沙尘与大雾天气对京津石空气质量影响

采用北京、天津、石家庄2001-2010年沙尘与大雾天气的统计数据以及城市空气污染指数（API），分析北京、天津、石家庄3市空气污染指数变化特征及大雾和沙尘天气下北京、天津、石家庄3市空气质量情况，进而得出沙尘大雾天气对京津石空气质量的影响。结果表明：2001-2010年间北京、天津、石家庄3市API总体呈下降趋势，天津、石家庄相对于北京空气质量改善较为明显，且空气质量夏季〉秋季〉春冬季。沙尘天气条件下，北京、天津、石家庄3市API平均值分别为255、179和167，空气质量出现良的比率天津为24%，北京、石家庄为10%左右，出现重污染的比率北京高达50%以上，天津和石家庄均在20%左右；3市沙尘天气高频次均出现在3-5月份，但北京沙尘天气发生次数远大于天津和石家庄。大雾天气条件下，北京、天津、石家庄3市API平均值为185、130和167，空气质量出现优或良的比率：天津〉石家庄〉北京，北京和石家庄出现重污染的比率均接近30%，天津不到10%，所以大雾天气对3市空气质量影响较小，大雾天气频次的变化波动并未对该地区空气质量的年际变化造成显著影响，3市高频次大雾天气集中在10-12月份，对该时段内空气污染呈现加重趋势有一定的贡献。所以沙尘和大雾天气均对北京、天津和石家庄空气质量存在不利影响，其中对北京影响最为严重，对天津影响最轻。整体上沙尘对3市的空气质量影响较大，大雾天气影响较小。

Influence of dust storms and fog on air quality of Beijing,Tianjin and Shijiazhuang

Paper discussed and analyzed the effect of dust storms and fog on air quality on the basis of statistical data of dust storms and fog and the air pollution index（API） data of Beijing, Tianjin and Shijiazhuang from 2001-2010. The results of the analysis show that the API of the three cities is on the decline as a whole. Relative to Beijing, Tianjin and Shijiazhuang＇s air quality improvement is more obvious, and air quality in summer〉autumn〉Spring Festival. The effect of dust storms and fog weather on three citiesair quality is negative, the most affected in Beijing, the lightest influence on Tianjin. On the whole, air quality is greatly influenced by dust storm and less influenced by fog. Under dust weather condition, the average API of Beijing, Tianjin, Shijiazhuang is 255, 179 and 167 respectively; the ratio of good weather in Tianjin is 24% and 10% approximately in two other cities; the prevalence of heavy pollution in Beijing is as high as 50%above, Tianjin and Shijiazhuang all around 20%;dust weather occurred in high frequency from March to May, but Beijing dust weather occurred more frequently than Tianjin and Shijiazhuang. Unser heavy fog weather condition, the average API of Beijing, Tianjin and Shijiazhuang is 185, 130 and 167;The proportion of excellent or good air quality：Tianjin〉Shijiazhuang〉Beijing;the ratio of Beijing and Shijiazhuang in heavy pollution are close to 30%, and Tianjin＇s less than 10%; the fog weather frequency changes in volatility is not impact on the interannual variation of the air quality in the region;high frequency of heavy fog weather is focused from October to December that contribute to the tendency of increase of air pollution in the period so heavy fog weather is less impact on air quality. Thus dust and fog weather all have negative effects on the air quality of Beijing, Tianjin and Shijiazhuang, the most affected on Beijing and the lightest influence on Tianjin. On the whole, dust weather have greater impact on air quality and heavy fog weather have less influence.