Characteristics of air quality and its relationship with meteorological factors from 2001 to 2012 in Harbin,China

The characteristic of air quality and its influencing factors are analyzed based on the daily report data of urban air quality and meteorological data in Harbin from 2001 to 2012. The seasonal change of the air pollution index( API) in Harbin showed relatively high in winter and spring and relatively low in summer and fall. The values of API were obviously higher in heating season than that in non-heating season. In Harbin,the key pollutant was inhaleble particles. In 75. 4% of the days,the air pollution levels showed good and moderate. During the 12 years,a significant decreasing trend of API indicates the improvement of air quality in Harbin. The variations of meteorological parameters can influence the level of air pollutants,which show a positive correlations between API and wind speed,and a negative correlations between API and rainfall,air temperature, and visibility. The pattern and origination of the middle-polluted air mass appeared in Harbin was analyzed by backward trajectory analysis.