运用三维数值模型开发蒸汽入侵影响筛选工具的研究

Nowadays it is a trend in China that residential and commercial buildings in cities were built on land previously occupied by industries. This kind of land was called Brownfield, and vapor intrusion could be easily caused in this scenario. Vapor intrusion (VI) is a process for the contaminant soil gas being released from sources and entering the concerned buildings on the surface. A key procedure to control the pollution by VI is to use models to predict its influences. The previous research showed that some environmental factors might play an important role in VI, while the current two-dimensional (2-D) screening tool, Analytical Approximation Method (AAM), failed to include such factors. This study will use a three-dimensional (3-D) numerical model and a 2-D model to examine the influences of those factors quantitatively, in order to obtain the relationship between source-to-subslab contaminant soil vapor concentration attenuation factor and the model parameters, extending the application of AAM to include aerobically biodegradable hydrocarbons, urban environment and a heterogeneous effective diffusivity in soil. This research will provide a better understanding of the influences of environmental factors, improving predictions by the current AAM, but also relevant scientific basis for the for pollution control on Brownfield.

目前全国范围内的一个趋势是旧工业用地上建造住宅和商业建筑，这极易造成vapor intrusion （VI，蒸汽入侵）污染：污染物气体从被污染的土壤和地下水中释放出来进入地表建筑物内。控制VI污染的一个关键措施是利用模型来预测其危害性。前期研究表明一些环境因素可能在VI过程中具有重要的作用，而当前二维VI筛选模型Analytical Approximation Method （AA法）却未能将其包括在内，本项目针对这一问题，用三维数值模型和二维解析模型对这些环境因素在VI中的影响进行量化分析，取得在不同VI场景中污染源-地基下污染物气体浓度衰减系数与各模型参数的关系，使得AA法得以应用于可好氧分解的有机污染物，城市地带或者是存在土壤分层情况下。本研究不仅可深入了解环境各因素在VI中的作用，解决目前VI影响预测模型预测误差大的问题，并且为棕色地块的污染控制提供相关科学依据。

伴随着中国城市化进程的加快，近年来出现了大量的污染场地。有效治理这些场地需要依靠科学合理的风险评估。我国的污染场地大多属于棕地，风险评估对象为未来居民，必须利用数学模型预测进行风险评估。而蒸气入侵是污染场地最主要的风险暴露途径，决定着场地修复的成本和目标值。.本项目利用三维数值模型和二维解析模型对土壤质地，水分含量，污染源与目标建筑相对位置等环境因素在蒸气入侵中的影响进行量化分析，取得在不同场景中污染源-室内污染物气体浓度衰减系数与各模型参数的关系，开发应用于可好氧分解的有机污染物，城市地带或者是存在土壤分层情况下的蒸气入侵风险评估模型。本研究不仅可深入了解环境各因素在蒸气入侵中的作用，解决目前蒸气入侵影响预测模型预测误差大的问题，并且为棕色地块的污染控制提供相关科学依据。 .截止2016年12月31日，本项目获得的研究成果发表SCI论文7篇，具体总结如下：.1..开发包括好氧降解可用于石油烃蒸气入侵风险评估的模型；.2..开发包括对流可用于乙醇汽油污染源导致的蒸气入侵风险评估模型；.3..发现地基下浓度与室内浓度的解析关系；.4..开发包括建筑物与污染源水平间隔的蒸气入侵风险评估模型