title: Indoor Air Contamination from Hazardous Waste Sites: Improving the Evidence Base for Decision-Making.
abstract: At hazardous waste sites, volatile chemicals can migrate through groundwater and soil into buildings, a process known as vapor intrusion. Due to increasing recognition of vapor intrusion as a potential indoor air pollution source, in 2015 the U.S. Environmental Protection Agency (EPA) released a new vapor intrusion guidance document. The guidance specifies two conditions for demonstrating that remediation is needed: (1) proof of a vapor intrusion pathway; and (2) evidence that human health risks exceed established thresholds (for example, one excess cancer among 10,000 exposed people). However, the guidance lacks details on methods for demonstrating these conditions. We review current evidence suggesting that monitoring and modeling approaches commonly employed at vapor intrusion sites do not adequately characterize long-term exposure and in many cases may underestimate risks. On the basis of this evidence, we recommend specific approaches to monitoring and modeling to account for these uncertainties. We propose a value of information approach to integrate the lines of evidence at a site and determine if more information is needed before deciding whether the two conditions specified in the vapor intrusion guidance are satisfied. To facilitate data collection and decision-making, we recommend a multi-directional community engagement strategy and consideration of environment justice concerns.
authors.affiliation: Division of Environmental Health, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA. jillj@usc.edu.
authors.forename: Jill
authors.initials: J
authors.lastname: Johnston
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. jackie.macdonald@unc.edu.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: MacDonald Gibson
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000592:standards*; D016902:Air Pollution, Indoor / Q000032:analysis; D004784:Environmental Monitoring / Q000592:standards; D052918:Environmental Restoration and Remediation / Q000592:standards; D060587:Groundwater / Q000032:analysis* / Q000592:standards*; D017408:Guidelines as Topic; D064371:Hazardous Waste Sites / Q000592:standards; D006801:Humans; D012989:Soil Pollutants / Q000032:analysis* / Q000592:standards*; D014481:United States; D014484:United States Environmental Protection Agency; D055549:Volatile Organic Compounds / Q000032:analysis / Q000592:standards; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000592:standards
chemical_list: D000393:Air Pollutants; D012989:Soil Pollutants; D055549:Volatile Organic Compounds; D014874:Water Pollutants, Chemical
keywords: contaminated sites; environmental decision-making; hazardous waste; indoor air quality; vapor intrusion