气候变化领域集成服务门户(CCPortal): Global impact of COVID-19 restrictions on the surface concentrations of nitrogen dioxide and ozone

CCPortal

DOI	10.5194/acp-21-3555-2021
	Global impact of COVID-19 restrictions on the surface concentrations of nitrogen dioxide and ozone
	Keller C.A.; Evans M.J.; Emma Knowland K.; Hasenkopf C.A.; Modekurty S.; Lucchesi R.A.; Oda T.; Franca B.B.; Mandarino F.C.; Valeria Díaz Suárez M.; Ryan R.G.; Fakes L.H.; Pawson S.
发表日期	2021
ISSN	1680-7316
起始页码	3555
结束页码	3592
卷号	21 期号:5
英文摘要	Social distancing to combat the COVID-19 pandemic has led to widespread reductions in air pollutant emissions. Quantifying these changes requires a business-as-usual counterfactual that accounts for the synoptic and seasonal variability of air pollutants. We use a machine learning algorithm driven by information from the NASA GEOS-CF model to assess changes in nitrogen dioxide (NO2) and ozone (O3) at 5756 observation sites in 46 countries from January through June 2020. Reductions in NO2 coincide with the timing and intensity of COVID-19 restrictions, ranging from 60 % in severely affected cities (e.g., Wuhan, Milan) to little change (e.g., Rio de Janeiro, Taipei). On average, NO2 concentrations were 18 (13-23) % lower than business as usual from February 2020 onward. China experienced the earliest and steepest decline, but concentrations since April have mostly recovered and remained within 5 % of the business-as-usual estimate. NO2 reductions in Europe and the US have been more gradual, with a halting recovery starting in late March. We estimate that the global NOx (NO + NO2) emission reduction during the first 6 months of 2020 amounted to 3.1 (2.6-3.6) TgN, equivalent to 5.5 (4.7-6.4) % of the annual anthropogenic total. The response of surface O3 is complicated by competing influences of nonlinear atmospheric chemistry. While surface O3 increased by up to 50 % in some locations, we find the overall net impact on daily average O3 between February-June 2020 to be small. However, our analysis indicates a flattening of the O3 diurnal cycle with an increase in nighttime ozone due to reduced titration and a decrease in daytime ozone, reflecting a reduction in photochemical production. The O3 response is dependent on season, timescale, and environment, with declines in surface O3 forecasted if NOx emission reductions continue. © 2021 BMJ Publishing Group. All rights reserved.
语种	英语
scopus关键词	air quality; algorithm; atmospheric pollution; concentration (composition); COVID-19; machine learning; nitrogen dioxide; ozone; China; Europe; United States
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/247077
作者单位	Nasa Global Modeling and Assimilation Office, Goddard Space Flight Center, Greenbelt, MD, United States; Universities Space Research Association, Columbia, MD, United States; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, YO10 5DD, United Kingdom; National Centre for Atmospheric Science, University of York, York, YO10 5DD, United Kingdom; OpenAQ, Washington, DC, United States; Science Systems and Applications, Inc., Lanham, MD, United States; Municipal Government of Rio de Janeiro, Rio de Janeiro, Brazil; Secretaria de Ambiente, Quito, Ecuador; School of Earth Sciences, The University of Melbourne, Melbourne, Australia
推荐引用方式 GB/T 7714	Keller C.A.,Evans M.J.,Emma Knowland K.,et al. Global impact of COVID-19 restrictions on the surface concentrations of nitrogen dioxide and ozone[J],2021,21(5).
APA	Keller C.A..,Evans M.J..,Emma Knowland K..,Hasenkopf C.A..,Modekurty S..,...&Pawson S..(2021).Global impact of COVID-19 restrictions on the surface concentrations of nitrogen dioxide and ozone.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(5).
MLA	Keller C.A.,et al."Global impact of COVID-19 restrictions on the surface concentrations of nitrogen dioxide and ozone".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.5(2021).