摘要
西安市是我国承东启西、连接南北的战略性枢纽城市,但其长期受到重空气污染的影响.基于2018年11月24日—12月3日西安市及其周边7个地级市共38个环境质量监测站点的逐时数据,利用空间插值、趋势分析和相关性分析方法,研究了西安市一次重空气污染期间六大污染物(PM2.5、PM10、CO、NO2、SO2和O3)的质量浓度时空变化及彼此间的相关关系.结果表明:①IDW(inverse distance weighting,反距加权插值法)和OKri(ordinary Kriging,普通克里格插值法)均能较好地获得西安市空气污染物的时空变化情况,但IDW的插值精度优于OKri,距离指数为7的IDW可以满足西安市空气污染物时空变化模拟的要求.②研究期间,西安市首要污染物为PM2.5和PM10,二者分别是中度-重度污染及严重-“爆表”污染天气的首要贡献因子.③ρ(PM2.5)、ρ(PM10)、ρ(CO)、ρ(NO2)和ρ(SO2)均呈中部高、两边低,北部高、南部低的空间分布特点,而ρ(O3)则相反;PM2.5、PM10、O3污染程度日趋严重,NO2污染程度逐渐缓解.④ρ(PM2.5)、ρ(NO2)、ρ(CO)之间呈中等正相关,三者在时空变化上具有较高的一致性;ρ(SO2)与ρ(PM2.5)、ρ(NO2)、ρ(CO)均呈弱正相关;ρ(O3)与ρ(NO2)、ρ(CO)均呈弱负相关.受扬尘天气和特殊风向及地形共同影响,西安市PM 10出现“爆表”现象,导致ρ(PM10)与其他污染物质量浓度之间的相关性不明显.研究显示,距离指数为7的IDW适合西安市空气污染情况时空变化的模拟,重污染天气条件下,西安市ρ(PM2.5)、ρ(NO2)、ρ(CO)之间具有较高的同源性,但各污染物间时空变化和相关性关系较复杂.
Based on the hourly observations of air quality monitor stations during November 24 th to December 3 rd,2018 of Xi′an City and 7 cities surrounding it,we studied the spatiotemporal characteristics of the main air pollutant concentrations(PM2.5,PM10,CO,NO2,SO2 and O3)and their interrelationships during a typical heavy air pollution event in Xi′an City by means of spatial interpolation method,trend and correlation analysis.The results showed:(1)Both Inverse Distance Weight interpolation(IDW)method and the Ordinary Kriging Interpolation method could obtain the spatiotemporal distributions and variations of the air-pollutants′concentrations,but the former performed better.The IDW with a distance index of 7 was picked as the best interpolation method for Xi′an City in the end.(2)The main air-pollutants of Xi′an City during the ten days were PM2.5 and PM 10,which were the primary contributing factors of moderate to severe air pollution and severe to extreme air pollution,respectively.(3)The concentrations of the first five pollutants were relatively high in the north and or middle of Xi′an City,but low in the south and or out sides of Xi′an City,which was just the opposite of O3 concentration.Besides,the concentrations of PM2.5,PM10 and O3 showed increasing trends throughout Xi′an City during the ten days,and the inverse of NO2 was true.(4)PM2.5,NO2 and CO were positively correlated,and the spatial-distribution patterns and temporal trends of these three air-pollutants showed high consistency and homology.SO2 had weak positive correlations with PM2.5,NO2 and CO,while O3 had weak negative correlations with NO2 and CO.SO2 weakly but positively correlated with PM2.5,NO2 and CO.PM10 had little and insignificant correlations with all the other air-pollutants because the extremely heavy air-pollution led by PM 10 disturbed the normal interactions between PM10 and other air-pollutants.In this heavy air pollution event,high degree of homology exhibited in the variations of PM2.5,NO2 and CO,but typical attentions should be paid to distinguish the complicated correlations between PM10 and other air-pollutants.
作者
白杨
杨剑
陈鹏
温宥越
邝红艳
何煜然
张亚青
BAI Yang;YANG Jian;CHEN Peng;WEN Youyue;KUANG Hongyan;HE Yuran;ZHANG Yaqing(Chinese Research Academy of Environmental Sciences,Beijing 100012,China;South China Institute of Environmental Science,Ministry of Environmental Protection,Guangzhou 510535,China;Information Center of Ministry of Ecology and Environment,Beijing 100029,China)
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2020年第4期809-819,共11页
Research of Environmental Sciences
基金
国家重点研发计划重点专项(No.2016YFC0208200)
生态环境部华南科学研究所中央级公益性科研院所基本科研业务专项(No.PM-zx421-201904-060)。
关键词
重污染
主要空气污染物
西安市
时空变化
相关分析
heavy air pollution
major air pollutants
Xi′an City
spatiotemporal variations
correlation analysis
