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Volatile organic compounds (VOC) represent a broad spectrum of compounds and there is growing concern that VOC exposures, in addition to increasing risks for cancer, may be implicated in exacerbating asthma and other adverse respiratory effects. Yet little is known about exposures in the U.S. population beyond the seminal Total Exposure Assessment Methodology (TEAM) studies that were conducted by the U.S. Environmental Protection Agency (U.S. EPA) between 1979 and 1987. This investigation was carried out to evaluate the relationship between personal exposures to benzene, toluene, ethylbenzene, and xylenes (BTEX) and socioeconomic, behavioral, demographic, and residential characteristics using a subsample from the National Health and Nutrition Examination Survey (NHANES) (636 participants who represented an estimated 141,363,503 persons aged 20 to 59 yr in the United States). Personal VOC exposures were evaluated using organic vapor monitors for periods that ranged from 48 to 72 h, and participants were administered a questionnaire regarding personal behaviors and residential characteristics while wearing the monitor. Geometric mean (GM) levels were significantly higher for males for all compounds except toluene. For benzene, GM levels were elevated among smokers and Hispanics. Sociodemographic characteristics could not be evaluated simultaneously in the weighted multiple regression models with the VOC questionnaire data because of issues associated with multicollinearity. Results from the regression analyses suggest that the presence of an attached garage (BTEX), having windows closed in the home during the monitoring period (benzene, toluene), pumping gasoline (toluene, ethylbenzene, and xylenes), or using paint thinner, brush cleaner, or stripper (xylenes) results in higher exposure in the general population and confirm previous findings of studies that were more regional in scope. Once the complete NHANES VOC data are released, additional study is warranted to explore whether risk factors associated with elevated VOC exposures differ in subgroups of U.S. adults, which should inform efforts to develop approaches for minimizing VOC exposures and ameliorating environmental health risks. [ABSTRACT FROM AUTHOR]

Exposure to ambient particulate matter (PM) is known as a significant risk factor for mortality and morbidity due to cardiorespiratory causes. Owing to increased interest in assessing personal and community exposures to PM, we evaluated the feasibility of employing a low-cost portable direct-reading instrument for measurement of ambient air PM exposure. A Dylos DC 1700 PM sensor was collocated with a Grimm 11-R in an urban residential area of Houston Texas. The 1-min averages of particle number concentrations for sizes between 0.5 and 2.5 µm (small size) and sizes larger than 2.5 µm (large size) from a DC 1700 were compared with the 1-min averages of PM2.5(aerodynamic size less than 2.5 µm) and coarse PM (aerodynamic size between 2.5 and 10 µm) concentrations from a Grimm 11-R. We used a linear regression equation to convert DC 1700 number concentrations to mass concentrations, utilizing measurements from the Grimm 11-R. The estimated average DC 1700 PM2.5concentration (13.2 ± 13.7 µg/m3) was similar to the average measured Grimm 11-R PM2.5concentration (11.3 ± 15.1 µg/m3). The overall correlation (r2) for PM2.5between the DC 1700 and Grimm 11-R was 0.778. The estimated average coarse PM concentration from the DC 1700 (5.6 ± 12.1 µg/m3) was also similar to that measured with the Grimm 11-R (4.8 ± 16.5 µg/m3) with anr2of 0.481. The effects of relative humidity and particle size on the association between the DC 1700 and the Grimm 11-R results were also examined. The calculated PM mass concentrations from the DC 1700 were close to those measured with the Grimm 11-R when relative humidity was less than 60% for both PM2.5and coarse PM. Particle size distribution was more important for the association of coarse PM between the DC 1700 and Grimm 11-R than it was for PM2.5. Implications: The performance of a low-cost particulate matter (PM) sensor was evaluated in an urban residential area. Both PM2.5and coarse PM (PM10-2.5) mass concentrations were estimated using a DC1700 PM sensor. The calculated PM mass concentrations from the number concentrations of DC 1700 were close to those measured with the Grimm 11-R when relative humidity was less than 60% for both PM2.5and coarse PM. Particle size distribution was more important for the association of coarse PM between the DC 1700 and Grimm 11-R than it was for PM2.5. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]