An indoor air cleaner helps you combat one aspect of indoor air pollution: airborne particulates. They play a major role in making indoor air as much as 100 times more polluted than outdoor air. Particulates are known sources of allergens and are implicated in more serious illnesses such as childhood asthma.
Inorganic dust particles as well as microorganisms like dust mites and mold spores are buoyant and continually stirred up in household air. Additionally, they are drawn into HVAC ducts and re-circulated throughout living spaces. Attempts to eliminate airborne particulates at their source are often ineffective as the particulates can infiltrate the home in many ways. Use of an indoor air cleaner to control the level of airborne pollutants is a more direct way of addressing the problem.
Indoor air cleaners are available in portable or whole-house technologies. Portable models are free-standing units limited to cleaning the air in a single room or zone in the home. A whole-house model is installed in the HVAC ductwork so that it can filter the full air volume of the home as it passes through the ducts.
Most cleaners use either mechanical or electronic air filtration.
- Mechanical cleaners capture particulates in a filter. Filters may be standard flat-panel filters with a media consisting of fiberglass, foam or synthetic or metallic wools, usually with a MERV (minimum efficiency reporting value) of 10 or less. Pleated filters offer higher MERV ratings than the panel variety. Some in-duct units use medical-grade high-efficiency particulate air (HEPA) filters. These filters have MERV ratings above 16 and remove more than 99 percent of particulates down to 0.3 micron size.
- Electronic cleaners use the properties of electricity to filter the air. Electrostatic models clean the air as it passes through a grid charged with static electricity to attract and capture airborne particulates. Ion generators disperse ions that bond to airborne particulates, causing them to settle out of the air and onto surfaces where they are dusted or vacuumed away.