Assessing vapor intrusion and risk from an environmental justice perspective: A mental models approach

Vapor intrusion, the migration of subsurface contaminants into overlying buildings, is an emerging area of exposure assessment and risk analysis in communities affected by pollution from hazardous waste sites. Recent research has suggested that human exposure to chlorinated solvents via the vapor intrusion pathway exceeds exposure from all other pathways combined. Nonetheless, the study and remediation of the vapor intrusion pathway faces there are numerous technical and policy challenges that are not likely to be resolved in the short term. Thus far, the national conversation has been largely driven by technical consideration, has yet to integrate the experiences, attitudes and opinions of communities likely to be affected by vapor intrusion. Since the study and regulation of indoor air involves an intimate and private space, it is important to understand the belief systems of the local communities.

We conducted qualitative interviews with residents of an environmental justice community in San Antonio, Texas that sits atop a large shallow chlorinated solvent plume. We employed a mental models design that aims to characterize public understanding of indoor air contamination sources and identify what missing information is most critical to the decision-making processes of the public. We conducted semi-structured interviews to determine people's ”mental models” of a particular risk problem--that is, their thought process in evaluating the potential risk they face. The approach allows the interviewees the opportunity to express their ideas, which fits well with a preeminent principle of environmental justice: residents are able to “speak for themselves.” Better understanding how the community understands the information can lead to improvement in content and design of risk communications. We will present the results from the analysis, offer insights into the beliefs of the impacted residents and make recommendations about engaging environmental justice community around vapor intrusion.