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To investigate the characteristics of fine particle and establish source-receptor relationship between pollutant concentrations and long-range air masses transport, PM2.5 were collected during two different sampling periods (every-6-day samplings and intensive samplings) at Taean background station, South Korea. High correlation among PM2.5, SO42-, NO3- and NH4- suggested that SO42-, NO3-, and NH4+ were primary ionic components of fine particles. The sum of SO42-, NO3- and NH4+ accounted for 35%, 32% of PM2.5 mass for every-6-day samplings and intensive samplings, respectively. Backward trajectories were used to interpret the possible air mass sources. Most of back-trajectories passed through northwestern quadrant, where one of the dominant dust-storm source regions, gobi desert is located. On average, 75% back-trajectory at 2000 m above ground level (agl) crossed through northwestern quadrant during the above two different sampling periods. Cluster memberships were also inspected in detail for better understanding of transport patterns during different sampling periods. The trajectories passed through northwestern China with low speed in winter and spring considered as ones that carried much aerosol particles to Taean. In addition, the airflow that arrived at Taean in winter and spring carried more pollutants than that in summer and autumn. (C) 2002 Elsevier Science Ltd. All rights reserved.