Smoke alerts have been issued for several suburbs south of Mandurah.
Residents in North Dandalup, Preston Beach, Dawesville and Bouvard are included in the alert.
The smoke is due to a number of prescribed burns.
Motorists travelling along the South Western Highway between Del Park Road and Morrell Road may be impacted by smoke.
Other affected roads include Preston Beach Road North and Old Coast Road between White Hills Road and Tims Thickett Road.
The smoke is expected to clear over the coming days.

PIC: Emergency WA
Teen accused of ordering firebomb attack on Baldivis tobacco shop
City of Mandurah sees sharp rise in animal cruelty reports
Geoff Valentine returns to Peel Thunder as senior coach
Golden Bay woman charged with lacing colleague's curry lunch with snail poison
Cooloongup man charged over alleged sexualised online conversations with a child
Bushfire readiness takes centre stage at City of Kwinana's free Summer Sounds festival
WA Open Golf Championship to tee off at Secret Harbour Golf Links
Halls Head named WA's most persistent storm damage hotspot
Four illegal e-bikes to be crushed after police crackdown in Halls Head, Falcon