My first question about trendy new products is “Do they actually work, and if so, how?” Many health and wellness products are subject few, if any, regulations which allows manufacturers to make audacious claims with little or no evidence to prove them. This is regularly seen with vitamins and supplements, but also happens with other products, such as air purifiers.
I remember my first exposure to air purifiers at Sharper Image stores in the mid 90s. With a hole in the ozone layer, smog, and all the other pollution concerns purified air sounded like a no brainer! The claims sound too good to be true, and for the most part they are. However, they are not all hocus pocus. Some people swear by air purifiers, while others experience no benefit at all. In some cases they may even cause harm. Read on to learn more about how air purifiers work and if they hold any benefits.
Why use an Air Purifier?
Indoor air tends to be less clean than outdoor air, because indoor air is stagnant. What comes in rarely goes out allowing allergens and irritants to linger. Air purifiers are marketed for general well-being, but tend to target people with allergies, asthma, and other respiratory conditions.
Manufacturers claim that air purifiers reduce allergens and irritants in several ways. They also claim that these devices reduce bacteria, mold, and other microorganisms.
What are Air Purifiers?
Air purifiers come in a variety of forms, and most new air purifiers contain a combination of these technologies. The most common varieties are:
Just like the filter in your vacuum cleaner, filter air purifiers use high efficiency particulate air (HEPA) filters. They clean the air by filtering large particles, such as dust and animal dander. However, these particles often “settle” on the ground before passing through the filter. Even though HEPA filters work, their overall impact on air purity is quite small, and they do not filter out any substance entirely.
Filters within heating, ventilation, and cooling (HVAC) units are assessed by a grading system known as the minimum efficiency reporting value (MERV). This scale ranges from 1-20 with one being low and 20 being high, which provides a tool for comparison between filters. For an additional frame of reference, high efficiency particulate air (HEPA) filters would fall in the range of 7-13 on the MERV scale.
A recent study published in 2017 shows a decrease in allergy symptoms with the use of an air filtration system. However, this study uses a standardized purification chamber, so generalizing the results would not be prudent. However, it does stand to reason that symptom reduction is possible with filtration.
UV technology sounds fancy and official. Most of the top home air purifiers on the market include UV technology in addition to a HEPA filter, because UV light is effective at killing microbes (e.g. bacteria and mold). While this is true, the dose of UV light present in air purifiers is often not high enough to have antimicrobial effects. Another issue is that the amount of time the microbes are exposed to the UV light is very small. Studies do show that UV light is effective at destroying microorganisms growing on the surface of HVAC units,
Ionizers utilize charged particles to add an overall negative charge to dust and other particulate matter. These particles are then attracted to the positively charged plates within the purifier, which cleans the air. A recent study in guinea pigs found that ionizers help to inactivate viruses also. The biggest problem with commercially available ionizers like The Sharper Image’s Ionic Breeze, is that they only work in a limited area. Like other purification devices, ionizers only purify whatever is within their grasp, so once the particles have settled or are out of the devices reach, they will not be removed.
The bactericidal and fungicidal mechanism of ionizers is an area of interest for scientists and companies due to its potential applications in health care. Research is being conducted to assess the effectiveness of ionizers in operating rooms and on medical equipment. Ionization indeed exerts a bactericidal effect, and can do so without generating large amounts of ozone, which has been a concern in the past. Further studies need to be conducted on this topic, but ionization is a promising mechanism for cleaning surfaces, which could be successfully adapted to air purification.
A controversial topic, ozone generators utilize UV light or ionization to produce ozone. Ozone destroys pollutants due to its ability to give up an oxygen molecule, which attaches to the pollutant. The problem is that this same mechanism causes ozone to be harmful to humans. Apropos of this, the EPA has developed strict standards on the amount of ozone generation that is acceptable. Any air purifier that adheres to these guidelines produces an insufficient amount of ozone to remove pollutants.
This is a positive thing, because ozone is a significant respiratory irritant and actually aggravates many respiratory conditions (e.g. asthma) that air purifiers claim to quell. In addition to worsening these conditions, ozone can increase the likelihood of respiratory infection and even cause chest pain.
Do Air Purifiers Work?
The is sort of, but not really. While all of these modalities do have purifying effects, they only purify a very limited area. In the case of ozone, they actually produce an insufficient amount of the purifying substance to be effective. Filters, UV light, and ionizers are all limited by the fact that the particles must pass through the device or interact with it in some way. Although some particles are removed, many more settle on surfaces before they interact with the device.
If you suffer from a chronic respiratory condition such as asthma or allergies, it may be worth trying an air purifier to see if it helps. However, the first line of treatment should be talking with your health care provider about medications and lifestyle modification. It is likely that regularly dusting, vacuuming, and cleaning along with medications (if necessary) will do more than an air purifier since most of the irritants will never be removed by the device.
Where Can I Learn More?
For more information on air purifiers, check out the references below. Do you own an air purifier? Have you considered purchasing one? Whatever the case may be, please leave your thoughts in the comments below. Feel free to contact us through social media, email, or whatever method you prefer. Have a great day and be well.
Bergmann K-C, Sehlinger T, Gildemeister J, Zuberbier T. A novel experimental technology for testing efficacy of air purifiers on pollen reduction. Allergo Journal International. 2017;26(1):1-6. doi:10.1007/s40629-016-0001-z.
Guide to Air Cleaners in the Home. EPA. https://www.epa.gov/indoor-air-quality-iaq/guide-air-cleaners-home. Published September 6, 2016. Accessed March 14, 2017.
Hagbom M, Nordgren J, Nybom R, Hedlund K-O, Wigzell H, Svensson L. Ionizing air affects influenza virus infectivity and prevents airborne-transmission. Scientific Reports. 2015;5:11431. doi:10.1038/srep11431.
Ozone generators that are sold as air cleaners. https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-are-sold-air-cleaners. Updated 02/22/2017. Accessed 03/15, 2017.
Park J-S, Sung B-J, Yoon K-S, Jeong C-S. The bactericidal effect of an ionizer under low concentration of ozone. BMC Microbiology. 2016;16:173. doi:10.1186/s12866-016-0785-5.