中文摘要：

为了解兰州市大气污染现状,评价其环境质量和健康风险,选择兰州市污染较重的西固区和污染较轻的榆中县为研究区域,定位监测并分析颗粒物、SO2和NOx等大气主要污染物的分布特征,采用环境空气质量指数法评价兰州市大气污染现状,重点分析颗粒物的构成特征和健康风险.结果表明：兰州市大气污染物分布呈明显的季节性、区域性特点;大气颗粒物MMD（质量中值直径）在3.2～7.9μm之间,属细颗粒型;西固区环境空气质量指数及污染水平普遍高于榆中县,其中位于西固区的西固第二小学采样点污染较为严重,污染水平为五级,需要采取控制措施;兰州市15 m大气高度PM10的健康风险高于30和1.5 m,兰州市PM2.5和PM10的健康风险属于可接受风险范围.

英文摘要：

To investigate the air pollution status of Lanzhou City and assess its environment quality and health risk, the seriously-polluted Xigu District and slightly-polluted Yuzhong Town were chosen as research sites to monitor and analyze the constitutive characteristics of major pollutants such as particulate matter, sulfur dioxide, and nitrogen oxides. The approach of Air Quality Index was used to assess air pollution conditions at different sampling points, and to analyze the constitutive characteristics and health risk of particulate matter emphatically. The results showed that air pollution was distributed seasonally and regionally in Lanzhou City. The mass median diameter （MMD） of atmospheric particles in Lanzhou City was between 3.2 and 7.9 μm, which belongs to the fine particles category. The Air Quality Index of Xigu District was higher than that of Yuzhong Town. The Air Quality Index of the Xigu No. 2 Primary School in Xigu District was relatively serious, with a pollution level of Grade Five; measures should be taken in this area to control the pollution. The health risk of PMto at 15 m height in Lanzhou City was greater than at 30 m or 1.5 m. The health risk of PM2.5 and PM10 in Lanzhou City was within acceptable range.