室内空气净化对降低居民氡照射的效果研究

The control of public exposure to radon has been one of the key and hot topics in the field of radiation protection and environmental protection in the world. The method of indoor air purification is suitable for reducing radon exposure in built constructions, but its actual effect is still in doubt. Our analysis found that previous studies did not take into account the significant impact of changes in size distributions of radon progeny on the dose estimation due to air purification, and both the methods and objects of studies were limited. In this project, based on the production mechanisms and their dynamic behavior of indoor radon progeny, both the theoretical research and experimental studies will be systematically carried out to clarify the changing behavior on both activity concentrations and size distributions of both the attached and unattached radon progeny due to the air purification, and to establish corresponding models for the evaluation of radon progeny concentrations and radiation dose, respectively. At the same time, by considering the practical application of different technology and using patterns of air purifiers in different indoor environment, further studies will be continued to develop a set of software to assess the effect of radon exposure for common uses. The results of this project will not only reveal the changing behavior on both the concentration and size distribution of indoor aerosols due to air purification, but also help to assess the actual effect of various air purification technologies in reduction of public radon exposure. Furthermore, the results of this project will provide some theoretical guidance for the optimizing design and rational use of air purifiers in order to achieve the better control of public radon exposure.

控制公众氡照射是国内外辐射防护及环境保护学科领域的重点和热点课题之一。净化室内空气降低氡照射方法适于在已建住宅内应用，但其实际效果一直存疑。我们的分析发现既往的研究未考虑空气净化引起氡子体粒径变化对辐射剂量准确估算的重大影响，且研究方法与对象均欠系统。本项目拟结合室内氡子体的产生机制及其动态的行为规律，通过系统的理论研究和实验验证，以阐明在对空气进行净化情况下居室内未结合态和结合态氡子体浓度及其粒径分布变化的规律，并建立相应的氡子体浓度和辐射剂量变化评价模式；同时，还将结合不同空气净化技术和使用模式在不同室内环境中的实际应用，研发通用的可评估降低氡照射效果的软件。所得的研究结果，不仅可揭示空气净化改变室内气溶胶浓度及其粒径分布的规律，有助于正确评估各种空气净化技术对降低居民氡照射的实际效果，还可为空气净化器的优化设计和合理使用以期达到更佳的控制氡照射效果提供理论指导。

控制公众氡照射是国内外辐射防护及环境保护学科领域的重点和热点课题之一。多种氡照射方法适于在已建住宅内应用，但其实际效果一直存疑。既往的研究未考虑空气净化引起氡子体粒径变化对辐射剂量准确估算的重大影响，且研究方法与对象均欠系统。本项目从理论分析、模拟计算和实验研究三个研究角度对抑制氡进入、增加室外换气率以及过滤室内空气三种室内降氡方法的效能、适用性、代价进行了系统的研究与分析。.首先，本项目建立了基于室内氡子体行为的氡及其子体行为仿真模型，并开发了相应的剂量估算软件。不仅可以用于对日常情况下氡及其子体行为的仿真计算和剂量估计，还可以用于不同环境条件变化情况下，预估氡及其子体浓度水平的变化规律，为今后的降氡措施研究提供指导。其次，本项目搭建了国内第一个专为氡干预/氡降低设计的模拟实验平台，不仅构建了氡及其子体浓度监测、气溶胶浓度和粒径分布监测、环境条件监测等组成的完整监测体系，也适配了可定量控制的主被动通风系统、氡源室控制系统和空气净化系统3种氡干预措施。此后，通过实验研究掌握了三种不同降氡措施对室内氡降低和受照剂量减少的作用，从降低效果、作用时间、经济成本等多个方面对不同降氡措施的效果进行了综合评价。在大量实验室研究的基础上，我们还构建了当前最大规模的全国室内氡调查数据库，建立了自1980至2019年间覆盖国内147个城市的国内最完整室内氡数据集合，并开展了氡的疾病负担评价和降氡措施的利益代价分析。.本项目的研究结果对于我国室内氡监测、干预及氡危害的防控有重要的指导意义，为解决当前关于多种措施降氡（氡照射剂量）效果这一个学术争议提供科学的理论依据，而且还可为更好保护广大公众身体健康提供技术方案，具有重要的学术和社会价值，也具有广泛的应用前景。