Vulnerable people should try and stay in doors as experts warn about the air quality in Geelong and Melbourne.
A lack of wind has meant smoke from wood heaters and other urban pollution has not blown away from the cities, The Environment Protection Authority says.
People over 65, children 14 years and younger, pregnant women and those with existing heart or lung conditions are most at risk.
“These people should reduce prolonged or heavy physical activity and, where possible, limit the time spent outdoors,” a warning posted on the EPA website said.
EPA Head of Applied Science Anthony Boxshall told the Herald Sun the poor air quality could continue over the weekend.
“It’s really down to the weather,” Dr Boxshall said.
“It’s a beautiful still day out there — but it’s retaining the pollution, we might be stuck with it for a couple of days.”
“We’re lucky in Melbourne that our air quality is usually good or fair — but it’s this weather system that is causing it all,” he said.