Measured and estimated air concentrations of chloroform in showers: Effects of water temperature and aerosols

Air concentrations of chloroform (CHCl3) in an experimental shower chamber were compared with estimates predicted by determining CHCl3 loss between the shower nozzle and drain and treating the shower chamber as a single, well-mixed compartment. CHCl3 water-to-air transfer efficiencies for experimental nozzles producing droplets of 1800 and 300 μm diameters were 0.90 and 0.80, respectively, and 0.65 for a standard domestic shower nozzle. Significant differences were observed in the transfer efficiencies when the experimental nozzles were operated at 35 and 45°C but not when the standard nozzle was operated in either jet or spray flow at 40°C. Aerosol concentrations were measured continuously with a hot-wire probe and ranged between 3000 and 17,000 aerosols/cm3 for the three nozzles. Measured air concentrations showed variable agreement with predicted values; under certain conditions, air concentrations were between 10 and 50% less than the predicted values. These discrepancies were observed at the highest aerosol concentrations and when peak aerosol concentrations occurred between 2 and 4 min of the 10 min shower.