城市生态空间PM2.5削减效益研究——以北京市为例

以生态系统服务的空间依赖性为理论基础，利用2000年与2015年北京市土地利用数据以及PM_2.5年均浓度数据，以30m*30m的土地利用栅格为研究单元，通过建立多元线性回归模型，发现其他条件相同的情况下，生态用地上的PM_2.5浓度比非生态用地上低32.29%，进而探究了生态空间的PM_2.5削减效益及其空间依赖性.结果表明，2000年与2015年，北京市生态空间削减全市范围内PM_2.5浓度4.64和9.03μg/m³，带来的以非意外总死亡健康终点记的人群健康经济效益分别达7954~15896万元与21980~43927万元；生态空间的PM_2.5削减效益存在着空间溢出作用，且不同土地利用类型对其响应方式不同；结构和规模会影响生态空间的效益发挥，线状生态空间在影响范围、污染物削减效果以及人群健康效益方面均优于面状生态空间，且其比较优势随着规模的扩大愈发凸显.建议城市生态空间建设中合理利用其空间特性以提高生态效益与资源利用效率，在城市中心地区增建小型、点状或线状的生态空间，从而在土地资源极度稀缺的情况下最大化其空气质量改善效益.

Effect and benefit of PM2.5 reduction from urban ecological space: The case of Beijing

Based on the theory of spatial dependency in ecosystem service, a multiple linear regression was estimated, which used the data of land use and annual average PM_2.5 concentration of Beijing in 2000 and 2015, and took land-use grids of 30m*30m as the research unit. The average PM_2.5 concentration in ecological space was found to be 32.29% lower than that in non-ecological space. The result was subsequently adopted to analyze the function of ecological space to reduce PM_2.5 and its spatial dependency. Results revealed that ecological space in Beijing reduced the PM_2.5 concentration by 4.64 and 9.03μg/m³ in 2000 and 2015, respectively, and produced population health benefit amounting to 79.54~158.96 and 219.80~439.27million RMB; the performance of ecological space in reducing PM_2.5 concentration presented a spatial spillover effect, triggering converse responses depending on the land use type; and both the structure and scale affected the functioning of ecological space, with linear-structured ones outperforming planar-structured ones in terms of the non-ecological area being affected, pollutant concentration reduction as well as health benefit, and such competitive advantage grew with the scale of ecological space. Therefore, making sophisticated use of the spatial characteristic of ecological space helps in promoting the ecological benefit as well as the effective use of resources. Adding small, dot or linear-structured ecological space in the metropolitan areas could maximize the ecological benefit under the land constraint.