Passive samplers have been used for personal, indoor, and outdoor air monitoring of VOCs at ppb concentrations in community and office environments. The path length of modified passive sampler was shortened, so it was intended to increase an uptake rate.
The performance of the modified 3M 3500 organic vapor monitor(OVM) as a tool for assessing exposures to toxic air pollutants in nonoccupational community environments was evaluated using combined controlled test atmospheres of six selected target volatile organic compounds(VOCs): benzene, methyl tert-butyl ether(MTBE), chloroform, 1,4-dichloro-benzene, tetrachloroethylene, and toluene. The experiments were conducted by exposing the dosimeters to concen-trations of 50∼100 ㎍/㎥ on six velocity(0.00, 0.02, 0.06, 0.12, 0.20. 0.30 m/sec) for 24 hours.
IF the uptake rate was increased, that means that we could use the passive sampler more effectively. The uptake rates were increased linearly according to reduce the path length. Although the diffusion path length was shortened, the change of uptake rate was with ±25％ of theoretical value, in-dicating that the modified passive sampler(TM) can be effectively used over the range of concentrations and enviro-nmental conditions tested with a 24-h sampling period if the face velocities were over 0.12㎧ for 6 components of VOCs. But when the face velocities were less than 0.12㎧, uptake rates were reduced more than expected values. So, the passive sampler with the shortened path length should be used at indoor or outdoor environment where the face velocity should be over about 0.10 ㎧. If the path length was shortened more, the uptake rate was more effected by starvation.
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