key: cord-0799267-nks0lns3
authors: Naqvi, Hasan Raja; Datta, Manali; Mutreja, Guneet; Siddiqui, Masood Ahsan; Naqvi, Daraksha Fatima; Naqvi, Afsar Raza
title: Improved Air Quality and Associated Mortalities in India under COVID-19 Lockdown()
date: 2020-10-27
journal: Environ Pollut
DOI: 10.1016/j.envpol.2020.115691
sha: 74104c14522683eaa993653fa9caf4226e8bad62
doc_id: 799267
cord_uid: nks0lns3

India enforced stringent lockdown measures on March 24, 2020 to mitigate the spread of the Severe Acute Respiratory Syndrome Coronovirus-2 (SARS-CoV-2). Here, we examined the impact of lockdown on the air quality index (AQI) [including ambient particulate matter (PM(10) and PM(2.5)), nitrogen dioxide (NO(2)), sulfur dioxide (SO(2)), carbon monoxide (CO), ozone (O(3)), and ammonia (NH(3))] and tropospheric NO(2) and O(3) densities through Sentinel-5 satellite data approximately 1 d post-lockdown and one month pre-lockdown and post-lockdown. Our findings revealed a marked reduction in the ambient AQI (estimated mean reduction of 17.75% and 20.70%, respectively), tropospheric NO(2) density, and land surface temperature (LST) during post-lockdown compared with the pre-lockdown period or corresponding months in 2019, except for a few sites with substantial coal mining and active power plants. We observed a modest increase in the O(3) density post-lockdown, thereby indicating improved tropospheric air quality. As a favorable outcome of the COVID-19 lockdown, road accident-related mortalities declined by 72-folds. Cities with poor air quality correlate with higher COVID-19 cases and deaths (r=0.504 and r=0.590 for NO(2); r=0.744 and r=0.435 for AQI). Conversely, low mortality was reported in cities with better air quality. These results show a correlation between the COVID-19 vulnerable regions and AQI hotspots, thereby suggesting that air pollution may exacerbate clinical manifestations of the disease. However, a prolonged lockdown may nullify the beneficial environmental outcomes by adversely affecting socioeconomic and health aspects.

The year 2020 commenced with the incidence of a highly contagious SARS-CoV-2 that rapidly performed for a few sampled metropolitan cities (based on data availability up to May 5, 2020) 120 with high and low air quality concentrations using ambient NO 2 (µg/m 3 ) and AQI (mainly 121 dominated by SPM) pollution data. A schematic of the data collection sources and methodology 122 adopted for the study is shown in Fig. 2 . 

Air Quality Index (AQI) post-COVID-19 lockdown in India

Reduction in the tropospheric NO 2 , O 3 and LST was observed post-lockdown

Lockdown had a beneficial impact on AP-associated mortalities and RAs

NO 2 and AQI pollutants positively correlated with SARS-CoV-2 cases and mortalities

 263 We thanks the editor and the anonymous reviewers for their useful suggestions. We also thank 264 Nuzhat Arzoo for her help with graphical abstract.