Vapor intrusion (VI) is emerging as a significant concern at contaminated sites around the country. Soil and groundwater contamination is able to migrate in a vapor form into occupied structures, and even at relatively low concentrations, these vapors are harmful to human health. If a Vapor Intrusion Investigation indicates that VI is occurring and has the potential to harm human health, mitigation or remediation of the vapors will be necessary.
Several mitigation and/or remediation strategies are available to address the VI pathway. For new construction on contaminated or brownfield sites, presumptive mitigation might include installing a soil vapor barrier and/or a sub-slab depressurization system (SSDS) below the foundation. For existing buildings, the two primary mitigation options include applying a vapor proof sealant to the floor, or installing a SSDS below the foundation. Evacuating the inhabitants or utilizing indoor air filters can also be used as a short-term option until a more permanent long-term solution is implemented. VI remediation often consists of removing and remediating the source of the vapors, which is usually contaminated soil or groundwater.