Summertime characteristics of aerosol composition at Cheju Island, Korea

To understand the characteristics of air quality during summer in Northeastern Asia, an intensive field study had been carried out at Cheju Island, Korea during the period of 20 July to 10 August 1994. Total suspended particles and PM2.5 particles were collected and their mass and ion concentrations were analyzed. Along with PM2.5, gaseous species were collected on impregnated filters. Also, another low volume sampler collected carbonaceous species analysis. The sampling period could be classified into two distinctive periods, with a highly polluted period between 20 July and 1 August and an unpolluted period between 2 and 10 August. During the polluted period, the mean non sea-salt sulfate concentrations in TSP and PM2.5 were 16.6 and 13.4 μg m-3, respectively. Backward trajectory analysis showed that air parcels arriving at the sampling site during the former period were mainly from Korea and Japan while air parcels during the latter period were from the North Pacific Ocean. It was suggested that the air pollutant levels during the latter period could be considered as marine background concentrations in the region during summer.