Residential Air Cleaner Use to Improve Indoor Air Quality and Health: A Review of the Evidence
Air cleaners are designed to remove pollutants from indoor air, but their effectiveness depends on the air cleaner design and set-up, as well as on the presence of specific pollutants, their concentrations, and air exchange rates in the room/home. Ozone generators and some electrostatic precipitators produce ozone at levels that pose health concerns. Little evidence is available on removal of gases from indoor air by air cleaners. Evaluations of HEPA filter air cleaners show that these units can effectively filter both indoor and outdoor-generated particulate matter (PM) from indoor air. On days when outdoor air quality is poor, HEPA filter air cleaners can reduce infiltration of outdoor-generated PM; lowered exposure may also lead to some health benefits, including improvements in blood vessel health. The use of HEPA filter air cleaners has been associated with reductions in some asthma and allergy-related symptoms. Greater benefits are observed when other interventions, including HEPA-filter vacuums, impermeable bed coverings, and carpet removal, are employed in conjunction with air cleaners to improve indoor air quality.