The Spatial And Temporal Characteristics Of Atmospheric Particulates And The Influencing Factors In Chongqing

Atmospheric particulates, as the primary atmospheric pollutants, that have brought severe harm to human health, environment and many other aspects, have come to the public’s focus. Meanwhile, various researches on it have been in process. And in this research, based on the air quality monitoring data of Chongqing from 2013 to 2015, ArcGIS was used to analyze the time-space distribution characteristics of the air particulates in Chongqing. And SPSS rank correlation method was used to explore the influences of meteorological factor and gaseous pollutants to atmospheric particulates respectively, and the effect on typical pollution days. As well, the paper analyzed the regional transmission sources of atmospheric particulates and the typical pollution days based on Trajstat backward trajectory simulation.(1) In the daily variation, PM2.5 and PM10 show the obvious double peak curve. Meanwhile in the seasonal variation, the trend of atmospheric particulate concentrations changed from high to low is: winter, autumn, spring, summer. During the observation of 85 days, the number of typical pollution day is 11. Typical pollution days occurred 11 times (a total of 85 days) in the observation time(2) GIS based analyses of air particulates distribution illustrated that tendency of atmospheric particulates concentrations gradually increased from the northern region to the southern region; Besides, regions with high population and developed commerce and industry tended to have higher particulate concentration due to high emission of pollution sources.(3) Gaseous pollutants were closely related to atmospheric particulates. For instance, sulfur dioxide and nitrogen dioxide were crucial precursor of atmospheric particulates, for their similar concentration change tendency. Furthermore, O3 had a kind of relatively complex relation with air particulates, which meant that O3 could accelerate the formation of pollutants and, at the same time, atmospheric particulates could restrain the formation of O3 by reducing photochemical reaction in atmosphere.(4) Under the certain condition of pollution sources, meteorological condition was a major factor that affected the change of atmospheric particulates. Generally, particulates were positively correlated with air pressure, while negative correlated with wind speed, air temperature, relative humidity and rainfall.In typical pollution days, the atmospheric particulates were negatively correlated with air pressure, wind speed, air temperature and rainfall, while positively correlated with relative humidity. Typical pollution always occurred in the weather conditions of low temperature, light wind and no rainfall, or of little precipitation, steady atmospheric stratification and thick thermal inversion layer.(5) Influenced by the subtropical monsoon climate, there were obvious seasonal difference in the transmission paths of air particulates. For the transmission distance, short-haul regional transmission path counting the major part reflects that the main source of atmospheric particulates was from local transmission. The results of the trajectory simulation of typical pollution weather indicated that, the phenomenon of pollutants transmission among regions was evident and local pollutants emission was the vital source, of which the performance was that, the climate pattern controlled by regional circulation restrains the transmission of atmospheric particulates and make it difficult to spread and transfer the particulates to other areas, only to cause the accumulation of atmospheric particulates locally, and then, the typical pollution.