A Mass Balance Framework for Assessing Flows of Environmental Pollutants: Application to Lead as a Case Study

城市人口暴露在各种环境污染物中。为了制定最大限度地减少暴露的战略，有必要了解污染物从源头向最终汇输送的过程。这个项目将提高我们对所涉及的关键过程的了解，并将开发评估污染物流动的工具，重点是洛杉矶盆地的元素铅。总体目标有三个。首先，将确定涉及铅排放以及含铅颗粒的沉积和再悬浮的过程。这将通过收集几年来空气中铅浓度的现有信息和对已实现的过滤器上的铅特性进行测量来实现。将应用目前研究颗粒从表面沉积和再悬浮的结果。第二，将开发一个改进的质量平衡模型，可用于确定铅的关键来源类别和汇。将确定降低空气中铅浓度的可能控制策略。该项目的这一部分将利用现有的质量平衡模型，这些模型将根据敏感性分析和工程近似进行修改和评估。第三，该项目将根据铅源和铅汇的知识、人类接触的估计减少量以及减排成本，确定若干控制战略中每一项的净效益。总体而言，该项目的结果将有助于我们了解影响人类接触环境污染物的因素，并将有助于制定减少接触的控制战略。

Urban populations are exposed to a variety of environmental pollutants. To develop strategies for minimizing exposure, it is necessary to understand the processes by which pollutants are transported from their sources to eventual sinks. This project will improve our understanding of the key processes involved and will develop tools for assessing pollutant flows, focusing on the element lead in the Los Angeles Basin. There are three general goals. First, processes involving emissions of lead, as well as deposition and resuspension of lead-containing particles, will be identified. This will be achieved by gathering existing information on airborne lead concentrations over several years and by conducting measurements of lead characteristic on achived filters. Results of current research investigating deposition and resuspension of particles from surfaces will be applied. Second, an improved mass balance model will be developed that can be used to identify key source categories and sinks of lead. Possible control strategies for reducing airborne concentrations of lead will be identified. This part of the project will make use of existing mass balance models, which will be modified and evaluated based on sensitivity analyses and use of engineering approximations. Third, the project will include determination of the net benefits of each of several control strategies based on knowledge of lead sources and sinks, estimated reductions in human exposure, and costs of abatement. Overall, the results of this project will help our understanding of factors influencing human exposure to environmental pollutants and will assist in developing control strategies to reduce exposure.