2005-2010年乌鲁木齐市空气质量达标特征研究

利用近6年（2005-2010年）乌鲁木齐市环境空气质量监测数据，分析研究了乌鲁木齐市PM10／SO2、NO2等主要污染物浓度时间变化和空气质量分级特征。结果表明：近6年来乌鲁木齐市空气质量保持稳定，并持续改善。主要污染物SO：和PM10年均浓度超标但整体呈下降趋势，N02浓度达标但逐年升高。冬季（1月、12月）空气质量达标天数显著增加，空气质量达标率由2005年的4．8％提高到2010年的24．2％；同期，重污染天气发生频率则由21％降低至3．2％。PM10是乌鲁木齐市冬季出现频数最高的首要污染物。

Characteristics of Air Quality in Urumqi during 2005 -2010

In order to understand the air quality changing characteristics in recent six years（2005 -2010） in Urumqi City, the temporal characteristics of air pollutants concentration were studied using daily atmospheric monitoring data. The results showed that the air quality in Urumqi during the past six years was stable and improved continuously. The annual average concen tration of PMj0 and SO2 exceeded the National Ambient Air Quality Standard II, but its concentrations have all decreased as a whole during the Eleventh Five - Year Plan. Meanwhile the NO2 annual concentration met the Air Quality Standard II, but showed an increase. The number of days satisfying the Chinese Grade II air quality standard increases significantly in recent six winters. Theratio for the number of days that have reached standards increased from 4. 8% in 2005 to 24. 2% in 2010. Meanwhile the fre quency of heavy pollution days decreases from 21% in 2005 to 3.2% in 2010. PM~0 is the primary pollutant with the highest fre quency among the main air pollutants in winter of Urumqi.