The clue to what they do is in the name, but do air purifiers help with bad smells too? As concerns around indoor and outdoor air pollution rise, the air purifier market has expanded, and with more research emerging every day on how air purifiers may also help to reduce airborne viruses according to the CDC (opens in new tab), it's no wonder they’re becoming more popular.
Manufacturers of the best air purifiers claim they can remove bad odors from our environments by improving air quality, but is this really true? We look at the research around air purifiers and consider whether there’s enough evidence to prove that air purifiers really can tackle and remove bad smells in our homes. If you're looking for more advice, we have a separate investigation on 'do air purifiers help with allergies', which digs deeper into the subject.
Can air purifiers really help with bad smells?
The jury seems to be out for the time being. According to the United States Environmental Protection Agency (opens in new tab) (EPA), it’s possible that by removing indoor air pollutants the air may be cleaner and fresher, but it’s not guaranteed to work for all odors and lingering smells.
The EPA's 2018 Consumer Guide to Air Cleaners in the Home (opens in new tab) recommends indoor air purifiers as a supplementary method, alongside good ventilation, to freshen indoor air, remove bad odors, and improve air quality. So, while it’s not quite the panacea to an odor-free home, it may be a helpful step in improving your surroundings while you’re working indoors.
There isn’t a great deal of reliable research around odor removal and air purifiers. Most of the available research focuses on air quality and health outcomes. For example, a 2021 systematic review in the Science of The Total Environment Journal (opens in new tab) of over 20 studies into the effectiveness of air purifiers in schools, homes, and offices, found these appliances could reduce poor indoor air quality by between 22% and 92%. A 2020 study in the International Journal of Environmental Research and Public Health (opens in new tab) found that air purifiers could slightly, but not significantly, improve indoor environments in ordinary homes.
Air purifiers work by filtering and removing particles that may cause bad smells. However, the EPA (opens in new tab) states that no air cleaner or filter will be able to eliminate all the particles that can cause foul odors.
Air purifiers tend to work best in one room, so a single air purifier won’t be enough if you want to remove bad smells from your home. The larger the area you’re trying to tackle, the bigger the air purifier needs to be. An air purifier with a high CADR (Clean Air Delivery Rate) can filter more particles, tackling a larger area. If you want more, we have created a guide to how air purifiers work, which goes into more detail around the technical functions of these devices.
Which types of odors do air purifiers help with?
This may depend on the air purifier you’re buying. According to the EPA (opens in new tab), some air purifiers can tackle moldy odors, alongside the usual offenders of cooking smells, pet odors, tobacco smoke, and other lingering aromas.
Some air purifiers also have an activated carbon filter as well as a particle filter, which means they can tackle gas and chemical odors that may come from building materials, pesticides, and fire retardants.
How do air purifiers remove odors?
Air purifiers work by using fans to draw in allergens from the air. The exact particles they remove depends on the type of air purifier.
Some purifiers use negative ion emitting technology, which helps to attract particles. However, the EPA (opens in new tab) warns that these air purifiers can release ozone emissions into the home, which is a health risk. The California Air Resource Board (opens in new tab) also recommends against using ozone-generating devices at home because of the risks to health.
Most air purifiers typically use filtering technologies to capture polluting particles and gases from the air. A washable or disposable prefilter captures pet dander, hair, and other larger particles. Don’t forget to follow your manufacturer’s instructions on replacing or cleaning this filter.
Smaller particles that pass through the prefilter are then captured by a high-efficiency particulate air (HEPA) filter, which is made up of layers of fiberglass threads. As the particles are drawn in, they become trapped within this high-density mesh.
It’s worth knowing, however, that HEPA filters designed for home use have no widely accepted definition of good performance, so quality may vary across products. They also need to be replaced according to the manufacturer’s guidelines. The ability of HEPA filters to remove viruses is a complicated one, so we created a separate investigation into this.
Several air purifiers feature a further gas-phase air filter. It uses a material called a sorbent, such as activated carbon, to absorb harmful gas pollutants as they move through it. It’s worth knowing that these filters can usually only remove a limited number of gas pollutants. The EPA (opens in new tab) states that carbon monoxide, which is a dangerous gaseous pollutant, cannot currently be absorbed by residential air purifiers. So, if you have a wood burning stove, gas fire, or kerosene lamp burning, your air purifier won’t capture any of the carbon monoxide it emits.
Some air purifiers use ultra-violet light technology to destroy indoor air pollutants, such as bacteria, viruses, and allergens such as mold spores and pollen. However, many bacteria and mold spores require more exposure to UV light than these devices actually provide in order to be effectively destroyed according to the EPA (opens in new tab). So, they may not be as effective as their manufacturers claim.
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