Estimating the Inadvertent Decrement in Mortality due to Reduction in Ambient Fine Particulate Concentrations During COVID-19 Lockdown in India

Abstract

The adverse health effects of long and short-term exposure to ambient air pollutants are well established in the epidemiological literature. Amongst all pollutants, fine particulate matter (PM 2.5), poses a significant mortality risk because of its toxicity and extensive human exposure. During COVID-19 lockdowns, numerous studies have reported a reduction in ambient PM 2.5 concentrations due to decreased anthropogenic activities. Therefore, potential health benefits are plausible during this period. In this pursuit, the current study aims to estimate the potential deaths that might have been avoided due to the reductions in PM 2.5 levels during COVID-19 lockdowns in India's 12 states. For the same, concentration-response functions are developed, and the changes in PM 2.5 levels were calculated. Overall, PM 2.5 levels in the analysed states decreased by an average of 19.61 µg/m 3 (SD = 10.34 µg/m 3) during the months of April-June 2020 compared to the previous year. The concentration-response coefficient (β) obtained for the Indian states is 0.02272 (0.01063-0.03481, 95% Confidence Interval). Upon using these values in the calculation, our analysis estimates that nearly 73,853-92,116 mortalities might have been avoided in the 12 analysed Indian states for the period of April-June 2020 due to the COVID-19 lockdown. Given the high levels of PM 2.5 in India with its well-known associated health risks and the results of this study, it is likely that the number of lives potentially saved during the COVID-19 lockdown due to reduced concentrations of PM 2.5 might surpass the COVID-19 deaths in the country.

COVID-19 Lockdown and the Aerosphere in India: Lessons Learned on How to Reduce Air Pollution

“…Several reports showed a significant plummet in primary emission sources or SLCPs (>30%) leading to the emergence of the blue sky after several decades in India [11,15,16]. Furthermore, a recent model-based study by our group predicted the drastic decline in fine particulate pollutant level during the lockdown had potentially avoided 73,853-92,116 mortalities during April-June 2020 that might have surpassed the fatality due to the pandemic [17]. Thus, lockdown provides a unique opportunity for environment researchers to collect baseline data of various pollutants, which could help develop new mitigation strategies in the future.…”