Aerosol Transport Pathways and Source Attribution in China During the COVID-19

Abstract:

Due to the coronavirus disease 2019 (COVID-19) pandemic, human activities and industrial productions have been strictly restricted since January 23, 2020 in China. Despite the anthropogenic aerosol emissions decreased during this time period, haze pollution still occurred. Beside its environmental impact, aerosol may transmit COVID-19 virus. Knowing the aerosol transport pathways and identifying aerosol sources from specific regions is beneficial to the air quality and pandemic control strategies. This study establishes source-receptor relationships and transport pathways in various regions of China from January 23 to February 27, 2020, during the COVID-19, using the Community Atmosphere Model version 5 with Explicit Aerosol Source Tagging (CAM5-EAST). Our analysis shows that PM_2.5 emitted in northern China are generally transported southward along with the northwesterly wind, while emissions from southern China are transported northward. During polluted days, North China Plain local emissions contribute about 95% of the total increase in PM_2.5 concentrations. The polluted days in eastern China are caused by both the accumulation of local emissions (32%) and the transport of PM_2.5 from the rest of China (26%) and the rest of the world (42%). The emissions from the rest of the world contributes about 80% on the increases in PM_2.5 concentrations over southwestern China during polluted days.