Measurements and evaluation of the water-to-air transfer and air concentration for trichloroethylene in a shower chamber.

摘要

Measurements and Evaluation of the Water-to-Air Transfer and Air Indoor-air models for the transfer of contaminants from tap water to air typically rely on physical properties such as the Henry's Law constant, diffusion coefficients, etc. and on room-air exchange rates to determine personal-air concentrations. These models do not address other potential sinks or sources for airborne contaminants that could effect exposure. A study was conducted to examine the build-up and decay of trichloroethylene (TCE) in the air of a 1 m(sup 3) shower chamber into which water containing 210 (mu)g/L TCE flowed through nozzles of different flow rates (3--6 L/min) and droplet size (300--1500 microns). The concentrations of TCE in the air of the chamber and in the drain water were measured and the water-to-air transfer efficiency for the three nozzles was determined. The aerosol concentration and size distribution generated by the nozzles was measured. Significant differences were observed between the measured air concentrations and the concentrations predicted by the transfer efficiencies and air exchange rate. These differences are observed to depend on the aerosol concentrations for the three nozzles. Consideration is given to processes such as deposition, incomplete mixing, scavenging, and measurement precision as explanations for these differences.