中文摘要：

根据兰州市空气质量日报数据和同期的常规气象资料,研究了2001～2009年该市的空气质量特征,探讨了气象要素和城市空气质量之间的相互关系。结果表明：随着近年来该市开展大规模的环境综合治理工作,空气质量有了明显得改善。研究期间的空气质量以Ⅱ和Ⅲ级天气为主。主要污染物PM10、SO2、NO2年平均浓度在大部分年份超过国家空气质量二级标准,这表明该市的空气污染已呈现扬尘、煤烟和机动车尾气混合型污染特征。空气质量具有明显的季节变化。夏季的空气质量最好,冬季最差,春季次之。风速、气温、大气能见度、降水等气象条件的优劣对当地的空气质量影响显著。四季的API指数与同期的各个常规气象要素密切相关。API指数与风速、降水、能见度、露点温度、总云量在大部分情况下存在显著的负相关关系,与温度存在正相关关系。

英文摘要：

Based on the monitoring air environmental and ground meteorological data,the characteristics of the air quality in Lanzhou during 2001～2009 were analyzed,and the relationships between the air pollution index（API） and ground meteorological factors were discussed.The results indicated that the air quality had been improved evidently due to some effective air quality regulations taken.Ⅱ-and-Ⅲ-air-quality primarily occurred in Lanzhou.The main pollutants PM10,SO2,NO2 had exceeded the two class standard of the State Environmental Protection Bureau on air quality in most of years,showing that Lanzhou belonged to a typical soil dust,coal smoke and mobile pollution city.The seasonal variation of air quality was distinct,the most serious air pollution accurred in winter,followed by in spring;Air quality was the best in summer.The air quality was greatly influenced by the meteorological factors such as wind velocity,air temperature,visibility,precipitation.The API index in every season had a close correlation with the meteorological factors by the correlation analysis.There was a strong negative correlation between the API index and wind velocity,precipitation,visibility,dew-point temperature,total cloud cover,and a positive correlation with air temperature.