Characteristic changes of ozone and its precursors in London during COVID-19 lockdown and the ozone surge reason analysis. (15th March 2022)

• Record Type: Journal Article
• Authors: Zhang, Chenyue; Stevenson, David
• Is Part Of: Atmospheric environment. Volume 273(2022)
• Publication Date: 2022-03-15
• Subjects: COVID-19 lockdown -- Sensitivity analysis -- VOC-Limited regime; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2022.118980
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: The London COVID-19 lockdown reduced emissions from anthropogenic sources, providing unique conditions for air contamination research. This research uses tropospheric ozone (O3 ), volatile organic compounds (VOCs) and NOx (NO+NO2 ) hourly monitoring data at the London Marylebone Road station from 2001 to 2020 to investigate the effects of lockdown on (O3 ) and its precursors. Both NOx and VOCs pollution showed a decreasing trend between 2001 and 2021, with a gradual increase in O3 in contrast. During the COVID-19 lockdown period (from 23rd March to July 4, 2020), there was a surge in O3 concentration, accompanied by a sharp reduction in NOx concentrations. Because all the monitoring VOCs/NOx results were less than eight during the lockdown, indicating that O3 formation in urban London was in the VOC-limited regime. The rapid increase in O3 concentrations caused by the lockdown was closely related to the rapid decrease in NOx emissions. Highlights: Form 2001 to 2021, O3 concentrations increase by 0.3 ppb·yr -1, while other pollutants experience varying degrees of decline. During the COVID-19, NOx concentrations fall to 30% of the original levels, while O3 concentrations increase exponentially. Urban London O3 pollution is in the VOC-limited regime. The surge of O3 concentrations during the COVID-19 is because NOx declined rapidly.