城市形态对空气质量的影响机制研究

Air quality problem emerges as a challenge to public health and environmental sustainability, which received research interests from both scholars and decision makers. Accumulated researches show that certain pollutants indeed relate to certain urban activities and their harm to human health, such us heavy industry, burning, and vehicle using. It also finds that certain urban form indicator has direct or indirect impact on urban air quality, which influencing through the combined effects such us urban density, land use and traffic patterns. Current domestic researches focus on the impact of weather condition and pollution sources of urban air pollution, but no consistence agreement has achieved. .Under the background of fast urbanization and economic growth of Chinese cities, this research tries to explore the influence mechanism of urban form on air quality on both inter-city and intra-city scale. It applies three successive process models: tracing model between urban activity and main air pollutants, impacting model of urban form to certain urban activity, and measuring model of urban form factors which relating to air quality. .On inter-city scale, it selects urban area of 74 cities which are on daily air quality report list from Department of Environmental Protection of China, using the panel data come from Chinese City Year Book data(1998-2013), Daily Air Quality Report (2000-2013), and also the spatial data of China national wide in GIS format. By employing the method of spatial auto-correlation, spatial regression and principal component, it reveals the interaction of urban form factors on air quality. On intra-city scale, it selects Beijing municipal area as case study because it is the capital city which in large scale of population and economy activities, and also suffering from the air quality problems since recent years. Data comes from air quality data from 35 air testing station, and also the urban form characters such as land use and transportation measuring by GIS analysis from the location of 35 air testing station. Additionally, it uses the data of population and job density by residential district and township from the population census in year 2000 and 2010, and the basic economic unit survey in 2001 and 2008.It applies the local impact model of spatial regression to explore the impact mechanism. .By revealing the important urban form factors on air quality, this research will help to identify the environmental friendly urban form patterns which good to improve air quality. This research will provide implication in making healthy and sustainable land use and transportation policies, and also promote quality of life China in the future.

中国城市严峻的空气质量问题对环境和公众健康提出挑战。国内外研究证实了空气污染物与城市形态单因素的关联，但尚无一致性结论。本研究旨在中国快速城市化背景下，分别在全国城际和城市内部等两个尺度，通过建立污染物发生、城市活动影响、城市形态测度等过程模型，逐步揭示城市形态对空气质量的影响机制。在全国城际尺度以74个环保部公布空气质量的城市城区为例，辅以1998到2013年中国城市统计年鉴和图像数据，通过基于GIS的空间自相关与空间回归、主成分分析等方法，识别城市形态对空气质量全局性的作用规律。在城市内部以北京市域为例，以35个空气监测站空气质量和GIS空间分析提取的土地利用、交通布局等截面数据，辅以分街道乡镇的人口、就业统计数据，通过空间回归分析和模拟，揭示城市形态对空气质量的地方性影响规律。识别影响空气质量的关键城市形态要素，将为制定环境友好的城市规划和发展政策、提升居民生活品质提供借鉴。

近年来随着中国出现持续面积广、持续时间长的雾霾天气现象，城市空气质量问题引起了学者和决策者的关注。传统上国内对雾霾的研究主要关注污染物来源、排放及污染物形成、迁移和转化的机理以及影响污染物传输及扩散的气象条件；而从上世纪七十年代开始，国际文献对于空气质量的探讨也开始关注城市本身因素的影响，认为好的规划和不良的规划会影响到长期的空气质量和市民健康。本文致力于研究城市形态对空气质量的影响，基于2001至2011年288个地级城市市辖区面板数据中的PM10、PM2.5和城市形态相关数据，采取带有空间变量的回归模型考察城市形态因素对PM10和PM2.5的影响。分析结果显示，小城市、东部城市和南部冬季供暖区之外的城市平均可吸入颗粒物浓度较低，同时PM10和PM2.5浓度的空间分布高度自相关，并且随时间变化自相关更显著。在控制城市规模和所在区域后，回归模型结果显示二产比重、污染性产业规模、工业能耗、人口密度、建成区面积会对空气质量起到负面作用，而公共交通供给、液化气等替代性家庭能源、公共绿地面积和人均绿地面积则对空气质量起到正向作用。研究结果表明通过优化用地布局、提倡公交先导、提高能源利用效率等城市规划政策引导良好的城市形态，可以对提升环境质量和公共健康起到积极促进作用。