What are Air Purifiers?

An air purifier is a device that sounds exactly like what it is: an appliance that cleans the air in your home to remove pollutants like animal dander, odors, dust, smoke and other undesirable airborne particles. Air purifiers are often used by people who experience allergies and who have sensitivities to odors. They can be placed anywhere in the home, including common areas like the living room and dining room, or in the bedroom, for a more relaxing night’s rest.

If you’re thinking about using an air purifier in your home, knowing how they work, what features are most important and how to optimize your use of the air purifier can help you get the most out of the experience of owning and using such a device. Here’s what you need to know.

How Does an Air Purifier Work?

Air purifiers work by sucking in air, circulating the air through a filter or device for cleaning, and then blowing the air back into the room. Filters for air purifiers can be made from a variety of materials including paper or fiberglass. Air filters need to be replaced periodically as they become dirty with pollutants. Failure to replace the air filter can force the device to work harder than necessary to clean the air, and can eventually compromise its ability to do its job. Anyone who uses an air purifier must budget for the periodic replacement of the filters. The annual cost of replacement filters can vary depending on the type of purifier being used and the type of filter required for that device.

Who Needs Air Purifiers?

Indoor air quality suffers for many reasons. Common reasons for poor indoor air quality include poor ventilation, old ducts, use of chemicals in the home or a tight building envelope that prevents the home from “breathing.” All of these features can lead to a buildup of moisture mold, dust, pollen and dander. In some homes, tobacco smoke, firewood smoke, radon, pesticides, newly installed carpeting, paint and even asbestos can also have an effect on indoor air quality.

Almost everyone can benefit from an air purifier, but some people benefit more than others. The following are populations that benefit more from air purifiers than other people:

  • Pregnant women
  • Children
  • Seniors
  • People with allergies
  • People with a compromised immune system
  • Asthma sufferers
  • People who live near industrial sites

You may also benefit from an air purifier if you live on a property with many trees, flowers and other plant life that produces pollen. People who have a hard time keeping a clean house can reduce the amount of dust they breathe in by using an air purifier on a regular basis.

What Are the Different Types of Air Purifiers?

Like so many other appliances, air purifiers come in different styles. Each type of air purifier works in slightly different ways and targets different pollutants.

HEPA Air Purifiers

HEPA stands for high-efficiency particulate air. HEPA filters remove much smaller particles than standard air filters. HEPA filters are often recommended for people suffering from allergies and asthma, because these devices are generally very effective at removing small particles like pollen and dander.

UV Air Purifiers

Ultraviolet light can destroy bacteria, viruses and pathogens in the air. These devices contain a special UV bulb in a chamber in the center of the device. The purifier passes the air through the chamber, where the light kills the bacteria. UV air purifiers can be used to kill mold spores and are especially effective for people who are allergic to mold. These light bulbs must be replaced, often annually, for the device to keep working.

Ionic Air Purifier

An ionic air purifier works by emitting negative ions into the air. These ions bond with positively charged particles (like dust, dander and bacteria). When the bond is created, the dust becomes too heavy to remain airborne, and falls out of the air. Some air purifiers work by trapping the particles inside the device to be cleaned out later. Some models are self-cleaning, others must be cleaned regularly in order to maintain functionality.

Activated Carbon Air Purifiers

Activated carbon air purifiers are designed to remove odors from smoke and fumes inside the home, but do not help with viruses, bacteria, allergies, pet dander and dust. These appliances help people who live close to industrial sites and landfills, where odors can decrease quality of life. Some activated carbon air purifiers also contain a HEPA filter to remove dander.

Buying an Air Purifier? What to Watch For

If you’re buying an air purifier, do your research before purchasing a model for your home. Watch for the following:

  • Filter price and recommended replacement rate. Find out through consumer reports and manufacturer notes how often an air purifier’s parts (like the air filter or UV bulb) need to be replaced, and how much those parts cost. This will help you decide whether you can afford to maintain that particular air purifier.
  • No ozone. Some ionic air purifiers produce ozone, a gas that can irritate the lungs. Check the packaging information to ensure the purifier you buy does not produce ozone.
  • CADR (clean-air delivery rating). The CADR rating indicates how fast the purifier will work. The best devices have a rating of 300 or more.
  • Sizing. Measure the space where the purifier will be operating, then find a model that is properly fitted for that size.

Check for certifications as well. The Association of Home Appliance Manufacturers is an association designed to ensure the efficiency of a home appliance like an air purifier. Buying an air purifier with AHAM’s logo ensures that this device is certified, effective and reputable.

Do They Really Work?

Dr. Nicholas BuSaba, Associate Professor of otolaryng-ology at Harvard-Medical School, recommends a well-chosen air purifier for anyone who has allergies and who lives with allergens in their home. Pet owners in particular may find air purifiers to be an effective way to eliminate dander and other airborne particles that can affect quality of life. Air purifiers most are effective if the consumer buys a well-rated device that is designed to eliminate the specific pollutants they need to eliminate. Doing research and reading online reviews, consumers can choose the best device for them.


Hey, I'm Chad. I started Skyonic because I genuinely believe air quality is one of the most important contributors to the overall quality of our health. When I'm not blogging about air purifiers, you can catch me traveling and exploring some of...

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