High concentrations of fine particulate matter (PM2.5) in India have severe impacts on public health.   While high PM2.5 levels are primarily due to intensive local emissions, they can be further worsened by meteorological patterns known as atmospheric stagnation, which trap pollutants close to the Earth’s surface. Understanding how climate change might influence these stagnation events is crucial, as changes in stagnation will influence  the effectiveness of air quality policies. A recent Princeton study) published in Nature Communications shows that as the climate warms, stagnation events are projected to become more frequent during winter in northern India’s Indo-Gangetic Plain (IGP). This shift is expected to further worsen the already hazardous winter air pollution in the region unless stringent emission controls are implemented. 

Given stagnation is projected to increase during the winter over the IGP, wintertime air pollution controls  will be crucial as the climate warms.  Co-author Denise Mauzerall emphasizes the co-benefits of a clean energy transition in addressing both air pollution and climate change induced increases in pollution levels over the IGP.   

“Reductions of air pollutant emissions resulting from direct controls on emission sources as well as reduced emissions from a clean energy transition will improve air quality while reducing future stagnation occurrences, thus providing additional co-benefits for air quality and health” explains Mauzerall, a faculty member at Princeton’s School of Public and International Affairs and the Department of Civil and Environmental Engineering.