As indoor air cleaners have large sizes and high air flow rates, the test methods for particle cleaning capacity need to be reconsidered because the prescribed test chamber size becomes relatively smaller. In this study, air flow rate of air cleaners compared to test chamber size (Q/V) has been investigated by comparing the short-circuit factor which indicates the air mixed condition in the test chamber. The test method of Korea Air Cleaning Association (KACA) has been analysed and compared to that of Association of Home Appliance Manufacturers (AHAM) for clean air delivery rate (CADR) of two household air conditioners equipped with air cleaners having a maximum air flow rate of 15 m³/min in terms of initial particle concentrations, neutralized/non-charged particles, delay time before acquiring initial particle concentration, sampling positions. Constant short-circuit factor of about 0.9 was obtained in the range of Q/V less than 0.73 min^-1. CADR based on KACA test method was somewhat dependent on initial particle concentrations, delay time before acquiring initial concentration, sampling positions. However, CADR based on AHAM test method was less dependent. Two or three minutes of delay time before acquiring initial concentration was necessary to reduce the variation of CADR according to initial particle concentration and sampling position.

Test methods of Korea Air Cleaning Association (KACA) and Association of Home Appliance Manufacturers (AHAM) for particle cleaning capacity performance of an indoor air cleaner were compared in terms of the conditions of the test particle generation, the range of particle measurement and the calculation methods for particle cleaning capacity, and types of the test particles. The performance test was conducted in a 30 m³ chamber with the same test specimen and the test particles of each test were generated until the number concentration of 0.3 ㎛ particles reached 2.2 × 108 #/m³. The performance test results showed that the cleaning capacity with the particles of higher surface area and volume density, regardless of the type of test particles, was higher than with those of lower and the capacity from calculation with 0.3～1 ㎛ particles was higher than with 0.3 ㎛ particles. Moreover, the cleaning capacity with the calculation of KACA method was lower than with that of AHAM method in spite of using the same test specimen.

A high efficiency roll-type electret polypropylene (PP) filter with an external electric field was developed and its particle collection efficiency and air cleaning capacity was investigated in a room when applied to an air cleaner having a fan. To enhance air cleaning performance of the cleaner, a wire-plate type ionizer was installed in front of the filter to enhance electric field to filter and one side of the filter was embossed by press of a pattern with a lot of circular projection. Performance test results showed that the newly developed electret PP filter with an ionizer becomes an appropriate filter to be applied to indoor air cleaner due to its low pressure drop and high air cleaning performance.