Air purifiers: What can help my asthmatic mother to keep her home smoke-free during wildfire season?

Wildfire smoke can enter the home from windows, doors, vents and other openings. Seniors and people with lung conditions are especially vulnerable to the fine particles in smoke. Closing doors and windows can reduce the amount of smoke coming into the home, but an air purifier is a great way to reduce the particles in the air.

When choosing an air purifier look for one that has a High Efficiency Particulate Air (HEPA) filter since they are able to trap the smallest particles.

Ideally, the air purifier is placed in the room you spend the most of your time in. The Association of Home Appliance Manufacturers (AHAM) certifies air purifiers. These AHAM-certified units will have a label that indicates the Clean Air Delivery Rate (CADR). Each unit will have a CADR for tobacco smoke, dust, and pollen – follow the CADR for tobacco smoke as it is the most similar to wildfire smoke.

There are many factors that can influence what CADR will be appropriate: the dimensions of the room and the Air Changes per Hour (ACH). Most air purifiers are assume an ACH of two for most people, but five is a minimum for those with asthma, and eight ACH is a minimum for heavily contaminated air.  For seniors with lung conditions consider a high ACH, probably around eight depending on the contamination in the air. You may want to consult with a health professional if you’re unsure about what ACH is appropriate.

It’s better to calculate the CADR that works best for the user and the room instead of reading what sized room the air purifier recommends. AHAM-certified units will mention on the label that their calculation is based on 4.8 ACH. Thankfully, Reviews of Air Purifiers has a CADR calculator to help you to determine what CADR is right for you. Enter the room area, and selected the desired ACH and the calculator will determine the minimum require CADR for that room (follow the number in cubic feet per minute).

Once you’ve determined the CADR you can begin to look at what product are available. During wildfire season it may be difficult to find the exact product you’re looking for because of supply shortages. Visiting the local London Drugs, Canadian Tire, or Home Depot can be a good place to start. Look first for products with the appropriate CADR, then check to see that they have a HEPA filter, and finally check to see that the unit has been verified by AHAM. If you are unsure about whether or not the product has been verified, you can check the AHAM website to search by brand.

Some examples of different products and their prices include:

• HPA-060C by Honeywell (at Amazon Canada) is an AHAM-certified air purifier with a HEPA filter. The CADR for smoke is 48, and if an ACH of at least eight is needed, then this unit would work best in a room that has about 45 square feet of space. If five ACH is sufficient then it would work best in a room with about 72 square feet of space. This product cost about $100 (CDN).
• GermGuardian 4-in-1 Air Purifier by Guardian Technologies (at Canadian Tire) is an AHAM-certified air purifier with a HEPA filter and a smoke CADR of 100. Assuming the user needs an ACH of at least eight, then this unit would work best in a room that has about 94 square feet of space. If only five ACH is needed, then a room of up to 150 square feet would work. This product costs about $170 (CDN).
• D360 by Winix (at Home Depot) is an AHAM-certified air purifier with a HEPA filter and a smoke CADR of 233. Again, assuming the user needs an ACH of at least eight, then this unit would work best in a room that has about 218 square feet of space. And if five ACH is sufficient, then this a room of up to 350 square feet works. This product costs about $250 (CDN).

Be careful when looking at products online on places such as amazon.ca. Products marketed as air purifiers are often in fact air ionizers. Research is unclear on the benefits of ionizers since that can produce harmful ozone and are not as effective at removing particles from the air. That is why it is important to find an AHAM-certified unit.

You can also refer to Wildfire smoke 101, a health publication from the Government of Canada.