PROJECT SUMMARY (Project 3) This proposed work is to advance airborne volatile organic compound (VOC) detection and quantification technologies, and to robustly characterize indoor/outdoor contrast and in-home determinants for exposures to target Superfund-relevant VOCs. This research will continue to grow and expand two VOC real-time in situ measurement platforms developed by the University of Louisville Superfund Research Center established in 2017. One platform comprises small, low-cost sensors that can be deployed alone or in networks. Novel gas sensors and sensor arrays are being developed to measure target Superfund-relevant VOCs including acrolein, trichloroethene (TCE), benzene, toluene, ethylbenzene, and xylene (BTEX). The devices use novel surface chemistries to address the common challenges of selectivity and sensitivity and are fabricated using microelectromechanical systems (MEMS) technology. Another platform addresses the need for flexibly designed, field-deployable instruments that can measure with high sensitivity a large range of compounds to interrogate microenvironments with complex VOC mixtures. The Multichannel Organics In-situ enviRonmental Analyzer (MOIRA) instrument, developed in the first cycle of Center funding for mobile monitoring, will be expanded and optimized for indoor/outdoor VOC monitoring studies. MOIRA is a gas chromatography–mass spectrometry (GC-MS) instrument with high time resolution (e.g., ten minutes). Its capabilities will be expanded to measure both higher and lower volatility compounds than can be achieved with the current design. These innovative, high time resolution in situ measurements will be coupled with conventional time-integrated VOC passive sampling to measure target Superfund-relevant VOCs at homes of some participants in the allied clinical study. These data will be used to build spatiotemporal models to estimate ambient VOCs at the homes of all clinical study participants, and to gain new insights into VOC levels and their determinants in the home microenvironment. In addition to exposure assessment, the two measurement platforms are responsive to ongoing Superfund program advancements; these innovative developments will expand future capacities to monitor VOC indoor vapor intrusion, monitor outdoor VOC levels during site remediation, and monitor both indoors and outdoors during post-remediation surveillance.