深圳大气挥发性有机物污染特征及臭氧生成潜势

Pollution Characteristics and Ozone Formation Potential of Ambient Volatile Organic Compounds in Shenzhen

该研究选取深圳市工业区、城区、郊区等不同类型的5个典型地区在2017年8月(夏季)、10-11月(秋季)、12月(冬季)开展了挥发性有机物(VOCs)离线手工采样及监测,获得了113种VOCs物种的体积分数数据并分析了VOCs污染特征及臭氧生成潜势(OFP)。研究表明,观测期间深圳市VOCs平均体积分数为37.3×10^(-9),以含氧挥发性有机物(OVOCs)和烷烃为主要组分,共占总体积分数的57.2%。秋冬季体积分数约为夏季的2倍,日变化上烷烃、烯烃、芳香烃体积分数在中午达到谷值,较早晚平均值偏低46.7%~48.3%,但OVOCs日变化曲线较为平缓。观测期间VOCs的OFP平均为121.2×10^(-9),OVOCs、烯烃和芳香烃是主要贡献来源,分别占42.0%、33.0%和15.3%,1,3-丁二烯、丙醛、乙醛、甲苯是对OFP贡献最大的前4个物种,共占55.8%。工业排放对臭氧生成影响显著,工业区点位OFP较高(182.2×10^(-9)),城区次之(98.6×10^(-9)),郊区最低(68.9×10^(-9)),同时工业区甲苯/苯(T/B)比值较高(10.7),表明受溶剂使用源的影响较大。加强控制溶剂使用源、工业源和机动车的VOCs排放将有利于降低深圳市大气OFP,从而减少臭氧生成。

The ambient concentration of 113 volatile organic compounds(VOCs)species were obtained through offline monitoring of VOCs in summer,autumn and winter of 2017 at five typical industrial,urban or suburb sites in Shenzhen.The pollution characteristics of VOCs and ozone generation potential(OFP)were analyzed.The results showed that the average volume fraction of VOCs was 37.3×10^(-9),oxygenated VOCs(OVOCs)and alkanes were identified as the main components which together accounted for 57.2%of the total VOCs.Seasonally,the average volume fraction of VOCs in autumn and winter was about twice of that in summer.For daily fluctuation,alkanes,alkenes and aromatics dropped to the valley value at noon,which was 46.7%~48.3% lower than the average concentration in the morning and evening,while the diurnal variation of OVOCs was relatively flat.The average OFP was 121.2×10^(-9),and OVOCs,alkenes and aromatics were the most abundant components,accounting for 42.0%,33.0% and 15.3% of the total,respectively.1,3-butadiene,propanal,acetaldehyde and toluene were the most abundant species of OFP accounting for 55.8%in total.Industrial emissions had significant impact on ozone production,as for that the industrial site had the highest OFP(182.2×10^(-9)),followed by urban site(98.6×10^(-9))and the lowest at suburban site(68.9×10^(-9)).Besides,the toluene/benzene(T/B)ratio was also higher at industrial site(10.7),indicating the greater influence of solvent sources.Based on the above,it would be important to strengthen control of the VOCs emissions from solvent sources,industrial sources and motor vehicles so that to reduce OFP and ozone production in Shenzhen.