difference from the time of the sea breeze lull (dT) was considered in evaluating the influence of meteorological parameters on hourly pollutant concentrations. It was found that the wind direction index (WDI) is a significant predictor for the sea breeze, and wind speed, relative humidity, and dT are significant for the land breeze. A very high index of agreement of 0.9 was obtained by the MLR model for the land breeze, and 0.8 for the sea breeze. Low SO2 concentrations are observed at night, and increased values are found between 0800 and 1800 UTC. With WDI being the only predictor during sea breeze, local traffic is found to be the main anthropogenic source of SO2 pollution.
... The eruption at Sinabung continues at the time of writing (June 2022) despite a deflationary trend identified in 2014 that has continued through at least 2016 (Hotta et al., 2019), though the eruption has recently transitioned to predominantly effusive in nature. Based on sulfur dioxide (SO 2 ) emissions, Sinabung ranked among the three most active degassing volcanoes in Indonesia in the 2010-2019 period (Bani et al., 2022). ...
Dome-building volcanic eruptions are often associated with frequent Vulcanian explosions, which constitute a substantial threat to proximal communities. One proposed mechanism driving such explosions is the sealing of the shallow volcanic system followed by pressurization due to gas accumulation beneath the seal. We investigate this hypothesis at Sinabung Volcano (Sumatra, Indonesia), which has been in a state of eruption since August 2010. In 2013, the volcano began erupting a lava dome and lava flow, and frequent explosions produced eruptive columns that rose many kilometers into the atmosphere and at times sent pyroclastic density currents down the southeast flanks. A network of scanning Differential Optical Absorption Spectrometers (DOAS) was installed on the volcano’s eastern flank in 2016 to continuously monitor SO2 emission rates during daytime hours. Analysis of the DOAS data from October 2016 to September 2017 revealed that passive SO2 emissions were generally lower in the 5 days leading up to explosive events (∼100 t/d) than was common in 5-day periods leading up to days on which no explosions occurred (∼200 t/d). The variability of passive SO2 emissions, expressed as the standard deviation, also took on a slightly wider range of values before days with explosions (0–103 t/d at 1-sigma) than before days without explosions (43–117 t/d). These observations are consistent with the aforementioned seal-failure model, where the sealing of the volcanic conduit blocks gas emissions and leads to pressurization and potential Vulcanian explosions. We develop a forecasting methodology that allows calculation of a relative daily explosion probability based solely on measurements of the SO2 emission rate in the preceding days. We then calculate forecast explosion probabilities for the remaining SO2 emissions dataset (October 2017—September 2021). While the absolute accuracy of forecast explosion probabilities is variable, the method can inform the probability of an explosion occurring relative to that on other days in each test period. This information can be used operationally by volcano observatories to assess relative risk. The SO2 emissions-based forecasting method is likely applicable to other open vent volcanoes experiencing dome-forming eruptions.
The La Palma 2021 volcanic eruption was the first subaerial eruption in a 50-year period in the Canary Islands (Spain), emitting ~1.8 Tg of sulphur dioxide (SO2) into the troposphere over nearly 3 months (19 September-13 December 2021), exceeding the total anthropogenic SO2 emitted from the 27 European Union countries in 2019. We conducted a comprehensive evaluation of the impact of the 2021 volcanic eruption on air quality (SO2, PM10 and PM2.5 concentrations) utilising a multidisciplinary approach, combining ground and satellite-based measurements with height-resolved aerosol and meteorological information. High concentrations of SO2, PM10 and PM2.5 were observed in La Palma (hourly mean SO2 up to ~2600 μg m-3 and also sporadically at ~140 km distance on the island of Tenerife (> 7700 μg m-3) in the free troposphere. PM10 and PM2.5 daily mean concentrations in La Palma peaked at ~380 and 60 μg m-3. Volcanic aerosols and desert dust both impacted the lower troposphere in a similar height range (~ 0-6 km) during the eruption, providing a unique opportunity to study the combined effect of both natural phenomena. The impact of the 2021 volcanic eruption on SO2 and PM concentrations was strongly influenced by the magnitude of the volcanic emissions, the injection height, the vertical stratification of the atmosphere and its seasonal dynamics. Mean daily SO2 concentrations increased during the eruption, from 38 μg m-3 (Phase I) to 92 μg m-3 (Phase II), showing an opposite temporal trend to mean daily SO2 emissions, which decreased from 34 kt (Phase I) to 7 kt (Phase II). The results of this study are relevant for emergency preparedness in all international areas at risk of volcanic eruptions; a multidisciplinary approach is key to understand the processes by which volcanic eruptions affect air quality and to mitigate and minimise impacts on the population.
Many crustal magmatic reservoirs are fundamentally powered by basalt injection at their base. Asides from transfer of silicate liquid and crystals and accompanying heat, basaltic magma also provides large amounts of fluids to the overlying magma. This work explores how water activity and temperature, hence degree of crystallisation, of magmatic reservoirs are affected by such a mechanism at various levels in the crust. By using recent experimental phase equilibria, thermodynamic relationships between gas and silicate melts, and heat balance, it is shown that, depending on the level of magma storage, diffusive exchange during bubble uprise and stalling may produce either crystallisation or melting of magmas. Long term fluxing of felsic to intermediate magma bodies stored in upper crust by mafic volatiles will generally lead to their near isothermal solidification. Conversely, for bodies stagnating in the mid to deep crust, such a process almost inevitably enhances melting, driving or maintaining magmas beyond the threshold of mobility needed for upward material transfer, unless the percolating fluid is very CO2-rich. Compilation of basaltic melt inclusion data gathered in arc, hot-spot and ridge settings, shows that the two last categories coexist with CO2-rich fluids at high pressures (XH2Ofluid < 0.1), which will almost always enhance crystallisation. In contrast arc basalts record a wide and continuous range of fluid compositions, from dry to almost H2O-saturated conditions, which may either favour (low pressure) or inhibit (high pressure) the crystallisation of felsic reservoirs which they underplate. Crustal growth may thus be in part limited by the difficulty of crystallising deep-seated magma bodies, in particular in arc settings. This pressure controlled effect is related to the contrasted solubilities of H2O and CO2 in silicate melts, and to the much stronger non-ideal behaviour of CO2 relative to H2O as pressure increases. Asides from tectonic and density inversion processes, a thick crust may fundamentally reflect the fact that basalt underplating in the lower crust has proceeded at a rate sufficiently slow so as to prevent remelting of earlier intrusions (or melting of lower crust lithologies) or that the outcoming fluid was CO2-rich, or both. Application to other terrestrial planets is hindered by the paucity of data regarding crust thickness and composition, and it can be only conjectured that the thin crust of large planets (Earth, Venus) reflects in part the operation of subduction process during their evolution, while the comparatively thicker crust inferred for smaller bodies (Mars, the Moon, Vesta) reflects in turn processes related to a primordial crust.
