南京典型道路绿地对大气污染物的消减作用

Study on the correlation mechanism of air pollutant reduction in typical roadside greenbelts in Nanjing City

【目的】研究道路绿地不同条件及环境因子影响对于大气污染物的消减作用,可为南京市典型道路绿地消减大气污染物机制研究提供理论依据。【方法】以南京市江北大道作为研究对象,选择道路绿地、小区出入口和立交下绿地3个地段,采用大气质量检测仪和氮氧化物分析仪,实地测定大气污染物浓度,分析不同环境因子与大气污染物之间的相关性及其拟合关系。【结果】颗粒物质量浓度变化趋于一致,而氮氧化物则没有一致的变化趋势。周边环境对大气污染物浓度产生明显影响,高架覆盖的街谷周围形成的涡流导致颗粒物不易离开,而植被覆盖具有促进氮氧化物转化同化或阻碍氮氧化物扩散的生态净化功能。3个监测区的大气污染物浓度受环境因素影响,颗粒物与湿度呈极显著正相关(P<0.01);NO_(2)与气压在监测区1呈极显著负相关(P<0.01),在监测区3中呈显著负相关(P<0.05);NO_(x)与气压在监测区1中呈显著负相关(P<0.05),在监测区3中呈极显著负相关(P<0.01),说明近地面气压越低,越不利于氮氧化物的扩散。【结论】大气污染物浓度受到气象因素及周边环境关系的影响,植被对大气污染物具有一定的生态净化功能。

【Objective】This research aimed to study the effect of different conditions and environmental factors on the reduction of air pollutants in roadside greenbelts,which can provide a theoretical basis for the study of the correlation mechanism of air pollutants reduction in typical roadside greenbelts in Nanjing.【Method】Taking Jiangbei Avenue in Nanjing as the research object,three sections of roadside greenbelts,the entrance and exit of residential areas and the greenbelts under overpass were selected to measure the concentration of air pollutants by Bramc Hol series professional air quality detector and Thermo ScientifiTMModel 42i(NO-NO_(2)-NO_(x))analyzer.On this basis,the correlation and the fitting relationship between different environmental factors and air pollutants were analyzed.【Result】The concentration of particulate matter tended to be consistent,while nitrogen oxide had no consistent changing trend.The surrounding environment had a significant impact on the concentration of air pollutants.The vortex formed around elevated street valleys made it difficult for particles to leave,while vegetation cover could promote the transformation and assimilation of nitrogen oxide or hinder diffusion.The concentration of air pollutants in the three sample areas was affected by environmental factors,and the particulate matter was positively correlated with humidity(P<0.01).NO_(2)was significantly negatively correlated with air pressure in sample area 1(P<0.01)and sample area 3(P<0.05).There was a significant negative correlation between NO_(x)and air pressure in sample area 1(P<0.05)and sample area 3(P<0.01),indicating that the lower the near-surface pressure,the more unfavorable the diffusion of nitrogen oxides.【Conclusion】The concentration of air pollutants is affected by meteorological factors and the surrounding environment,and vegetation has a certain ecological purification function for air pollutants.