Puzzling haze events in China during the coronavirus (COVID-19) shutdown | Health & Environmental Research Online (HERO)

Health & Environmental Research Online (HERO)

Print Feedback Export to File

This record has one attached file:

Citation
Tags

HERO ID

7018486

Reference Type

Journal Article

Title

Puzzling haze events in China during the coronavirus (COVID-19) shutdown

Author(s)

Chang, Y; Huang, RJ; Ge, X; Huang, X; Hu, J; Duan, Y; Zou, Z; Liu, X; Lehmann, MF; ,

Year

2020

Is Peer Reviewed?

Yes

Journal

Geophysical Research Letters
ISSN: 0094-8276
EISSN: 1944-8007

Language

English

PMID

32836517

DOI

10.1029/2020GL088533

Web of Science Id

WOS:000551464800033

Abstract

It is a puzzle as to why more severe haze formed during the New Year Holiday in 2020 (NYH-20), when China was in an unprecedented state of shutdown to contain the coronavirus (COVID-19) outbreak, than in 2019 (NYH-19). We performed a comprehensive measurement and modeling analysis of the aerosol chemistry and physics at multiple sites in China (mainly in Shanghai) before, during, and after NYH-19 and NYH-20. Much higher secondary aerosol fraction in PM2.5 were observed during NYH-20 (73%) than during NYH-19 (59%). During NYH-20, PM2.5 levels correlated significantly with the oxidation ratio of nitrogen (r2 = 0.77, p < 0.01), and aged particles from northern China were found to impede atmospheric new particle formation and growth in Shanghai. A markedly enhanced efficiency of nitrate aerosol formation was observed along the transport pathways during NYH-20, despite the overall low atmospheric NO2 levels.