Data published on the Environment Protection Authority’s (EPA) AirWatch website this morning showed air pollution levels were “hazardous” at the Melton, Macleod, Mooroolbark, Alphington, Box Hill, Dandenong, Brighton, Brooklyn, Footscray and Coolaroo monitoring sites.

The same rating was also given to towns in the firegrounds such as Omeo and Orbost, while the north-east is forecast to experience hazardous air pollution later today.

Firefighters have been using milder conditions to their advantage this week as they work to contain massive bushfires across the Alpine region, East Gippsland and the north-east which have burnt 1.4 million hectares of land.

People living in an area with hazardous air quality are advised to limit their time outdoors and follow treatment plans if they suffer from respiratory conditions.

EPA state agency commander Dan Hunt said yesterday that most parts of the state except the north-east and Gippsland would see some improvement in the air quality by Thursday.

“Our advice to people, particularly to sensitive groups — people with asthma, people that are pregnant, over the age of 65 or under the age of 14 — is where possible, try to avoid being in the smoke,” he said.

When air quality dropped significantly in Victoria last week, Ambulance Victoria saw a 51 per cent increase in asthma and pollution-related call-outs.

United States space agency NASA has predicted that the smoke from Australia’s bushfires will lap the world and could make its way back over Australian skies in the coming days.