南京市北郊夏季挥发性有机物的源解析

2012年8月利用在线气相色谱仪对南京市北郊大气环境中的挥发性有机物(VOCs)进行连续监测,分析VOCs时间变化规律,并利用PMF(positive matrix factorization)受体模型和CPF(conditional probability function)方法对其来源进行解析.结果表明,南京市北郊夏季VOCs日变化呈双峰分布,小时平均体积分数为(33.84±27.77)×10-9,夜间高于昼间.其中含量最高的是烷烃,其次是烯烃和芳烃,分别占到总挥发性有机物(TVOCs)的49.3%、24.4%和18.5%,乙炔占7.8%.南京市北郊夏季VOCs主要来源有5个,分别是交通尾气、燃料挥发、工业排放、有机溶剂挥发和植物排放源,各自对TVOCs贡献为33.1%、25.8%、23.2%、8.1%和9.7%.烷烃主要来源于汽车尾气排放、工业排放和燃料挥发,贡献百分比分别为23.7%、35.3%和31.3%;烯烃主要来源于燃料挥发、工业排放和汽车尾气排放,分别占41.1%、18.4%和24.3%;对芳烃贡献最大的为汽车尾气排放,占到49.2%,其次是有机溶剂挥发排放占30.8%.

Source Apportionment of VOCs in the Northern Suburb of Nanjing in Summer

Hourly concentrations of ambient volatile organic compounds (VOCs) were sampled in August 2012 in the northern suburb of Nanjing. Emissions of VOCs were analyzed by using PMF (positive matrix factorization) and CPF (conditional probability function). The hourly average mixing ratio of the TVOCs in summer was (33.84±27.77)×10^-9, with a bimodal diurnal variation trend. 49.3% of the TVOCs were alkanes, 24.4% were alkenes, 18.5% were aromatics and 7.81% were acetylene. Five sources were identified as summer major contributors to ambient VOCs concentrations by PMF. 33.1% of the total VOCs was attributed to vehicle related emissions, 25.8% to fuel evaporation, 23.2% to industrial emissions, 8.1% to solvent evaporation and 9.7% to plant emissions. For alkanes, vehicle emissions, industrial emissions, fuel and solvent evaporation accounted for 23.7%, 35.3%, 31.3% and 2%, respectively. For alkenes, fuel evaporation accounted for 41.1%, industrial emissions for 18.4%, and vehicle emission for 24.3%. Vehicle emission was the major contributor to aromatics, accounting for 49.2%, followed by solvent evaporation, which accounted for 30.8%.