Evaluation of emission test chambers by use of recovery rate determinations under dynamic conditions

The evaluation procedure of an emission test chamber normally includes the determination of recovery rates for certain compounds. Often these measurements are carried out under static conditions. In order to determine the dynamic recovery rates of different emission test chambers, an integration of the concentration vs. time data acquired during and after the continuous addition of a test substance mixture was carried out. By comparing the added and the recovered amount of substance recovery rates of more than 95 % could be measured for chamber test with and without a sink and a typical time range of two to four days. The measurements indicate an almost complete recovery for most of the test substances, whereas static recovery rates for the same compounds show a considerable chamber wall adsorption and therefore low static recovery rates.