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IGERT Trainee Tackles Issue of Exposure to Toxic Chemicals in Low-Income Homes
Achievement/Results
Diana Hun, a doctoral candidate funded through the National Science Foundation’s (NSF) Integrative Graduate Education and Research Traineeship (IGERT) program in Indoor Environmental Science and Engineering at The University of Texas at Austin (UT), is studying human exposure to toxic air contaminants in low-income housing. She has begun to find important associations between risks of exposure to specific toxic air contaminants in households characterized by socio-economic status. Importantly, Hun’s work is aimed at identifying sources of toxic air contaminants in lower-income homes, and finding approaches for lowering risks of exposure to these toxic chemicals, e.g., from source removal or control to simple changes in home design or operation. Hun is “mining” data from the multi-city Relationships between Indoor, Outdoor, and Personal Air (RIOPA) study. Her work indicates that chemicals that lead to the highest cancer risks in low-income households are formaldehyde, p-dichlorobenzene [DCB], benzene, chloroform, and acetaldehyde. Indoor sources of nearly all of the targeted toxic air contaminants are far more important than outdoor sources, even for homes located near large petro-chemical complexes. Results indicate that in the absence of sources of DCB, formaldehyde is generally the greatest contributor to overall cancer risks in low-income homes. In homes that contain sources of DCB, e.g., moth repellants, toilet deodorizers and some air “fresheners”, this contaminant tends to dominate overall cancer risks.
Through an NSF-funded IGERT internship, Hun is also participating in a study entitled Houston Exposure to Air Toxics Study (HEATS). HEATS involves measurement of human exposure to airborne toxic chemicals in 200 low-income households. Samples are collected at an outdoor fixed monitoring site, backyard of each home, at an interior location, and attached to at least one member of the household, including children in some cases. Target chemicals include a wide range (over 30) of volatile organic compounds (VOCs) and aldehydes. Hun is assisting with field measurements, source characterization, in-person surveys, and statistical analysis of data. Combined with data from the RIOPA study, HEATS will allow Hun to characterize primary sources of important toxic air contaminants, and to develop strategies for reducing human inhalation exposures to those contaminants. Hun will also use HEAT data to study the roles of environmental conditions such as relative humidity on formaldehyde off-gassing, inter-zonal transport of toxic chemicals, e.g., benzene from garage to occupied space, and novel approaches to reduce human exposure to toxic chemicals through economically-viable changes to low-income homes.
Address Goals
Diana Hun’s research related to exposure of humans to toxic air contaminants (TACs) in low-income housing is novel on several fronts, and is therefore advancing the frontiers of knowledge related to human inhalation exposure to TACs. Her findings are unique in that they explore risks associated to TACs and how they differ between socio-economic classes (discovery). Importantly, Hun is studying the reasons for these differences in terms of the nature of consumer products used by lower-income populations, activity patterns, location of housing, nature of housing (attached garage, etc.) and operation of housing. Her work will ultimately distinguish the extent to which outdoor sources contribute to indoor inhalation exposures. Since Hun is an engineer with a strong building science background, her efforts will also lead to insights related to how to solve high exposure scenarios in lower-income households (discovery).
Hun’s participation in HEATS is made possible because of an NSF-funded IGERT program, and is a prime example of how funding from NSF has allowed a Ph.D. student in Environmental Engineering to work alongside health scientists on a novel and important study that benefits from the synergy of interdisciplinary teamwork. This goes to the strategic goal of learning, and the fact that interdisciplinary collaboration lends “value added” the learning process for all committed participants.
Hun’s research involves passive (diffusive) monitoring methods that are not currently employed by her co-supervisors (Drs. Corsi and Siegel) at The University of Texas. As such, they are learning these new methods along with Diana, and as engineers are now working with health scientists at the UT Health Science Center to improve the passive monitoring devices. Knowledge gained from this interdisciplinary/collaborative effort will therefore provide improved research infrastructure for scientists at the UT Health Science Center, and new research infrastructure for Drs. Corsi and Siegel as they implement new tools in their own laboratories.
