Quantitative Passive Sampling Methods for Vapor Intrusion Assessments
The presentation will discuss the use of passive sorbent samplers to provide time-weighted average measurements of VOCs and SVOCs over days or weeks to assess vapor intrusion risks and/or characterize sites. The ability to easily collect long duration samples overcomes the challenges of the documented temporal variability of vapor concentrations. Further, for soil vapor sampling, a passive method has the additional advantage of sampling under steady state conditions, which is more representative of actual soil vapor concentrations as compared to a canister method that actively samples in a vacuum-induced condition that can bias the results. Passive samplers, which are easy to employ and transport, do not require flow controllers, pumps, helium shrouds, or other equipment that can present opportunites for failure or error. The use of passive samplers and adoption by state regulators to sample soil vapor, sewer gas, crawl spaces, vent pipes, indoor air, and ambient air will be discussed.