Impacts of the COVID-19 responses on traffic-related air pollution in a Northwestern US city

doi:10.1016/j.scitotenv.2020.141325

	Impacts of the COVID-19 responses on traffic-related air pollution in a Northwestern US city
	Xiang, Jianbang; Austin, Elena; Larson, Timothy; Shirai, Jeffry; Liu, Yisi; Seto, Edmund; Gould, Timothy; Marshall, Julian
	2020-12
发表期刊	SCIENCE OF THE TOTAL ENVIRONMENT
ISSN	0048-9697
EISSN	1879-1026
摘要	This study evaluates the COVID-19 impacts on traffic-related air pollution, including ultrafine particles (UFPs), PM2.5, black carbon (BC), NO, NO2, NOx, and CO in a Northwestern US city. Hourly traffic, air pollutants, and meteorological data on/near a major freeway in the downtown of Seattle, Washington, were collected for fiveweeks before and tenweeks after the Washington Stay Home Order (SHO) was enacted, respectively (February 17-May 31, 2020). The pollutants between pre- and post-SHO periods were compared, and their differences were statistically tested. Besides, first-order multivariate autoregressive (MAR(1)) modelswere developed to reveal the impacts specific to the change of traffic due to the COVID-19 responses while controlling for meteorological conditions. Results indicate that compared with those in the post-SHO period, the median traffic volume and road occupancy decreased by 37% and 52%, respectively. As for pollutants, the median BC and PM2.5 levels significantly decreased by 25% and 33%, relatively, while NO, NO2, NOx, and CO decreased by 33%, 29%, 30%, and 17%, respectively. In contrast, neither size-resolved UFPs nor total UFPs showed significant changes between the two periods, although larger particles (>= 115.5 nm) decreased by 4-29%. Additionally, significant differences were found in meteorological conditions between the two periods. Based on the MAR(1) models, controlling for meteorological conditions, the COVID-19 responses were associated with significant decreases in median levels of traffic-related pollutants including 11.5-154.0 nmparticles (ranging from -3% [95% confidence interval (CI):-1%,-4%] to -12% [95% CI:-10%,-14%]), total UFPs (-7% [95% CI: -5%,-8%]), BC (-6% [95% CI:-5%, -7%]), PM2.5 (-2% [95% CI:-1%,-3%]), NO, NO2, NOx (ranging from-3% [95% CI:-2%,-4%] to-10% [95% CI: -18%,-12%]), and CO (-4% [95% CI,-3%,-5%]). These findings illustrate that the conclusion of the COVID-19 impacts on urban traffic-related air pollutant levels could be completely different in scenarios whether meteorology was adjusted for or not. Fully adjusting for meteorology, this study shows that the COVID-19 responses were associated with much more reductions in traffic-related UFPs than PM2.5 in the Seattle region, in contrast to the reverse trend from the direct empirical data comparison. (C) 2020 Elsevier B.V. All rights reserved.
关键词	COVID-19 Traffic Air pollution PM2.5 Ultrafine particle (UFP) Meteorology
DOI	10.1016/j.scitotenv.2020.141325
WOS关键词	SOURCE APPORTIONMENT ; REGIONAL TRANSPORT ; BLACK CARBON ; EMISSIONS ; PM2.5 ; QUALITY ; SEATTLE
WOS研究方向	Environmental Sciences & Ecology
WOS类目	Environmental Sciences
出版者	ELSEVIER
引用统计
文献类型	期刊论文
专题	新冠肺炎循证社会科学证据集成
作者单位	Univ Washington
推荐引用方式 GB/T 7714	Xiang, Jianbang,Austin, Elena,Larson, Timothy,et al. Impacts of the COVID-19 responses on traffic-related air pollution in a Northwestern US city[J]. SCIENCE OF THE TOTAL ENVIRONMENT,2020.
APA	Xiang, Jianbang.,Austin, Elena.,Larson, Timothy.,Shirai, Jeffry.,Liu, Yisi.,...&Marshall, Julian.(2020).Impacts of the COVID-19 responses on traffic-related air pollution in a Northwestern US city.SCIENCE OF THE TOTAL ENVIRONMENT.
MLA	Xiang, Jianbang,et al."Impacts of the COVID-19 responses on traffic-related air pollution in a Northwestern US city".SCIENCE OF THE TOTAL ENVIRONMENT (2020).