A portable air purifier in a bedroom

Over the past year, you’ve probably spent more time than ever hunkered down at home and may have started to wonder about the air quality—whether you live with allergies, have noticed funky smells in your kitchen or worry about the spread of germs. As it turns out, the air inside your home can be up to five times more polluted than the air outdoors[1] thanks to a mix of dust, pet dander, mould, aerosols and other sprays, smoke and outdoor pollutants that get trapped indoors. Thankfully, there’s something you can do about it: make an air purifier one part of your home cleaning plan.

Jump to

plus icon

1How do air purifiers work?

Portable air purifiers are small devices that reduce some potential allergens such as smoke, dust, pollen and pet dander in the air of your home. This process is done by mesh filter, odour-absorbing carbon filter or technology that neutralizes airborne particles like bacteria and mould.[2] You can also have a whole-home air purifier installed through your HVAC system if you have the time and budget.

2Do you need an air purifier in your home?

If you or anyone in your family has asthma or is prone to allergies or sinusitis, an air purifier may minimize triggers. Some types of air purifiers also target viruses and bacteria, which may make them helpful during cold and flu season.

  • What air purifiers can do: An air purifier can improve the overall quality of air in your home, particularly in the room where it’s located, and reduce some of the most common allergens.
  • What air purifiers can’t do: One portable air purifier can’t “treat” allergies or eliminate 100 per cent of allergens.[3] It also won’t make your home smell “fresher,” though it may remove some odours. Even if you have a great air purifier, you’ll get the best results if you also open windows to increase airflow, vacuum frequently and reduce indoor air pollution at its source when possible.[4]

3What are the main types of air purifiers?

Brondell O2+ Revive Truehepa Air Purifier + Humidifier PR50-B This Brondell air purifier combines true HEPA and activated carbon filters. It's also a humidifier.

Portable air purifiers generally fall into two categories: those that remove allergens via a filter and those that eliminate allergens like bacteria or viruses by neutralizing the particles in the air. Within these two categories, there are four main types of air purifiers. Some devices rely on a combination of filters (for example, combining HEPA and carbon filters) or techniques (UV light!) to target different types of particles.[5]

There are four common air purifier types:

HEPA Filter Air Purifiers

HEPA (a.k.a. high-efficiency particulate air) filters capture particles within a multi-layered netting or mesh, usually made from very fine fibreglass threads.[6] These filters are often folded or pleated like an accordion. HEPA air purifiers use fans to draw air in and force it through the filter which then traps or captures those particles, blowing only the clean air back out and into your home.[6]

When shopping for a HEPA air purifier, watch out for terms like HEPA-type or HEPA-like as these are not subject to any industry standard. Many brands now use the phrase “true HEPA” to differentiate their HEPA filter product from imitators.[5]

Pros Cons
HEPA filters may remove 99.97 per cent of particles measuring 0.3 microns or more (think: dust, pet dander, pollen, mould and other common household allergens).[7] The type of filter won’t remove particles smaller than 0.3 microns such as viruses, bacteria and volatile organic chemicals (VOCs) that are emitted from some household products including paints, aerosol sprays, disinfectants and air fresheners.[9]
HEPA filters only need to be changed about once a year.[8]

Shop Air Purifiers with True HEPA Filters

Activated Carbon Air Purifiers

Activated carbon (or charcoal) filters work by absorbing odour-causing molecules from the air. They’re ideal for eliminating odours and vapours from smoke, VOCs, fumes and gases, but won’t be as effective at removing pollen, dander, dust or mould. This type of filter is often used in combination with another type (such as a true HEPA filter) to target both vapours and larger particles.[5]

Pros Cons
Activated carbon is the only type of filter that can remove odours from the air. A carbon filter can’t remove large particles such as dust and pet dander.
Carbon filters need to be replaced every three to six months.[8]

Shop Air Purifiers with Activated Carbon Filters

UV Air Purifiers

UV air purifiers work to essentially sanitize the air with ultraviolet light bulbs, targeting and killing mould, germs and other bacteria. The technology is sometimes used in hospitals to disinfect patient rooms.[10]

Pros Cons
By reducing germs and bacteria, this type of air purifier may cut down on the spread of illness. UV alone can’t remove dust or other large particles.
UV light bulbs only need to be replaced every year or so, depending on how often the device is used.[11]

Shop Air Purifiers with UV Lights

Ionic Air Purifiers

Ionic air purifiers are built around negative ion generators, which send out a negative ion stream to attract positively charged airborne allergens and dust particles. They attach to the particles, making them heavy so they fall to the floor or other room surfaces. To completely remove these particles, you’ll need to vacuum or wipe them away.[12]

Pros Cons
They’re can target particles as small as 0.01 microns. This type of filter clears particles from the air but doesn’t eliminate them completely.
There’s no motor or fan, so ionic air purifiers are much quieter when running. Some ionic air purifiers have ozone generators that produce ozone, which can trigger asthma or damage lungs when inhaled. Do not buy this kind of ionic air purifier.[13]
These machines are generally less expensive to run. You may notice floors and surfaces look dustier because of fallen particles.[12]

Shop Air Purifiers with Ionizing Technology

4What factors should you consider when buying an air purifier?

You’ll want to keep in mind these technical requirements for efficacy and maintenance:

  • CADR (clean-air delivery rate): This number measures the cleaning speed of the air purifier. The higher the number, the faster the device works to eliminate particles. It’s usually measured in cubic feet per minute.[14]
  • Energy Star certification: Air purifiers that are Energy Star certified use up to 60 per cent less energy than a standard model and save you money on your utility bill.[15]
  • Room size: Choose an air purifier that can replace your room’s volume of air at least four times per hour.[16] Use this calculator if you know your room’s measurements and the CADR of the air purifier you’re considering.
  • How often you’ll need to clean or replace the filter: Some air purifier filters are reusable, while others need to be changed every couple of months or each year. Stick to the replacement guidelines; waiting too long to replace a filter means it’ll be too dirty to clean the air properly.
  • Noise level: You’ll need to run your air purifier almost constantly for it to be effective and a noisy device may disrupt your day.

5What extra features should you look for?

bblüv - Püre - 3 in 1 HEPA Air Purifier B0165 The bblüv Püre air purifier has two speeds and an LED indicator light.

Your air purifier should get daily use—so think of it as a permanent fixture even though it’s portable. A few of these features may make it blend more seamlessly into your life:

  • Wheels: If you want to easily move the air purifier from room to room, make sure your model has coasters.
  • Number of speeds: Having the option to turn down the air purifier, while still allowing it to run, is a good way to lower the noise level when needed.
  • Device size: If you have limited space, a more compact device may suit your living area best.
  • Washable prefilters: A reusable prefilter will collect larger particles before they reach the primary filter, which can prolong the life of the main filter and save you money on replacements.
  • Service indicator: A light or message will notify you when it’s time to replace or clean a filter.
  • Remote control: A remote control is a nice-to-have feature if you’d like to be able to adjust the air purifier from across the room.

6What should you avoid?

It’s rare, but some types of air purifiers may actually put pollution into the air. These types are not widely available, but keep an eye out and avoid them if you see them for sale:

  • Ozone generators: Ozone generators are a type of air purifier that produces ozone to react with certain pollutants and alter their chemical composition. They’re not considered particularly effective by experts and studies have linked ozone to lung damage and throat irritation.[5]
  • PCO (photocatalytic oxidation) air purifiers: This type of technology uses ultraviolet radiation and a photocatalyst to oxidize gas pollutants. The reaction may generate harmful by-products including ozone, formaldehyde and carbon monoxide.[5]

7Are air purifiers worth it?

An air purifier is one great tool to help you improve your home’s air quality and will work best if it’s part of an overall plan that includes reducing allergens at the source. Otherwise, your effort—and cash—will be wasted. To cover more ground, look for an air purifier with a combination of filters to target and reduce a variety of allergens.

More Ways to Keep Allergens at Bay