Biomass burning rather than firecrackers makes Delhi’s air quality poor, says IIT Delhi study

Every year post the Diwali festival, the national capital Delhi is seen clouded with hazardous and unbreathable air. And it is squarely blamed either on stubble burning, as it coincides with crop harvesting season and fireworks. However, a recent study done by the Indian Institute of Technology (IIT) Delhi has dispelled this notion.

According to their study, the reason air quality dips in the national capital a day after Diwali is because of biomass burning emissions rather than firecrackers.

The study titled 'Chemical speciation and source apportionment of ambient PM2.5’ has shed light on the pollution sources impacting the ambient air quality in New Delhi before, during, and after Diwali.

The researchers found that the metal content in PM2.5 levels rose by 1100 per cent, and the fireworks alone accounted for 95 per cent of the metal PM2.5during Diwali.

“However, the impact of the fireworks plummets within around 12 hours following Diwali,” reveals Chirag Manchanda, the lead author of this study.

The research study published in the journal “Atmospheric Pollution Research” has presented source-apportionment results for highly time-resolved elemental and organic fractions of PM2.5 to address the challenge.

“Both stubble burning and increased heating requirements of the region in winters drive the biomass burning activity”, adds Prof Vikram Singh, Department of Chemical Engineering, IIT Delhi, who was one of the investigators.

The study concludes by arguing, “The result of this study provides crucial insights into a topic of long-standing debate and concern between air quality experts and policymakers committed to alleviating the extreme air pollution events in the capital of Delhi following Diwali,” said the principal investigator Prof. Mayank Kumar, Department of Mechanical Engineering, IIT Delhi.

This study was partly funded by IIT Delhi and the Ministry of Education, Government of India and conducted as part of a collaborative effort between IIT Delhi, IIT Kanpur, and PRL Ahmedabad.