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Intercomparison of Ethylene Oxide Measurement Methods Under Controlled and Relevant Atmospheric Conditions
Citation:
Gitipour, A., I. George, E. Thoma, T. Yelverton, M. Lewandowski, G. Queiroz, K. Loftis, J. Nwia, M. Sieffert, P. Burnette, AND C. Singer. Intercomparison of Ethylene Oxide Measurement Methods Under Controlled and Relevant Atmospheric Conditions. Air & Waste Management Association (Air Quality Measurement Methods and Technology), San Diego, California, March 08 - 09, 2022.
Impact/Purpose:
The results from this study highlight limitations associated with various instruments and analytical methods, as well as assist in understanding the optimal instruments/methods to be used for quantifying EtO given specific environmental scenarios (e.g., relative humidity levels and presence of interferant gases). Further, this investigation demonstrates the importance of considering the intended environmental scenario when selecting an instrument/method carefully for proper detection and quantification of EtO in air as fluctuations in relative humidity and presence of interferant ambient gas mixtures may impact the quality of the data.
Description:
Ethylene oxide (EtO) is a flammable, colorless gas used for making a range of products, including antifreeze, textiles, plastics, detergents, and adhesives. In addition, EtO is used to sterilize equipment and plastic devices that cannot be sterilized by high temperature processes such as steam, particularly medical equipment. EtO in the air can come from different sources, including chemical manufacturers and sterilizers, and potentially others that are not yet identified. In 2016, the US Environmental Protection Agency (EPA) updated the Integrated Risk Information System (IRIS) for EtO, identifying it as a human carcinogen with long-term exposure and issuing a unit risk estimate (URE) 60x more potent than previously identified. Little is currently understood on additional suspected sources of EtO emissions to the atmosphere due to limitations with analytical instrumentation detection boundaries and lack of current methodology for quantitation of EtO at lower concentrations (e.g., fugitive, ambient and near-source). With this in mind, the current investigation presents a direct comparison of novel technologies (analytical instrumentation and methodologies) for ppb and sub-ppb level detection of EtO. This research was conducted utilizing an atmospheric aging chamber. A total of eight instruments and analytical methods were compared for their performance under relevant, consistent environmental scenarios to investigate EtO mixed in the chamber with several known interferants (including CO, CH4, C3H8 and C2H4, as well as the presence of inorganic particulate matter, both fresh and aged) at different relative humidity levels. The results from this study highlight limitations associated with various instruments and analytical methods, as well as assist in understanding the optimal instruments/methods to be used for measuring EtO given specific environmental scenarios (e.g., relative humidity levels and presence of interferant gases). Further, this investigation demonstrates the importance of considering the intended environmental scenario when selecting an instrument/method carefully for proper detection and quantitation of EtO in air as fluctuations in relative humidity and presence of interferant ambient gas mixtures may impact the quality of the data. This abstract was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.