西安夏季碳气溶胶细粒子时间变化特征分析  

Temporal variations of carbonaceous aerosols in PM_(2.5) during summer in Xi'an,China

作　　者：刘随心[1,2] 曹军骥[1,2] 赵竹子[1,2,3] 沈振兴[1,4] 

机构地区：[1]中国科学院地球环境研究所中国科学院气溶胶化学与物理重点实验室,西安710075 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710075 [3]中国科学院大学,北京100049 [4]西安交通大学环境科学与工程系,西安710049

出　　处：《地球环境学报》2014年第5期311-318,共8页Journal of Earth Environment

基　　金：陕西省科技统筹创新工程项目(2012KTZB03-01;2011KTCQ03-04)

摘　　要：为了探讨西安高分辨率的大气碳气溶胶细粒子的变化特征,在2008年夏季8月4日—7日太阳辐射强烈、高温晴朗天气进行每2小时的连续PM_(2.5)样品采集,通过热光碳分析仪和TOC分析仪分析获得OC、EC、WSOC浓度变化序列,其日序列显示出机动车尾气排放为主导的昼夜变化特征。观测期OC/EC比值平均水平为6.41,应用EC示踪法估算出SOC每2小时平均浓度为11.64μg·m^(-3),占OC浓度的63.37%,与WSOC占OC浓度的60.22%相当,两者比值为1.01,说明西安夏季高温和强烈的太阳辐射利于光化学反应的发生形成二次有机气溶胶,而且两者大部分为同一碳组分。分析SOC与O_3以及OC/EC比值序列变化,发现以O_3浓度和OC/EC比值来判断西安大气二次有机气溶胶的存在优于单纯应用OC/EC比值。2-hr time-resolved carbonaceous particulate organic （OC）, elemental carbon （EC） and watersoluble organics （WSOC） data measured by thermal/optical carbon and TOC analyzer in Xi＇an during sunny days from 4 to 7 Aug 2008 in summer were investigated the temporal pattems of carbonaceous aerosols in PM2.5, the result suggests that the motor vehicle source is dominant sources for the variation of carbonaceous aerosols in day-night variation. Mean 2-hr average OC/EC ration is 6.41, the secondary organic carbon （SOC） was estimated using an EC tracer method and the average concentration is 11.64 μg·m-3, SOC contributions 63.37% of measured OC approximating that of WSOC, and the WSOC/SOC equaled to 1.01, it indicates that the high temperature and solar radiation are favorable case to SOC formed by photochemical reactions. In this study, ozone and OC/EC ratios were used as the indicator of photochemical activity to identify SOC production in Xi＇an during summer.

关 键 词：OC EC WSOC SOC 

分 类 号：X513[环境科学与工程—环境工程]