Abstract: Background, aim, and scope With the rapid development of urbanization, characteristics of air pollution has changed from soot type to mixed mode in China. Urumqi was in the list of the 10 cities that reported the worst air quality during the first nine months in 2016, according to a report published by the Ministry of Environmental Protection. The study aimed at discovering the main influencing factors of the air pollution in Urumqi. Materials and methods Based on the daily air pollution levels (6 regular monitoring pollutants (PM2.5, PM10, SO2, NO2, CO, O3) concentrations, and air quality index (AQI) classification standard) in January 2016 in Urumqi, analyzing temporal and spatial distribution of air pollution in Urumqi by GIS. Main materials including the concentrations of PM2.5, PM10, SO2, NO2, CO, O3 (Xinjiang Department of Environmental Protection, http://188.8.131.52:8011/),meteorological factors (China Meteorological Administration, http://data.cma.cn/user/toLogin.html/), and Landsat 8 TM image of Urumqi (Geospatial Data Cloud, http://www.gscloud.cn/). Combing analytic hierarchy process (AHP) with land use classification and distribution of important pollutant enterprises, by correlation analysis of air pollution factors and meteorological factors to evaluate the influencing factors of air pollution distribution characteristics in Urumqi. Results The research showed that lightly polluted, moderately polluted, severely polluted, heavily polluted days accounted for 3%, 26%, 32%, 39% of the whole month in January2016 respectively. Midong District was the most polluted area, there were significant correlations between air pollution factors and meteorological factors. Discussion This research studied the temporal and spatial distribution characteristics of air pollution in Urumqi and its correlation with meteorological factors. The coldest month (January) of Urumqi in 2016 was selected as the study period. Firstly, the temporal and spatial distribution of air pollutant factors and temporal variation of meteorological factors in Urumqi were analyzed. Secondly, correlation analysis was carried out on pollutants and meteorological factors, and it was found that meteorological factors had significant effects on air pollutant factors. Finally, the air pollution assessment model of Urumqi was constructed by AHP, and the relationship of air pollution with land use, important pollutant enterprises and meteorological factorsin Urumqi was further analyzed. In the study, some impacts that leaded to special cases were ignored, for example, breeze and calm wind. Conclusions Land use (weighting coefficient was 0.0852), important pollutant enterprises (weighting coefficient was 0.7375) and meteorological factors (weighting coefficient was 0.1773) were the main influencing factors of air pollution in Urumqi. Recommendations and perspectives Pollutant discharge type should be considered when the government regulate the pollution emissions to deal with the air pollution.
Keywords: air quality; correlation analysis; analytic hierarchy process; Urumqi