Jun-Oh Bu

Influences of Asian Dust, Haze, and Mist Events on Chemical Compositions of Fine Particulate Matters at Gosan Site, Jeju Island in 2014

In order to examine the variation characteristics of chemical compositions in accordance with the different meteorological conditions, PM10 and PM2.5 were collected at Gosan site of Jeju Island in 2014, and then their ionic and elemental species were analyzed. The concentrations of nss-SO4 and NH4 were respectively 4.3 and 3.3 times higher in fine particle mode (PM2.5) compared to coarse particle mode (PM10-2.5), however NO3concentration was 1.6 times higher in coarse mode compared to fine particle mode. During Asian dust days, the concentrations of nssCa and NO3increased highly as 7.7 and 4.5 times in coarse particle mode, and 3.0 and 4.9 times higher in fine particles, respectively. Especially, the concentrations of the crustal species (Al, Fe, Ca, K, Mn, Ba, Sr, etc.) indicated a noticeable increase during the Asian dust days. For the haze days, the concentrations of secondary pollutants increased 2.2~2.7 and 2.9~6.0 times in coarse and fine particles, respectively, and they were 0.8~1.1 and 1.8~2.4 times, respectively, during the mist days. The aerosols were acidified largely by sulfuric and nitric acids, and neutralized mainly by ammonia in fine particle mode during the haze days, but neutralized by calcium carbonate in coarse particle mode during the Asian dust days. The clustered back trajectory analysis showed that the concentrations of nss-SO4, NO3-, and NH4 + were relatively high when the inflow pathway of air mass was from the southern part of China.

Pollution Characteristics of Rainwater at Jeju Island during 2009~2010

The collection of rainwater samples was made at Jeju area during 2009~2010, and the major ionic species were analyzed. In the comparison of ion balance, conductivity, and acid fraction for the validation of analytical data, the correlation coefficients showed a good linear relationship within the range of 0.966~0.990. The volume-weighted mean pH and electric conductivity were 4.9 and 17.8 μS/cm, respectively, at the Jeju area. The volume-weighted mean concentrations of ionic species in rainwater were in the order of Cl¤Na¤nss-SO4 2¤NH4 + ¤NO3 ¤Mg ¤H¤nss-Ca¤HCOO¤K¤PO4 3¤CH3COO ¤NO2 ¤F¤HCO3 ¤CH3SO3 . The ionic strength of rainwater was 0.26±0.21 mM during the study period. The composition ratios of ionic species were such as 50.1% for the marine sources (Na, Mg, Cl), 30.9% for the anthropogenic sources (NH4 , nss-SO4 , NO3 ), and 4.7% for the soil source (nss-Ca), and 3.1% for organic acids (HCOO, CH3COO ). From the seasonal comparison, the concentrations of NO3 , nss-Ca, and nss-SO4 2increased in winter and spring seasons, indicating a reasonable possibility of long range transport from Asia continent. Especially, the acidifying contributions by major inorganic acids (nss-SO4 2and NO3 ) and organic acids (HCOO and CH3COO ) were 87.6% and 12.4%, respectively. In comparison by sectional inflow pathway of air mass during the rainy sampling days, the concentrations of nss-SO4 2and NO3 were relatively high when the air mass was moved from the China continent into Jeju area.

Background Level and Time Series Variation of Atmospheric Radon Concentrations at Gosan Site in Jeju Island

The background level and timely variation characteristics of atmospheric Rn concentrations have been evaluated by the real time monitoring at Gosan site of Jeju Island, Korea, during 2008~2015. The average concentration of atmospheric radon was 2,480 mBq m for the study period. The cyclic seasonality of radon was characterized such as winter maximum and summer minimum, consistent with the reduction in terrestrial fetch going to summer. On monthly variations of radon, the mean concentration in October was the highest as 3,041 mBq m, almost twice as that in July (1,481 mBq m). The diurnal radon concentrations increased throughout the nighttime approaching to the maximum (2,819 mBq m) at around 7 a.m., and then gradually decreased throughout the daytime by the minimum (2,069 mBq m) at around 3 p.m. The diurnal radon cycle in winter showed comparatively small amplitude due to little variability in atmospheric mixing depth, conversely, large amplitude was observed in summer due to relatively a big change in atmospheric mixing depth. The cluster back-trajectories of air masses showed that the high radon events occurred by the predominant continental fetch over through Asia continent, and the radon concentrations from China continent were about 1.9 times higher on the whole than those from the North Pacific Ocean. The concentrations of PM10 also increased in proportion to the high radon concentrations, showing a good linear correlation between PM10 and radon concentrations.

Variation Characteristics of TSP Ionic Compositions by Meteorological Phenomena in Jeju Island

The ionic compositions were analyzed from the TSP samples collected at Gosan site in Jeju Island between 2000 and 2008, in order to examine the characteristics of atmospheric aerosols in accordance with the meteorological conditions. For the Asian Dust influence on the ionic compositions, the concentration ratios of , nss-, , and were about 1.2~2.3 during Asian Dust over Non-Asian Dust periods, noticeably that of nss- was 6.8. Meanwhile the concentrations of nss-, , and have increased as 1.8~4.4 times during the haze event periods, and 1.0~1.6 times during the fog and mist events. The ion balance has resulted that the anionic concentrations are relatively lower than the cationic concentrations, and the discrepancy appears more decidedly as a strong Asian Dust effect. The ammonium ion balance has shown that it exists as a mixture of and . The concentration ratios of nss- for Asian Dust, haze, fog-mist, and non-event periods were respectively 1.8, 5.9, 4.6, and 2.9, which were higher values compared to those in urban areas of China as well as other domestic regions. Especially, the high ratios of sulfur oxides could be presumed by the fact that the longrange transport of air pollutants from Asia continent might affect the atmospheric aerosols of Jeju Island.