上海北郊大气挥发性有机物(VOCs)变化特征及来源解析

2019年1月1日到10月31日期间在上海北部郊区,采用在线气相色谱仪对58种VOCs定量检测,分析了大气VOCs组成、季节变化特征和日变化规律,并利用最大增量反应活性(MIR)估算了VOCs的臭氧生成潜势(OFP),应用因子分析法对VOCs来源进行了解析。结果表明,上海大气总VOCs体积浓度为25.79×10-9,其中烷烃占比63.2%,烯烃占比11.6%,芳香烃占比19.8%,炔烃占比5.4%。总VOCs体积浓度呈现夏季高,秋季低的季节变化特征。大气臭氧生成潜势为76.99×10-9,烷烃贡献率为22.1%,烯烃为37.5%,芳香烃为38.7%,炔烃为1.7%。VOCs特征物比值(V(TVOC)/V(NO_x)和T/B比值)法表明观测点为VOCs控制区,受周边工业区源和交通源影响。大气VOCs主要来源为机动车排放、工厂生产、燃料燃烧、工业溶剂挥发及天然源。

Change Characteristics and Source Apportionment of Volatile Organic Compounds (VOCs) in the Northern Suburb of Shanghai

From January 1 to October 31, 2019, 58 kinds of VOCs were quantitatively detected by on-line gas chromatograph in the northern suburb of Shanghai. The composition, seasonal variation and daily variation of VOCs were analyzed. The ozone formation potential (OFP) of VOCs was estimated by the maximum incremental reactivity (MIR). The source of VOCs was analyzed by factor analysis. The results showed that the total volume concentration of VOCs was 25.79×10-9, in which alkanes accounted for 63.2%, olefins accounted for 11.6%, aromatics accounted for 19.8%, and alkynes accounted for 5.4%. There was an obviously seasonal variation of VOCs, with the maximum in summer and the minimum in autumn. The ozone formation potential was 76.99×10-9, in which alkanes accounted for 22.1%, olefins accounted for 37.5%, aromatics accounted for 38.7%, and alkynes accounted for 1.7%. By using the specific pollutant ratios (Total VOCs/Nitrogen Oxide and Toluene/Benzene) method, it indicated that the observation site was greatly affected by the surrounding industrial areas and vehicle emission sources. Source analysis of VOCs by factor analysis showed that the sources consisted of vehicle emission sources, industrial production sources, combustion sources, industrial production solvent use sources and biogenic emission sources.