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a Average annual SO2 column mass density as analysed from MERRA–2 (1980–2020), overlaid with the location of thermal power plants with their installed capacity over Indian regions. b SO2 surface mass concentration derived from MERRA–2 and CPCB measurements (Circle) from 2013 to 2020. c SO2 column mass density as analysed from MERRA–2 (2003–2020) overlaid with the location of steel and refinery Industries. d SO2 column mass density as analysed from CAMS (2003–2020) overlaid with the location of cement plants. The specific areas marked in the India maps are considered for regional analysis as discussed in the text (e.g. CI is Central India)
Source publication
India relies heavily on coal-based thermal power plants to meet its energy demands. Sulphur dioxide (SO2) emitted from these plants and industries is a major air pollutant. Analysis of spatial and temporal changes in SO2 using accurate and continuous
observations is required to formulate mitigation strategies to curb the increasing air pollution in...
Citations
... The IGP region and its surrounding areas are hotspots for sulfur dioxide (SO 2 ) emissions, mainly due to the presence of multiple thermal power plants, construction industries, and petroleum refineries. These sources contribute to the region's SO 2 and nitrogen oxide (NO x ) levels (Guttikunda and Jawahar, 2014;Kuttippurath et al., 2022). Furthermore, a previous study conducted at the MCOH found that dimethyl sulfide (DMS) accounts for only up to 3 % of nss-SO 2− 4 in polluted air (Granat et al., 2010). ...
Atmospheric aerosols strongly influence the global climate through their light absorption properties (e.g., black carbon (BC) and brown carbon (BrC)) and scattering properties (e.g., sulfate). This study presents simultaneous measurements of ambient-aerosol light absorption properties and chemical composition obtained at three large-footprint southern Asian receptor sites during the South Asian Pollution Experiment (SAPOEX) from December 2017 to March 2018. The BC mass absorption cross section (BC-MAC678) values increased from 3.5 ± 1.3 at the Bangladesh Climate Observatory at Bhola (BCOB), located at the exit outflow of the Indo-Gangetic Plain, to 6.4 ± 1.3 at two regional receptor observatories, the Maldives Climate Observatory at Hanimaadhoo (MCOH) and the Maldives Climate Observatory at Gan (MCOG), representing an increase of 80 %. This likely reflects a scavenging fractionation, resulting in a population of finer BC with higher MAC678 that has greater longevity. At the same time, BrC-MAC365 decreased by a factor of 3 from the Indo-Gangetic Plain (IGP) exit to the equatorial Indian Ocean, likely due to photochemical bleaching of organic chromophores. The high chlorine-to-sodium ratio at the BCOB, located near the source region, suggests a significant contribution of chorine from anthropogenic activities. Particulate Cl⁻ has the potential to be converted into Cl radicals, which can affect the oxidation capacity of polluted air. Moreover, Cl⁻ is shown to be nearly fully consumed during long-range transport. The results of this synoptic study, conducted on a large southern Asian scale, provide rare observational constraints on the optical properties of ambient BC (and BrC) aerosols over regional scales, away from emission sources. They also contribute significantly to understanding the aging effect of the optical and chemical properties of aerosols as pollution from the Indo-Gangetic Plain disperses over the tropical ocean.
... There are many sources of atmospheric SO₂ varying from natural to anthropogenic. Emissions from coal-based thermal power plants, refineries and fossil fuel burning are the typical examples of human driven SO₂ pollution [4,5]. On the other hand, emissions from volcanic activities and biomass burning are the natural sources. ...
... For example, SO₂ emissions in China have declined significantly since 2013 due to the Air Pollution Prevention and Control Action Plan [9]. Similarly, SO₂ pollution in India has declined in the past decade due to the implementation of control technology and environmental regulations [5]. As there were no strategic plan to curb air pollution, SO₂ pollution has shown rising trends in many other developing countries in the past decades; indicating also the growth of electricity demand there [8,10,11]. ...
... For instance, there are various point sources in Russia, South America, North America, Southeast Asia and Australia, and some are shown in Fig. 1. Both human-made factors, including industrial processes, and natural events such as biomass burning, wildfires and volcanic activity collectively contribute to the release of SO₂ in these hotspots [5,39,40]. The highest amount of SO₂ is in EC, about >10 mg/m 3 . ...
Sulphur dioxide (SO2) is a hazardous air pollutant, which is mostly emitted from burning of fossil fuels, and has an adverse impact on the human health and ecosystem functioning. The COVID-19 natural anthropause (lockdown) provides a great opportunity to understand the changes in SO2 pollution across the globe, as there was a temporary standstill for most human activities. Therefore, we analyse the changes in global SO₂ pollution during lockdown compared to pre-lockdown and identify its hotspots driven by human activities using satellite measurements, reanalysis data and emission inventory. We observe a decline in SO₂ pollution of about 2.21 % in its global average, −21.05 % in Indo-Gangatic Plain, −16 % in East China, −7.67 % in East United States of America, −3.99 % in Western Europe and −3.85 % in Middle East owing to the halt in human activities such as industrial and transport operations, as found from the emissions inventory. There are point and aerial hotspots of SO₂ pollution across the globe (e.g. cities or industrial units), which also show a decrease (20–30 %) in SO₂ pollution during the anthropause. Fossil fuel burning in thermal power plants is a major source of SO2 pollution, and it has declined notably (1–12 %) during the lockdown in the major coal consuming countries such as the United States, China, Japan, Canada, Brazil, Australia, France, Germany, Spain, Italy and the United Kingdom. Therefore, lockdown provides a clear understanding of global human-driven hotspots of SO₂ pollution and their changes, which would help us to make better and effective air pollution mitigation strategies.
... There have been profound changes regarding global anthropogenic SO2 emissions in the past decades. Specifically, 50 global SO2 emissions have decreased by 31% between 1990-2015 due to the mitigation efforts in Europe and the USA, which have reduced regional SO2 emissions, while East Asia witnessed a 70% increase in 1990-2005, followed by a decreasing trend thereafter (Kuttippurath et al., 2022). Contrary to the declining trend in China (Klimont et al., 2013;Li et al., 2017b;Zheng et al., 2018;van der A et al., 2017;Qu et al., 2019), Indian emissions have surged from 4.5 to 15.0 TgS per year between 1990 and 2015 (Crippa et al., 2018;Aas et al., 2019), after 55 which India became the world's largest emitter of anthropogenic SO2. ...
The rapid development of the economy and the implementation of environmental policies adapted in India has led to fast changes of regional SO2 emissions. We present a monthly SO2 emission inventory for India covering December 2018 to November 2023 based on the TROPOMI Level-2 COBRA SO2 dataset, by using an improved flux-divergence method and estimated local SO2 lifetime which includes both its chemical loss and dry deposition. We update the methodology to use the daily CAMS model output estimates of the hydroxyl-radical distribution as well as the measured dry deposition velocity to account for the variability in the tropospheric SO2 lifetime. The results show the application of the local SO2 lifetime improves the accuracy of SO2 emissions estimation when compared to calculations using a constant lifetime. Our improved flux-divergence method reduced the spreading of the point source emissions compared to the standard flux-divergence method. The averaged SO2 emissions covering the recent 5 years are about 5.2 Tg year-1, which is lower than the bottom-up emissions of 11.0 Tg year-1 from CAMS-GLOB-ANT v5.3. The total emissions from the 92 largest point source emissions are estimated to be 2.9 Tg year-1, lower than the estimation of 5.2 Tg year-1 from the global SO2 catalog MSAQSO2LV4. We argue that for other important regions that have high SO2 emissions, the variability in the SO2 lifetime becomes more important to account for estimating top-down SO2 emissions.
... The annual average values of columnar NO 2 estimated from OMI for the entire Indian region varied from a maximum value of about 12.3 × 10 15 molecules/cm 2 to a minimum value of 8 × 10 13 molecules/cm 2 with an average value of 1.54 × 10 15 molecules/cm 2 (Singh et al., 2023). The northeastern parts of Hyd and the eastern belt of India comprise the majority of coal-powered power plants (Kuttippurath et al., 2022;Chutia et al., 2022) and contribute largely to the regional pollutant loading depending on the airmass (Sinha et al., 2012). The autumn time enhancement in SO 2 over the study region is due to the northeasterly airmass (Fig. 2) within the PBL and above PBL which traverses through the polluted IGP and regions where many power plants are located. ...
India is experiencing a rapid urban growth in recent decades modifying the regional air quality around urban agglomerations. Hyderabad, the capital city of Telangana state in India, has been experiencing significant urbanization of about 17 % growth in urban agglomeration over the past two decades. We investigated the long-term pollution characteristics along with the meteorology in and around Hyderabad (300 km × 300 km) using satellite-based remote sensing, and reanalysis data. Columnar aerosol loading was highest during the Spring while the positive trend was more during the Winter. The northeastern and southeastern parts of the study domain experienced higher aerosol loading. A significant increasing linear trend in AOD and PM 2.5 is observed over the urban region as well as the northern and eastern parts. The NO 2 and SO 2 columnar concentrations showed considerable enhancement over the northeast sub-region where numerous thermal power plants are located, and over the urban centre. The SO 2 concentration and SSA values were higher during the Autumn, while the NO 2 values peaked along with lower SSA values during the Spring. The observed spatio-temporal features in air pollutants are further investigated using rainfall information, transport pathways, vegetation index, and fire events. Higher surface temperature and the polluted northeasterlies caused the comparative enhancement of NO 2 concentration during Spring. The investigation on the NDVI and the fire events in different sub-regions points to the possibility of enhanced human settlement, and thereby the associated anthropogenic activities are notable over the West and South parts of Hyderabad. However, the presence of thermal power plants in the northeast and natural gas plants along the coast act as persistent regional sources for aerosols and pollutant gases irrespective of the wet removal.
... The annual average values of columnar NO 2 estimated from OMI for the entire Indian region varied from a maximum value of about 12.3 × 10 15 molecules/cm 2 to a minimum value of 8 × 10 13 molecules/cm 2 with an average value of 1.54 × 10 15 molecules/cm 2 (Singh et al., 2023). The northeastern parts of Hyd and the eastern belt of India comprise the majority of coal-powered power plants (Kuttippurath et al., 2022;Chutia et al., 2022) and contribute largely to the regional pollutant loading depending on the airmass (Sinha et al., 2012). The autumn time enhancement in SO 2 over the study region is due to the northeasterly airmass (Fig. 2) within the PBL and above PBL which traverses through the polluted IGP and regions where many power plants are located. ...
India is experiencing a rapid urban growth in recent decades modifying the regional air quality around urban
agglomerations. Hyderabad, the capital city of Telangana state in India, has been experiencing significant urbanization
of about 17 % growth in urban agglomeration over the past two decades. We investigated the longterm
pollution characteristics along with the meteorology in and around Hyderabad (300 km × 300 km) using
satellite-based remote sensing, and reanalysis data. Columnar aerosol loading was highest during the Spring
while the positive trend was more during the Winter. The northeastern and southeastern parts of the study
domain experienced higher aerosol loading. A significant increasing linear trend in AOD and PM2.5 is observed
over the urban region as well as the northern and eastern parts. The NO2 and SO2 columnar concentrations
showed considerable enhancement over the northeast sub-region where numerous thermal power plants are
located, and over the urban centre. The SO2 concentration and SSA values were higher during the Autumn, while
the NO2 values peaked along with lower SSA values during the Spring. The observed spatio-temporal features in
air pollutants are further investigated using rainfall information, transport pathways, vegetation index, and fire
events. Higher surface temperature and the polluted northeasterlies caused the comparative enhancement of NO2
concentration during Spring. The investigation on the NDVI and the fire events in different sub-regions points to
the possibility of enhanced human settlement, and thereby the associated anthropogenic activities are notable
over the West and South parts of Hyderabad. However, the presence of thermal power plants in the northeast and
natural gas plants along the coast act as persistent regional sources for aerosols and pollutant gases irrespective of
the wet removal.
... FGD gypsum is a waste material generated during desulphurization of flue gas in thermal power plants [46][47][48][49][50][51][52]. It primarily consists of CaSO 4 , it is both technically and economically viable to produce valuable calcium CSW using two methods: the hydrothermal method and the atmospheric acidification method [26], [40]. ...
This paper provides a comprehensive review of calcium sulfate whiskers (CSW), focusing on their synthesis methods, morphological characteristics, and diverse applications across industries. Whiskers, known for their specific length-to-diameter ratio and ordered atomic structure, offer exceptional physical and mechanical properties, making them valuable reinforcements for various materials. Through a bibliometric analysis, a comprehensive overview of the existing research landscape within this field is provided, offering valuable insights into potential future research directions, and identifying promising avenues for further investigation The paper highlights the significance of controlling reaction parameters to achieve high-quality whiskers with desirable morphologies. Furthermore, the crystal symmetry and composition of calcium sulfate whiskers play crucial roles in determining the thermal behavior and performance of CSW. The multifaceted applications of CSW are extensively discussed, ranging from enhancing the mechanical properties of plastics, ceramics, and rubber to improving friction materials, paper production, and environmental filter materials. This review underscores the growing importance of CSW as versatile reinforcements and highlights the need for further research to optimize synthesis techniques and explore novel applications in emerging fields.
... The NO2 emissions from nine thermal power plants near Delhi, India using TROPOMI data are estimated and [6] discusses the necessity for precise bottom-up estimations. The investigations of the effect of SO2 emissions from thermal coal power stations on air pollution in India are provided in [11] and it also suggests using renewable energy sources to reduce SO2 emissions. The paper [12] compares ground-level air pollution measurements from Ukrainian monitoring sites with TROPOMI NO2, CO, HCHO, and SO2 data and shows that TROPOMI can detect highly polluted areas and qualitatively reflect air pollution in Ukraine. ...
... In contrast to Europe and North America, Fig. 2 illustrates the trend of a significant increase in NH 3 concentrations in India from 2011 to 2015, with NH 3 emissions increasing by 13% between 2008 and 2018 [122]. During the period from 2007 to 2016, NO x emissions increased by over 50% [123], while SO 2 exhibited a slight decreasing trend from 2010 to 2020 [124]. Consequently, the current increase in NH 3 concentration in India is still influenced by rising emissions. ...
Purpose of Review
As the most abundant alkaline trace gas in the atmosphere, NH3 plays a critical role in the formation of atmospheric particulate matter and nitrogen cycling in ecosystems. NH3 emissions have been increasing globally over the past few decades. To provide a clearer understanding of atmospheric NH3, this paper presents a systematic review of the literature on the sources and variability of atmospheric NH3 and describes the contribution of atmospheric NH3 to PM2.5.
Recent Findings
(1) The primary source of atmospheric NH3 emissions is agriculture; other sources include combustion-related emissions and volatilization from soil and oceans. However, recent studies have revealed the major role of nonagricultural sources in urban areas. (2) The spatiotemporal variability of atmospheric NH3 is complex, and its mechanisms are not entirely clear. (3) Atmospheric NH3 can participate in multiple atmospheric chemical processes and to the formation of fine particulate matter.
Summary
This review summarizes the latest knowledge on the sources and variability of atmospheric NH3 and highlights the necessity of controlling atmospheric NH3 emissions. However, significant knowledge gaps still exist in understanding the sources, trends, and effects of atmospheric NH3. Therefore, further research is essential to investigate the influencing factors and environmental effects of atmospheric NH3 concentrations, providing a scientific basis for the development of effective NH3 control strategies.
... One exception was SO4 2-. The high concentration 190 of SO4 2and NH4 + at MCOH is mainly from the central and east parts of India and IGP, as these are hotspots of SO2 since these regions house a cluster of thermal power plants, construction industries, and petroleum refineries as a primary source of SO2 (Guttikunda et al., 2014;Kuttippurath et al., 2022). The IGP is a hotspot of high anthropogenic aerosol loading due to intense agriculture crop residue burning, biomass burning, open waste burning, industries, and high urban activities (Dasari et al., 2020;Ansari and Ramachandran, 2023). ...
Atmospheric aerosols strongly influence the global climate by their light absorption (e.g., black carbon, BC, brown carbon, BrC) and scattering (e.g., sulfate) properties. This study presents simultaneous measurements of ambient aerosol light absorption properties and chemical composition from three large-footprint South Asian receptor sites during the South Asian Pollution Experiment (SAPOEX) in December-March 2018. The BC mass absorption cross-section (BC-MAC678) values increased from 3.5 ± 1.3 at the Bhola Climate Observatory-Bangladesh (i.e., located at exit outflow of Indo-Gangetic Plain) to 6.4 ± 1.3 at the two regional receptor observatories at Maldives Climate Observatory-Hanimaadhoo (MCOH) and Maldives Climate Observatory-Gan (MCOG). This likely reflects a coating-enhancement effect due to ageing of the aerosols during long-range transport. At the same time, the BrC-MAC365 decreased by a factor of three from the IGP exit to the equatorial Indian Ocean, likely due to photochemical bleaching of organic chromophores. The high chlorine-to-sodium ratio at the near-source-region BCOB suggests a significant contribution of chorine from anthropogenic activities. This particulate Cl- has the potential to convert into Cl-radicals that can affect the oxidation capacity of the polluted air. Moreover, Cl- is shown to be near-fully consumed during the long-range transport. The results of this synoptic study over the large South Asian scale have significance for understanding the ageing effect of the optical and chemical properties of aerosols as the pollution from the Indo-Gangetic Plain disperses over regional scales.
... This study finds that environmental regulations can reduce emissions, consistent with previous research [3][4][5]. Vikas et al. observed a significant dec 2 SO emission in India from 2010 to 2020, attributing this improvement to the im tation of stringent environmental regulations [46]. Teng Wang et al. [28] also fou environmental regulation had a significant negative effect on air pollution and th cient was −0.123 based on panel data of 248 Chinese cities from 2003 to 2016. ...
... This study finds that environmental regulations can reduce emissions, which is consistent with previous research [3][4][5]. Vikas et al. observed a significant decrease in SO 2 emission in India from 2010 to 2020, attributing this improvement to the implementation of stringent environmental regulations [46]. Teng Wang et al. [28] also found that environmental regulation had a significant negative effect on air pollution and the coefficient was −0.123 based on panel data of 248 Chinese cities from 2003 to 2016. ...
Air pollution is an important factor affecting human health and daily life. The Chinese government is making vigorous efforts to control air pollution. The upgrading of the industrial structure is a problem-solving tool in the environment and economic growth cases. This paper aims to explore the relationships among environmental regulation, the upgrading of the industrial structure and air pollution. The PVAR (Panel Vector Auto Regression) model and moderating effect model are used to conduct empirical analysis based on panel data of 30 provinces in China from 2004 to 2020. The analysis of the results provides the following findings. Firstly, environmental regulations can significantly reduce emissions, but the deterioration of air quality does not have a significant impact on the improvement of environmental regulations. Secondly, industrial structure upgrading can reduce air pollution, but the worsening of the air quality will hinder the upgrading of industrial structures. Thirdly, environmental regulation can promote industrial structure upgrading. Lastly, industrial structure upgrading is a moderating variable and can positively moderate the impact of environmental regulations on air pollution.
