An application of exposure modeling in exposure assessments for a university chemistry teaching laboratory.
Chemical exposures in a university teaching lab were assessed using a tiered approach to modeling. Zero ventilation and well mixed room models estimated air concentrations of ethyl ether, n-hexane, and methylene chloride during distillation and extraction exercises. A simple, zero ventilation model determined that health risks from the ethyl ether exercise were minimum. N-hexane and methylene chloride exposures were evaluated with higher tiered, well mixed room models. An assumption that all of the solvent evaporated during the lab resulted in estimated n-hexane concentrations well below the occupational exposure limit. Methylene chloride concentration estimates using this approach were only one-half the occupational exposure limit, so the model was refined using information on the actual amount of solvent that evaporated. This resulted in a concentration estimate approximately one-fifth of the occupational exposure limit. Air sampling was done to evaluate model performance. Measured concentrations were higher than modeled concentrations by up to a factor of two but were still below applicable occupational exposure limits. The exposure models selected were deemed useful in the assessment of exposure acceptability in these labs.
Keil
Chris
C
Environmental Health Program, College of Health and Services, Bowling Green State University, Bowling Green, Ohio 43403, USA.
Murphy
Robert
R
D016902:Air Pollution, Indoor / Q000032:analysis*; D002621:Chemistry / Q000193:education*; D006801:Humans; D007753:Laboratories; D008962:Models, Theoretical; D016273:Occupational Exposure; D009930:Organic Chemicals / Q000032:analysis*; D012016:Reference Values; D014495:Universities; D014691:Ventilation
D009930:Organic Chemicals