摘要
挥发性有机物(VOCs)是大气中光化学污染臭氧(O3)的重要前体物,其在大气中的浓度水平往往直接影响着臭氧的污染水平.以2008年夏季北京大气中VOCs浓度观测资料为基础,分析了VOCs浓度和组分随时间的变化特征,比较了各组分对臭氧产生的影响潜势,并利用主成分分析法研究了VOCs主要来源.结果表明,北京大气总VOCs在上午和下午的浓度分别是34.38×10-9(体积分数)和27.13×10-9(体积分数),组分中以烷烃最高,芳烃次之,烯烃最低,下午大气中VOCs浓度显著低于上午,烯烃、芳烃和烷烃依次下降28%、26%和15%;其中1,2,4-三甲苯等效丙烯浓度最高(8.05×10-9C),其次为间对二甲苯(6.97×10-9C)、甲苯(6.41×10-9C)和1,3,5-三甲苯(5.64×10-9C);芳烃对大气O3生成贡献最大(47%),其次是烯烃(40%),烷烃最低(13%).北京大气中VOCs主要来源于机动车(28%)、溶剂挥发(19%)、液化气泄漏(15%)和工业排放(12%).为遏制近年来夏季O污染加重趋势,北京应大力减少VOCs排放,特别是芳香烃的排放量.
Volatile organic compounds（VOCs） is one of the key precursors of atmospheric ozone（O3）,whose concentration variation influences directly the level of the photochemical pollutant O3.During Beijing Olympics,VOCs were measured near the Beijing National Stadium.Two and half-hour integrated canister samples were collected and analyzed in the morning and afternoon of each sampling day.Simultaneously,concentration,potential ozone production and sources of VOCs in the atmosphere of Beijing were studied.And the results indicated that the total VOCs species had higher concentrations in the morning（34.38×10^-9）,and lower in the afternoon（27.13×10^-9）,where the concentration of alkanes was the highest,and aromatics and alkenes came next.However,the concentrations of alkenes in the afternoon were significantly lower than those in the morning,which was 28%,and aromatics（26%）and alkanes（15%） came next.1,2,4-Trimethylbenzene has the highest propylene-equivalent concentration（8.05×10^-9C）,and m/p-xylene.（6.97×10^-9C）,toluene（6.41×10^-9C） and 1,3,5-trimethylbenzene（5.64×10^-9C） came next.Aromatics（47%）gives the most significant contribution to the production of O3 in the atmospheric VOCs of Beijing,and then were alkenes（40%） and alkanes（13%）.Automobile emissions accounted for approximately 28% of the total VOCs,and solvent volatilization（19%）,LPG leakage（15%） and industrial sources（12%） came next,from which Beijing may decrease the atmospheric VOCs.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2010年第1期10-16,共7页
Environmental Science
基金
国家重点基础研究发展规划(973)项目(2007CB407303,2005CB422001)
中国科学院大气物理所LAPC开放课题项目(LAPC-KF-2008-08)
关键词
挥发性有机物
等效丙烯浓度
主成分分析
芳香烃
volatile organic compounds（VOCs）
propylene-equivalent concentration
principal compound analysis（PCA）
aromatic
