Chemical composition of the background aerosol at two sites in southwestern and northwestern China: potential influences of regional transport |
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| Authors: | WEN J QU XIAO Y ZHANG RICHARD ARIMOTO DAN WANG YA Q WANG LI W YAN YANG LI |
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| Institution: | Key Laboratory of Physical Oceanography, Department of Marine Meteorology, College of Physical and Environmental Oceanography, Ocean University of China, 238 Songling Road, Laoshan District, Qingdao 266100, China;;Key Laboratory of Atmospheric Chemistry, Centre for Atmosphere Watch &Services (CAWAS), Chinese Academy of Metrological Sciences, China Meteorological Administration, 46 Zhong-Guan-Cun S. Ave., Beijing 100081, China;;Carlsbad Environmental Monitoring &Research Center, New Mexico State University, Carlsbad, New Mexico, USA;;State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 10 Fenghui S. Rd., PO Box 17, XiAn 710075, China |
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| Abstract: | Concentrations of organic carbon (OC), elemental carbon (EC), selected trace elements and water-soluble (WS) ions were determined for samples collected from August 2004 to February 2005 to assess the aerosol background at two remote sites in China. The OC and EC concentrations in PM10 from near the Tibetan Plateau at Zhuzhang (ZUZ) were comparable with other background sites, averaging 3.1 and 0.34 μg m?3, respectively, with no pronounced seasonality. At Akdala (AKD) on northern margin of the Zhungaer Basin, the average concentrations were similar (mean OC = 2.9 μg m?3 and EC = 0.35 μg m?3), but the concentrations were higher in winter. The aerosol mass at both sites was dominated by OC and SO42?, but a stronger contribution from soil dust was observed at AKD. At ZUZ, NO3? showed a unique weather-related fluctuation in PM10 with a periodicity of ～1 week. Anthropogenic sources in the Sichuan Basin and southeastern Yunnan Province evidently influence ZUZ in summer and autumn while pollutants from Russia and the China–Mongolia border affect AKD nearly all year. The identification of these upwind sources demonstrates that transboundary transport needs to be taken into account when assessing air quality in remote parts of China. |
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