Study: Vehicle, factory emissions contribute most to foul winter air – Times of India

Kolkata News

Kolkata: A quarter of the pollutants in Kolkata’s winter air is contributed by vehicular emission, the result of a two-year study on sources and quantum of pollutants has revealed. The largest contributor to the foul winter air is secondary aerosol formed by the reaction between salts in the atmosphere and chemicals released in the exhaust of vehicles, factories and thermal stations, as well as burning of waste.
According to the source apportionment study commissioned by West Bengal Pollution Control Board (WBPCB) and conducted by National Environmental Engineering & Research Institute (NEERI), secondary aerosol comprise nearly a third of the PM2.5 pollutants during winter. What this essentially means is that if strategies can be formulated to reduce these two pollutant sources, nearly 60% of the city’s air pollution can be addressed.
The study also revealed that biomass combustion has increased during winter in Kolkata. Burning of wood and coal by civic agencies during road repair and roadside pice hotel operators, among others, contribute to another quarter of pollutants.
The study, which started in the summer of 2017, is crucial for strategizing where to invest in pollution combat measures. “The measures we had adopted were based on the preliminary report in 2019. The results have been encouraging. The final report will help us fine-tune the strategies further,” said WBPCB chairman Kalyan Rudra.
“Secondary aerosols get self-neutralized in summer. But during winter, they become a major contributor of particulate matter. It isn’t clear whether these secondary aerosols are formed locally or get carried in from outside,” said Deepanjan Maumdar, principal scientist and head of CSIR-NEERI, Kolkata zonal centre.
“The results of the study is in line with the source apportionment studies in a majority of cities in southeast Asia,” said Amitava Bandyopadhyay, an expert on chemical components of pollutants.
However, Kankana Das, an environment analyst with Legal Initiative for Forest and Environment (LIFE), an environmental research and advocacy organization, found the 12-location study inadequate for a city the size of Kolkata.
“Almost all the locations were a mix of traffic junction, residential area, residential and traffic mixture and traffic and commercial mixture. The construction-intensive locations were largely kept out, which eventually led to lower percentage contribution from the construction sector,” she said.