The U.S. Association of Home Appliance Manufacturers (AHAM) has set a voluntary standard for testing the initial dust-removal capacity of portable air cleaners. In our test of portable air cleaners for the local consumer council, the AHAM method was extended to test the initial removal capacity for gaseous phase pollutants. Also, carbon filters' efficiency change over time in toluene removal on a number of air cleaners was tested. In using a large chamber to carry out these tests, the chamber wall adsorption and re-emission effects were experimentally quantified. These tests indicated that a large chamber, with its wall surface adsorption controlled, is simple and robust to use to quantify the initial cleaning capacity for gaseous phase pollutants. Based on these test results, a large chamber method is proposed to test the performance lifetimes of portable air cleaners. The system advantages of the method over the in-duct performance life test methods are that no continuous air-cleaning system is required and that the chamber's humidity and temperature can be maintained at the desired values more easily with the combination of a unitary dehumidifier and a bubbler system. This paper will present our trial results with portable air cleaner tests and discuss the large environmental chamber techniques.Units: SI