Influence of Chinese New Year overlapping COVID-19 lockdown on HONO sources in Shijiazhuang.
Sci Total Environ
; 745: 141025, 2020 Nov 25.
Article
in English
| MEDLINE | ID: covidwho-664503
ABSTRACT
Nitrous acid (HONO) is an important precursor of hydroxyl radical (OH) in the atmosphere. It is also toxic to human health. In this work, HONO concentrations were measured in Shijiazhuang using a Monitor for AeRosols and Gases in ambient Air (MARGA) from December 15, 2019 to March 15, 2020, which covered the heavy air pollution season, the Chinese New Year (CNY) vocation and the Corona Virus Disease-19 (COVID-19) lockdown period. During & after CNY overlapping COVID-19 lockdown, the air quality was significantly improved because of both the emission reduction and the increase in diffusion ability of air masses. The mean HONO concentration was 2.43 ± 1.08 ppbv before CNY, while it decreased to 1.53 ± 1.16 ppbv during CNY and 0.97 ± 0.76 ppbv after CNY. The lockdown during & after CNY reduced ~31% of ambient HONO along with ~62% of NO and ~36% of NO2 compared with those before CNY after the improvement of diffusion ability had been taken into consideration. Heterogeneous reaction of NO2 on ground surface dominated the nocturnal HONO sources, followed by heterogeneous reaction on aerosol surface, vehicle emission, reaction between NO and OH and emission from soil on pollution days throughout the observation. Except for elevated soil emission, other nighttime HONO sources and sinks decreased significantly during & after CNY. The relative importance of heterogeneous reaction of NO2 on surfaces further increased because of both the decrease in vehicle emission and the increase in the heterogeneous conversion kinetics from NO2 to HONO during & after CNY.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Pneumonia, Viral
/
Coronavirus Infections
/
Air Pollution
/
Pandemics
/
Nitrous Acid
Type of study:
Experimental Studies
/
Observational study
/
Prognostic study
Language:
English
Journal:
Sci Total Environ
Year:
2020
Document Type:
Article
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