Impact of SARS-CoV-2 Pandemic Lockdown on Air Quality Using Satellite Imagery with Ground Station Monitoring Data in Most Polluted City Kolkata, India

Abstract

Immediate lockdown (March 24-May 31, 2020) of industrial activity and traffic flows has been announced by the government of India across the country after the declaration of World Health Organization that the Novel Coronavirus (SARS-CoV-2) outbreak is pandemic. In this study, we tried to estimate the air quality improvement during the pre-lockdown period (January 1-March 23, 2020) by comparing the lockdown period (March 24-May 31, 2020). From the results, we found the highest reduction in the concentration of NO 2 (81.98%) during the lockdown period. The average concentration of NO 2 was 51.57 µg/m 3 during pre-lockdown has changed to 9.29 µg/m 3. The average PM 2.5 concentration was 80.09 µg/m 3 during the pre-lockdown period has reduced to 20.24 µg/m 3 with 74.72% of reduction during the lockdown period. From the overall analysis of various parameters, we observed significant improvement with the range of 73.

Impact of COVID‐19 lockdown on the elemental profile of PM10 present in the ambient aerosol of an educational institute in Kolkata, India

“…This reduction is mainly influenced by the combined effect from the higher mixing layer, low anthropogenic activities (Sarkar et al., 2021 ) and disintegration of PM 10 into smaller particles (Gogikar et al., 2018 ). The NS, PL and PT sampling phase exhibited the concentration level range of 82.17‐546.21 μgm −3 , 82.15‐272.06 μgm −3 and 60.61‐186.77 μgm −3 , respectively, where the concentration levels during NS and PT were found to be mainly contributed from clusters of small industries (Kabiraj & Gavli, 2020 ), tanneries (Sarkar et al., 2021 ), thermal power plant (Biswas & Ayantika, 2021 ) and vehicular emissions (Banerji & Mitra, 2021 ).…”

“…The aerosol sampling was carried out in the University of Calcutta's Taraknath Palit Siksha Prangan campus (22.526 N 88.363 E) as illustrated in Exhibit 1 , which is situated in Ballygunge, an urban locality in the central part of Kolkata. The sampling site is surrounded by clusters of small‐scale industrial units mainly comprised of tanneries and metal processing units as described by Kabiraj and Gavli ( 2020 ) in their study. They also mentioned the major pollutant contributors as traffic, industrial units and power plants, which was further elaborated in a study by Sarkar et al.…”

“…Coincidentally COVID‐19 pandemic was one such moment in recent times where restrictions over most of the anthropogenic activities paved the much‐needed air pollution assessment in identifying the areas which need the right implementation of solutions for minimizing the emission of pollutants (Mahato et al., 2020 ; Sarkar et al., 2021 ). The abrupt restriction of anthropogenic activities was implemented in India from March 24, 2020 (Kabiraj & Gavli, 2020 ; Srivastava et al., 2020 ), constraining the normal movement of the population (Gautam & Hens, 2020 ). Like the whole country, interstate and intrastate transportation from Kolkata were suspended till May 3, 2020, which was further extended till June 30, 2020 in areas with large COVID‐19 cases categorized as red zones (Banerji & Mitra, 2021 ; Nath et al., 2021 ).…”

COVID-19 induced restriction in developing countries and its impacts on pollution load: case study of Lagos mega city

“…Some studies on the effect of total lockdown due to COVID-19 pandemic on air quality across the globe have been reported, indicating various degrees of decline in the air pollution levels in their respective study areas. In India, effects of controlled emission on the quality of atmospheric air during the pandemic era was investigated and improved air quality was reported with reduced pollution levels ranging from 10% to 53.61% (Sharma et al, 2020;Kabiraj and Gavli, 2020;Singh, 2021a). Study by Ambade et al (2021) showed that COVID-19 lockdowns significantly reduced the concentrations of Black carbon, PAHs and PM 2.5 .…”

Strict lockdown measures reduced PM2.5 concentrations during the COVID-19 pandemic in Kolkata, India

“…Therefore, according to (Son et al 2020 ) the lower level of air pollution made indirect health benefits to the public health. However, it has had a positive impact on the environment, specifically on air quality, as a result of partial to total lockdown in various countries around the world (Kabiraj and Gavli 2020 ). The level of air pollution remarkably decreased during different lockdown phases in India (The Central Pollution Control Board, 2020).…”