Guide · Updated 2026-10-12

Air purifiers and wildfire smoke: what to check

Wildfire smoke has made air purifiers a common purchase in Canada. The label matters less than a few numbers.

Look for a true HEPA filter

A true HEPA filter is built to capture very small particles. Terms like "HEPA-type" or "HEPA-like" are marketing and do not mean the same thing.

Match CADR to your room

CADR (clean air delivery rate) tells you how much filtered air a purifier produces. A common rule of thumb is a smoke CADR of about two-thirds of your room's floor area in square feet, for a standard ceiling height. A bigger room needs a bigger unit or more than one.

Avoid ozone producers

Some devices intentionally generate ozone. Avoid them. Look for models listed as certified low-emission, for example on the California Air Resources Board list.

Count the running costs

• Replacement filter price and how often it changes.
• Noise at the speed you will actually use.
• Electricity use if it runs all day during smoke season.

Use it well

Keep doors and windows closed while it runs, and place it away from walls and furniture that block airflow. For health guidance on smoke, follow Health Canada and your local public health authority.

See related picks: Lighting Climate & Air Security Tools