Applicability of Activated Carbon Felt to the Dosimetry of Solvent Vapor Mixture

Affirmative results were obtained to prove that diffusion-absorption on carbon-desorption dosimetry is applicable to monitor exposure to mixed vapors of organic solvents (n-hexane:ethyl acetate:toluene=1:4:1). While most of seven carbon felt preparations tested failed to absorb n-hexane in humid air or the amounts absorbed were no longer proportional to vapor concentrations even in dry air when the sum of the three vapor concentrations were over 3 times workroom threshold limits, two preparations revealed capacity to absorb n-hexane even in the air with relative humidity of 95%. Furthermore, the amounts absorbed during four hour exposures were linearly related to the vapor concentrations of at least 4.5 times workroom threshold limits when the three vapor concentrations were summed up, and, at lower concentrations, the absorbed amounts were proportional to the exposure duration of up to eight hours. Short term peak exposure could also be detected; the ratio between the observed and the expected was about 80% at lowest.