TY - JOUR
T1 - Composition and hygroscopicity of aerosol particles at Mt. Lu in South China
T2 - implications for acid precipitation
AU - Li, Weijun
AU - Chi, Jianwei
AU - Shi, Zongbo
AU - Wang, Xinfeng
AU - Chen, Bin
AU - Wang, Yan
AU - Li, Tao
AU - Chen, Jianmin
AU - Zhang, Daizhou
AU - Wang, Zifa
AU - Shi, Chune
AU - Liu, Liangke
AU - Wang, Wenxing
PY - 2014/9
Y1 - 2014/9
N2 - Physicochemical properties of aerosol particles were studied at Mt. Lu, an elevated site (115°59′E, 29°35′N, 1165 m) within the acid precipitation area. Northeast winds transport copious amounts of air pollutants and water vapor from the Yangtze River Delta into this acid precipitation area. NH4+ and SO42− are the dominant ions in PM2.5 and determine aerosol acidity. Individual particle analysis shows abundant S-rich and metals (i.e. Fe-, Zn-, Mn-, and Pb-rich) particles. Unlike aerosol particles in North China and urban areas, there are little soot and mineral particles at Mt. Lu. Lack of mineral particles contributed to the higher acidity in precipitation in the research area. Nano-sized spherical metal particles were observed to be embedded in 37% of S-rich particles. These metal particles were likely originated from heavy industries and fired-power plants. Hygroscopic experiments show that most particles start to deliquesce at 73–76% but organic coating lowers the particle deliquescence relative humidity (DRH) to 63–73%. The DRHs of these aerosol particles are clearly smaller than that of pure ammonium sulfate particles which is 80%. Since RH in ambient air was relatively high, ranging from 65% to 85% during our study period, most particles at our sampling site were in liquid phase. Our results suggest that liquid phase reactions in aerosol particles may contribute to SO2 to sulfuric acid conversion in the acid precipitation area.
AB - Physicochemical properties of aerosol particles were studied at Mt. Lu, an elevated site (115°59′E, 29°35′N, 1165 m) within the acid precipitation area. Northeast winds transport copious amounts of air pollutants and water vapor from the Yangtze River Delta into this acid precipitation area. NH4+ and SO42− are the dominant ions in PM2.5 and determine aerosol acidity. Individual particle analysis shows abundant S-rich and metals (i.e. Fe-, Zn-, Mn-, and Pb-rich) particles. Unlike aerosol particles in North China and urban areas, there are little soot and mineral particles at Mt. Lu. Lack of mineral particles contributed to the higher acidity in precipitation in the research area. Nano-sized spherical metal particles were observed to be embedded in 37% of S-rich particles. These metal particles were likely originated from heavy industries and fired-power plants. Hygroscopic experiments show that most particles start to deliquesce at 73–76% but organic coating lowers the particle deliquescence relative humidity (DRH) to 63–73%. The DRHs of these aerosol particles are clearly smaller than that of pure ammonium sulfate particles which is 80%. Since RH in ambient air was relatively high, ranging from 65% to 85% during our study period, most particles at our sampling site were in liquid phase. Our results suggest that liquid phase reactions in aerosol particles may contribute to SO2 to sulfuric acid conversion in the acid precipitation area.
KW - Acid precipitation
KW - Hygroscopicity
KW - Aerosol formation
KW - Individual particle
U2 - 10.1016/j.atmosenv.2014.06.003
DO - 10.1016/j.atmosenv.2014.06.003
M3 - Article
SN - 1352-2310
VL - 94
SP - 626
EP - 636
JO - Atmospheric Environment
JF - Atmospheric Environment
ER -