Ho K F, Lee S C, Cao J J, Chow Judith C, Watson John G, Chan Chak K
Research Center for Urban Environmental Technology and Management, Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Sci Total Environ. 2006 Feb 15;355(1-3):276-87. doi: 10.1016/j.scitotenv.2005.03.013.
The chemical characteristics of ambient particulate matters in urban and rural areas of Hong Kong were determined in this study. A monitoring program starting from November 2000 to February 2001 (winter) and June 2001 to August 2001 (summer) for PM10 and PM2.5 was performed at three monitoring stations in Hong Kong. Twenty-four-hour PM10 and PM2.5 samples were collected once every 6 days at two urban sites, PolyU and KT, and every 12 days at a background site, HT, with Hi-Vol samplers. High concentrations of OC, EC (except in PolyU), water-soluble ions and elements were observed in winter among the three sampling sites for PM10 and PM2.5 fractions. Seasonal variations were significant in background HT. Dilution effect due to the increase in mixing depth and precipitation in summer reduced the concentrations of particulate matters. Long-range transport could contribute to the higher concentrations of particulate matter in the winter. Chemical mass closure calculations were performed for PM10 and PM2.5 observed. Mass closure improved when separate factors (1.4 and 1.9 respectively) were used to convert water-soluble organic carbon (WSOC) and water-insoluble organic carbon (WINSOC) into corresponding organic masses. The urban sites showed high percentages of water-soluble ions in winter and high percentages of carbonaceous species in summer. Better results were obtained for the chemical mass closure analysis in winter than in summer. High temperature and solar radiation in summer increased the rate of the complex photochemical reaction in the atmosphere. Therefore the chemical mass closure analysis would underestimate the volatized species and secondary aerosols during summer.
本研究测定了香港城乡地区环境颗粒物的化学特性。于2000年11月至2001年2月（冬季）以及2001年6月至2001年8月（夏季）开展了一项监测计划，在香港的三个监测站对PM10和PM2.5进行监测。使用高容量采样器，在两个城市站点（理大及观塘）每6天采集一次24小时的PM10和PM2.5样本，在一个背景站点（沙田）每12天采集一次。在冬季，三个采样站点的PM10和PM2.5组分中均观测到高浓度的有机碳、元素碳（理大站除外）、水溶性离子和元素。背景站点沙田的季节性变化显著。夏季混合层深度增加和降水导致的稀释效应降低了颗粒物浓度。长距离传输可能导致冬季颗粒物浓度较高。对观测到的PM10和PM2.5进行了化学质量平衡计算。当使用单独的因子（分别为1.4和1.9）将水溶性有机碳（WSOC）和水不溶性有机碳（WINSOC）转化为相应的有机质量时，质量平衡得到改善。城市站点在冬季水溶性离子百分比高，在夏季碳质物种百分比高。冬季化学质量平衡分析的结果优于夏季。夏季的高温和太阳辐射增加了大气中复杂光化学反应的速率。因此，化学质量平衡分析在夏季会低估挥发物种和二次气溶胶。
