北京市沙尘暴天气环境质量等级划分

为进一步认知沙尘天气对北京空气质量的定量影响,本文通过对2001-2009年发生在我国北方显著沙尘天气过程的分析,结合同期北京空气污染指数(API)的变化,研究了沙尘天气对北京空气质量等级划分的影响。结果如下:①构建了一个空气质量等级划分的复合指标体系。将沙尘天气过程对北京空气质量的影响划分为4个等级。分别是覆盖型重污染、边缘型中度污染、远距离轻微污染和远距离无影响;②2001-2009年,我国北方共计发生136次沙尘天气过程,对北京大气环境质量影响贡献的最高值出现在秋末(11月)和冬初(12月),以覆盖型重污染等级为主,共计发生17次,期间北京地区平均API为306;③从传输路径上划分,则是以西北路径为主,共计发生59次,其中24次显著影响到北京,占41%。期间,北京地区平均API为242;④沙尘天气过程持续时间以2天为主,共计发生56次,共有14次显著影响到北京,占25%,期间北京地区平均API为216。

Sandstorm Event Environmental Quality Classification in Beijing

To further quantify the impact of cognitive dust weather on Beijing air quality we analyzed a series of dust weather processes in northern China between 2001 and 2009. Combined with the same period for the Beijing air pollution index(API),we studied the effect of dust weather on Beijing's air quality. We constructed a composite index system for the classification of air quality and the establishment of this sandstorm weather environmental grade index system will further strengthen research in this area. Air quality in Beijing affected by dust weather processes is divided into four levels:Heavy Dust-covered Pollution, Marginal Medium Pollution, Long-Distance Light Pollution and Long-Distance No Pollution. Between 2001 and 2009,there were 136 dust weather process in northern China,and the contribution of effects of sandstorm events on air quality in Beijing is most frequent in November and December and mainly Heavy Dust-covered pollution(occurred 17 times)with an average API of 306. According to transport paths,the main dust transport path that influences Beijing is the northwest route:this occurred 59 times,of which 24 dust weather processes accounted for 41% of the time that Beijing was affected, resulting in an average API of 242 during these times. Sandstorm process that influence Beijing usually last two days and occurred 56 times,of which,14 sandstorm processes accounted for 25% of the time Beijing was affected(the average API was 216 during these periods).