COVID?19 Impact on the Concentration and Composition of Submicron Particulate Matter in a Typical City of Northwest China
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ABSTRACT: Abstract In this study, we evaluated the variations of air quality in Lanzhou, a typical city in Northwestern China impacted by the COVID?19 lockdown. The mass concentration and chemical composition of non?refractory submicron particulate matter (NR?PM1) were determined by a high?resolution aerosol mass spectrometer during January?March 2020. The concentration of NR?PM1 dropped by 50% from before to during control period. The five aerosol components (sulfate, nitrate, ammonium, chloride, and organic aerosol [OA]) all decreased during the control period with the biggest decrease observed for secondary inorganic species (70% of the total reduction). Though the mass concentration of OA decreased during the control period, its source emissions varied differently. OA from coal and biomass burning remained stable from before to during control period, while traffic and cooking related emissions were reduced by 25% and 50%, respectively. The low concentration during the control period was attributed to the lower production rate for secondary aerosols. Key Points The submicron aerosol mass concentration was reduced by 50% during COVID?19 lockdown in Lanzhou The reduction of aerosol was mainly due to a decline in secondary species; we identify an overall low production rate as the main driver The result is contrast to those reported recently in East China where the reductions were offset by an increase in secondary species production
SUBMITTER: Xu J
PROVIDER: S-EPMC7536917 | biostudies-literature | 2020 Oct
REPOSITORIES: biostudies-literature
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