济南市环境空气VOCs的化学反应活性及关键活性组分研究

对济南市2010年6月—2012年5月环境空气中55种VOCs监测数据进行分析,研究其反应活性及关键活性组分。结果表明,济南市环境空气VOCs的LOH和OFP的月变化规律与其月浓度变化趋势一致,夏季环境空气VOCs的浓度、LOH和OFP较大,是容易发生复合型大气污染的时段;济南市环境空气VOCs化学活性与其混合比之间具有良好的线性相关性,表明济南市环境空气中VOCs的化学组成具有一定的稳定性;VOCs的平均KOH远远超过乙烯的KOH,MIR与乙烯相当,说明济南市环境空气VOCs的化学反应活性较强;烯烃体积分数远远小于烷烃,但化学反应活性贡献率最高,且顺-二丁烯、丙烯、乙烯、丁烯、反-二丁烯、异戊二烯、苯乙烯、2-甲基-1-戊烯、顺-二戊烯、间,对-二甲苯、邻-二甲苯、甲苯、1,2,4-三甲基苯和环戊烷为济南市关键活性组分,因此,济南市高活性VOCs物种为烯烃,同时芳香烃和环戊烷对环境空气活性的贡献也不容忽视。

Research of chemical reactivity and key active components of VOCs in ambient air of Jinan City

Fifty-five kinds of VOCs in the atmosphere were analyzed for the potential reactivity and active components identification, based on two-year air pollution monitor data in Jinan City. The results showed that the atmospheric hydroxyl radical consumption rate (LOH) and ozone formation potential (OFP) of VOCs corresponded with the concentration profiles. The numbers were higher in summer, which was easier to cause the compound atmosphere pollution. The VOCs atmospheric chemical activity had a good linear correlation with the mixing ratio, which mean that the composition of VOCs in the atmosphere was constant. The average·OH radical loss rate constant (KOH)value of VOCs was much higher than that of alkenes while the mixing incremental reactivity(MIR) value was similar to that of ethylene. It means that the chemical reactivity of atmospheric VOCs was stronger. The alkenes volumetric fraction was far less than alkanes while the chemical reactivity contribution rate was high, demonstrating that alkenes were the key active component, including cis-2-butene, propylene, ethylene, butene, trans-2-butene, isoprene, styrene, 2-methyl-1-pentene, cis-dipentene, m/p-xylene, o-xylene, toluene, 1,2,4-trimethylbenzene and cyclopentane. Meanwhile, the effect of aromatics and cyclopentane also played an important role.