Evaluation Of Atmospheric Pollutants In Main Urban Areas Of Chongqing And Analysis Of Influencing Factors

Based on the data of PM2.5,PM10,CO,NO₂ and SO₂ from 17 stations in Chongqing City,which were collected from May,2016 to April,2017,this paper discusses the temporal and spatial variation of air pollutants in the main urban areas and its influencing factors.The analyses and tests of samples from two sampling points in the Southwest University Meteorological Park and Yuzhong District Middle School,the correlation analyses of inhalable particulate matters,particulate matters and other contaminants,meteorological factors and particulate matters,the research of the limitation of terrain condition by comparing the hourly characteristics of pollutants in Zhengzhou,Chengdu and Chongqing and the study of the transport sources of pollutants in the four seasons and typical polluted weather conditions give the following conclusions:?1?The hourly trend of PM2.5 and PM10 in the main urban area of Chongqing showed two peaks and two troughs.Day change is more consistent,and the typical pollution weather time and holidays have good consistency.The monthly trend of change showed a peak and a trough.The average concentration of particulate matter in the Four Seasons showed the state of winter,autumn,spring,summer.PM2.5/PM10=0.66,which showed that PM2.5 accounted for a large proportion in the composition of particulate matter.CaSO₄ type pollution took up a large proportion in the Southwest University Meteorological Park and Yuzhong District Middle School,but the concentration of water soluble ions in Yuzhong District Middle School is significantly lower than the Southwest University Meteorological Park.?2?The average annual concentration of PM2.5 decreased progressively in accordance with the Midwest?Shapingba District,Yuzhong District?,Central-South?Jiulongpo District,Dadukou District?,Central-eastern?Yubei District,Jiangbei District,Nanan District?,South?Banan?,Northern?Beibei?while the average annual concentration of PM10 went down slowly from the middle?Yuzhong District,Nanan District?,Midwest?Shapingba District?,Southwest?Jiulongpo District,Dadukou District?,north-Central?Jiangbei District,Yubei District?,and South?Banan?to Northwest?Beibei?.The core polluted area didn't move with the seasonal change,but the change of the concentration in different seasons shows that human activity is the main cause of the pollution of particulate matters in Chongqing and the meteorological condition can only affect the concentration value but can not determine the spatial distribution of pollutants.?3?PM2.5 and PM10 showed the positive correlation with CO,NO₂ and SO₂ in typical polluted weather conditions but showed negative correlation with O₃.The correlation coefficient between PM10 and other pollutants is higher than that of PM2.5.In the meteorological factors affecting typical pollution,the influence of heavy rainfall is obvious;the temperature condition is consistent with the whole pollution incident;the trend of air pressure has a good consistency;the wind speed has a certain effect on the concentration of particulate matter.The correlation coefficients of PM2.5 and PM10 in different seasons showed in winter?0.993?,Autumn?0.986?,Spring?0.94?,Summer?0.85?,and the correlation coefficients between particulate matter and NO₂,SO₂,CO,and O₃ showed no uniformity with the actual concentration.?4?Due to the special terrain?high humidity,static wind frequency?,the concentration value and the peak time of particulate matters and other pollutants Chongqing is obviously different from the plain cities.Besides,the hourly and monthly change of pollutants is also different.?5?The long distance air transmission has contributed little to the typical polluted weather in the main urban area while the air transmission at low altitude is the main cause of the typical pollution.The rainfall caused by the long-distance aerial mass has obvious effect on decreasing the pollutant concentration.