Crop burning pollutes Delhi’s urban air

Abstract

Air pollution spreads not just from urban areas to rural ones. Rural activities can also pollute urban air and result in high economic costs, new studies find. Studying the source of air pollution in New Delhi, researchers found that emissions from burning crop residues or other biomass in rural areas neighboring the city contribute nearly half of the airborne black-carbon particulate matter—soot—in New Delhi during the fall and winter (Nat. Sustainability 2019, DOI: 10.1038/s41893-019-0219-0). The rest of the black-carbon pollution comes from fossil-fuel burning, such as from cars and trucks. The biomass-burning contribution drops to 20% in the summer. Reseachers from Stockholm University and the Indian Institute for Tropical Meteorology conducted the analysis. “No other study has reported high amounts of black carbon from biomass burning in the middle of a megacity where the only source should be traffic,” says August Andersson, one of the researchers from Stockholm University. “The