Trends of fine particulate matter concentrations in South Korea derived from satellite and in-situ observations: long-term changes versus the COVID-19 impact

The COVID-19 pandemic affected human life from all around world, and also resulted in substantial changes in anthropogenic emissions. The Korean Peninsula is located in the downwind region of China. Thus, the air quality in South Korea is affected by both local and regional changes in emissions and chemistry. There were regional differences in the periods of lockdowns and restrictions during COVID-19, which allows us to explore the impact of local versus regional emission reductions on air quality in South Korea, in particular fine particulate matter concentrations. In this study, we utilize the advanced international and Korean satellite data as well as the SO2, NO2, CO, O3, PM10, PM2.5 data acquired from the surface networks in South Korea to derive and understand the trend of particulate matter concentrations. Both long-term trend and the COVID-19 impacts during the government social distancing and lockdown period will be presented.