Differences in Organic Vapor Concentrations in the Breathing Zone Resulting from Convective Transport from Spillage on Clothing

Abstract

Solvent spillage on personal clothing may cause a spatial, highly nonuniform, vapor concentration in the breathing zone. In an environmental chamber study, a minor spillage of an organic solvent was simulated by spilling of 1 cm³ of o-xylene on the front of the personal clothing of a seated person. The rising convective flow around the body brought the evaporated o-xylene into the breathing zone. The concentration was simultaneously measured at four positions within the breathing zone. In calm air, the concentrations ranged from less than 2 mg/m³ to 65 mg/m³.

The results suggest that the concentration within the space defined as the breathing zone is spatially highly nonuniform for exposures caused by convective transport of solvents evaporated from a minor spillage on front of personal clothing. In these situations, for some sampler positions within the breathing zone, inhalation exposure from liquid spills on clothing may go undetected. The conventional breathing zone concept can thus lead to misclassification of exposure.