An ozone detector was built and evaluated for its applicability in smog chamber studies. The detection method is based on reaction of ozone with ethylene and measurement of resultant chemiluminescence. In the first phase of evaluation, the detector's response to ozone was studied as a function of several instrument parameters, and optimum conditions were defined for maximum and most stable response to ozone. In subsequent evaluations, the method was checked for sensitivity, precision, and interferences and was compared with two alternative methods (Mast, KI). Results showed the chemiluminescence method to be acceptably sensitive and precise for smog chamber studies and superior to the Mast and KI methods in that it is specific for ozone. (NTIS)