Study On Spatial And Temporal Distribution Of Air Pollution In Beijing-tianjin-hebei

With development of economical integration, character of pollution emission in the Beijing-Tianjin-Hebei region showed a high degree of concentration trend, the problems of urban and regional air pollution have become increasingly outstanding. And the region’s air quality has become the attentive focus of government departments and social public. In view of this, research on temporal and spatial distribution of air pollution in the Beijing-Tianjin-Hebei is of great of significance for air quality control and improvement.In this paper, by using the air pollution index (API) data from2001to2010of three typical cities (Beijing, Tianjin and Shijiazhuang) in the Beijing-Tianjin-Hebei region, the variation characteristics of air pollution status, primary pollutant and air quality levels in different time scales are analyzed. In the meantime, the region pollution in December2006is simulated based on the air quality model WRF-chem, while selecting25December00:00and12:00as the case analysis of the vertical distribution of pollutants. The paper concludes the following conclusion:1) From2001to2010, the annual average API of three typical cities showed a downward trend in Beijing-Tianjin-Hebei region and the most dominant pollutant was inhaled particle matter every year. The rate of excellent or good air quality days in one year showed an increasing tendency. The overall status of air quality in Tianjin was better than Shijiazhuang, and Beijing was the poorest.2) Air quality in the three cities has a significant monthly and seasonal variation. The best air quality appeared in summer, secondary in autumn and worst in spring and winter. Inhaled particle matter accounted the majority of city pollutant in different seasons and in every month except that sulphur dioxide, as the most dominant pollutant, was only occurred in Tianjin in winter months.3) Through analyzing the influence of dust and heavy fog on three cities’air quality, we can safely draw the conclusion that dust and heavy fog have an adverse effect on air quality. Beijing was most affected, followed by Shijiazhuang. Tianjin was least affected.4) During the simulation period, character of PM10in horizontal and vertical distribution agreed with PM2.5. Affected by the horizontal wind fields, atmospheric boundary layer height, pressure near the surface, vapor pressure and other factors, the horizontal distribution of average monthly pollution concentration near the surface presented increasing trend from the northwest to the southeast, and high pollution region concentrated in the southeast of Beijing-Tianjin-Hebei. The regional pollution was kept under2500m and showed a decreasing tendency from ground to high altitude. Pollution in day was relatively lighter than in night.