A smoke alert has been issued for the Perth Hills, Perth metropolitan area and the southern suburbs.
The smoke is from prescribed burns in the Perth Hills and is expected to clear late on Wednesday morning.
The Department of Parks and Wildlife has the following advice for residents.
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.