Numerical modeling: USEPA supports the use of numerical models as one of many lines of evidence during vapor intrusion site characterization efforts. While I was working as a policy liaison within the Brown University SRP, governmental agencies approached me to explore 3D modeling to improve estimates of vapor intrusion exposure risks. In response to this request, we developed a finite element computation fluid dynamics (CFD) 3D model that could be used to investigate issues that were of interest to governmental agencies. Pennell et al. 2009 and Bozkurt et al. 2009 describe the model we developed and represent the first vapor intrusion articles to be published by our group. Since that time, we have published more than 20 articles related to vapor intrusion, and we have expanded our model to include the effects of preferential pathways, heterogeneous soil types, and rainfall events (Shen et al., 2012). As discussed in Contribution 2 below, we have also published a landmark article that establishes sewer gas entry as an important pathway to consider when assessing vapor intrusion exposure risks. My NSF CAREER award (Vapor Intrusion, Knowledge Brokers and Environmental Health: A Three-Dimensional Perspective, 2015-2020) allows new scientific discoveries related to the role of air transport into and around buildings (e.g. Shirazi and Pennell, 2017), which is critical for understanding indoor air pollutant concentrations.
Pennell, K. G., Bozkurt, O., Suuberg, E. M. (2009) “Development and Application of a 3-D Model for Evaluating Site-Specific Features on Vapor Intrusion Rates in Homogenous Geologies.” Journal of Air and Waste Management Association. 59: 447-460. PMID: 19418819
Bozkurt, O., Pennell, K. G., Suuberg, E. M. (2009) “Simulation of the Vapor Intrusion Process for Nonhomogeneous Soils Using a Three-Dimensional Numerical Model.” Groundwater Monitoring and Remediation. 29 (1): 92-104. PMID: 20664816
Shen, R., Pennell, K. G., Suuberg, E. M (2012) “A Numerical Investigation of Vapor Intrusion–The Dynamic Response of Contaminant Vapors to Rainfall Events,” Science of the Total Environment. 437:110-120. PMC3756695
Shirazi, E. and Pennell, K.G. (2017). Three-Dimensional Vapor Intrusion Modeling Approach that Combines Wind and Stack Effects on Indoor, Atmospheric, and Subsurface Domains. Environmental Science: Processes and Impacts, 19(12), pp. 1594-1607. PMC5755378
Field and laboratory studies to investigate fate and transport processes: Environmental toxicity is a key area of concern for high-volume production of anthropogenic chemicals and their ultimate deposal into natural and engineered environments. My research in this area aims to better understand the forms of chemicals that exist in various environmental systems. With researchers from Brown University (Liu et al., 2011), we established sulfidation kinetics and evaluated various environmental systems that might be important for fate and transport considerations of nAg. I have also collaborated with USEPA research labs to investigate sampling methodologies for persistent organic pollutants. We investigated passive sampling techniques in the Narragansett Bay (Perron et al., 2013) and continue to evaluate these methods within regulatory context for characterizing human and ecological health risks. Most recently, we have been conducting field studies with NIEHS SRP researchers from Boston University and Brown University (Pennell et al. 2013) and with USEPA and an NIEHS SBIR Grantee (Roghani et al., 2018) to better understand how volatile organic compounds present in liquids disposed of in aging sewer networks are transported in multi-phases, and consequently pose exposure risks to communities. These studies established a new exposure pathway for chlorinated ethenes and informed risk management approaches to prevent exposure risks to toxic chemicals.
Lui, J., Pennell, K.G., Hurt, R.H. (2011) “Kinetics and Mechanisms of Nanosilver Oxysulfidation.” Environmental Science and Technology, 45: 7345-7353. PMID: 21770469
Perron, M.M. Burgess, R. M., Cantwell, M. G., Suuberg, E.M., Pennell, K.G. (2013) “Performance of passive samplers for monitoring estuarine water column concentrations: 1. Contaminants of concern.” Environmental Toxicology and Chemistry. 32(10): 2182-2189. PMID: 23832638
Pennell, K.G., Scammell, M.K., McClean, D., Ames, J., Weldon, B., Friguglietti, L., Suuberg, E. M., Shen, R., Indeglia, P.A., Heiger-Bernays, W. J. (2013) “Sewer Gas: An Indoor Air Source of PCE to Consider During Vapor Intrusion Investigations.” Ground Water Monitoring and Remediation, 33(3): 119-126. DOI:10.1111/gwmr.12021. PMID: 23950637
Roghani, M., Jacobs, O.P., Miller, A., Willett, E.J., Jacobs, J.A., Viteri, C.R., Shirazi, E., Pennell, K.G. (2018). Occurrence of chlorinated volatile organic compounds (VOCs) in a sanitary sewer system: Implications for assessing vapor intrusion alternative pathways. Science of the Total Environment, 616-617: 1149-1162. PMID:29146079
Data management and multidisciplinary research: Our group’s past experience working within multidisciplinary research teams, translating research for policy decision makers, and conducting research at field sites managing data from thousands of samples has well-prepared us to work with different types of data and different researcher cultures. This broad appreciation of different types of expertise and information has nurtured a sense of epistemic empathy, which Little and Pennell (2017) discuss is critical for addressing complex environmental health challenges. We have quantitatively honed skills to analyze large, complex data sets. Yao et al (2013) examines USEPA’s vapor intrusion database, which is the largest collection of vapor intrusion data in the United States and contains nearly 3000 paired measurements from 42 vapor intrusion sites. Pennell et al. (2016) summarizes the results of a research project that was conducted in accordance regulatory standards. We collected and analyzed field data using strict regulatory protocols in a Metro-Boston neighborhood and harmonized them with field data collected years prior by other parties who had been working to satisfy regulatory requirements. Because of our ability to bridge academic and environmental policy realms, we are approached by policy decision makers who are interested in how environmental health science can inform regulatory decisions. For example, policy makers have approached us several recent articles we published related to building exchange rates and implications for vapor intrusion exposure risks (e.g. Reichman et al. 2017) and solicited information about their activities related to revisions to flexible data infrastructure to integrate and report complex datasets from hazardous waste sites.
Yao, Y., Shen, R., Pennell, K. G., Suuberg, E. M. (2013) “Examination of the Influence of Environmental Factors in Contaminant Vapor Concentration Attenuation Factor with the U.S. EPA’s Vapor Intrusion Database.” Environmental Science & Technology. 47(2): 906-913. PMID: 23252837
Pennell, K.G., Scammell, M.K., McClean, D., Suuberg, E., Moradi, A., Rohgani, M., Ames, J., Friguglietti, L., M., Indeglia, P.A., Shen, R., Yao, Y., Heiger-Bernays, W. J. (2016). “Field Data and Numerical Modeling: A Multiple Lines of Evidence Approach for Assessing Vapor Intrusion Exposure Risks” Science of the Total Environment, 556: 291-301. PMID: 26977535
Little, P.C. & Pennell, K.G. (2017). Measuring Vapor Intrusion: From Source Science Politics to a Transdisciplinary Approach. Journal of Environmental Sociology, 3(2), pp. 145-154. PMID: 28367475
Reichman, R., Shirazi*, E., Colliver, D. & Pennell, K.G. (2017). US Residential Building Air Exchange Rates: New Perspectives to Improve Decision Making at Vapor Intrusion Sites.” Environmental Science: Processes and Impacts, 19(2), pp. 87-100. PMID: 2816210