Andrew Horwath

Successful Air & Vapor Data Collection: Best Practices for Vapor Intrusion Investigations

Vapor Intrusion (VI) is usually a crucial component in the environmental assessment and cleanup process because exposure at relatively low contaminant concentrations can pose significant risk concerns both on your site as well as past your property lines. VI concerns have gained momentum over the years and most regulators now have a good understanding of what “good” or “great” VI evaluations look like, and you should know how to tell the difference.

VI is often one of the biggest concerns at contaminated sites because chronic toxicity occurs at low concentrations, exposure paths can be numerous and we need to breathe all day, every day. VI concerns are usually determined during due diligence/property transactions, site development or site investigation often while working with state/federal regulators. Sometimes VI concerns delay case closure, even when soil or groundwater concentrations may be significantly less than associated direct contact / ingestion closure goals.

Once your VI data is collected, the information is added to the Conceptual Site Model that describes the full characteristics of a site. This model can then be relayed to others to facilitate understanding of your site and help understand potential exposure risks and support planning for further investigations and/or cleanup activities, if warranted. These models are created from data generated after determining each site’s Data Quality Objectives, that ultimately tell you if you need soil gas, or sub-slab soil gas or indoor air samples, and what method you’ll need to run to get the precision you need. As is usually the case, proper planning goes a long way when evaluating VI concerns at contaminated sites, and can save you time and money in the long run.