A smoke alert has been issued for North Bannister, Serpentine, Keysbrook, Mandurah and Rockingham.
The smoke is due to a prescribed burn north-east of Dwellingup.
"People travelling along Albany Highway and surrounding roads in the area are advised smoke may impact visibility," a Department of Fire and Emergency Services alert read.
"Please be aware of crews working in the area and drive to the conditions."
The smoke is expected to clear overnight.
Affected residents are advised to shut doors and windows and turn off airconditioners.
If driving through the area, turn on headlights and drive slowly.

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
Aboriginal jobs and careers expo to attract 1000 attendees in Rockingham
Firefighters attend Lakelands home after reports of thick smoke
WA Government to ban screen use for younger students as part of six-month trial
Singleton General Store shutdown over illicit tobacco, vape sales
Concerns for missing Bertram woman
