제주도 고산지역 PM10, PM2.5 화학조성의 장기변동 특성

Abstract

The atmospheric PM10 and PM2.5 aerosols were collected at Gosan site of Jeju Island, which is one of the background sites of Korea, during 2000-2015. Their ionic and elemental species were analyzed, in order to examine the long-term variation of chemical compositions and their characteristics in accordance with the meteorological conditions and the inflow pathways of air mass. The mean mass concentrations of PM10 and PM2.5 were 30.5 and 16.8 μg/m3, respectively. The concentrations of the secondary pollutants such as nss-SO4 2-, NO3 -, and NH4 + were 5.29, 2.73 and 1.98 μg/m3 for PM10, and 4.38, 1.26, 1.69 μg/m3 for PM2.5, respectively. The elemental compositions of PM10 showed 35.1% for marine (Na, Mg), 32.8% for anthropogenic (S, Zn, Pb, Ni), and 25.6% for soil (Al, Fe, Ca). Those of PM2.5 were 19.3%, 57.5%, 16.7%, respectively. From the study of long-term variation of aerosol compositions, NO3 - concentrations showed a bit higher variation slope (0.15) compared to that of nss-SO4 2- concentrations (0.14) in PM10, though the slope of NO3 - concentrations in PM2.5 was almost negligible. This could be explained by that NO3 - existed mostly in coarse particle mode. The concentrations of the anthropogenic and soil species increased noticeably through the prevailing northwesterly winds. From the clustered back trajectory analysis, the concentrations of the anthropogenic components increased when the airflow moved from the China continent, on the other hand, they decreased when the airflow moved from the Northern Pacific into Jeju Island. During Asian dust periods, the concentrations of nss-Ca2+ and NO3- were increased highly as 12.7 and 3.7 times in PM10, and 7.7 and 2.8 times in PM2.5, respectively, compared to non-event days. Especially, the concentrations of the crustal species such as Al, Fe, Ca, K, Mn, Ba, and Sr showed a noticeable increase during the Asian dust periods. During the haze days, the concentrations of the secondary pollutants were increased by 3.1～4.8 times in PM10 and 3.3～5.4 times in PM2.5. Futhermore, the remarkable increase of NO3 concentration was observed in PM2.5 aerosols during haze days. During the study periods, the concentrations of the major anthropogenic species showed a steady increase during haze as well as Asian dust periods.