Hourly organic tracers-based source apportionment of PM_2.5 before and during the Covid-19 lockdown in suburban Shanghai, China: Insights into regional transport influences and response to urban emission reductions.

ABSTRACT: During the Covid-19 outbreak, strict lockdown measures led to notable reductions in transportation-related emissions and significantly altered atmospheric pollution characteristics in urban and suburban areas. In this work, we compare comprehensive online measurements of PM_2.5 major components and organic molecular markers in a suburban location in Shanghai, China before lockdown (Dec. 28, 2019 to Jan. 23, 2020) and during lockdown (Jan. 24 to Feb. 9, 2020). The NO_x levels declined sharply by 59% from 44 to 18 ppb during the lockdown, while O₃ rose two times higher to 42 ppb. The PM_2.5 level dropped from 64 to 49 μg m^-3 (-24%). The major components all showed reductions, with the reduction of nitrate most prominent at -58%, followed by

SUBMITTER: Wang S 

PROVIDER: S-EPMC9359772 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature