A field method for measuring solvent vapors in exhaled air--application to styrene exposure

A method is described for measuring solvent vapors in mixed-exhaled air. The subject exhales through a carbon-containing tube connected to a Wright respirometer. Adsorbed vapors are subsequently eluted by carbon disulfide and analyzed by gas chromatography. Twenty-minute exposures to styrene and the corresponding concentrations of styrene in the breath and venous blood were repeatedly measured for two subjects. Regression analyses indicated that the breath measurements were highly correlated with both the exposures and the blood concentrations of styrene. In another study, styrene was measured simultaneously in the mixed-exhaled air by this technique and in the end-exhaled air by a portable gas chromatograph. The mixed-exhaled air obtained with this method contained about half alveolar air. Analysis of the components of the variance obtained from all the data indicated that the error in measurement by this method was about one-fourth of the total variance.