COLLABORATIVE RESEARCH: Particle-mediated enhanced transport of semi-volatile organic compounds in indoor environments

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CBET 1336807/1335722/1336202Glenn Morrison/Jennifer Benning/John LittleMissouri University of Science & Technology/So Dak School of Mines/ Tech/VA Polytechnic Inst & St. Univ.Occupants of buildings are exposed to toxic chemicals from the vast number of modern building products and furnishings that continuously release these compounds. Occupants absorb semi-volatile organic compounds (SVOCs) such as plasticizers, pesticides, flame-retardants, and others through inhaling, eating, drinking and even by absorbing them through the skin. The presence of airborne particles in the indoor environment from smog, cooking, smoking and other sources may dramatically increase dermal absorption for these compounds. This research will test the hypothesis that airborne particles increase chemical emission rates from sources of SVOCs and deposition of these chemicals onto surfaces such as skin and clothing by altering the way these chemicals are transported from surface-to-surface. A theoretical model of this system predicts as much as a 10-fold increase in the rate of transport from indoor surfaces and materials to occupants, thereby increasing inhalation and dermal (skin) dose. This occurs because particles can absorb and release very large amounts of SVOCs as they move in and out of regions near surfaces. The proposed research will carefully combine experimental quantification of relevant parameters (partition and transport phenomena) with model analysis. Under realistic environmental conditions, organic and salt particles will be equilibrated with a pure SVOC (phthalate esters, polybrominated diphenyl ethers, polychlorinated biphenyls) and the gas-phase deposition rates will be measured for flat plate and tubular geometries. The results will be used to test theoretical models of particle-mediated enhanced emissions and uptake. Further, experimental results and mass-transfer models will be integrated into indoor air quality models to improve predictions of exposure, dose and risk to indoor sources of SVOCs. The research team will integrate undergraduate and graduate students in field collection of samples, model analysis and exposure predictions. Their experiences will inform the development of a student-vetted educational module on SVOCs which will be disseminated through the Association for Environmental Engineering and Science Professors.Building occupants can absorb toxic plasticizers, pesticides, flame-retardants, and others chemicals through inhalation, consumption of food and beverages, and even absorption through the skin. This research examines the extent to which airborne particles in the indoor environment from smog, cooking, smoking and other sources may dramatically increase absorption for these compounds. Although this possibility has been predicted by a recent theoretical model, this project will be the first to test the model experimentally and under real-world conditions. This new knowledge will provide health professionals with tools to better understand and predict exposure and risk associated with low-volatility chemicals in a wide range of environmental scenarios. The results will help to better understand and mitigate the health risks of high-particulate environments that result from activities such as smoking and cooking. The research will also help manufacturers reformulate products such as building materials by identifying those chemicals that should be avoided.