Significant changes in the chemical compositions and sources of PM2.5 in Wuhan since the city lockdown as COVID-19
Fecha
2020Autor
Zheng, Huang
Kong, Shaofei
Chen, Nan
Yan, Yingying
Liu, Dantong
Zhu, Bo
Xu, Ke
Cao, Wenxiang
Ding, Qingqing
Lan, Bo
Zhang, Zhouxiang
Zheng, Mingming
Fan, Zewei
Cheng, Yi
Zheng, Shurui
Yao, Liquan
Bai, Yongqing
Zhao, Tianliang
Qi, Shihua
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Resumen
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 (PM2.5) during January 23–February 22 of 2020, compared with the same period in 2019. The average mass concentration of PM2.5 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 PM2.5 all decreased with the reductions ranging from
0.85 μg m−3 (chloride) to 9.86 μg m−3 (nitrate) (p b 0.01). Positive matrix factorization model indicated that
the mass contributions of seven PM2.5 sources all decreased. However, their contribution percentages varied
from −11.0% (industrial processes) to 8.70% (secondary inorganic aerosol). Source contributions of PM2.5
transported from potential geographical regions showed reductions with mean values ranging from 0.22 to
4.36 μg m−3
. However, increased contributions of firework burning, secondary inorganic aerosol, road dust,
and vehicle emissions from transboundary transport were observed. This study highlighted the complex and
nonlinear response of chemical compositions and sources of PM2.5 to air pollution control measures, suggesting
the importance of regional-joint control.
Palabras clave
COVID-2019; Fine particle; Chemical composition; Source apportionmen; Random forest tree; Regional transportationEnlace al recurso
https://doi.org/10.1016/j.scitotenv.2020.140000Colecciones
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