Sources and significance of VOC exposures in microenvironments: Schools, offices, residences, outdoors and vehicles

Knowledge of exposures to volatile organic compounds (VOCs) is based largely on studies that have been limited in one or several respects, e.g., few VOC species have been monitored, sampling durations have been short, sample sizes have been small and not necessarily representative, geographic coverage may be limited, and personal activities affecting exposure not recorded. For these and other reasons, the distribution and sources of VOC exposures for representative populations remain inadequately understood. In this study, VOC concentrations were measured for 49 teachers in 9 elementary and middle schools in a midsize Michigan town and simultaneously outdoors and in teachers\u27 homes. Duplicate passive thermally-desorbed samplers were used to collect 3 to 4 day integrated samples. VOC samples previously collected during rush hour commutes using duplicate active 2 hour samples were also incorporated. We also utilize samples collected in office building to represent another microenvironment. Overall, approximately 450 sorbent tubes were analyzed for \u3e70 target species by GC-MS. For many - but not all - species the following holds: (1) Concentrations and variability are highest in homes, then commutes, schools, and outdoors. (2) Home exposures account for the largest portion of total exposure, and exposures as a concentration-time product may be ranked as home\u3ecommuting\u3eschool = office\u3eoutdoor. (3) VOC levels differ among homes and among school rooms, while differences among commuting routes or among schools are minor. (4) Concentrations of certain VOCs are correlated and can be associated with sources, e.g., VOC levels in residences are associated with certain home hobbies, cleaning products, the presence of an attached garage and other factors, as well as ventilation system design and functioning. Estimates of typical or expected exposures to home, commuting and work environments (in schools) are provided for the most prevalent VOCs