Estimating volatile organic compound concentrations in selected microenvironments using time-activity and personal exposure data.
Repeated measures of personal exposure to 14 volatile organic compounds (VOC) were obtained over 3 seasons for 70 healthy, nonsmoking adults living in Minneapolis-St. Paul. Matched data were also available for participants' time-activity patterns, and measured VOC concentrations outdoors in the community and indoors in residences. A novel modeling approach employing hierarchical Bayesian techniques was used to estimate VOC concentrations (posterior mode) and variability (credible intervals) in five microenvironments: (1) indoors at home; (2) indoors at work/school; (3) indoors in other locations; (4) outdoors in any location; and (5) in transit. Estimated concentrations tended to be highest in "other" indoor microenvironments (e.g., grocery stores, restaurants, shopping malls), intermediate in the indoor work/school and residential microenvironments, and lowest in the outside and in-transit microenvironments. Model estimates for all 14 VOC were reasonable approximations of measured median concentrations in the indoor residential microenvironment. The largest predicted contributor to cumulative (2-day) personal exposure for all 14 VOC was the indoor residential environment. Model-based results suggest that indoors-at-work/school and indoors-at-other-location microenvironments were the second or third largest contributors for all VOC, while the outside-in-any-location and in-transit microenvironments appeared to contribute negligibly to cumulative personal exposure. Results from a mixed-effects model indicate that being in or near a garage increased personal exposure to o-xylene, m/p-xylene, benzene, ethylbenzene, and toluene, and leaving windows and doors at home open for 6 h or more decreased personal exposure to 13 of 14 VOC, all except trichloroethylene.
Sexton
Ken
K
Brownsville Regional Campus, University of Texas School of Public Health, Brownsville, Texas 78520, USA. Ken.Sexton@utb.edu
Mongin
Steven J
SJ
Adgate
John L
JL
Pratt
Gregory C
GC
Ramachandran
Gurumurthy
G
Stock
Thomas H
TH
Morandi
Maria T
MT
D000328:Adult; D000393:Air Pollutants / Q000032:analysis*; D001499:Bayes Theorem; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008910:Minnesota; D015233:Models, Statistical; D009930:Organic Chemicals / Q000032:analysis*; D014505:Urban Population; D014835:Volatilization
D000393:Air Pollutants; D009930:Organic Chemicals