P15     A numerical and observational study on the particulate matters from extremely high temperature condition in 2018 in Busan, Korea.

Yang, Geum-Hee, Hyo-Jung Lee, Hyun-Young Jo, Shin-Young Park, Yu-Jin Jo, Jong-min Kim and Cheol-Hee Kim, Pusan National University, Korea

Korea underwent extremely hot summer in 2018, with the longest continuous heat wave alerts with the maximum temperature of higher than 35℃. This record heat wave period started at the time when East Asian heavy rainfall ended, and since then lasted for 41 days. Even worse, during this period, severely high PM2.5 with daily average of more than 35㎍/㎥ were observed in Busan, the southernmost city in Korea and continued for 7 days. Essentially, the concentrations of both PM10 and PM2.5 are the lowest at this season of year because of both a well-developed mixed layer (ML) with heated air during the daytime, and the stronger wash-out process of frequent precipitations.
To analyze the chemical and meteorological processes of high concentrations of particulate matter that caused this episode, the WRF-Chem model was employed and carried out for the indicated period. Modeling period was defined by using the meteorological in-situ data collected by KMA (Korea Meteorological Administration) and air quality data from KECO (Korea Environmental Corporation). Including 7 days of spin-up time, WRF (Weather Research and Forecasting) model was run from July 05 to 23, 2018 with 3 domains with the resolutions of 27km, 9km, and 3km each, and the air quality model was also simulated subsequently to interpret the distribution of the concentrations of various chemical compounds such as PM2.5 and PM10 and its process. The photochemical activities caused by record heat waves were evaluated, and the results of some sensitivity tests of WRF-Chem from the tentative emission changes of organic matters according to the temperature variations were also discussed here.