Composition and Pollution Characteristics of Precipitation in Jeju Island, Korea for 1997-2015

This study focuses on the long-range chemical composition and pollution characteristics of precipitation components. Samples were collected from Jeju Island in 1997-2015, and their major ionic components were analyzed. Comparison of ion balance, electrical conductivity, and acid fraction of precipitation samples yielded correlation coefficients in the range of 0.937-0.980. The volume-weighted mean pH and electrical conductivity of the wet precipitation of the Jeju area were 4.81 and 21.7 mu S/cm, respectively. Ionic strengths of the wet precipitation samples were within the range of 0.24 +/- 0.26 mM, indicating that more than 30% of the total precipitation satisfied the pure precipitation criterion. Of the total precipitation in the Jeju area, 44% exhibited a pH in the range of 4.5-5.0, indicating weak acidity. The composition of sea salts and secondary pollutants in the precipitation were 56.8% and 28.7%, respectively, indicating that the precipitation in the Jeju area was affected by the surrounding coastal area. The acidity contributions by inorganic and organic acids were 92.3% and 7.7%, respectively, whereas, the neutralization factors for ammonia and calcium carbonate were 47.0% and 20.0%, respectively. Clustered back trajectory analysis indicates that the concentrations of most ionic components were higher in the airflow pathways to the Jeju area.