北京建筑施工裸地时空变化及扬尘污染排放

近年来北京城市格局逐步调整,伴随城市扩张与功能疏解,大规模建设工程使建筑施工裸地广泛分布于城市内部,施工扬尘带来的颗粒物污染已经成为影响空气质量的重要因素.选取北京平原区为研究区域,遥感反演了2013~2017年的建筑施工裸地,并分析了其时空分布特征.结合地面颗粒物浓度进行相关性分析,探讨城市建筑施工裸地对空气质量的影响.在此基础上,估算北京平原区2013~2017年建筑施工裸地的扬尘排放量.结果表明,北京建筑施工裸地沿中心城区向四周辐射,呈现出环形的带状分布,以城乡结合部最为集中.2013~2017年建筑施工裸地面积呈现先减后增的变化趋势,2015年后重心向东南偏移,逐步呈现出不均衡的分布特征.建筑施工裸地面积与PM10呈正相关,23个地面自动监测站点的相关系数均在0.80以上.2017年北京平原区建筑施工裸地颗粒物排放量核算结果如下:TSP排放量为39.5×10~4t、PM10排放量为19.4×10~4t、PM_(2.5)排放量为4.0×10~4t.单元网格的建筑施工裸地颗粒物排放强度向两级化发展,建筑施工裸地的局部集中导致高污染单元网格排放强度进一步增大.以标准化的PM10网格排放量为依据,将北京平原区分为低污染排放区、较低污染排放区、中污染排放区、较高污染排放区及高污染排放区5个级别,分级管控可以更有效地减轻扬尘污染影响.

Spatial and Temporal Distribution Characteristics and Fugitive Dust Emission of Building Sites in Beijing

Because of the continuous expansion of the city and the evacuation of non-core functions, the city pattern of Beijing has gradually changed in recent years. Based on many construction projects, building sites are widely distributed within the city. Therefore, fugitive dust emission is an important factor affecting the air quality in Beijing. This article focuses on the plain area in Beijing. Remote sensing was used to extract building sites from 2013 to 2017, analyze the spatial and temporal distribution characteristics of the building sites, estimate the fugitive dust emission, and propose a grid-based emission classification management program. Research shows that the building sites form a belt surrounding the central urban area, mainly distributed in the urban-rural integration area. From 2013 to 2017, the area of the building sites first decreased and then increased. After 2015, the center of the building sites in Beijing shifted to the southeast and started to show an uneven distribution. The area of the building sites is positively correlated with the PM₁₀ concentration. The correlation coefficients of 23 automatic ground monitoring stations are all above 0.80. Combined with the building site activity levels and emission factors, the estimated air pollutant emissions of TSP, PM₁₀, and PM_2.5 from building sites in 2017 were 39.5×10⁴, 19.4×10⁴, and 4.0×10⁴ t, respectively. The emission intensity of the pollution in the grid has developed towards polarization, which further increased the emission intensity of high-strength pollution grids. Based on standardized PM₁₀ grid emissions of building suites, the plain area of Beijing can be divided into five categories:lower pollution, low pollution, medium pollution, high pollution, and higher pollution.