How purifiers work

Simply put, some are passive, others are active. Passive systems clean (or purify) the air that passes through the machine. Active systems also work on air in the environment. The system we recommend is an active system. It uses a combination of ionization, UV and RCI, and can even have an ozone option if you choose. Our experience shows they are more effective. Technologies include:

· Ionization - Technology primarily designed to get particulates out of the air. It works by charging particles in the air or as they come through the air purifier, so that they will drop out of the air. “Plating” can occur if only negative ions are emitted; it is best to use one that also emits positive ions.

· Electrostatic precipitation - This works just as a TV screen does: it electrically charges airborne particles near the unit and then traps them on plates. These plates must be cleaned frequently for proper performance. (The unit most frequently advertised on TV uses this technology.)

· Ultraviolet - This is a safe way to kill germs. It's included in many air purifiers— basically, they send the air past an ultraviolet lamp. The problem is that, depending on air speed, there may not be enough exposure time to kill the microbes. Also, only the microbes that are exposed to the rays will be killed. If the UV is used as part of the entire purifying system it will be more effective.

· RCI^® - An improvement over PHI, this patented technology is used by only one company (the one we recommend). It uses UV and a catalyst to produce hydroperoxides (like hydrogen peroxide) and OH-negative hydroxyl radicals to kill germs.

· Ozone - This is extremely effective in killing germs and odors. It is best used as a component in a multi-technology purifier. Be sure the ozone is adjustable or optional. Our ozone page has more information.

Some types of filters:

· HEPA - This is a form of disposable filter that is highly effective at getting rid of smaller particles. However, it only filters the air that passes through the machine and can be extremely expensive. If the air purifier you want has a HEPA filter, find out how often it needs to be replaced and budget for it. Sometimes it can cost almost as much as the air purifier itself.

· Mechanical filters draw air through a filter and may use a high efficiency particulate air (HEPA) surface to trap particles.

· Hybrid filters are made up of two or more of the above filters. An example is one which uses electrically charged fabric to attract airborne particles. These are efficient when clean, but as they fill with particles the efficiency decreases and they must be replaced or cleaned.

Questions to ask:

· In-room or in-duct? Air cleaning devices are either central filtration (often called "in-duct") systems put into the heating, ventilation, and air conditioning (HVAC) system of a home or portable units with an attached fan to assist in reducing indoor air pollutants.

· Filter or purifier? Air filters clean only whatever air passes through the unit. Purifiers, on the other hand, emit ions and/or put a purifying plasma into the air.

· How much noise will it make? Nearly all air purifiers are noisy at the highest level. This is extremely subjective - one person may think it's making a racket and another think it's just background noise. But there are some easy solutions: first, make SURE that the product you buy has multiple settings so you can adjust it if the noise bothers you. Second, some of the more expensive models have remote controls and timers - they can be set on high while you are at work or out of the house, and go back to low when you're at home or asleep.

· Does it use a filter? If it does, how often does it need to be replaced and how much does it cost?

· How many do I need? Are you trying to knock dust out of the air or kill molds and bacteria? Is it pet odors or smoke? If you smoke or keep your pets in one room, you may need a smaller unit. If it's allergens, you might just need one for the bedroom of the person who's allergic. But if it’s mold, you’ll need something that treats a larger area. If you want to cover an entire house, you either need multiple air purifiers or you need one designed to cover that much square footage. Another option: If you have ductwork, consider a combination or in-duct and whole home.

· Is it noisy? This is subjective … some people can tune it out and others are easily irritated. Nearly all air purifiers that use fans are noisy at the highest level.

· Does it really work? Lots of people report a great improvement in allergies, odors, etc. The cheaper units usually aren’t very effective on cigarette smoke. The best suggestions: check with friends, ask about their return policy or see if you can try before you buy.

How purifiers work

FAITH, LLC

Fresh Air In The Home