2012—2014年常州市空气质量与气象要素关系分析

Analysis of Relationship between Air Quality and Meteorological Elements over Past 3 Years in Changzhou

利用常州市空气质量资料、常规气象观测资料,分析了2012—2014年常州市空气质量与气象要素之间的关系。结果表明:1)近3 a常州市总体空气质量特征以良为主,污染率接近40%,夏季空气质量最好,秋季次之,冬季为空气质量最差的季节。2)风向对污染物的输送有重要影响,常州市常年以偏东南风向为主导风向,风带来的海上清洁空气对污染物的稀释有一定作用,当空气达重污染时,西北风分量显著增大,说明上游地区污染物的输送对常州市空气质量有较大影响;风速对污染物的扩散作用明显,风速越大,空气污染率越低。3)降水对空气污染具有显著的净化作用,降水量级增大时,空气质量的优良率增大。4)气温与空气质量直接关系较小,气温低时,大气层结稳定,加之人类供暖致使能耗增大,导致空气污染概率较大,气温高时,大气对流活动较多,易产生降水,空气质量优良率较高;湿度与空气质量关系则较为复杂,当未形成降水时,相对较高的湿度有利于空气重污染的产生。

Based on 2012-2014 air quality data and conventional meteorological observation data of Changzhou,the relationship between air quality and meteorological elements is analyzed. The results show that the overall air quality of recent three years is mainly good,but the contamination rate is nearly 40%. Summer is the best in air quality of the seasons,followed by autumn,while winter is the worst. Wind direction plays an important role in transportation of air pollutants. The prevailing main wind direction of Changzhou is southeast. The southeast wind brings clean air from the ocean which is conducive to dilute pollutants. When the air quality reaches heavy contamination,there is a significant increase of the northwest wind which means the transportation of pollutants from upstream has a great impact on the air quality in Changzhou. Wind speed is important in the diffusion of pollutants. The faster the wind speed,the lower the air pollution rate. Precipitation has significant air purification effects,when precipitation level increases,the air quality excellent rate increases. The direct relationship between air quality and temperature is rather small. When the temperature is low,the atmospheric stratification is relatively stable,combined with an increasing of human energy consumption for heating,which leads to a greater probability of air pollution. When the temperature is high,there are more atmospheric convective activities such as strong precipitation,which result in a higher air quality excellent rate. The relationship between air quality and humidity is complicated. If there is no precipitation,a relatively high humidity would be conducive to the formation of heavy air pollution.