Human Exposure in Indoor Environments
In indoor environments, humans are exposed to a complex mixture of semi-volatile organic compounds (SVOCs), which can have significant health implications, particularly due to the extended periods spent indoors. SVOCs are a diverse group of compounds found in various household products and building materials. Due to prolonged exposure and potential health risks associated with SVOCs, it is essential to understand and address indoor air quality to safeguard human health. Among residents indoors, some are considered vulnerable populations and have reported experiencing elevated levels of SVOCs.
The overall goal is to improve our understanding of exposure to SVOCs arising from indoor sources, with a specific focus on vulnerable populations. To achieve this goal, three projects were developed:
The overall goal is to improve our understanding of exposure to SVOCs arising from indoor sources, with a specific focus on vulnerable populations. To achieve this goal, three projects were developed:
Project 1:
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Individuals with low socioeconomic status may have higher exposure to pesticides, particularly those residing in social housing. We measured the concentration of 28 pesticides, including both legacy and current-use, in particle phase in seven low-income social housing multi-unit residential buildings (MURBs) in Toronto, Canada, using a portable air cleaner. We found at least one pesticide in 89% of the units, with detection frequencies for individual pesticides reaching up to 50%. Current-use pyrethroids exhibited the highest detection frequencies and concentrations. Additionally, we measured concentrations of some pesticides, including heptachlor, lindane, endosulfan I, chlorothalonil, and allethrin, higher than those reported in low-income residences elsewhere. In addition to known sources of indoor pesticides (e.g., intentional use, building materials, etc.), tobacco smoking was significantly correlated with the concentrations of five pesticides used on tobacco crops. We observed a distribution of pesticides with high detection frequencies within individual buildings, suggesting that pest eradication programs by building management and/or pesticide use by residents were the major sources of measured pesticides. The manuscript of this study has been submitted. |
Project 2:
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Mattresses in sleeping environments can be a source of semi-volatile organic compounds (SVOCs). Since SVOCs are not chemically bonded to these materials, they can migrate and partition into various compartments, including dust, surfaces, skin, clothing, and toys. Therefore, individuals can be exposed to sourced SVOCs from mattresses through inhalation, dermal absorption, and ingestion. Young children face an elevated risk of SVOC exposures for several reasons, most importantly, spending a significant amount of time in sleeping environments. The objectives of our study are to: - Determine mattresses as a source for SVOCs emission and, consequently, exposure in the sleeping environment (SME). - Explore factors impacting the emission rates of SVOCs in sleeping environments, including children's body temperature and weight. The target SVOCs in our study are phthalate plasticizers (PAEs), organophosphate esters (OPEs), and flame retardants. To achieve these objectives, we have designed and conducted two studies: In-Lab Experiment: We measured SVOC concentrations in eight new mattresses using a silicon rubber sampler (PDMS) and through direct extractions of product samples. We also investigated the influence of children's body temperature and weight. In-Home Experiment: We are interested in measuring the concentrations of chemical additives that could be released from infants' or children's beds and/or other items in the child's sleeping area and bedroom. Thus, we recruited 25 participants from the Greater Toronto Area, Barrie, and Ottawa to deploy PDMS samplers in their children's sleeping environments and bedrooms. Both studies are in progress. Stay tuned for publication of our study's results. SVOCs enter residential buildings during construction and after occupation, originating from various sources, including consumer products and occupant activities. Building materials incorporate PAEs and OPEs. SVOCs emitted from construction materials can persist throughout the building's lifespan. As homes are occupied, additional contaminants are introduced through consumer products and residents' activities.
The goal of this project is to determine SVOC levels and profiles in Canadian new homes before and after occupancy through: - Measuring SVOC concentrations in indoor media before and after a home is occupied. - Identifying factors that affect the concentrations and profiles of SVOCs in indoor media before and after home occupancy. To achieve our goal, we have benefited from multi-media sampling by collecting air samples through active and passive methods, dust, and surface wipes. This study is in progress. Stay tuned for the results! 
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