城市公园绿地对周边环境空气PM_(10)和PM_(2.5)的影响及效应场特征——以武汉市中山公园为例

Effects of urban park green space on air PM_(10) and PM_(2.5) and its effect field characteristics: A case of Wuhan Zhongshan Park

选取武汉市中山公园及其周边建成环境作为研究对象,采用LUR模型、小尺度指标测试与空间插值相结合的技术方法,分析春、夏、秋、冬公园绿地周边建成环境空气PM_(10)、PM_(2.5)浓度时空效应场特征,旨在为公园绿地周边建成环境的规划与建设提供科学依据。结果表明:城市公园绿地周边建成环境500 m缓冲区范围对空气PM_(10)、PM_(2.5)浓度关键影响因子(交通道路、水体面积、非硬质下垫面面积、距城市中心距离、距公园绿地边界距离地理变量和气温、相对湿度、风速气象变量)构建的LUR模型具有一定的可行性,调整后的R2值分别为0.203~0.873(PM_(10))、0.306~0.837(PM_(2.5)),经留一交叉验证调整后R2分别为0.302~0.999(PM_(10))、0.344~0.991(PM_(2.5))(P<0.05);构建的不同季节LUR模型中交通道路、空气温度、距城市中心距离变量对空气PM_(10)、PM_(2.5)浓度空间分布相关性显著;冬、春季节公园绿地显著降低空气PM_(10)、PM_(2.5),对周边250 m(冬季)、400 m(春季)范围建成环境影响更为显著;空气PM_(10)日均消减量(公园内部与周边500 m缓冲区建成环境空气PM_(10)平均浓度差值)最大值为47.2μg·m^(-3),PM_(2.5)日均消减量最大值为15.5μg·m^(-3);空气PM_(10)、PM_(2.5)浓度在春、夏、秋三季的8:00—9:00时段最高,在冬季的15:00—16:00时段最高。

We analyzed the effect field of green space in Wuhan Zhongshan Park on the air PM_(10)and PM_(2.5)concentrations of surrounding built-up environment in four seasons using the LUR model,small-scale measurement,and spatial interpolation technology,aiming to provide scientific basis for the planning and construction of the built-up environment in the surrounding of green space.The results showed that the LUR model for air PM_(10)and PM_(2.5)concentrations was successfully developed according to the key variables including geographic variables (the length of traffic road,area of water bodies,area of non-hard underlying surface,distance from the city center,and distance from the edge of green space) and meteorological variables (air temperature,relative humidity,and wind speed),with an adjusted R2of 0.203-0.873 for PM_(10)and 0.306-0.837for PM_(2.5)and a leave-one-out cross-validation R2of 0.302-0.999 for PM_(10)and 0.344-0.991 for PM_(2.5).In addition,the spatial distribution of air PM_(10)and PM_(2.5)concentrations was significantly correlated with traffic road length,air temperature,and distance from the city center in the seasonal LUR models (P<0.05).A significant effect of green space on air PM_(10)and PM_(2.5)attenuation was detected with an effect field of 250-m in winter and 400-m in spring,with the maximum of daily reduction of 47.2μg·m^(-3)for air PM_(10)and 15.5μg·m^(-3)for air PM_(2.5).The highest air PM_(10)and PM_(2.5)concentration occurred at 8:00-9:00 in spring,summer,and autumn,and at15:00-16:00 in winter.