西安市区大气污染物时空分布特征分析

Analysis of Temporal and Spatial Distribution Characteristics of Air Pollutants in Xi'an

利用2014年10月31日～2015年11月31日西安市区13个环境空气质量监测站AQI、CO、SO_2、NO_2、O_3、PM_(2.5)和PM_(10)逐日数据,分析了西安市区各种污染物的时空分布特征,研究污染物之间的相关性及西安和周边城市的空气质量相关性。结果表明,西安市空气主要分布国家标准在二三级之间,长安区超标率最低(24.41%)。利用空间插值法分析污染物空间分布各监测点夏季空气质量均优于冬季,长安区空气质量较好,主城区污染严重,西安大气污染物呈现明显的主城区向郊区递减变化趋势。月平均气温与CO、SO_2和PM_(10)显著负相关,与O_3显著正相关;月降雨量与CO、SO_2和PM_(10)显著负相关;日照时数与O_3显著正相关。SO_2月均浓度值在监测期中达到一级标准;O_3在5～8月份月均浓度值达到最大,其他月份均达到一级标准;NO_2在11月～次年1月月均浓度为全年最高,其他月份达到一级标准;CO在1～2月份浓度达到最高值,其他月份满足一级标准;PM_(2.5)和PM_(10)在整个监测期内均未达到一级标准。西安和周边城市空气质量存在显著相关性,需要城市间协同解决大气污染问题。

Using the daily data of AQI,CO,SO2,NO2,O3,PM2.5 and PM 10 of 13 environmental air quality monitoring stations in Xi an urban area from October 31,2014 to November 31,2015,the spatial and temporal distribution characteristics of various pollutants in Xi an city were analyzed,the correlation between pollutants and the correlation of air quality between Xi an and surrounding cities was studied.The results showed that the national standard of air distribution in Xi an is between the second and third grades,and the Chang an District has the lowest rate of exceeding the standard(24.41%).Using spatial interpolation method to analyze the spatial distribution of pollutants,the air quality in each monitoring point is better than that in winter.The air quality in Chang an District is good,the pollution in the main urban area is serious,and the air pollutants in Xi an show an obvious decreasing trend from the main urban area to the suburb.The monthly mean temperature was significantly negatively correlated with CO,SO 2 and PM 10,and significant positive correlation with O 3.The monthly rainfall was significantly negatively correlated with CO,SO 2 and PM 10,and the sunshine hours were significantly positively correlated with O 3.The monthly average concentration of SO2 reached the first-class standard during the monitoring period;the monthly average concentration of O3 reached the maximum in May^August,and reached the first-class standard in other months;the monthly average concentration of NO2 from November to January was the highest in the whole year.In other months,the first-class standard was reached;the CO reached the highest value in January-February,and the first-grade standard was met in other months;PM 2.5 and PM 10 did not reach the first-level standard during the whole monitoring period.There is a significant correlation between air quality in Xi an and surrounding cities,and the problem of air pollution should be solved cooperatively among cities.