2014年重庆市大气污染物浓度变化特征及其与气象条件的关系

Variation Characteristics of Atmospheric Pollutants Concentration in the Urban Area of Chongqing in 2014 and The Relationship with Meteorological Conditions

根据重庆市2014年1月-12月大气空气质量指数(AQI)以及大气首要污染物PM_(2.5),PM_(10),CO,SO_2,NO_2和O_3等相关数据,分析了重庆市大气污染物浓度的变化特征,并结合月平均降水量、平均气温、日照时数、平均相对湿度、平均风速和平均气压等气象数据,运用相关分析法,研究气象要素对重庆市大气污染物的影响.研究结果表明:AQI和PM_(2.5),PM_(10)质量浓度变化在月尺度上呈明显的"U"型变化,表现为两端高中间低的态势;季节变化尺度上,冬季最高,夏季最低,即夏季空气质量最好,冬季空气污染最严重;PM_(2.5)和PM_(10)质量浓度显著相关,相关系数达0.99,PM_(2.5)对PM_(10)贡献较大,两者质量浓度的比值达0.80.PM_(2.5)和PM_(10)质量浓度与平均相对湿度正相关,主要是因为相对湿度越大越有利于颗粒物的形成;与平均气压显著正相关,这与重庆市夏季受低压控制,冬季受高压控制,进而影响大气环流有关;与降水量和平均风速弱负相关,主要是雨水的清除作用和风的稀释作用造成;与平均气温和日照时数显著负相关.

According to the air quality data in Chongqing from January to December in 2014,air quality index（AQI）PM（2.5）,PM（10）,CO,SO2,NO2 and O3,as well as the variation characteristic of atmospheric pollutants concentrations were analyzed in Chongqing.Combined with the monthly average precipitation,average temperature,sunshine time,average relative humidity,average wind speed and air pressure and other meteorological data,in order to study the atmospheric pollutants impact of meteorological factors in Chongqing through the correlation analysis.The results showed that the changes of concentrations of AQI and PM（2.5）,PM（10） on the monthly scale are obviously U-shaped variation,appeared the low in middle and high on both ends.On the quarterly scale,the concentrations feature of AQI and PM（2.5）,PM（10） with highest in winter and lowest in summer,and it means air quality is the worst in winter and the best in summer.The concentrations of PM（2.5）and PM（10） are significantly correlated.Correlation analysis showed that the correlation coefficient of mass concentration of PM（2.5）and PM（10） was 0.99,and the ratio of PM（2.5）/PM（10）was0.80 revealing a significant contribution of PM（2.5）to PM（10）.A positive correlation existed between the mass concentration of PM（2.5）,PM（10） and high average relative humidity,mainly because it tended to cause the formation of particulate.And there is a significantly positive correlation existed between the mass concentration of PM（2.5）,PM（10） and average air pressure,because atmospheric circulation is affected by low pressure in summer,but high pressure in winter in Chongqing.While precipitation and wind speed had slight negative influence on it mainly through clearing and promoting diffusion.And there is a significantly negative correlation between the mean temperature and sunshine time.