HR: 1340h
AN: A23B-1258    [Abstracts]
TI: Aerosol Chemistry and Humidity Effect on Visibility Impairment in Guangzhou During the 2006 PRD Campaign
AU: * Jung, J
EM: buddych@gist.ac.kr
AF: Advanced Environmental Monitoring Research Center (ADEMRC), Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan- gwagiro(Oryong-dong), Buk-Gu, Gwangju, 500-712, Korea, Republic of
AU: Kim, Y
EM: yjkim@gist.ac.kr
AF: Advanced Environmental Monitoring Research Center (ADEMRC), Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan- gwagiro(Oryong-dong), Buk-Gu, Gwangju, 500-712, Korea, Republic of
AU: Lee, H
EM: hanlim@gist.ac.kr
AF: Advanced Environmental Monitoring Research Center (ADEMRC), Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan- gwagiro(Oryong-dong), Buk-Gu, Gwangju, 500-712, Korea, Republic of
AU: Liu, X
EM: lxgstar@126.com
AF: College of Environmental Science, Peking University, Beijing 100871, Beijing, 100871, China
AU: Gu, J
EM: jianweigu83@yahoo.com.cn
AF: College of Environmental Science, Peking University, Beijing 100871, Beijing, 100871, China
AU: Zhang, Y
EM: yhzhang@pku.edu.cn
AF: College of Environmental Science, Peking University, Beijing 100871, Beijing, 100871, China
AB: In order to characterize the cause of visibility impairment in the metropolitan area of Guangzhou, China, aerosol optical and chemical measurements were conducted from 2 to 31 July 2006 at a Guangzhou urban site as part of the Observation Experiment for Regional Air Quality in Pearl River Delta of China. Light extinction, scattering, and absorption coefficients were measured simultaneously with a transmissometer, a nephelometer and an aethalometer, respectively. Continuous aerosol chemical measurements were also made with Sunset elemental carbon/organic carbon (EC/OC) analyzers and on-line ion monitors. Humidograph coupling with a nephelometry was used to estimate relative humidity scattering enhancement factor, f(RH) of each aerosol component including sulfate, nitrate, and sea salt. During the intensive monitoring period, the average visual range and light extinction coefficient were 11.4 ╳取 4.0 km and 419.2 ╳取 188.1 Mm-1, respectively. The latter was found to be composed of 210.9 ╳取 145.8 Mm-1 (46.9 %) by NHSO, 33.0 ╳取 32.9 Mm-1 (7.3 %) by NHNO, 65.4 ╳取 37.9 Mm-1 (14.6 %) by OMC, 51.6 ╳取 24.9 Mm-1 (11.5 %) by EC, 40.2 ╳取 48.8 Mm-1 (8.9 %) by sea salt, 10.2 ╳取 7.7 Mm-1 (2.3 %) by fine soil, and 12.0 ╳取 6.5 Mm-1 (2.7 %) by coarse particles. Average humidity effect on visibility impairment was estimated to be 38 % of total light extinction coefficient, which consists of 25.7 % (115.4 Mm-1) by NHSO, 4.1 % (18.6 Mm-1) by NHNO, and 8.2 % (36.8 Mm-1) by sea salt. Two episodes of severe visibility impairment were observed during the intensive measurement period. The 1st one was classified as a local accumulation case based on the Hysplit back trajectory analyses while the 2nd one as a transport case from mainland China. During the 1st haze episode, concentration of each aerosol component increased up to 30 % ~ 70 % compared to the relatively clean days with an average increase in light extinction coefficient of 152.2 Mm-1. During the 2nd haze episode, sulfate and nitrate dominantly increased up to 280 % ~ 360 %, resulting in 150 % increase in light extinction coefficient of 409.1 Mm-1.
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting