Study links high pollution in Delhi with biofuel burning at crematoria in peak of 2nd Covid wave

The devastating second Covid-19 wave in Delhi saw unusually high air pollution despite a lockdown during the March-May period which could be attributed to exceptionally high biofuel burning at crematoria and higher-than-normal frequency of dust storms, according to a new study.

The study conducted by researchers from the National Institute of Advanced Science, Bengaluru; Delhi Pollution Control Committee; Indian Institute of Tropical Meteorology, Pune; Utkal University and Indraprastha Institute of Information Technology has been published in the multidisciplinary journal Chemosphere.

Led by scientist and senior meteorologist Gufran Beig, the research explained the reasons for the worsening air quality instead of improvement under lockdown by using India's first air quality forecasting framework model of SAFAR.

It revealed that an unaccounted emission source was playing a leading role in high air pollution after balancing off the impact of curtailed lockdown emissions. The hidden source of emission is believed to be associated with additional carbonaceous biofuel burning related to crematories whose emissions could not be accounted for in modeling.

Read | Air pollution led to 1,00,000 premature deaths in India: Study

"The model failed to reproduce some observed unusual features mainly related to an unaccounted hidden source of emission which was related to biomass burning at the crematorium in all likelihood," the paper read.

The sudden increasing trend in PM2.5 followed the steep surge in infection counts and the peak mortality period (around 400 deaths per day) was directly coinciding with peak levels of PM2.5, it showed.

The study modelled the emission as per the wood required for cremation (around 300-400 kg per pyre) for open pyre and accounted for the chemistry of crematoria flue gases which contain higher percentage of organic, inorganic matter and particulate dust material.

The increased carbon rich PM2.5 and PM10 further aggravated the severity of Covid-19 patients and vulnerable population adding to the misery. The impact lasted longer as carbonaceous PM2.5 have relatively longer life to remain suspended in the air, it said.

The researchers further found that other peaks in the later part of lockdown were related to the north-westerly winds which often brought dust particles from the desert region to Delhi.

The frequency of such dust storms was unusually higher than normal, probably due to free and faster flow of dust without much resistance under the lockdown period.

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