- Program Areas
- Installation Energy and Water
- Environmental Restoration
- Munitions Response
- Resource Conservation and Resiliency
- Weapons Systems and Platforms
Demonstration of a Long-Term Sampling Approach for Distinguishing Sources of Volatile Organic Compounds in Indoor Air
Dr. Alan Rossner | Clarkson University
The objective of this project is to demonstrate and validate the use of a capillary canister sampling system to enable long-term and representative sampling of volatile organic compounds (VOCs) in indoor environments impacted by vapor intrusion (VI). The new canister method captures the advantages of both canisters and sorbent samplers without their limitations by allowing for long-term (1-3 weeks) sample collection and characterization of VOCs in buildings at risk for vapor intrusion.
The long-term low flow capillary canister sampling system will be demonstrated and validated by characterizing VOCs from vapor intrusion collected from Department of Defense (DoD) sites using the innovative low flow sampling system and comparing the results to those from both long term diffusion tube sampling (2 weeks) and consecutive multiple day 24-hour canister sampling. The innovative low flow rate capillary flow controller provides flow rates ranging from 0.1 to 0.5 mL/min, allowing collection of samples over a 1-3 week sampling period. To demonstrate and validate the capillary canister system, the project team will collect VOC data at Navy and/or Air Force sites for which existing VOC data have been compiled in the database developed under the Navy's Environmental Sustainability Development to Integration (NESDI) project 476, “A Quantitative Decision Framework for Assessing Navy Vapor Intrusion.” The NESDI database contains information for more than 50 buildings and 150 sample locations that were historically sampled. At these NESDI sites, the occurrence of VI has been established and concentrations of VOCs in the indoor air are known.
Sampling and measurement of VOCs using the new low flow capillary canister system, traditional canisters, and diffusion tubes has been completed at NWS Yorktown, Site 31. Two locations in each of two large buildings impacted by VI were sampled for six consecutive quarters spanning May 2017 through January 2018. Results, focused on TCE which was the highest concentration VOC sampled, demonstrate that the low flow capillary canister system samples collected concentrations over two-week sampling periods that were comparable to average values collected daily over two weeks using the traditional canister sampling approach. TCE concentrations measured using diffusion samplers were significantly different. Seasonal impacts on VOCs concentrations were noted, but did not negatively affect capillary canister performance. Sampling using the capillary canister system required no additional expertise relative to the traditional approach. A comparison of the cost-effectiveness of the two canister sampling approaches is in progress.
The capillary flow controller can substantially reduce sampling and analysis costs by decreasing the number of samples collected over the course of an investigation or long-term monitoring period as a result of minimizing variability. While most sampling strategies currently used do not involve multiple consecutive day long samples, there is a regulatory and stakeholder drive for increasing numbers of sampling rounds due to temporal variability concern; the longer sample durations using the capillary canister can address this concern. The approach to be demonstrated is robust, comparable in cost or less expensive than current methods, allows for long-term sample collection, and requires only one sample to capture a full range of analytes and concentrations. This sampling approach could lead to more effective VI assessments. (Anticipated Project Completion - 2019)