A smoke alert has been issued for the area between the Perth CBD, Perth Hills and Mandurah, including Armadale.
The Parks and Wildlife Service at the Department of Biodiversity, Conservation and Attractions issued the alert on Monday afternoon.
The smoke is the result of prescribed burns being carried out 25 kilometres south-east of Mundaring and in the locality of Dawesville.
The smoke is expected to be cleared by Tuesday morning.
The following advise has been issued:
WHAT TO DO:
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.
KEEP UP TO DATE:
The next update will be issued when the situation changes.