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The concentration characteristics of four aerosol chemical components (water-soluble, insoluble, black carbon (BC), and sea-salt) and their direct radiative forcing (DRF) were analyzed using the daily or hourly data (PM2.5) measured at urban (Yeonsan, Gwangbok, Hakjang, and Gijang in Busan) and background sites (Aewol in Jeju Island) during haze events, based on a modeling approach. Overall, the concentrations of water-soluble component and its impact on the DRF were predominant over all other components at most of the sites (especially at Aewol, Gwangbok and/or Hakjang). The DRFs at the surface (DRFSFC), top of the atmosphere (DRFTOA), and the atmosphere (DRFATM) for most aerosol components (except for BC) at most of the sites (except for Yeonsan) were high in spring or winter and low in summer or fall. Meanwhile, the DRFs at Yeonsan were highest in summer (for DRFTOA) or fall (for DRFSFC) and lowest in spring (for both). These seasonal DRF characteristics in the study sites might be closely related to the seasonal patterns of aerosol component concentrations and/ or meteorological conditions (e.g., relative humidity). In addition, the positive DRFATM of BC in the study sites was highest among the all aerosol components due to strong radiative absorption. The differences in DRFs for water-soluble component between haze and non-haze periods were largest in the all study sites. In particular, the DRFTOA (and DRFSFC) of water-soluble at the sites of Gwangbok and Aewol during the haze periods were higher by a factor of 1.8 and 2.3 (and a factor of 1.9 and 2.4) than those during the non-haze periods.

来源平台：JOURNAL OF KOREAN SOCIETY FOR ATMOSPHERIC ENVIRONMENT