Significant changes in the chemical compositions and sources of PM_2.5 in Wuhan since the city lockdown as COVID-19.

ABSTRACT: Wuhan was the first city to adopt the lockdown measures to prevent COVID-19 spreading, which improved the air quality accordingly. This study investigated the variations in chemical compositions, source contributions, and regional transport of fine particles (PM_2.5) during January 23-February 22 of 2020, compared with the same period in 2019. The average mass concentration of PM_2.5 decreased from 72.9 μg m^-3 (2019) to 45.9 μg m^-3 (2020), by 27.0 μg m^-3. It was predominantly contributed by the emission reduction (92.0%), retrieved from a random forest tree approach. The main chemical species of PM_2.5 all decreased with the reductions ranging from 0.85 μg m^-3 (chloride) to 9.86 μg m^-3 (nitrate) (p < 0.01)

SUBMITTER: Zheng H 

PROVIDER: S-EPMC7274103 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature