Intra- and inter-regional contributions to PM2.5 concentrations during wintertime episodes in the Gangwon province in South Korea

Intra- and inter-regional contributions to PM_2.5 concentrations during wintertime episodes in the Gangwon province in South Korea

Dongwon Choi¹⁾, Taehee Kim¹⁾, Kyung-Hwan Kwak^2),*

¹⁾Department of Integrated Particulate Matter Management, Kangwon National University, Chuncheon, Republic of Korea,

²⁾Department of Environmental Science, Kangwon National University, Chuncheon, Republic of Korea

PM_2.5 concentration has many determining factors including emission sources, physical/chemical transformation, and atmospheric transport/stagnation. In the wintertime, atmospheric stagnation appears frequently under the high-pressure synoptic system for a few consecutive days, which increases the PM_2.5 concentration. On the other hand, air plumes originated from neighboring regions can also impact on the regional PM_2.5 concentration relatively in a short period of time. As of 2020, Gangwon province in South Korea accounts for only 6.2% of the national PM_2.5 emission amounts, but experiences higher PM_2.5 concentrations than nation-wide average of PM_2.5 concentration. For establishing effective air quality management strategies, at first, it is necessary to identify the intra-regional (i.e., self) contribution to PM_2.5 concentration in Gangwon province. In this study, a 3-D chemistry-transport model that is Community Multi-scale Air Quality (CMAQ) model is used in combination with a mesoscale model that is the Weather Researcher Forecast (WRF) model to identify the intra- and inter-regional contribution to PM_2.5 concentration. We divided the national anthropogenic air pollutant emissions into 4 different emission sectors such as metropolitan area, Western Gangwon province, Eastern Gangwon province, and other domestic areas. The period of interest for WRF-CMAQ simulation is three consecutive weeks in February 2023, when the influence of foreign inflow was known to be relatively small. The inter-regional contributions from neighboring regions to PM_2.5 concentration in Gangwon province appeared to be larger than intra-regional (or self) contribution. The contributions are mainly attributed to atmospheric secondary PM_2.5 production and the primary PM_2.5 emissions in neighboring regions followed by the atmospheric recirculation. the process analysis (PA) method to quantify the individual process contribution is applied for PM_2.5 components from city to city in Gangwon province and will be presented.

This work was supported by the National research Foundation of Korea(NRF) grant founded by the Korea government(MIST)(RS-2023-00219830) and "Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute(KEITI) funded by the Ministry of Environment(MOE)"