Abstract
The use of room air cleaners is becoming increasingly popular to improve the quality of the indoor air environment and provide a healthier, more comfortable living space. However, the performance of the room air cleaners commonly deteriorates when used for a long time. Thus, it is necessary to determine the relationship between time of use and deterioration characteristics. Up to now, no quantitative study has been reported on the deterioration characteristics in the performance of room air cleaners. In present study, a new method was proposed to determine the performance degradation of air cleaner for removal of gaseous pollutants by combining a large scale chamber method for measuring precise equivalent clean air rates and exposure device for degradation of a room air cleaner under ambient air concentration levels. The method was practically applied to test one sorption type air cleaner over four months for removing formaldehyde, which is known as a major causative agent of "Sick House Syndrome". As a result, the formaldehyde removal performance of the room air cleaner greatly deteriorated with increased time of use. Specifically, the air cleaner performance at initial startup was 99.6 m3/h. After one, two, three, and four months of continuous use, the performance declined to 40.7 m3/h (rate of decrease: about 59 %), 29.1 m3/h (about 71 %), 29.2 m3/h (about 71 %), and 25.5 m3/h (about 74 %), respectively. In particular, there was a remarkable decline in removal performance between startup and one month of use. This method can be applied to inspect various kinds of room air cleaners. In addition, future studies are necessary to clarify the actual situation of performance deterioration in developed and distributed room air cleaners.
