Major Health Gains Identified
Researchers at IIT Delhi have published findings indicating that India could significantly reduce annual fatalities by controlling sulphur dioxide (SO2)
discharged from coal-fired power plants (CFPPs). This comprehensive study, which has been featured in the journal Nature, is among the first to thoroughly investigate the dual role of SO2: not only does it directly impact ambient SO2 concentrations, but it also plays a crucial part in the atmospheric creation of secondary fine particulate matter, known as PM2.5. The study projects that by completely eliminating SO2 emissions from these power sources, an astonishing 1,24,564 lives could be saved each year. This reduction in emissions is expected to lead to a measurable decrease in average PM2.5 exposure, potentially ranging from 0.3 to 12 microgrammes per cubic metre, and a drop in ambient SO2 levels across various states by 0.1 to 13.6 parts per billion. These improvements are vital for public health, given the established links between PM2.5 and serious conditions like cardiovascular and respiratory diseases.
SO2's Role in Air Pollution
Sulphur dioxide (SO2) released from coal power plants undergoes chemical transformations in the atmosphere, leading to the formation of secondary inorganic aerosols. These include sulphates, nitrates, and ammonium, which then aggregate and contribute to the fine particulate matter (PM2.5) that poses a significant threat to human health. Debajit Sarkar from IIT Delhi, a co-author of the study, explained that extensive source apportionment studies have consistently identified the energy sector, alongside the household sector, as a primary contributor to India's air pollution crisis. The researchers aimed to precisely quantify the impact of CFPPs to enable targeted policy-making at the state level. Utilizing advanced air pollution models, satellite data on SO2 emissions, and the Global Burden of Disease framework, they were able to estimate the number of deaths preventable by mitigating these emissions, considering various age groups and sexes. The study further cross-referenced air quality data with the National Family Health Survey-5 to understand how these health benefits would be distributed across different demographic groups, including gender, caste, and income strata.
Disparities in Health Benefits
The IIT Delhi study projects substantial public health dividends from a complete cessation of SO2 emissions from coal power plants. Annually, an estimated 14,777 cardiovascular deaths and 8,476 respiratory deaths could be averted, in addition to the overall reduction in all-cause mortality. However, the impact of these improvements is not uniform across the country. States like Maharashtra, Tamil Nadu, and Karnataka are expected to witness the highest number of avoidable deaths, largely due to their high population density and significant exposure to pollution. Conversely, Chhattisgarh and Odisha are poised for the most dramatic enhancements in air quality, owing to the presence of numerous coal-power-driven pollution hotspots within their borders. Furthermore, the study highlights significant disparities in the distribution of these health benefits. Vulnerable populations, including those belonging to Other Backward Classes, Scheduled Castes, and Scheduled Tribes, as well as individuals from lower and middle-income households, are anticipated to experience greater improvements in air quality compared to wealthier segments of society and general category groups. This uneven distribution underscores that SO2 mitigation is not merely an air quality concern but also a pressing issue of environmental justice and equity.
Policy, Technology, and Equity
The study's findings are particularly relevant amidst ongoing discussions regarding the installation of flue gas desulphurisation (FGD) systems in coal-fired power plants. FGD technology effectively removes SO2 from exhaust gases, thereby mitigating acid rain and reducing air pollution. A key argument against the widespread adoption of FGD in India has centered on the perception that Indian coal contains relatively low sulfur content, making the technology economically unviable. However, the IIT Delhi research strongly suggests that the monetary gains derived from improved public health and reduced mortality are likely to surpass the costs associated with implementing emission control technologies. Manoj Kumar, a researcher at the Centre for Research on Energy and Clean Air, emphasized the significance of these findings, noting that earlier estimations had not fully captured the SO2-related health consequences. He also pointed out that these insights were not adequately considered during the previous reversals of the 2015 emission norms for thermal plants. The study's attention to the health impacts on marginalized communities and the geographical distribution of benefits further amplifies its importance. While SO2 emissions from coal power plants have decreased globally, India has seen an increase, with emissions rising from 2.36 thousand kilotonnes in 2005 to 5.05 thousand kilotonnes in 2021, and further by approximately 30% in 2023. The study advocates for stringent enforcement of SO2 emission regulations, broader implementation of FGD and other pollution control technologies, and a focus on high-pollution areas, alongside promoting cleaner fuels and reducing agricultural burning.
