中文摘要：

为研究关中地区远郊背景点位大气PM2.5污染来源,于2014年12月—2015年10月在西安市区西南方向约34 km的背景点位（农村区域,108°44’13″E、34°00’53″N）开展样品采集,共获得218个有效样品,对29种化学组分进行了分析,并运用ME2和PMF模型进行同步解析、相互验证.结果表明：ME2和PMF模型各解析出5类因子,分别为二次无机盐、机动车尾气排放、生物质燃烧、煤烟尘和土壤尘.其中,二次无机盐分担率为42.23%42.74%,是首要贡献源类,机动车尾气排放（22.40%24.53%）、煤烟尘（14.57%14.73%）、生物质燃烧（11.88%13.42%）是另外3种主要贡献源,而土壤尘（6.28%7.22%）分担率相对较小.2种模型同步解析大气颗粒物来源对比表明,ME2和PMF模型同步解析结果一致,各源类的日贡献浓度均呈正相关,其中二次无机盐、机动车尾气排放、土壤尘的相关性较强,R2在0.8760.960之间,表明解析结果可信.

英文摘要：

In order to identify the main emission sources of fine particulate matter（PM2.5） over the suburbs of Guanzhong area,a total of218 daily PM2.5samples were collected continuously from December 2014 to October 2015 in background sites（rural area,108°44’13″E,34°00’53″ N） about 34 km southwest of downtown Xi’ an City,and the concentrations of 29 chemical compositions were determined.Chemical characteristics and temporal patterns of PM2.5were discussed.The average PM2.5mass for the entire measurement period was（79.78 ± 59.12） μg/m3,which was 2.28 times that of the Chinese national ambient air quality standard（35 μg/m3）.The PM2.5mass,OC and inorganic ions showed similar seasonal patterns in the measurement sites,the concentrations of which were highest in winter and lowest in summer.Meanwhile,two factor analysis models,including positive matrix factorization（PMF） and Multilinear Engine 2（ME2）,were applied to apportion the PM2.5sources; the results showed that five PM2.5sources were identified：secondary sources,vehicle exhaust,coal combustion,biomass burning and crustal dust.The secondary sources（42.23%-42.74%） were found to be the most important contributor to PM2.5,and the other three main source were vehicle exhaust（22.40%-24.53%）,coal combustion（14.57%-14.73%）and biomass burning（11.88%-13.43%）,while crustal dust（6.28%-7.22%） was a slightly lower contributor.Similar source profiles and contributions of PM2.5were derived from the ME2 and PMF models.The contributed concentrations of each source were positively correlated,and the correlation of secondary source,vehicle exhaust and soil dust were strong（R2= 0.876-0.960）,indicating the results of the two models were reasonable.There were still differences of the profiles of the same source from thePMF and ME2 models,which might be caused by the calculation process from different models as well as uncertainties of the environmental datasets.The present study attempts to do further research on the characteristi