the truth about air purifiers

Air Purifiers


We'll review the various types of air purifiers, a handy "quick comparison chart" of different purifier technologies, the nasty pollutants living inside your home, a 10-point purchasing checklist so you can buy with confidence, and a new purifier with exciting proprietary technology that removes every category of pollutant from your household air without using filters!.

Let’s talk about home air purifiers, but first your house. Dust mites with tiny claws that hold onto your carpeting (vacuum resistant); windows closed for the winter and stagnant air; windows open during pollen season; chemicals like formaldehyde and benzene from new carpets, furniture, and cleaning products; and have you looked on top of the refrigerator? Uuuugh!

Face it, the air inside your house is downright dirty; up to 100 times more dirty than outside air! What happens when you take this polluted air into your lungs? Allergies, asthma, dizziness, sinus issues, ear infections, headaches, nausea, and respiratory infections. Indeed, about 50 million americans suffer from allergies and asthma, and this equates to nine million doctor visits per year!

why do we need air purifiers?

Dr. Laura Schlessinger once said, “If you do not have an air purifier, you ARE the air purifier.” How unfortunately true that is! Have you ever considered that your lungs could be your only air filter at home? Well it’s true for many families and households. The airborne contaminants and allergens that circulate throughout your home eventually settle on floors, furniture, table surfaces...and your lungs! That is, unless you are using a good air purifier.

So what exactly are the dangerous substances floating around your home? Take a look:

Microbes: germs, viruses, bacteria, and mold spores

Odors: cigarette smoke, litter boxes, cooking, body, and pets

Gases and Chemical Fumes (volatile organic compounds - VOC’s): benzene, cigarette smoke, formaldehyde, nail treatment products, etc.

Particulates: allergens, dust, dust mites, pollen, pet dander, particles in smoke

How do air purifiers eliminate these pollutants from the air? It depends on whether you are using a mechanical air purifier like a HEPA system, or electrostatic filtration such as an ionic purifier (or some combination of both). Let’s review several kinds of air purifier systems: mechanical devices with hepa filters, electronic devices such as ionizers, ozone air purifiers, carbon devices, and ultra violet light devices. Afterwards, a convenient chart we’ve created will help you to easily distinguish the differences of each type.

types of air purifiers

hepa air purifier

HEPA Filter air purifiers

HEPA filters employ a cloth type filter that can trap 99.9% of particles 0.3 microns or larger in size, and a fan to move air through the machine. HEPA filters can be very effective in clearing out almost any harmful particles from the air in a room. These devices usually have a replaceable filter that can last several years depending on how filthy the air is in your home. Although some don’t like the noise level of a HEPA machine, it can usually remove more pollutants than a ionic machine.

Advantages: allergens are captured; not being released into the air once trapped.

Disadvantages: Does not eliminate chemical fumes, gases, cigarette smoke, or odors

Ozone air purifiers

Ozone is a highly reactive oxidant that destroys certain bacteria, chemicals, bacteria and chemicals. Although ozone is very effective against strong odors, there is a caution you should consider.

When ozone reacts with substances in the air, the substances are broken down into other materials that are also pollutants. This is where the controversy lies with ozone machines. You can run ozone machines on low (if they are adjustable), which manufacturers often advise. However, if you are clearing a room from smoke or odors you can run it on high while keeping people out of the environment altogether. Later, turn the machine off and open windows to clear out the ozone.

Advantages: Extremely effective against odors.

Disadvantages: Not effective on allergens and most chemicals.

Carbon air purifiers

Activated carbon air filters consist of a system of pores that are tiny in size. These pores are highly adsorbent, chemically reacting to particles that pass through them and the particles and odors actually bond with the carbon.

This is the most absorbent filter on the market today, so it is extremely effective in capturing certain types of particles (see the chart below for more information). Note that most carbon activated devices also incorporate HEPA technology, thereby combining the advantages of both types of technology.

Advantages: Highly effective with chemicals, gases, smoke, and odors.

Disadvantages: Not effective with allergens and micro-organisms.

ionic air purifier

Ionic air purifiers

Ionic air purifiers do not have a cloth filter like the HEPA machines. They work by "ionizing" the air, causing particulates to gain a positive or negative charge. Why charge the particles?

The charge is necessary for two reasons. The air ionizer contains collection plates that have an opposite charge from the particles in the air, so the particles are drawn to the collection plates (these are referred to as “capture” ionic purifiers). Also, the particulates can be attracted to other particles that have an opposite charge. When this happens the two particles with opposite charges wind up sticking together and falling out of the air (these machines simply release ions into the air without capturing them on plates). By the way, many people like ionizers because they are very quiet compared to most HEPA machines.

Advantages: can remove extremely fine particles anywhere in a room; even several feet away from the machine.

Disadvantages: Not effective on odors; doesn't kill germs but removes them from household air.

Ultraviolet light air purifiers

Ultraviolet (UV) lamps are known to sterilize micro-organisms that pass through it, including germs, viruses, bacteria, and mold; so microorganisms, after treated with this light, can no longer reproduce and grow. At least we know this to be true when UV light is used in sufficient dosage and a sufficiently long period of time to do its job.

When used in an air purifier, does the UV light have enough time to perform and sterilize correctly while air is moving through it, possibly at a brisk rate of speed? There is an innovative approach that uses UV lamp combined with a HEPA filter, so particles trapped in the filter can be treated with UV light for an effective amount of time.

Advantages: Helps destroy microorganisms that cause disease.

Disadvantages: Not effective on allergens, smoke, odors, or chemicals.

hydroxyl air purifier

Purifying hydroxyl radicals

Hydroxyl radicals are powerful cleansing agents that occur naturally in the Earth’s atmosphere. They are created when oxygen atoms pull a hydrogen atom from water vapor, which then form the radical. Hydroxyl radicals are 1,000,000 times faster at destroying pollutants in the air than ozone. They are the most powerful method of neutralizing mold, bacteria, and viruses.

New proprietary technology has combined hydroxyl radical technology with ultra violet light and negative ions resulting in an air purifying system that neutralizes every category of pollutant in your home, including odors, without the need for filters! click here for more about hydroxyl radical air purifiers

Advantages: removes every category of pollutants when combined with negative ions and UV light technologies; no filters needed; inexpensive.

Disadvantages: only available from two manufacturers.

what is the best air purifier for you?

There are some very good air cleaners by Biozone, Oreck, Honeywell, Austin, Air Oasis, Friedrich, Hunter, Kenmore, IQAir, Blueair, Electrolux, Panasonic, Airfree, and Surround Air, but you must understand the technical differences among these purifiers before you can find one that's right for you.

Use the "Quick Comparison" chart below to easily distinguish the differences between purifiers and identify the features that are best for you.

Quick Comparison of Air Purifier Technology
Type of Purifier Size of Particles Removed Removes Allergens (dust, pollen, mold spores) Removes Bacteria Removes Odors Removes Viruses & Germs Removes Cigarette Smoke Removes Chemical Fumes
HEPA down to 0.3 microns Yes some bacteria no no no no
Ionizer down to 0.1 microns Yes Yes no viruses Yes some
Ultra Violet Lamp N/A Some Yes no Yes no no
Carbon Filter N/A some some Yes no Yes Yes
Ozone Generator N/A no some Yes some Yes some
purifying hydroxyl radicals 0.1 microns mold Yes no Yes no some

10 point purchasing checklist

• It is desirable to find a unit with a high percentage of particulates removed from the air, together with the capability of capturing a small particle size

• Air volume capacity. Look at the recommended room size of the unit, usually expressed in square feet

• Specific health concerns. When you look at our quick comparison chart above, what substance do you most want to remove: cigarette smoke, bacteria, germs?

• Reputable manufacturer. The Association of Home Appliance Manufacturers ( a reliable source of informaton for air purifiers

• Indoor factors. Is there a particular pollutant (cigarette smoke, mold spores, dust, etc.) that is affecting your health? Look for a unit that can best eliminate that substance

• Operating cost. Replacement filters can be a significant cost. Check the manufacturer’s replacement interval and filter cost

• Construction quality. Does the warranty cover internal components? Is the machine listed with an organization that requires standards for quality and safety?

• Ease of use. Make sure that filter changing, operating, and cleaning are not too much of a challenge

• Warranty. Look for a comprehensive, long-term warranty. Usually the best you can find is a limited warranty.

• Operating noise. Does the manufacturer claim their unit is “whisper quiet?” Confirm exaggerated claims by requesting operating noise values (expressed in decibels). Quiter units are about 35 decibels.

Click for unbiased reviews and consumer ratings of the top air purifiers on the market.

tips for keeping your inside air clean

• Don’t use aerosol sprays

• Remove glues, adhesives, lighter fluids, shoe polish, and mothballs

• Don’t use glues, adhesives, or paints indoors

• Don’t use tobacco products inside your home

• Don’t use a fireplace

• Do not use candles or incense


Taylor, Frances, Krohn, Jacquelin, & Larson, Erla Mae. Allergy Relief & Prevention. Vancouver, BC: Hartley & Marks Publishers, Inc., 2000.

Source: Nursing Homes Long Term Care Management, Jul2002, Vol. 51 Issue 7, p33.

Mistretta, A.J.. New Orleans CityBusiness, 8/4/2003, Vol. 24 Issue 5, p34.