The role of indoor dust in modulating indoor air chemistry: assessing air-dust heterogeneous transformations and human exposures

This project is focused on characterizing indoor air chemistry that results from the interactions of organic compounds with airborne dust. This work will advance the understanding of indoor dust chemistry, especially in homes susceptible to higher pollutant concentrations from outside source emissions that infiltrate indoors. The results are expected to lead to a better understanding of individual compounds or compound groups in indoor air that pose significant human health risk. Experiments will be conducted to systematically characterize the interactions of gas- and particle-phase organic compounds with indoor dust, including their partitioning and subsequent heterogeneous chemistry. The objectives of this project are to: (1) Characterize the chemical transformation pathways and resulting products from target dust-bound precursors from within complex mixtures of outdoor pollutants (from sources such as motor vehicle, biomass burning, and cooking) that infiltrate the home and become exposed to indoor reactive gases (e.g., ozone, nitrogen oxides, hydroxyl radicals); (2) Identify novel chemical reaction products in lab-generated and genuine complex mixtures of fresh and aged indoor dust using non-targeted mass spectrometry approaches; and (3) Determine the oxidative potential and exposure risks of fresh and aged dust-bound and re-volatilized product mixtures. The chemical composition and exposure risk evaluations of the indoor air studied will be disseminated to the public via an interactive web tool. A series of workshops will be organized for middle school students and their teachers in collaboration with the Institute for School Partnership at Washington University in St. Louis. The project will support students from Lincoln University, a historically Black institution in Jefferson City, MO, to perform laboratory research each summer throughout the project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.