Impact of COVID-19 lockdown on air quality in Chandigarh, India: Understanding the emission sources during controlled anthropogenic activities

Abstract

The variation in ambient air quality during COVID-19 lockdown was studied in Chandigarh, located in the Indo-Gangetic plain of India. Total 14 air pollutants, including particulate matter (PM 10 , PM 2.5 ), trace gases (NO 2 , NO, NO x , SO 2 , O 3 , NH 3 , CO) and VOC’s (benzene, toluene, o-xylene, m,p-xylene, ethylbenzene) were examined along with meteorological parameters. The study duration was divided into four parts, i.e., a) 21 days of before lockdown b) 21 days of the first phase of lockdown c) 19 days of the second phase of lockdown d) 14 days of the third phase of lockdown. The results showed significant reductions during the first and second phases for all pollutants. However, concentrations increased during the third phase. The concentrations of SO 2 , O 3, and m,p-xylene kept on increasing throughout the study period, except for benzene, which continuously decreased. The percentage decrease in the concentrations during consecutive periods of lockdown were 28.8%, 23.4% and 1.1% for PM 2.5 and 36.8%, 22.8% and 2.4% for PM 10 respectively. The Principal Component Analysis (PCA) and characteristic ratios identified vehicular pollution as a primary source during different phases of lockdown. During the lockdown, residential sources showed a significant adverse impact on the air quality of the city. Regional atmospheric transfer of pollutants from coal-burning and stubble burning were identified as secondary sources of air pollution. The findings of the study offer the potential to plan air pollution reduction strategies in the extreme pollution episodes such as during crop residue burning period over Indo-Gangetic plain.

Impact of COVID-19 lockdown on ambient air quality in megacities of India and implication for air pollution control strategies

“…During the lockdown period, this work and other recent studies highlighted the impact of restricted anthropogenic activities on air quality across India and other parts of the world (Sharma et al 2020;Jain and Sharma 2020;Mahato et al 2020;Dantas et al 2020;Chauhan and Singh 2020;Mor et al 2020). In India, particulate matter (PM 2.5 and PM 10 ) and NO 2 show a significant reduction of up to 40-50% in the many megacities during the lockdown period as highlighted by Jain and Sharma (2020), Mahato et al (2020), Singh et al (2020a), and Biswal et al (2020).…”

“…The various lockdown phases have a difference in restrictions resulting in variation in PM 2.5 levels in different stages of lockdown. In the first phase of lockdown, all human activities were halted except for emergency services (Singh et al 2020a;Mor et al 2020). After that, in consecutive phases, increased activities, like movements of people stuck in lockdown, relaxation in timings to buy market goods, and the opening of essential industries, were allowed with limitations.…”

Impact of COVID-19 Lockdowns on Air Quality and Health. Association between Concentrations of Tropospheric Ozone and Infection Cases and Deaths in Spain

“…Regarding Gerena, the mine zone showed an increase of +67.9% in SO 2 in comparison with a decrease of -24.2% in NO 2 . All these extreme increases in SO 2 levels must be attributed to the increase in burning of coal [ 39 ] or other fossil fuels by thermal power plants [ 40 ] or other industrial activities, such as mines or re neries. According Wang et al [25], concentrations of SO 2 and other pollutants such as CO and NO 2 appeared to have positive effect on hospitalizations, especially at high concentrations, for instance by bronchiectasis.…”

Measurement report: An assessment of the impact of a nationwide lockdown on air pollution – a remote sensing perspective over India

“…Increase in the concentration levels of trace gases and particulate matter has been a challenging environmental issue in urban and industrial areas.Numerous studies have been attempted across the globe to understand the air pollution concentrations during lockdown period and results indicate varied range of percentage reductions in pollutant concentrations. These studies are based on ground based measurements alone (Mohato and Ghosh, 2020;Mor et al, 2020) or satellite data alone (Biswal et al, 2020a;Xu et al, 2020) orwith a combinationof ground and satellite (Ratnam et al, 2020;Biswal et al, 2020b;Singh and Chauhan, 2020). Biswal et al (2020aBiswal et al ( & 2020b reported lockdown induced changes in tropospheric NO2 variability over the urban and rural regions of Indian sub-continent with marked reduction of 30-50 % over https://doi.org/10.5194/acp-2020-1227 Preprint.…”