Air purifiers are must-haves for many. Experts share what to look for when you shop | Canada Voices

The average person takes about 22,000 breaths a day. For 20 to 25 per cent of Canadians, some of those breaths can be a struggle because of asthma or allergic rhinitis – the sneezy, stuffy-nosed, scratchy-throat reaction to mould, dust mites, pet dander or pollen.

Spring can be a particularly difficult time.

Blooming trees and flowers are often triggers that make respiratory issues worse, as are wildfires, which are becoming increasingly common. That is one reason sales of air purifiers – which purportedly clear out common irritants, including smoke and pollen – have been rising in recent years.

Sarah Henderson, scientific director of environmental health services at the B.C. Centre for Disease Control, who has a PhD in environmental epidemiology, says air purifiers can be “life-changing.”

“People spend up to 90 per cent of their time indoors,” she says. “Air filtration systems help make that air as clean as possible. We particularly recommend them for pregnant women, especially those with allergies.”

The question remains: how to find the right one?

Laura Dahmann, a registered respiratory therapist (RRT) who works on Asthma Canada’s Asthma and Allergy HelpLine, says she is increasingly asked which air purifiers are best. “It’s less about a big brand name,” she says, “more about a few key features. One is the filter itself. People want to look for something that simply says HEPA filter, not something that says HEPA-like or HEPA-type.” Well-known makers including Dyson and AirDoctor have high price tags and high design, but essentially perform the same core function as less expensive options.

How does wildfire smoke affect air quality and your health?

According to Dr. Jaime Del Carpio, an allergist at the McGill University Health Centre in Montreal, HEPA (high-efficiency particulate air) filters can be effective. “In principle, they can filter particles smaller than 0.3 microns,” he says. “That’s very small – even smaller than some of the smallest allergens.” (Wildfire smoke averages between 0.4 and 0.7 microns, pet dander 2 to 10 microns, and pollen 15 microns.)

HEPA filters are not foolproof. For one thing, they need to be changed, typically once or twice a year. “You have to look after them,” says Del Carpio. “If the filters are not properly maintained, they become a reservoir of allergens, a nest of all the things you don’t want.”

But HEPA filters tend to be more effective than the alternative: machines that use electrostatic precipitators. These are essentially electronically charged plates that act as magnets to attract and grip air particles. “Precipitators can produce ozone,” Dahmann explains. “Ozone can cause inflammation in the airways, which can make respiratory issues worse.”

The range of the purifier is another key consideration. “All the fancy air purifiers have a square footage associated with them,” says Dr. Mariam Hanna, an allergist and assistant clinical professor in McMaster University’s Department of Pediatrics. “They clean up to a certain square footage in a certain amount of time. So we tell people to pick a room where they spend the most time – often their bedroom, because it’s where they sleep – and run the air purifier with the door closed. Otherwise, it’s often the living room and kitchen areas.”

Another consideration is the use of secondary filters, which in some machines can be used in conjunction with HEPA filters to maximize performance. “Carbon filters help reduce gases in the air,” says Henderson, “like the gases produced by wildfires.”

“Carbon also helps with food odours,” adds Dahmann.

The drawbacks can be aesthetic – they tend to be bulky and sit in the middle of a room – and the cost. Many air purifiers run $300 and above, plus replacement filters that can cost as much as $100 every six to 12 months. “DIY solutions can help, like taping a high-quality filter to a box fan,” says Henderson. “It’s not fancy, but it can be effective and accessible. Everyone deserves clean air in their homes.”

Six buys to try

When considering an air purifier, look for one with a HEPA filter, as well as an option appropriately sized for your space.

Coway Airmega Mighty

Coway’s Airmega Mighty has three separate filters. In addition to a HEPA filter, it has a cleanable, reusable prefilter for hair and large dust, as well as a carbon layer to remove food smells and smoke. It is suitable for spaces up to 1,680 square feet.

Buy

Blueair Blue Pure 311i Max Smart Air Purifier

Blueair’s Blue Pure 311i Max Smart Air Purifier has a sleek appearance, resembling a minimalist speaker – perhaps fitting for a unit known for its quiet performance, including a night mode with reduced fan speed. It is suitable for spaces up to 929 square feet.

Buy

GermGuardian Airsafe+ Deluxe Intelligent HEPA Air Purifier with Air Quality Monitor

The GermGuardian Airsafe+ Deluxe Intelligent HEPA Air Purifier with Air Quality Monitor offers many high-end features at a lower price point. A built-in sensor monitors air quality and automatically adjusts fan strength. It is suitable for spaces up to 1,000 square feet.

Buy

Windmill Air Purifier

Air purifiers aren’t always the most attractive additions to a home’s decor. The Windmill Air Purifier is an exception, with a simple, slatted design available in multiple colours. Two sleep modes – one with white noise, the other silent – adjust sound levels to suit user preference. It is suitable for spaces up to 975 square feet.

Buy

Levoit Core 400S-P Smart Air Purifier

Levoit’s Core 400S-P Smart Air Purifier includes voice control, allowing settings to be adjusted remotely. A cylindrical fan pulls in air from all sides to maximize range. It is suitable for spaces up to 1,733 square feet.

Buy

Winix T810

The Winix T810 has an LED display that shows air quality in real time, as well as an indicator light that signals when it is time to change the carbon and HEPA filters. It is suitable for spaces up to 1,968 square feet.

Buy