Dispelling certain myths about factors contributing to the extremely high air pollution levels in Delhi, an IIT Kanpur professor said on Monday that biomass burning and vehicles were the most important sources of PM 2.5 emissions in winter.
Professor Mukesh Sharma, the author of IIT Kanpur’s source apportionment study on Delhi’s air pollution, was speaking at a programme organised by the Energy Policy Institute of the University of Chicago in the city. Treading carefully on questions pertaining to the highly toxic air in the national capital, he said, “An emission source may be very large but its impact may not be that significant. That needs to be studied very carefully.” Sharma also shed light on various details of the 300-page report that he authored.
“What you are breathing or what is at the breathing level may be very different from the emission load. It can be misleading because, for instance, the contribution from vehicles is 20% but it’s 25% closer to breathing level,” he said addressing a gathering of academics, scientists and journalists.
Sharma, who spoke at a public platform for the first time after his report was released, told TOI that biomass burning, secondary particles and vehicles played a crucial role in shooting up the pollution levels. The IIT Kanpur report has revealed that secondary particles, which are formed as a result of chemical reactions between gases such as sulphur dioxide (SO2) and oxides of nitrogen (NOx) and not emitted directly from a particular source, pose a large problem. The secondary particles could be from vehicles, power plants or other sources.