[A-AS11] Atmospheric Chemistry

[AAS11-P16] Organic aerosols at Fukue Island in 2020 before, during and after large scale lockdown in China due to COVID-19

*Zhu Chunmao¹, Takuma Miyakawa¹, Fumikazu Taketani¹, Yugo Kanaya¹ (1. Japan Agency for Marine-Earth Science and Technology)

Carbonaceous aerosols are one of the most important aerosol components affecting earth’s radiative forcing. Although it is quite clear that black carbon is a large climate forcer, the role of organic carbon is controversial. It had been considered cooling earth surface, until the light-absorbing fraction, brown carbon, was found to cause warming. Emission of black carbon in China had been increased before 2010, and decreased thereafter (Kanaya et al., 2020). However, the temporal trend of organic carbon is ambiguous, due to its diverse sources, such as from fossil fuel combustion, biomass burning, as well as direct biogenic emissions and secondary formation by the oxidation of volatile organic compounds. To better understand the characteristics of carbonaceous aerosols and the effects on climate, we have been collecting aerosol samples and analyzing carbonaceous components since late 2019 at Fukue Island, Nagasaki prefecture.
Due to the spread of COVID-19, Chinese government implemented large scale lockdown in major cities from late January to early April in 2020. As a result, economic activities are largely restricted, where emissions of carbonaceous aerosols would possibly change. In this work, we found that organic aerosols decreased in February and March, and rebounded in April, 2020 (Figure 1). Further analyses will be conducted along with molecular tracers, such as levoglucosan from November 2019 to November 2020. We will provide information to better understand the dynamics and emission controls of carbonaceous aerosols in East Asia.