Seasonal Differences of New Particle Formation Characteristics Based on the Real-Time Measurements of Aerosols in South Korea

YOONKYEONG HA, Jeongbeen Kim, Soodong Lee, Kyungil Cho, Ji Yi Lee, Kyoung-Soon Jang, Mijung Song, Joonyoung Ahn, Kwangyul Lee, Changhyuk Kim, Pusan National University

     Abstract Number: 50
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
New particle formation (NPF) including gas-to-particle conversion and the growth of particle nuclei is a key to understand secondary aerosol formation processes in the atmosphere. This is well known to contribute significantly to the haze episodes in the Northeast Asia including South Korea.

In this study, four monitoring campaigns for atmospheric aerosol characteristics were conducted during 2020/12/15 - 2021/01/15 (winter), 2021/06/01 - 2021/06/30 (summer), 2022/03/14 – 2022/04/13 (spring) and 2022/11/10 – 2022/12/10 (autumn) at suburban and metropolitan sites in South Korea (Seosan and Seoul, SS and SE). During these campaigns, number size distributions and mass concentrations of PM_2.5 (PNSD and C_PM2.5) were measured in real-time as well as particle chemical compositions, concentrations of gas pollutants and meteorology data. Seasonal NPF characteristics such as condensation sink (CS), coagulation sink (CoagS), growth rate (GR), formation rate (FR) and nucleation rate (NR) were calculated based on PNSD data. These were compared with other real-time measurement data. Yellow dust events influenced on the air quality of the partial periods in the winter and spring campaigns.

During the campaigns, CS followed the trend of CoagS with one higher order of magnitude. NPF events generally occurred when C_PM2.5 was below 35 μg/m³. In addition, frequency of NPF events was higher in winter than in summer. FRs observed at SE were higher in winter than in summer, but GRs at the site were higher in summer. Even though GRs monitored at SS were higher in summer as that at SE, FRs at SS were also higher in summer. FRs and GRs in spring and autumn campaigns were in the middle of the values shown in winter and summer. NRs for each season and site will be also discussed to compare the NPF characteristics with those reported in the literature for Chinese megacities.