The concentration of volatile organic compounds (VOCs) in indoor air varies widely across buildings and interior spaces at vapor intrusion (VI) sites, and only a minority of buildings include zones that exceed risk protective action levels. Yet, tens of thousands of VOC-impacted sites exist, many of which potentially impact dozens to hundreds of buildings per site. Therefore, regardless of whether investigation, mitigation and remediation are funded by corporate or governmental entities, resource-efficient strategies are needed to more-clearly identify the cases where mitigation or remediation is merited. Accurate decision-making in VI has been limited by: • The limited amount of published cost data or case studies including cost information • Uncertainty in decision-making inputs, such as the frequency of VOC exceedances in indoor air across a population of buildings and spatial extent of exceedances across zones in buildings. • The lack of publicly-available, widely-used cost models for VI investigation and mitigation To date several studies have examined the financial implications of specific types of VI site decisions, often based on generalized or nominal cost information: • Economics of preemptive mitigation , • Economics of relying on indicators, tracers, and surrogates (ITS) vs. conventional sampling • Economics of high temporal resolution sampling vs. conventional sampling • Economics of long- duration vs. conventional duration sampling • Prioritization across a large set of buildings for sampling efficiency • Blending economics with other decision-making criteria using multi-criteria decision analysis • Economics of single structure mitigation vs. mitigation of an area using soil vapor extraction This presentation will highlight the major findings of these studies and show how to put these insights together to select a cost-effective, health-protective VI site management strategy.
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