The Parks and Wildlife Service has issued a smoke alert for Armadale to Waroona, including areas of the Peel region.
The smoke is the result of prescribed burns being carried out on Tuesday by Parks and Wildlife Service and is expected to clear by tomorrow.
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.
People with asthma and pre-existing respiratory or cardiovascular illnesses should follow their pre-prepared treatment plan.
People with conditions exacerbated by smoke should take precautions in line with their medical advice for these circumstances.
To keep up to date visit www.emergency.wa.gov.au.