The Parks and Wildlife Service has issued a smoke alert for Mandurah and the surrounding Peel region as the result of a prescribed burn.
The burn is being carried out by the Department of Biodiversity, Conservation and Attractions 12km north of Walpole, with the smoke alert issued to areas ranging from Perth to Manjimup.
If the smoke is particularly thick, it is recommended people shut doors and windows and turn off air-conditioners.
Smoke may reduce visibility on some roads and motorists should take care, turn on headlights and travel at appropriate speeds when travelling in these areas according to the Service.
People with asthma and pre-existing respiratory or cardiovascular illnesses should follow their pre-prepared treatment plan.
Visit emergency.wa.gov.au or call 13 33 37 to keep up to date.