【作者】 田利伟；

【导师】 张国强；

【作者基本信息】 湖南大学 ， 供热、供燃气、通风及空调工程， 2009， 博士

【摘要】 目前,室内外颗粒物污染问题已经受到国内外学者的广泛关注,越来越多的流行病学研究表明,即使在非常低的浓度下,大气悬浮颗粒物质量浓度与人群发病率和死亡率仍存在显著的正相关性。大量资料及科研成果表明室外大气悬浮颗粒物与建筑室内颗粒物污染有明显的正相关性。当建筑室内没有明显污染源时,室外大气悬浮颗粒物可以通过建筑围护结构穿透进入室内环境,并较长时间的停留在室内空气中而不会发生沉降。因此大气悬浮颗粒物向室内的运动和传播规律是一个主要的研究课题。本文首先从流行病学和毒理学角度介绍了大气悬浮颗粒物对人体健康的影响,目的是认识颗粒物对人体健康的各种急性和慢性效应及其生物学机理。然后针对目前我国居民的日常生活习惯与室内颗粒物污染水平,进行了一次全国范围内的颗粒物污染调查研究,包括问卷调查和实地测试,问卷调查结果显示,居民平均每天约有85%以上的时间是在室内度过的,其中住宅室内约占50%;实地测试结果表明,目前我国住宅室内存在着相当严重的污染现象,尤其是当存在室内活动时。由于对室内环境进行检测不仅费时费力,而且费用昂贵,而室外大气中颗粒污染物监测体系已经建立,根据大气环境监测网络中的室外颗粒物数据,预测和分析室内环境中的大气悬浮颗粒物的粒径分布是一个可能的解决方案。由于很少见到将室内外浓度变化直接联系起来进行综合性观测与理论分析的研究结果,因此本研究以建立物理机理为基础的颗粒物传输半经验数学模型,颗粒物粒径和环境参数作为输入,预测和分析室内环境中悬浮颗粒物的粒径分布和浓度变化特征。其中,穿透因子和沉积率是该模型的两个重要输入参数。基于气溶胶力学理论,在假设围护结构隙缝内表面光滑、通过围护结构隙缝的气流均匀稳定的条件下,本文建立了颗粒物的穿透因子理论模型;同时,考虑到缝隙内表面的粗糙对颗粒物穿透因子的影响,将穿透因子理论模型进行了进一步的改进,得到了颗粒物在粗糙内表面缝隙中的穿透因子模型。利用颗粒物在壁面边界层的流通量平衡方程,得到了颗粒物在布朗扩散和紊流扩散沉积机理下向垂直表面的迁移微分方程;并在边界层的粘性底层、过渡层和紊流核心层三部分内对颗粒物的沉降速度进行积分,得到了颗粒物在室内各表面的沉降速度和室内沉积率模型利用得到的穿透因子理论模型、沉积率模型和实验测得的三类过滤器效率作为输入,结合颗粒物数量平衡模型,得到了预测室内大气悬浮颗粒物浓度的稳态模型和动态模型,并对五类具有代表性的建筑,预测了其室内颗粒物粒度分布。并讨论分析了房间换气次数、穿透因子、沉积率和再悬浮速度对颗粒物室内浓度的影响本文最后提出了室内颗粒物的污染控制措施,从减少或消除室内颗粒物污染源、控制颗粒物由室外向室内的传输量和净化室内污染空气三方面,对室内空气品质进行了改善。本文建立的根据室外环境监测数据来预测室内颗粒污染物粒度分布和浓度变化的模型,有助于了解和分析室内的颗粒物化学成分和粒度分布,揭示大气悬浮颗粒物影响人体健康的致病机理。同时结合实验结果得到的室内颗粒物污染控制措施,可以更好的指导人们的日常生活,降低室内人员的颗粒物污染暴露。更多还原

【Abstract】 The topic of indoor and outdoor particle pollution has triggered quite a lot of concern in recent years. Increasing epidemiological studies have reported that particulate air pollution is associated with increased morbidity and mortality even at the generally low levels of air pollution. However, the biological mechanisms have not been understood. This issue becomes more complicated in a situation when the outdoor air is always contaminated by traffic exhaust, industrial activities, construction activities, etc. Particles entering indoor environment suspend for a long time and are inhaled by humans which aggravates the risk of health. Thus, prediction of indoor particle concentration of outdoor origin is extremely important.In this paper, the impacts of ambient particle on human health are introduced, two methods are involved in current study: epidemiology and toxicology, which are used to cognize the chronic and acute effect based on biology mechanism. In order to advance our understand on the indoor particle level and habit of human during daily life, a large-scale investigation is carried out, results show that people spend 85% of their time indoors, and 50% for residential indoor environment; also, indoor particle pollution is a universal problem, especially when indoor activities exist. Due to the inconvenient and unpractical of measurement for indoor particle concentration in common residence, the establishing of modeling is an optimal method to predict and analyze indoor particle concentration.Developing and validating a model for predicting the indoor concentration of particles of outdoor origin is a key objective of this paper is to, taking particle diameter and climate parameter as input value. This model is based on aerosol dynamics, penetration factor and deposition loss-rate coefficient are two important parameters. For penetration factors, the roughness of crack inner surface is taken into consideration; for deposition loss-rate coefficient, the boundary layer is divided into three sublayers, the deposition velocity can be obtained by integrating particle flux equation in the three sublayers, and then deposition loss-rate coefficient is gained.Taking penetration model, deposition model and filter efficiency theory into particles mass & quantity equation, the evaluation model of indoor particle concentration is gained. As the level of ambient particles is steady or instantaneous, indoor particle concentration is evaluated under different condition in five kinds of typical buildings. Also, the impact of air exchange rate, penetration factor, deposition loss-rate coefficient and resuspension on indoor particle level are discussed.Control strategy of indoor particle pollution is another key objective in this paper, three types of control strategies are presented, which include: decreasing or eliminating indoor particle sources, reducing the transport of outdoor particles into indoor environment and cleaning indoor polluted air with appliances.The evaluation model, which is based on outdoor environmental monitoring data to predict indoor particle size distribution and concentrations of particle pollution, can help to analyze the chemical composition and particle size distribution of indoor particles and reveal the human health pathogens mechanism affected by atmospheric particles at the same time, indoor particulate pollution control strategy which was obtained by the experimental results can guide people’s daily lives and reduce indoor persons exposure to particulate pollution.更多还原