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Exposure to volatile organic compounds (VOCs) in the indoor environment has received substantial research attention in the past several years, with the goal of better understanding the impact of such exposures on human health and well-being. Many VOCs can arise from consumer products used within the indoor environment. The VOCs emitted from five representative consumer products were collected onto Tenax-GC and subjected to thermal desorption and analysis by gas chromatography, in combination with low-resolution mass spectrometry (MS), high-resolution MS, and matrix-isolation Fourier transform infrared spectroscopy for structural characterization. An emphasis was placed on the polar organic compounds often used to provide fragrance in these products. The structures of a number of these compounds were confirmed, and an electronic literature search was carried out on them to determine any known toxic properties. The search revealed that many of the VOCs possess toxic properties when studied at acute, relatively high-level exposures. In addition, toxic effects were reported for a few of the chemicals, such as benzaldehyde, alpha-terpineol, benzyl acetate, and ethanol, at relatively low dose levels of 9-14 mg/kg. In general, the data were unclear as to the effect of chronic, low-level exposures. The widespread use of such chemicals suggests that the health effects of chronic exposures need to be determined. Validated analytical methods for the quantitative characterization of polar organic compounds at low concentrations will be required to make such work possible.

As part of a program to determine the underlying factors responsible for genotoxicity and perhaps lung cancer risk in Chinese women, we qualitatively identified the volatile components emitted during the heating of cooking oils to 265 degrees C. 1,3-Butadiene, benzene, and a series of aldehydes, olefins, and saturated hydrocarbons were elucidated in vapors from Chinese rapeseed oil. On a relative basis, the intensity of 1,3-butadiene vapors from this were 15.7-, 6.3-, and 1.4-fold greater than in the vapors from peanut, soybean, and Canola oils, respectively. Thus, the Chinese rapeseed oil yielded a higher emission rate of 1,3-butadiene than the other three oils investigated. The benzene formation rate followed a similar trend, i.e., its intensity in Chinese rapeseed oil was 14-, 6.6-, and 1.7-fold greater than in vapors from peanut, soybean, and Canola oils, respectively.

A linear model relating levels of volatile organic chemicals (VOCs) in exhaled breath to personal exposures at environmental (parts per billion) levels has been developed and evaluated in a chamber study of four human volunteers. The purpose of the model is to allow estimation of VOC concentrations in the body from measurements of exposure, or conversely to estimate previous exposure from a measurement of exhaled breath. The model differs from previous models in considering long-term inhalation at low or moderate concentrations rather than instantaneous intake (as in drug administration) or intermittent exposure at high concentrations (as in occupational situations). The model is based on a mass balance approach using one or more compartments to represent distribution of the chemical in the body. The main observable parameters in the model are the residence times tau 1 in the compartments, their "capacities" Ai, and the fraction f of the parent compound that is exhaled under equilibrium conditions. The basic equations for the one-, two-, three-, and n-compartment cases are derived. Solutions to these equations for the cases of a sudden constant high exposure, a sudden constant low exposure, and a linearly increasing exposure are provided. These solutions can be readily applied to more complex exposure scenarios. The chamber study suggests residence times on the order of a few minutes in the blood and 1-2 hr in the vessel-rich group of tissues. The design of the chamber study did not allow an estimate of the model parameters for fat; a subsequent chamber study has provided initial estimates of 50-100 hr. Field studies of personal exposures and breath concentrations of several hundred persons suggest values of f ranging from 0.1 for xylenes and ethylbenzene to about 0.9 for tetrachloroethylene.

During the past decade significant strides have been made toward understanding the sources and factors which lead to volatile organic chemical (VOC) exposure in the general population. Less is known, however, about the impact of low-level environmental exposure on human health. Investigations are underway in a number of laboratories in an effort to determine the uptake, distribution, metabolism, and elimination kinetics for VOCs in humans. We examined the elimination kinetics for the third phase for ten VOCs--1,1,-trichloroethane, trichloroethylene, tetrachloroethylene, benzene, toluene, m,p-xylenes, o-xylene, ethylbenzene, p-dichlorobenzene, and limonene--in human subjects. Subjects were exposed to a variety of common consumer products and breath samples were collected post-exposure while the subjects spent up to 10 hr in a clean air environment. VOCs from breath samples were collected into canisters or onto Tenax GC cartridges and analyzed by gas chromatography-mass spectrometry. Exponential modeling of the decay data was performed to obtain kinetic parameters. The half-lives for trichloroethylene and 1,1,1-trichloroethane were approximately 5 to 8 hr for the four subjects. In general, the magnitude and range of variability was larger for toluene, limonene, and p-dichlorobenzene than for the other VOCs; the elimination rate spanning a few hours to a day or two. Thus, VOCs exhibit relatively short residence times in the body relative to other halo-carbons, such as polychlorinated biphenyls and dioxins.

Breath measurements offer the potential for a direct and noninvasive evaluation of human exposure to volatile organic compounds (VOCs) in the environments in which people live and work. This research study was conducted to further evaluate and develop the potential of this exposure assessment methodology. Several people were exposed to the atmosphere in six microenvironments for several hours. Air concentrations of VOCs were measured during these exposures and breath samples were collected and analyzed at multiple time points after the exposure to evaluate elimination kinetics for 21 VOCs. A new alveolar breath collection technique was applied. Elimination half-lives were estimated using a mono- and bi-exponential model. The alveolar breath collection and analysis methodology proved to be very useful for collecting many samples in short time intervals and this capability was very important for more accurately describing the initial phase of the decay curves. Breath decay curves were generated from samples collected over a four hour period after exposure for 21 of 24 target VOCs. A biexponential function generally provided a better fit for the decay data than did the monoexponential function, supporting a multi-compartment uptake and elimination model for the human body.

This report describes the development of a portable spirometer capable of collecting primarily alveolar breath into 1.8-L canisters for subsequent gas chromatographic/mass spectrometric (GC/MS) analysis. Based on CO2 measurements, greater than 97% of the breath collected is alveolar in origin. Sample collection takes place in approximately two minutes. Clean air for inhalation is provided by two organic vapor respirator cartridges. Studies of the breakthrough volume of test compounds at both the 5- and 50-micrograms/m3 levels indicate that each cartridge filter can be used to sample over 300 L of air and that this volume is not altered by intermittent use and storage of the filter for up to five days. In experiments designed to mimic human breathing, recoveries of test compounds through the device at the 5-mu/m3 level ranged from 87 to 112%. Essentially no volatile organic compound (VOC) memory (i.e., adsorption carryover by the device) was measured at the 50-micrograms/m3 level. The data suggest that the device can be used successfully for organic compounds with volatilities greater than that of p-dichlorobenzene.

A pilot study to test methods of estimating personal exposures to toxic substances and corresponding body burdens was carried out between July and December 1980. Individual exposures to about a dozen volatile organic compounds in air and drinking water were measured for nine volunteers in Bayonne and Elizabeth, New Jersey, and for three volunteers in Research Triangle Park, North Carolina during three 3-day visits over the 6-month period. Breath samples were also collected from all subjects on each visit. Composite food samples were collected in each locality. Sampling and analytical methods for air, water, food, and breath were evaluated and found generally capable of detecting concentrations as low as 1 microgram/m3 in air and breath, and 1 ng/g in water and food. About 230 personal air samples, 170 drinking water samples, 66 breath samples, and 4 food samples (16 composites) were analyzed for the target chemicals. Ten compounds were present in air and eight were transmitted mainly through that medium. The two target trihalomethanes (chloroform and bromodichloromethane) were predominantly transmitted through water and beverages. Food appeared to be a minor route of exposure, except possibly for trichloroethylene in margarine. Seven compounds were present in more than half of the breath samples. Diurnal and seasonal variations were noted in air and water concentrations of some compounds, with summer levels generally higher. For some chemicals, weekday air exposures were significantly higher than weekend exposures. Some, but not all, of the potentially occupationally exposed individuals had significantly higher workplace exposures to several chemicals. Distributions of air exposures were closer to log normal than normal for most chemicals. Several chemicals were highly correlated with each other in personal air samples, indicating possible common sources of exposure.

Personal air exposures and exhaled breath concentrations of 20 volatile organic compounds were measured for 198 smokers and 322 non-smokers in 5 U.S. cities (1980-84). Smokers showed significantly increased breath concentrations of six hydrocarbons: benzene, styrene, ethylbenzene, o-xylene, m + p-xylene, and octane. Homes with smokers had higher indoor air concentrations of the same compounds than homes without smokers during fall and winter. Passive smokers exposed at work had significantly higher levels of benzene and other aromatics in their breath than unexposed non-smokers.