北京市建筑施工裸地的空间分布及扬尘效应

北京市作为中国典型的快速城市化大城市之一,大规模的城市建设使得城市内部存在大量的建筑施工裸地,工地扬尘效应造成了严重的大气颗粒物污染。以北京市平原区为研究区,首先利用高分辨率卫星数据反演了建筑施工裸地的空间分布格局,在此基础上,结合建筑施工裸地的扬尘排放因子,在空间上定量分析建筑施工裸地的扬尘效应。结果显示,2012年全市平原区建筑施工裸地总面积为140.77 km2,主要分布在城市核心区向外拓展的城乡过渡带。建筑施工裸地的扬尘效应分析中发现北京市平原区建筑施工裸地中TSP、PM10和PM2.5的排放量分别是31.53、16.66、9.16万吨,并且这些污染物的排放量在城市发展新区与功能拓展区中较高,生态涵养发展区较小。以北京市的建筑施工裸地为例,示范了以遥感为技术手段结合污染排放因子的城市内部典型面源污染的监测和污染排放定量化,为今后面源污染的快速准确监测开辟了新的研究思路。

Spatial Distribution of Building Sites and Related Emissions of Particulate Across Beijing,China

Beijing,as the capital of China,is characterized by highly-developed socio-economy with speeding geographical expansion and high urbanization. Booming building of the city triggered appearance of numerous building sites and which witnessed significant deterioration of air quality due to massive emission of dusts. In recent years,deterioration of air quality due to emission of dusts has drawn great concerns from local residents and also Chinese government. In 2008,the Chinese government took a series of countermeasures to alleviate effects of bad air quality for the open of the Olympic Games,such as control of vehicle flow,consumption of fossil fuel (particular coal),removal of heavy industry with great potential of pollution. However,the particulate pollution has still been the major pollutant source although NO_x and SO₂ decreased. It should be noted here that appearance of numerous building sites due to urbanization triggered emission of dusts which have evident impacts on air quality of Beijing. In this study,the Earth observation technology and remote sensing techniques are used in mapping spatial distribution of building sites with high spatial resolution. The remote sensing technique and emission factors are combined to derive particulate emission in urban building sites. Building sites across the Beijing city are classified into five types: building demolition,Earth-rock allocation,main construction,after main construction before vegetated,and other bare-ground,with QuickBird images in 2012. The results indicate that: the total coverage of building sites is about 140.77 km² along the urban-rural transitional belt in the vicinity of the urban area. Building areas under main construction and Earth-rock allocation are subject to the largest and second largest portions with the largest contribution to the particulate pollution; the emissions of TSP,PM₁₀,and PM_2.5 are 31.53×10⁴,16.66×10⁴ and 9.16×10⁴ tons,respectively. The pollutants are found higher in concentration in the urban-expending and development areas but lower in the urban ecological conservation area. The follow-up investigation should be done based on multi-year/long term monitoring and evaluating results of urban building areas. Besides,a fast monitoring system is suggested to be built up by urban environmental management agency for the sake of better understanding of the urban building areas and also its contributions to particulate pollution at different spatiotemporal scales. This current study provides insightful viewpoints concerning sources of particulate pollutants and ongoing monitoring and management of the air quality across Beijing,China.