State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing 102249, China.
GSI Environmental, Houston, Texas 77098, United States.
Environ Sci Technol. 2020 Jun 16;54(12):7050-7069. doi: 10.1021/acs.est.0c00225. Epub 2020 May 27.
At sites impacted by volatile organic compounds (VOCs), vapor intrusion (VI) is the pathway with the greatest potential to result in actual human exposure. Since sites with VI were first widely publicized in late 1990s, the scientific understanding of VI has evolved considerably. The VI conceptual model has been extended beyond relatively simple scenarios to include nuances, such as biological and hydrogeological factors that may limit the potential for VI and alternative pathways, such as preferential pathways and direct building contact/infiltration that may enhance VI in some cases. Regulatory guidance documents typically recommend initial concentration- or distance-based screening to evaluate whether VI may be a concern, followed by a multiple-lines-of-evidence (MLE) investigation approach for sites that do not screen out. These recommendations for detailed evaluation of VI currently focus on monitoring of VOC concentrations in groundwater, soil gas, and indoor air and can be supplemented by other lines of evidence. In this Critical Review, we summarize key elements important to VI site characterization, provide the status and current understanding, and highlight data interpretation challenges, as well as innovative tools developed to help overcome the challenges. Although there have been significant advances in the understanding of VI in the past 20 years, limitations and knowledge gaps in screening, investigation methods, and modeling approaches still exist. Potential areas for further research include improved initial screening methods that account for the site-specific role of barriers, improved understanding of preferential pathways, and systematic study of buildings and infrastructure other than single-family residences.
在受挥发性有机化合物（VOCs）影响的场所，蒸气侵入（VI）是导致实际人体暴露的最大途径。自 20 世纪 90 年代末首次广泛宣传 VI 以来，人们对 VI 的科学认识已经有了很大的发展。VI 概念模型已经从相对简单的情景扩展到包括细微差别，例如可能限制 VI 潜力和替代途径的生物和水文地质因素，以及在某些情况下可能增强 VI 的优先途径和直接建筑接触/渗透。监管指南文件通常建议进行初始浓度或距离筛查，以评估 VI 是否可能成为一个问题，然后对未通过筛查的场地采用多线证据（MLE）调查方法。这些关于详细评估 VI 的建议目前侧重于监测地下水、土壤气体和室内空气中的 VOC 浓度，其他证据可以补充这些建议。在这篇评论中，我们总结了 VI 场地特征描述的重要元素，介绍了现状和当前的认识，并强调了数据解释的挑战，以及为帮助克服挑战而开发的创新工具。尽管在过去 20 年中，人们对 VI 的理解有了重大进展，但在筛选、调查方法和建模方法方面仍存在局限性和知识差距。进一步研究的潜在领域包括改进考虑到特定场地屏障作用的初始筛选方法、改进对优先途径的理解，以及对除单户住宅以外的建筑物和基础设施进行系统研究。
