公路绿化带对机动车尾气污染的净化作用

选择车流量大,且绿化良好的北京西北四环六郎庄段为试验地,在早高峰时段采集距公路0,16,36 m处的空气样品,利用ATD-GC/MS（自动热脱附—气相色谱/质谱联用）技术对空气中的苯系物和氯代烷烃进行分析.结果表明,与没有绿化带的对照地相比,随着距离的增加空气中的苯系物和氯代烷烃的种类和含量降低的程度更为明显,而空气中萜烯化合物含量表现出相反的趋势,随距离增加迅速升高,说明绿化带植物通过吸收污染物,并释放萜烯等挥发物改变空气组成,对机动车尾气排放所造成的空气污染起到净化作用.

Role of road green belt in the purification of vehicle exhaust pollution

The vehicle exhaust is a main source for the urban air pollution.In this study,the well-afforested Liulangzhuang'segment,on Northwest Forth Ring Road of Beijing,was selected as the typical experimental site.The air samples at sites 0m,16 m,and 36 mfar from the road were collected at the morning rush hour,then the benzene compounds and chloralkanes were analyzed by the ATD-GC/MS(thermal desorption-gas chromatography/mass spectrometry)technique.These results showed that the numbers and contents of benzene compounds and chloralkanes gradually decreased with the increasing distance,and the decreased range was far higher than that of the control.While the content of terpenoid compounds exhibited opposite change pattern,rising rapidly along with the increasing distance.These results suggested that the plants in the green belt could be purifying the air pollution from the vehicle exhaust through absorbing the pollutants and emitting the volatiles including terpenoid compounds to change the air composition.