典型海滨和内陆城市PM_(10)中的碳成分初步研究
Carbon components in PM_(10) aerosols in typical inland and coastal cities
Abstract
为了分析碳成分在海滨和内陆城市的浓度现状、季节变化和日变化特征,于2009-11-2—2009-11-4(秋季)、2009-12-21—2009-12-23(冬季)、2010-4-27—2010-4-30(春季)和2010-8-26—2010-8-29(夏季)连续同步密集采集了厦门和成都大气可吸入颗粒物(PM10)样品,并采用IMPrOVE热光分析法分析了PM10中有机碳(OC)和元素碳(EC),采用燃烧氧化-非分散红外吸收法测定了样品中的水溶性有机碳(WSOC),采用乙基紫-分光光度法测定样品中阴离子表面活性物质(EVAS)的浓度.结果显示,海滨和内陆城市PM10中碳成分含量季节分布明显,冬春季含量较高,夏秋季含量较低.各季碳成分含量日变化趋势不完全相同.WSOC与OC和EC相关分析结果显示,WSOCS主要来源于光化学反应形成的二次污染物. PM10 samples from two traffic sites in Xiamen and Chengdu were collected and analyzed to investigate the seasonal and diurnal variations of carbon components.The organic carbon(OC),elemental carbon(EC),water-soluble organic carbon(WSOC),and anionic surfactant(EVAS) concentrations were determined using thermal-optical,combustion oxidation-non dispersive infrared absorption,and ethyl violet active substancespectrophotometer method,respectively.A well defined seasonal pattern was found,characterized with higher concentrations in winter and spring but lower levels in summer and autumn.However,the diurnal variations showed different trends in different seasons and different cities.Based on the relationship between WSOC and EC or OC,the main sources of WSOCs in PM10 were proposed to be vehicle exhaust emissions and secondary organic formation.