Research Program Area: Health & Exposure
Little is known about the sources or magnitudes of exposure to more than 190 compounds designated by California legislation as "toxic air contaminants" (TACs). This study estimates the contribution of environmental tobacco smoke (ETS) to the exposure of nonsmoking Californians for 17 of these compounds known to be emitted from burning tobacco. Two distinct approaches were used in the assessment: (a) measured 24-h personal exposures to selected compounds, such as benzene, were compared for individuals who reported ETS exposure against those who reported no exposure; and (b) information on activity patterns of Californians was combined with estimates of ETS concentrations in indoor environments. The first method was applied for nonsmokers (age > 7 y) for the mid-to-late 1980's. The second method was separately applied for adults, adolescents, and children for both the mid-to-late 1980's and for the late 1990's. Averaged over all nonsmoking Californians in the late 1980's ETS is estimated to have contributed 5-15 µg h m-3 to daily benzene exposure, corresponding to 2-5% of the total inhalation exposure of nonsmokers. Among those nonsmokers exposed to ETS, average exposure for adolescents was in the range 65-95% of the average for adults; the corresponding range for children was 80-130%. In the late 1990's, as a result of reduced smoking prevalence among adults and legislation that severely restricts smoking in public buildings, ETS exposures are estimated to be reduced. The fraction of adult nonsmokers exposed to ETS indoors on a given day is predicted to have declined from 52% to 16-19% during the last decade. For adolescents, the corresponding change is from 63% to 33-35%, whereas for children the reduction is from 33% to 21-23% exposed. Among individuals still exposed, the average level of exposure is not predicted to have changed markedly. Using emission factor data, ETS contributions to exposure are estimated for these compounds; acetaldehyde, acetonitrile, acrylonitrile, benzene, 1,3-butadiene, 2-butanone, o-cresol, m,p-cresol, ethyl acrylate (upper bound, only), ethylbenzene, formaldehyde, n-nitrosodimethylamine, phenol, styrene, toluene, o-xylene, and m,p-xylene.
For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753
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