Australia — The thick haze hovering over metropolitan Perth was heavier than many polluted Asian cities and peaked at almost twice the national environmental standard this week.
Heavy smoke from a bushfire in the South West has travelled as far north as Geraldton as firefighters continue to battle the blaze near Northcliffe, which began during a lightning storm more than a week ago.
Air quality readings for particles in the air reported by the Department of Environment and Conservation have revealed the level of PM10, or coarse particles, peaked at 89.5 micrograms per cubic metre on Tuesday.
Australia’s national environmental protection measure is 50 micrograms per cubic metre.
A Department of Health spokesman said the average levels were high enough to be unhealthy but not hazardous to the general population.
“Most people manage their exposure quite well by staying inside or going to enclosed places such as shopping centres to get away from the smoke,” he said.
Director of the Lung Institute of WA Professor Philip Thompson said people with respiratory illness, including asthma, emphysema, bronchitis and cystic fibrosis, would be most at risk this week and should be on alert for any changes in symptoms.
Perth air is typically among the cleanest on the planet with PM10 levels usually averaging 13, the World Health Organisation reported.
Weather Bureau spokesman Neil Bennett said winds blowing from the south had pushed smoke as far north as Geraldton and a variety of weather conditions had created an “inversion” which trapped the haze close to the ground longer than usual.
“Instead of the temperatures cooling with height, they are actually warming with height,” Mr Bennett said.
“The inversion prevents the air from rising vertically – it traps it.”
He said Perth residents could expect thick haze again today but it was expected to clear by Saturday with the arrival of a cold front across the southern half of the State.
The Northcliffe blaze has been contained. It has burnt about 24,000ha but has not destroyed any homes. About 90 firefighters are working to protect the communities of Windy Harbour, Northcliffe, Camfield, surrounding rural areas and recreational parks.