杭州市临安区4种绿地内细颗粒物中重金属污染特征

Pollution characteristics of heavy metals in PM in four kinds of green space in Lin’an District of Hangzhou City

【目的】分析城市绿地内细颗粒物(PM_(2.5))中重金属质量浓度的时空变化规律及其影响因素,可为科学规划城市绿地、改善人居环境质量提供依据。【方法】在杭州市临安区选取居住绿地、商业绿地、广场绿地和公共绿地等4种类型绿地作为研究对象,采用智能中流量TSP采样器采集空气中的PM_(2.5),通过电感耦合等离子体质谱仪(ICP-MS)检测样品中重金属的组成及质量浓度,分析其来源。【结果】4种绿地内重金属总质量浓度平均值为冬季[(950.13±90.15)ng·m^(-3)]大于春季[(843.55±80.70)ng·m^(-3)],春、冬季重金属总质量浓度平均值从大到小依次为商业绿地[(1023.18±94.10)ng·m^(-3)]、居住绿地[(942.20±89.20)ng·m^(-3)]、广场绿地[(861.85±84.05)ng·m^(-3)]、公共绿地[(760.18±80.48)ng·m^(-3)]。绿地内的重金属主要来自复合源(自然源、道路扬尘、汽车尾气和工业污染)、以燃煤为主的工业源和交通源等。【结论】合理增加绿地面积,可有效减轻城市重金属污染,在商业绿地周边控制车流量、推广新能源汽车能显著降低重金属质量浓度。图6表2参41。

[Objective]This study aims to analyze the spatio-temporal variation of heavy metal concentration in PM_(2.5) in urban green space and probe into its influencing factors,so as to provide reference for scientific planning of urban green space and improvement of the quality of human settlement environment.[Method]Four kinds of green space in Lin’an District of Hangzhou were taken as the research objects,including residential green space,commercial green space,square green space and public green space.The intelligent medium volume TSP sampler was used to collect the airborne PM_(2.5).The component and mass concentration of heavy metals in the samples were detected by the inductively coupled plasma mass spectrometer(ICP-MS),and their sources were analyzed.[Result]The average concentrations of heavy metals in four kinds of green space were higher in winter[(950.13±90.15)ng·m^(-3)]than those in spring[(843.55±80.70)ng·m^(-3)].The average concentrations of heavy metals ranging from large to small in these two seasons were commercial green space[(1023.18±94.10)ng·m^(-3)],residential green space[(942.20±89.20)ng·m^(-3)],square green space[(861.85±84.05)ng·m^(-3)]and public green space[(760.18±80.48)ng·m^(-3)].The heavy metals in green space mainly came from complex pollution sources(natural sources,road dust,vehicle exhaust and industrial pollution),coal-based industrial sources and traffic sources,etc.[Conclusion]Reasonable increase of green space area can effectively reduce the heavy metal pollution in cities.Controlling traffic flow around commercial green space and promoting new energy vehicles can significantly lower the heavy metal concentration.[Ch,6 fig.2 tab.41 ref.].