2001-2011年西宁市空气质量特征及其与气象条件的关系

利用2001-2011年西宁市城市空气质量日报资料，研究西宁市区域性污染特征，并结合气象资料对空气质量变化特征和影响因素进行了分析。结果表明：西宁市空气污染以可吸入颗粒物为主要污染物，空气质量状况以优和良居多；空气质量季节变化特征明显，春季空气质量最差，其次是冬季和秋季，夏季空气质量最好，冬春季空气质量不稳定，夏秋季空气质量较稳定; 空气质量年变化幅度大，供暖期API指数明显高于非供暖期；沙尘影响指数呈现下降趋势；从年际变化来看，空气质量已经有了明显改善；气象要素对大气污染物有制约关系，其中起主要作用气象因子为沙尘日数、降水量、相对湿度和气温； 可吸入颗粒物长距离输送是西宁市冬春季重污染现象的主要原因，来源于新疆、甘肃西北部、内蒙古中西部及本省西北部的柴达木盆地。

Characteristics of air quality and its relationship with meteorological factors from 2001 to 2011 in Xining

Based on the dally air quality report and the corresponding meteorological data from 2001 to 2011 in Xining,the characteristic of regional pollution, air quality and its influencing factors were analyzed. The results show that the inhalable particle is the main pollutant and air quality is dominant by excellent and fine grades in Xining. Air quality has a clear seasonal change. It is better in summer, then in autumn and winter, while it is the worst in spring. The air quality is unstable in winter and spring, while it is stable in summer and autumn. The annu- al air quality changes significantly, and API is higher during winter heating period than during non-heating period. Sand-dust influencing index is in a declining trend in Xining. Air quality is remarkably improved based on analysis of interannual variability. The air pollution is restricted by meteorological factors such as sand-dust days, precipita- tion, relative humidity and air temperature. Long-range transport of inhalable particulate matters from the northwest of Xinjiang and Gansu provinces, middle and west of Inner Mongolia and Qaldam Basin are important sources of air pollution in spring in Xining.