Chennai: A study led by the Indian Institute of Technology Madras (IIT Madras) revealed how atmospheric conversion of gaseous emissions from power plants that are rich in sulphate contributes to an elevated mass load of aerosols, have a high cloud forming potential within the atmosphere.
The study was conducted to provide important scientific insights for framing the policies related to controlling the PM2.5 and to reduce particulate pollution originating from traffic and various industrial sources.
The group of 27 researchers from 17 distinct institutions across eight countries delved into the impact of emissions from the Neyveli coal-fired power plant located about 200 km south of Chennai, Tamil Nadu, on aerosol growth and cloud-forming properties during the COVID-19-induced lockdown.
Prof. Sachin S. Gunthe Coordinator, Centre for Atmospheric and Climate Sciences at IIT Madras, who led the research, “These findings have important implications for assessing the climate impacts of anthropogenic aerosols and highlight the need for comprehensive emission control measures.”
“Our study provides a rare opportunity to examine the sensitivity of cloud-forming aerosol particles to new particle formation and growth due to SO2 emissions from a coal-fired power plant under relatively cleaner conditions. Implications for Regional Air Pollution” he added.
Speaking about this research, Prof. Sachin S. Gunthe further added that, “This study’s outcomes imply that the existing strategies aimed at reducing PM2.5 levels from traffic and industries in India’s polluted coastal clusters need thorough revaluation.”
The study found that the conversion of gaseous sulfur dioxide (SO2) emissions from power plants into particulate matter contributes to an elevated mass load of aerosols rich in sulfates with high cloud-forming potential within the atmosphere.
These findings are of immense importance to climate modellers as they establish a baseline for comparison against the typically prevalent conditions in heavily polluted coastal Indian cities.
Role of atmospheric aerosol particles:
They are essential for cloud formation, ensuring the availability of freshwater to sustain life on Earth.
They also interact with incoming solar radiation, significantly impacting the planet’s radiative budget.
During the lockdown, as anthropogenic emissions, such as traffic and industries, significantly decreased, the researchers observed a drastic reduction in the overall aerosol burden over the study region.
This provided a unique opportunity to isolate the impact of specific emission sources, mainly from the power plant, which continued operation during the lockdown, to understand the underlying processes of aerosol formation and its impact on cloud formation and climate.
Implementing aggressive measures to reduce particulate pollution originating from traffic and various industrial sources within coastal regions such as Chennai might lead to outcomes that work against the intended goals. As a result, there is a pressing need for comprehensive reconsideration and the exploration of alternative strategies to address air pollution at the regional level effectively.
” These endeavours not only contribute to advancing our fundamental comprehension of how aerosol-cloud interactions may shape our climate but also deepen our insights into the regional implications of PM2.5 air pollution,” stated Dr. Shweta Yadav, an aerosol specialist from the Central University of Jammu.
The findings demonstrated that the SO2 plume from the power plant resulted in high particulate sulphate concentrations and subsequent particle growth.
These sulphate-rich particles rapidly grew into the size relevant and required for the cloud formation exhibiting a high ability to uptake water, thus enhancing the cloud-forming potential of the aerosol particles, which is nominally not the case during business-as-usual scenarios.
The researchers successfully demonstrated that when local sources of anthropogenic emissions stop, the SO2 emissions from power plants may amplify the mass of PM2.5 through the formation of new particles, which contradicts common assumptions.
The study emphasized that, therefore, under cleaner conditions with reduced human activities, the availability of low-volatility vapours of specific gases increases the chances of formation and growth of new aerosol particles, as opposed to the business-as-usual scenario where these low-volatile gases may condense on pre-existing aerosol particles resulting from human activities in an urban setup like Chennai.
