Aerosol hygroscopic properties during Asian dust, pollution, and biomass burning episodes at Gosan, Korea in April 2001

Measurements of the aerosol hygroscopic growth factor, f(RH), and the physical and optical properties of aerosols were made at Gosan, Korea during the aerosol characterization experiment (ACE)-Asia 2001 field campaign (April 2001). The optical and hygroscopic properties of aerosols were characterized in terms of the air mass transport pathways. During the Asian dust period, sigma(sp) and sigma(ap) were remarkably elevated with mean and standard deviation of 238.6 +/- 55.3 Mm(-1) and 24.2 +/- 10.9 Mm(-1) respectively. The mean f(RH) for the pollution aerosols from Chinese sectors (2.75 +/- 0.38) in this study was much higher than that for the anthropogenic aerosols in Europe during ACE-2 (1.46 +/- 0.10) as well as that of the urban/industrial aerosols of the US east coast during TARFOX (1.81 +/- 0.37-2.30 +/- 0.24). The mean f(RH) during the smoke period (1.60 +/- 0.20) was comparable to that during INDOEX (1.58 +/- 0.21), and higher than that for SCAR-B in Brazil (1.16). We found a negative correlation (r = 0.81) between f(RH) and OC concentration. This negative correlation suggests that organic aerosols have a strong influence on the smoke aerosol hygroscopicity. (c) 2005 Elsevier Ltd. All rights reserved.