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Using Personal Air Sensor and GPS to Determine Microenvironment-specific Exposures to Volatile Organic Compounds
Citation:
Breen, M., Lillian M. Alston, A. Rooney, K. Taylor, T. Buckley, V. Isakov, S. Prince, K. McGuinness, P. Egeghy, B. Stephens, S. Arunachalam, Dan Stout, AND R. Walker. Using Personal Air Sensor and GPS to Determine Microenvironment-specific Exposures to Volatile Organic Compounds. The International Society of Exposure Science (ISES) 2021 Annual Meeting, NA, NC, August 30 - September 02, 2021.
Impact/Purpose:
Human exposure to volatile organic compounds (VOCs) from indoor sources including consumer products is a public health concern that is understudied. In the context of a 10-day nine-person pilot study designed to test and demonstrate methods for monitoring personal VOC exposures, we examined time-resolved sensor-based measurements of geocoded total VOC (TVOC) exposures across individuals and microenvironments (ME). Our study demonstrates the ability to determine individual sensor-based time-resolved TVOC exposures in different ME, in support of identifying potential sources and exposure factors that can inform exposure mitigation strategies.
Description:
Human exposure to volatile organic compounds (VOCs) from indoor sources including consumer products is a public health concern that is understudied. In the context of a 10-day nine-person pilot study designed to test and demonstrate methods for monitoring personal VOC exposures, we examined time-resolved sensor-based measurements of geocoded total VOC (TVOC) exposures across individuals and microenvironments (ME). We integrated continuous (1-min) data from a personal TVOC sensor and a global positioning system (GPS) logger, with a GPS-based ME classification model to determine TVOC exposures in four ME, including indoors at home (Home-In), indoors at other buildings (Other-In), inside vehicles (In-Vehicle), and outdoors (Out) across 45 participant-days for a subset of five participants. To examine potential exposure factors when Home-In, we applied a residential air exchange rate (AER) model based on building characteristics and weather conditions. To help identify large emission sources, we identified high exposure events (HEE; TVOC > 500 ppb) and used geocoded TVOC time-course data overlaid on Google Earth maps to determine the type of place visited (e.g. store, restaurant). For HEE when Home-In, we estimated TVOC emission rates and removal rates with a dynamic mass-balance model. The ME ranked from highest to lowest median TVOC were: Home-In (165 ppb), Other-In (86 ppb), In-Vehicle (52 ppb), and Out (46 ppb). For the two participants living in single-family houses with attached garages, the median exposures when Home-In were substantially higher (209, 416 ppb) than the three participant homes without attached garages: one living in a single-family house (129 ppb), and two living in apartments (38, 60 ppb). The daily average Home-In exposures exceeded the LEED building guideline of 108 ppb for 60% of the participant-days. For the daily residential AER, the medians were lower for the homes with attached garages (0.04, 0.07 h-1) than the homes without attached garages (0.19, 0.23, 0.29 h-1), which corresponded to days with smaller and larger indoor-outdoor temperature differences, respectively. We identified 94 HEE across all participant-days, and 67% of the corresponding peak levels exceeded 1000 ppb. The ME ranked from highest to lowest number of HEE were: Home-In (60), Other-In (13), In-Vehicle (12), and Out (9). For Other-In and Out, most HEE occurred indoors at fast food restaurants and retail stores, and outdoors in parking lots, respectively. For Home-In HEE, the median TVOC emission and removal rates were 5.8 g h-1 and 1.1 h-1, respectively. Our study demonstrates the ability to determine individual sensor-based time-resolved TVOC exposures in different ME, in support of identifying potential sources and exposure factors that can inform exposure mitigation strategies.