Air Purifier Guidelines
Whether you are watching an air cleaner demo on TV or reading about an air purifier that removes 97% of contaminants, what are the facts and what is the “hype”? How much better is 99.97% than 97% when it comes to particle removal? Does a celebrity endorsement mean anything? Some manufacturers say their air purifiers are good for asthma sufferers while others do not mention asthma. Some purifiers include an ionizer while others do not. What do these terms really mean?
This article presents the answers you need to understand air purifiers.
First, consider removal of particles in your air. Most air purifiers remove airborne particles such as dust, pollen, pet dander, and mold spores. Some also remove dust mites, bacteria, viruses, and tobacco smoke. The key here is the HEPA (high efficiency particulate arrestance) filter. A 99.97 HEPA rating indicates a unit meets the highest HEPA standards, removing microscopic particles such as viruses and bacteria, and can be used during surgery.
Second, consider effectiveness. The ACH (Area Covered per Hour) is important because it tells you how many times the air is changed each hour. The area covered lets you know how many square feet or cubic feet the unit purifies. This information is needed to calculate how many air purifiers you need for your home or office area.
Third, some units also clean odors and gaseous pollutants such as those come from chemicals, paints, varnish, glue, pesticides, herbicides, cleaning products, printer operation, and some aspects of tobacco smoke.
Fourth, some air purifiers create negative ions for two reasons, one being they are said to combine with pollutants and remove them from circulation and the other that they are said to create a positive feeling, similar to the feeling of standing next to a waterfall. Some may create dark byproducts that settle into furniture, carpets, and drapes. Ionizers usually use an ultraviolet light that creates ozone, considered harmful to our health. Of these, some also remove the ozone before it spreads into the home air. In such cases, the manufacturer’s guarantee or an independent laboratory test deserves consideration.
Fifth, pay attention to the ACH (air changes per hour) and the square footage of the home or office covered by the unit.
Sixth, some are easily portable while others are not. A portable unit might be placed in the living room during the day and moved into a bedroom at night. (If the household members sleep with their doors closed, however, more than one unit will be needed.)
Features and benefits. If you want to make your indoor air clean enough to benefit someone with allergies or asthma, look for a unit with 99% or better particle remover. Particle removers are mechanical air purifiers that work by forcing air through a series of filters. The features and benefits of different kinds of air purifiers include:
HEPA: Ideally, an air purifier contains a HEPA filter (High Efficiency Particulate Arrestance) which is required in hospitals. The Department of Energy specifies that a true HEPA filter must remove at least 99.97% of particulate matter. However, this high standard may not be essential for your use and a “HEPA-like” filter or one that says it is “99% HEPA” may be fine. Any HEPA-grade purifier uses multi-stage filters to trap particles; high-efficiency ones can trap airborne particles smaller than viruses.
Gaseous pollutant removal. May involve wet scrubbers but, in a home unit, are more likely to use ionizers or activated carbon filters for this task.
Pollutant destruction cleaners. UVGI, PCO, and ozone generator may be used more in commercial settings. Ultraviolet generators and ionizers are featured more often in home units to remove biological contaminants. The EPA does cautions against ozone generators, saying ozone is a lung irritant. EPA also says that UVGI alone does not provide air filtration.
Ionizers that create negative ions. As mentioned above, verify whether ozone is a byproduct and how the unit handles it.
Air filter replacement is essential at the regular times recommended by the manufacturer to make sure that airborne particles are removed. Some feature a first filter or pre-filter that must be vacuumed clean at least once each month. An air purifier cannot do its job well unless it is properly maintained.