Assessment of Air Pollution before, during and after the COVID-19 Pandemic Lockdown in Nanjing, China
Open Access
- 9 June 2021
- journal article
- research article
- Published by MDPI AG in Atmosphere
- Vol. 12 (6), 743
- https://doi.org/10.3390/atmos12060743
Abstract
A unique illness, the coronavirus disease 2019 (COVID-19), emerged in Wuhan, People’s Republic of China, in December 2019. To reduce the spread of the virus, strict lockdown policies and control measures were put in place all over the world. Due to these enforced limitations, a drastic drop in air pollution and an improvement in air quality were observed. The present study used six air pollutants (PM10, PM2.5, SO2, NO2, CO and O3) to observe trends before, during and after the COVID-19 lockdown period in Nanjing, China. The data were divided into six phases: P1–P3, pre-lockdown (1 October–31 December 2019), lockdown (1 January–31 March 2020), after lockdown (1 April–30 June 2020), P4–P6: the same dates as the lockdown but during 2017, 2018 and 2019. The results indicate that compared with the pre-lockdown phase, the PM10 and PM2.5 average concentrations decreased by –27.71% and –5.09%. Compared with the previous three years, 2017–2019, the reductions in PM10 and PM2.5 were –37.99% and –33.56%, respectively. Among other pollutants, concentrations of SO2 (–32.90%), NO2 (–34.66%) and CO (–16.85%) also decreased during the lockdown, while the concentration of O3 increased by approximately 25.45%. Moreover, compared with the pre- and during lockdown phases, PM10, PM2.5 and NO2 showed decreasing trends while SO2, CO and O3 concentrations increased. These findings present a road map for upcoming studies and provide a new path for policymakers to create policies to improve air quality.Funding Information
- National Natural Science Foundation of China (41631175)
This publication has 47 references indexed in Scilit:
- Estimation of high resolution emissions from road transport sector in a megacity DelhiUrban Climate, 2018
- Lower tropospheric ozone over India and its linkage to the South Asian monsoonAtmospheric Chemistry and Physics, 2018
- Investigation of relationships between meteorological conditions and high PM10 pollution in a megacity in the western Yangtze River Delta, ChinaAir Quality, Atmosphere & Health, 2017
- Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: an analysis of data from the Global Burden of Diseases Study 2015The Lancet, 2017
- Spatial and temporal trends in the mortality burden of air pollution in China: 2004–2012Environment International, 2016
- Ozone Monitoring Instrument Observations of Interannual Increases in SO2 Emissions from Indian Coal-Fired Power Plants during 2005–2012Environmental Science & Technology, 2013
- Air quality and emissions in the Yangtze River Delta, ChinaAtmospheric Chemistry and Physics, 2011
- How Much, How Long, What, and Where: Air Pollution Exposure Assessment for Epidemiologic Studies of Respiratory DiseaseProceedings of the American Thoracic Society, 2010
- Seasonal variations in surface ozone and its precursors over an urban site in IndiaAtmospheric Environment, 2000
- Global distribution of carbon monoxideJournal of Geophysical Research: Atmospheres, 2000