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Do Air Purifiers Really Work? What You Need to Know

If the air quality in your home is poor, then you might be thinking about investing in an air purifier. When you start shopping for one of these appliances, however, you’ll quickly find that there are so many different options on the market. While choice is certainly a good thing, trying to figure out which one will best suit your needs can seem like a challenging task.

The right air purifier can significantly improve the air quality in your home by reducing the amount of pollutants that are circulating through your air. It can even help to minimize the level of toxic volatile organic compounds (VOCs), such as benzene or formaldehyde. With that said, the question remains: Which air purifier should you use for your home? To find out – and to learn more about air purifiers, in general – keep on reading.

How does an air purifier work?

An air purifier is an appliance that is designed to improve the air quality of the space that it is used in. The technologies that are used to do this can vary from simple to complex. Basic air purifiers feature fan that blows through an air filer; however, some models are outfitted with more advanced technologies, like electric ions, activated carbon, or photochemical reactions that eliminate or even destroy airborne particulate matter and gaseous materials.

Not all air purifiers are created equal. Studies have confirmed that a good-quality air purifier can significantly improve indoor air quality, while poor-quality models may actually contribute to air pollution. For this reason, purchasing the right air purifier for your home that will be able to address the air quality issues in your home is an absolute must.

Types of air purifiers and how they work on different kinds of airborne pollutants

There are several different types of technologies that air purifiers can use to remove airborne pollutants. The manner in which the most popular types of air purifiers work include the following:

  • HEPA filtration. Short for high-efficiency particulate air, HEPA filters need to meet rigorous standards that state they have to be able to effectively remove 99.97 percent of airborne particles that measures 0.3 microns in size. HEPA filters are mechanical in nature and they remove airborne particles by blowing air through a dense weave of fibers that are then pleated, and the combination of the dense weave of fibers and the pleating traps particles in the air as they pass through it. HEPA filters can effectively trap dust mites, pet dander and hair, pollen, particulate pollutants that are found in smoke, as well as mold spores. With use and over time, however, the effectiveness of a HEPA filter will decrease as it becomes over-saturated with pollutants.
  • Carbon filtration. The carbon that is used in this kind of air purifier is activated. Typically, the carbon that the filter is made of is charcoal. Carbon has been used to purify the air and water for centuries. The activation process creates a large amount of miniscule sites on the surface of the filter that attrite pollutants, such as volatile organic compounds (VOCs) and nitrogen oxide. While activated carbon filters are effective at trapping gaseous pollutants, they cannot trap particulate matter. Additionally, similar to a HEPA filter, carbon filters can become laden with pollutants overtime, which can reduce their effectiveness.
  • UV-C purifiers. This type of air purifier exposes the air and the pollutants that are floating through it to an ultraviolet (UV) light. In theory, the UV light works like the sun, which deactivates microbes, including bacteria and viruses. An air purifier that utilizes UV-C light as a way to destroy pathogens must be designed so that the contaminated stream of air is exposed to the UV light for a long enough period of time that it will actually be able to effectively work.
  • Ionizers. Ionic air purifiers are designed to emit an electrical charge to airborne particles as they pass through the device. When the particles are charged, they clump together and fall out of the air and land on surfaces that are within close proximity to the appliance, such as the floor or the walls. Some models feature a charged collector plate, which draws the charged particles to the plate. Ionizers are not able to remove gaseous pollutants from the air, and while they are supposed to be able to remove particles, some studies have found that they are actually ineffective at doing that, too. As multi-study review found that ionizers had little to no effect when compared to whole house filters or HEPA portable room air cleaners. Even more troubling, ionizers can generate and emit ozone into the air, a pollutant that is known to irritate the respiratory tract.
  • Ozone generators. Though ozone can effectively neutralize some types of airborne pollutants, ozone itself is a toxic substance. As such, ozone generators should only be used by a professional, and only when the space is well-ventilated and no one is present in the space when it is being used. Due to the dangerous byproduct that ozone generators produce, the US Environmental Protection Agency recommends homeowners not to use ozone generators.
  • PECO. Short for Photo Electrochemical Oxidation, PECO is cutting-edge technology that not only removes pollutants from the air, but that actually destroy pollutants at the molecular level. This includes both gaseous and particulate matter. PECO works by shining a light on the surface of the filter, which activates a catalytic reaction that turns harmful pollutants, such as mold spores, allergens, and VOCs, into harmless substances, such as carbon dioxide and water. Because PECO technology destroys pollutants at the molecular level, this type of air purifier does not pose the risk of reintroducing pollutants back into the air, which can happen with HEPA and carbon filters.

How long will it take for an air purifier to clean a room’s air?

This isn’t an easy question to answer, as it depends on a variety of factors, including the type of pollutants that are in the air, the size of the space, and the type of air purifier that is being used. With that said, however, a way in which the answer to this question can be approached is by examining how long it will take for all of the air in the room to pass through the appliance; in other words, how long it takes the air to “cycle” through the air purifier. This information can be found in the Clean Air Delivery Rate (CADR) rating that is displayed on the air purifier, which is measured in cubic feet per minute (CFM).

It’s important to note, however, that the CADR rating isn’t an accurate way to assess the effectiveness of an air purifier’s performance. Air purifiers that have a large fan and a low-efficiency filter can have a high cubic feet per minute (CFM) output, but it won’t efficiently clean the air. Smaller unites that have high-quality filters may take a longer time to cycle the room, but may do a more thorough job of removing airborne pollutants. Overall, the larger the room, the longer it will take any type of air purifier to cleanse the air.

How effective are air purifiers?

Air purifiers can remove several different types of airborne pollutants. Examples of which include:

  • VOCs. Short for “volatile organic compounds”, VOCs are chemicals, many of which are toxic, that are emitted into the air by several household products and objects. They largely come from petroleum-based products and are commonly emitted by paints and paint thinners, pharmaceutical products, cleaning supplies, furniture, carpeting, and building materials. Carbon filters and HEPA filters can effectively remove VOCs from the air; however, as discussed previously, there is a change that they can emit the compounds that they have collected back out into the air once the filter becomes saturated.
  • Mold. Mold is a broad term given to a large collection of fungi. Mold spreads by emitting spores into the air, and these spores are considered particulate pollutants. Once they land on a surface, as long as moisture is present, the spores can grow into clusters, those clusters will produce and release more spores, which will further exacerbate the problem. HEPA filters can effectively remove mold spores from the air; however, the filters do need to be changed regularly, as they can become over-saturated and when that happens, they will emit the spores back into the air. Furthermore, if there is high humidity levels in the space, mold spores can actually grow on the surface of and within the filter, rendering a HEPA filter useless, and actually, it will make the problem worse.
  • Smoke. Tobacco products, fireplaces,  or even cooking; smoke is a highly complex pollutant. It contains particulate matter and VOCs, and both can be harmful. Air purifiers can effectively remove the particulate part of smoke pollution; however, they often struggle to eliminate the VOCs. Carbon filters, or a dual-stage carbon and HEPA filter could be effective; however, a PECO filter, which destroys particulate matter and VOCs at the molecular level, would be the most effective.