Study On Air Pollution Situation And Its Influencing Factors Based On Geoscience In Beijing Area

Air pollution could have negative effects on human health, ecological environment, climate and socio-economic. The study of its situation and influence factors has become a hot topic, and drawn more attention in the recent years. The paper performs the analysis of spatio-temporal pattern of air pollution and its influencing factors in Beijing area. Firstly, the timing variation characteristics of air pollution, and its relationship with meteorological factors has been analyzed based on the air pollution index(API) data and meteorological data of Beijing area during 2001-2012. And the relationship between air pollution and aerosol optical depth(AOD) has been analyzed, by using API index date, meteorological data and MODIS AOD data in 2012. Secondly, based on Geostatistics, analyzed the spatial distribution characteristics of air pollution and its relationship with the underlying surface in Beijing area by using air quality index(AQI) data of 35 monitoring sites, land use types data and normalized difference vegetation index(NDVI) data in 2013. Finally, analyzed the main sources of air pollutants in Beijing and the influence from the surrounding area, by using energy consumption data, pollutant emissions data, digital elevation model(DEM) data, land use type data and meteorological data of beijing-tianjin-hebei in 2012. The results shown that:(1)The number of pollution days in the past 12 years presented a notable downtrend, and the primary pollutant was particulate matter. The air pollution was concentrated in spring, and good weather was concentrated in summer. The maximum annual value of PM10 mass concentration appeared in 2006, the maximum and minimum quarterly values appeared in spring and summer respectively, and the maximum and minimum monthly values appeared in March and July respectively. The kriging interpolations of AQI from 35 environmental monitor stations in Beijing area showed that, the trend of air pollution in Beijing has gradually reduced from south to north and east to west. AQI of different underlying surface types is obviously different.(2) The direct correlation between AOD and PM10 mass concentration is relative low(correlation coefficient is 0.545). After taking into account of the aerosol scale height and the humidity effect factors, the paper corrects the humidity, and the correlation coefficient between AOD and PM10 mass concentration is significantly raised(correlation coefficient is 0.623). After introducing meteorological factors such as average wind speed, average temperature, and average atmospheric pressure, etc., the paper performs multivariate regression analysis, the correlation index is further raised(correlation coefficient is 0.646). It concluded that MODIS AOD products, after vertical and humidity correction, and considering meteorological factors, can be utilized to monitor PM10 mass concentration in Beijing area.(3) Meteorological factors were closely associated with air pollution, such as temperature, relative humidity, and precipitation were significantly positively related to the pollution days and PM10 mass concentration, but wind speed was significantly negatively related to pollution days and PM10 mass concentration. AQI was significantly negatively related to NDVI. And the spatial distribution of air pollution was closely related to underlying surface types. The pollution levels above the cropland and buildings area are in the same level, forest area and grassland are also in the same level, but the value of AQI above cropland and buildings is higher than forest area and grassland.(4) From the perspective of the sources of pollutant emissions in Beijing, the pollutants emitted from the industrial has been the biggest influence on air pollution, followed by the motor and life emission impact, and the motor emission is slightly higher than the life emission. From the point of average daily energy consumption in Beijing, the Beijing area air pollution is affected by the consumption of coal and oil. Because of high emissions and high energy consumption of Hebai and Tianjin, special topography and land use type of the beijing-tianjin-hebei region the SSW, SW, NE and E wind had a greater influence to Beijing area pollution days.