AN ENVIRONMENTAL CHAMBER FOR INVESTIGATING THE EVAPORATION OF VOLATILE CHEMICALS

An inexpensive test chamber has been constructed that provides an envi ronment appropriate for testing the effects of temperature and chemica l interactions on gaseous emissions from test solutions. Temperature, relative humidity, and ventilation rate can be controlled and a well-m ixed atmosphere can be maintained. The system is relatively simple and relies on heated tap water or ice to adjust the temperature. Temperat ures ranging from 9 to 21 degrees C have been maintained. At an averag e temperature of 15.1 degrees C, temperatures at any location within t he chamber vary by no more than 0.5 degrees C, and the temperature of the test solution within the chamber varies by no more than 0.1 degree s C. The temperatures within the chamber are stable enough to generate precise steady-state concentrations. The wind velocities within the c hamber are reproducible from run to run. Consequently, the effect of v elocity on the rare of evaporation of a lest chemical is expected to b e uniform from run to run. Steady-state concentrations can be attained in less than 1 hour at an air exchange rate of about 5 per hour.