Vapor Intrusion and Air Quality Assessments
- Develop Sampling Programs
- Soil Gas and Sub-slab Sampling
- Indoor Air Sampling
- Transport and Fate Studies
- Data Validation and Human Health Exposure Assessments
- Indoor Air Quality Mitigation/Remediation
Dvirka and Bartilucci Consulting Engineers (D&B) has completed air sampling and air contaminant exposure assessment services for numerous clients and has conducted these services at a wide variety of sites including active and closed landfills, active and abandoned manufacturing facilities, former manufactured gas plant (MGP) sites and petroleum storage facilities.
The assessment of indoor air quality is an essential element associated with the investigation of many contaminated sites due to the fact that contaminants often migrate in groundwater and through subsurface soil and then enter buildings and other living spaces as a vapor. Since D&B’s area of practice has included numerous assignments focused on identifying and mitigating this potential exposure pathway, it is standard practice for the firm to include the evaluation of indoor air as part of its investigation of contaminated sites.
The typical components of assessing the indoor air exposure pathway include:
Soil Gas and Sub-slab Sampling: Most air quality assessments include the collection of soil gas samples either around the perimeter of structures or from directly beneath the foundation of a structure. The soil gas data, in conjunction with soil and groundwater data, is needed to confirm the link between site-related contaminants and the contaminants present in the air within a building suspected of being impacted.
Interview of Building Occupants: Prior to the collection of indoor air samples, the firm utilizes a standardized questionnaire to interview appropriate building occupants to determine what type of activities are performed at the structure and what type of chemicals are stored on-site.
Indoor Air Sampling: After selecting appropriate sample locations, air samples are typically collected utilizing Summa canisters. Generally, indoor air samples will be collected in basement or crawl space locations and on the first floor living space. In addition, at least one ambient air sample will be collected outside and adjacent to the structure.
Data Evaluation and Exposure Assessment: Using the data generated by the above activities, a qualitative risk/exposure assessment is completed by D&B. The purpose of this assessment is to determine if the contaminants identified in indoor air poses an unacceptable risk to human health based on current and anticipated use of the building, potential receptors and potential contaminant migration pathway.
Indoor Air Quality Mitigation/Remediation: The firm has designed and implemented a number of technologies to mitigate the exposure of building occupants to indoor air contaminants, both on a near and long-term basis. Selection of appropriate remedies for vapor intrusion and/or exposure mitigation is established based on criteria such as effectiveness, implementability and cost. Techniques commonly used to mitigate vapor intrusion include the elimination of contaminant migration pathways (e.g., installation of vapor barriers or sealing of cracks in building foundations and floor slabs), excavation of contaminant sources in subsurface soil and subsurface vapor extraction, including, but not limited to, active or passive sub-slab depressurization systems.
In closing, D&B has successfully completed numerous air quality assessments for a broad range of clients. The firm has performed air quality assessments for projects involving up to 25 separate buildings and has completed assessments that have involved only a single residential home.
For more information on D&B’s Environmental Remediation Services, please contact Senior Vice President, Richard W. Walka, at (516) 364-9890 x 3006.