中国城市绿地的区域差异及其对PM_(2.5)的消减作用

Regional Difference in Urban Green Spaces in China and Its PM_(2.5) Reduction Effect

空气污染是实现健康中国战略的挑战之一,以细颗粒物(PM_(2.5))为主的城市空气污染尤为突出。本文利用遥感数据获得2005—2015年PM_(2.5)浓度数据,采用变异系数和标准差分析中国276个地级及以上城市PM_(2.5)浓度和城市绿地指标的时空特征,并借助面板数据模型解析不同经济区城市绿地指标对PM_(2.5)浓度的影响。结果表明:1)2005—2015年中国PM_(2.5)浓度整体呈波动上升趋势,但区域差异显著,东部经济区高于其他经济区;2)表征城市绿地的5个指标存在明显的时空差异;3)城市绿地指标中人均绿地面积对不同经济区PM_(2.5)浓度影响差异明显,建成区绿地覆盖面积和建成区绿地覆盖率对各经济区的PM_(2.5)浓度均有较强的消减作用。因此,城市绿地对PM_(2.5)浓度的消减作用存在一定的区域差异。

Air pollution is one of the challenges in achieving the“Healthy China”strategy,especially the urban air pollution with fine particulate matter(PM_(2.5))as the major component.With the remote-sensing data on PM_(2.5)concentrations in 2005-2015,this paper analyzes the spatial-temporal characteristics of PM_(2.5)concentrations and urban green space indicators of 276 cities in China using coefficient of variation and standard deviation analysis,and then analyzes the impact of green spaces on PM_(2.5)concentrations in different regions with panel data models.The results show that:1)PM_(2.5)concentrations in China show a fluctuating upward trend with significant regional variations(e.g.,PM_(2.5)concentrations in eastern region is higher than that in other regions)from 2005-2015;2)There are significant spatial-temporal differences in five indicators of urban green space;and 3)The influences of per capita green space area on PM_(2.5)concentrations in different regions are significantly different,and the green space cover and the green space coverage rate of the built area have strong mitigating effects on PM_(2.5)concentrations in each region.In this sense,there are certain regional differences in the effects of urban green spaces on PM_(2.5)concentration reduction.