北京市2005年夏季大气颗粒物污染特征及影响因素
Pollution characteristics and influencing factors ofatmospheric particulates in Beijing during the summer of 2005
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摘要: 对2005年7~8月北京市不同功能区8个采样点PM10和PM2.5的浓度水平、空间分布、PM10/PM2.5比值进行了分析,并讨论了PM10和PM2.5的日变化特征及影响因素。结果表明,北京市夏季PM10和PM2.5日均浓度为155.37 μg/m3和87.70 μg/m3,分别为国家二级标准和美国PM2.5标准的1.04倍和1.35倍;PM2.5、PM10浓度在不同功能区存在一定差异;PM2.5和PM10的日变化以白天高,夜间低为主,且不同功能区的最高值对应于城市居民活动的不同高峰期;在湿度较高的情况下,PM2.5、PM10与湿度呈一定正相关性,且湿度对PM2.5的影响更大;降水前后PM2.5、PM10浓度变化情况表明降水的主要作用是清除粗粒子,对PM2.5的影响则较小。Abstract: Mass concentrations, space distribution, PM10/PM2.5 ratios in 8 sampling sites representing different environments of Beijing urban area from July to August, 2005 are analysed. Moreover, the relationship between concentration of PM and influencing factors were discussed. The results showed that the average 24 h PM10 and PM2.5 concentration were 155.37 μg/m3 and 87.70 μg/m3, respectively, being 1.04 and 1.35 times higher than Class II category of the National Ambient Air Quality Standards in China and US EPA enacted in air quality standards(PM10, 150 μg/m3; PM2.5, 65 μg/m3). The concentrations of PM10 and PM2.5 were different in different areas. The daily PM10 and PM2.5 concentrations were mostly high in the daytime and low at night, and maximum values in different functional areas corresponded different peak period of production activity. The particle concentration was negatively less correlated with temperature in the daytime. A stronger positive correlation was identified between the fine particle mass concentration and the high humidity, but a little lower for PM10. Precipitation mostly eliminated coarse particles in PM10.
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Key words:
- Beijing /
- summer /
- PM10 /
- PM2.5 /
- pollution characteristics /
- influencing factors
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