HR: 0830h
AN: A21A-23    [Abstracts]
TI: Aerosol Optical and Chemical Properties in Urban Guangzhou, China
AU: * Andreae, M O
EM: andreae@mpch-mainz.mpg.de
AF: Planck Institute for Chemistry, P O Box 3060, Mainz, 55020 Germany
AU: Schmid, O
EM: oschmid@mpch-mainz.mpg.de
AF: Planck Institute for Chemistry, P O Box 3060, Mainz, 55020 Germany
AU: Yang, H
EM: chyang@ust.hk
AF: Hong Kong University of Science and Technology, Clear Water Bay Kowloon, Hong Kong, China
AU: Chand, D
EM: duli@mailserver.mpch-mainz.mpg.de
AF: Planck Institute for Chemistry, P O Box 3060, Mainz, 55020 Germany
AU: Yu, J
EM: chjianyu
AF: Hong Kong University of Science and Technology, Clear Water Bay Kowloon, Hong Kong, China
AU: Zhang, Y
EM: yhzhang@pku.edu.cn
AF: Peking University, College of Environmental Sciences, Beijing, 100871 China
AU: Zeng, L
EM: lmzeng@pku.edu.cn
AF: Peking University, College of Environmental Sciences, Beijing, 100871 China
AB: During the intensive period of the Pearl River Delta (PRD) measurement campaign (4 Oct - 5 Nov 2004), we performed in-situ measurements of aerosol chemical and optical properties (PM2.5) in urban Guangzhou (23.08N, 113.16E, altitude 8m asl; ~150 km northwest of Hong Kong). A photoacoustic spectrometer (532 nm) and two integrating nephelometers (545 nm) were used to determine aerosol light absorption (dry, RH less than 40 percent) and scattering coefficients (dry and ambient), respectively. Twelve-hour averages of elemental (EC) and organic carbon (OC) aerosol mass concentration were determined by evolved gas analysis. Ionic constituents were determined by ion chromatography. The aerosol concentrations at this urban site were consistently very high, with average PM2.5, OC and EC mass concentrations of 103, 22.3 and 7.1 ęg m-3, respectively. The high average OC/EC ratio of about 3 suggests that traffic emissions are an important emission source in the sampled airshed. The average scattering and absorption coefficients for dry aerosol were 402 and 88 Mm-1, respectively. During some episodes, extremely high values of aerosol absorption were reached (up to 450 Mm-1). Consistent with the urban pollution sources and the exceptionally dry weather conditions, the average single scattering albedo (SSA) at ambient conditions was about 0.86, indicating strongly absorbing aerosol. The observed diurnal trends are consistent with particle growth by condensation during day, enhanced traffic activity in the morning and evening hours, and the build-up of a shallow nocturnal boundary layer during the night.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly