What Is an Effective Portable Air Cleaning Device? A Review

The use of portable air cleaning devices in residential settings has been steadily growing over the last 10 years. Three out of every 10 households now contain a portable air cleaning device. This increased use of air cleaners is accompanied by, if not influenced by, a fundamental belief by consumers that the air cleaners are providing an improved indoor air environment. However, there is a wide variation in the performance of air cleaners that is dependent on the specific air cleaner design and various indoor factors. The most widely used method in the United States to assess the performance of new air cleaners is the procedure described in the American National Standards Institute (ANSI)/Association of Home Appliance Manufacturers (AHAM) AC-1-2002. This method describes both the test conditions and the testing protocol. The protocol yields a performance metric that is based on the measured decay rate of contaminant concentrations with the air cleaner operating compared with the measured decay rate with the air cleaner turned off. The resulting metric, the clean air delivery rate (CADR), permits both an intercomparison of performance among various air cleaners and a comparison of air cleaner operation to other contaminant removal processes. In this article, we comment on the testing process, discuss its applicability to various contaminants, and evaluate the resulting performance metrics for effective air cleaning.

Keywords:

• air cleaner
• clean air delivery rate
• effectiveness
• gas
• particle
• portable air cleaner

Notes

^A Reported CADR values are averages based on a 12-hour test.

^B The highest CADR values listed here are for the UV-PCO device that incorporated a ∼ 9 cm thick carbon adsorber. When operated without the carbon bed, the UV-PCO device produced no significant removal.

^C VOC listed in order of decreasing vapor pressure (vp); the first three have vp > 100 mm Hg (at 23°C); compounds 4 through 8 have vp between 10 and 100 mmHg; the last two have vp of 10 mmHg or less.

^A Classification of particles based on approximate size = small: 0.1–0.8 micron; medium: 1–4 microns; large: 6–20 microns (see Figure 5).