TY - JOUR
T1 - Spring Festival and COVID-19 Lockdown
T2 - Disentangling PM Sources in Major Chinese Cities
AU - Dai, Qili
AU - Hou, Linlu
AU - Liu, Bowen
AU - Zhang, Yufen
AU - Song, Congbo
AU - Shi, Zongbo
AU - Hopke, Philip K.
AU - Feng, Yinchang
N1 - Funding Information:
This work was funded by the Ministry of Science and Technology of the People's Republic of China (2016YFC0208505).
Publisher Copyright:
© 2021. The Authors.
PY - 2021/6/16
Y1 - 2021/6/16
N2 - Responding to the 2020 COVID-19 outbreak, China imposed an unprecedented lockdown producing reductions in air pollutant emissions. However, the lockdown driven air pollution changes have not been fully quantified. We applied machine learning to quantify the effects of meteorology on surface air quality data in 31 major Chinese cities. The meteorologically normalized NO2, O3, and PM2.5 concentrations changed by −29.5%, +31.2%, and −7.0%, respectively, after the lockdown began. However, part of this effect was also associated with emission changes due to the Chinese Spring Festival, which led to ∼14.1% decrease in NO2, ∼6.6% increase in O3 and a mixed effect on PM2.5 in the studied cities that largely resulted from festival associated fireworks. After decoupling the weather and Spring Festival effects, changes in air quality attributable to the lockdown were much smaller: −15.4%, +24.6%, and −9.7% for NO2, O3, and PM2.5, respectively.
AB - Responding to the 2020 COVID-19 outbreak, China imposed an unprecedented lockdown producing reductions in air pollutant emissions. However, the lockdown driven air pollution changes have not been fully quantified. We applied machine learning to quantify the effects of meteorology on surface air quality data in 31 major Chinese cities. The meteorologically normalized NO2, O3, and PM2.5 concentrations changed by −29.5%, +31.2%, and −7.0%, respectively, after the lockdown began. However, part of this effect was also associated with emission changes due to the Chinese Spring Festival, which led to ∼14.1% decrease in NO2, ∼6.6% increase in O3 and a mixed effect on PM2.5 in the studied cities that largely resulted from festival associated fireworks. After decoupling the weather and Spring Festival effects, changes in air quality attributable to the lockdown were much smaller: −15.4%, +24.6%, and −9.7% for NO2, O3, and PM2.5, respectively.
KW - air quality
KW - COVID-19
KW - machine learning
KW - meteorological normalization
KW - source
KW - spring festival
UR - http://www.scopus.com/inward/record.url?scp=85107735215&partnerID=8YFLogxK
U2 - 10.1029/2021GL093403
DO - 10.1029/2021GL093403
M3 - Article
AN - SCOPUS:85107735215
SN - 0094-8276
VL - 48
SP - 1
EP - 12
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 11
M1 - e2021GL093403
ER -
