People with asthma and other breathing problems have been advised to stay indoors after a thick blanket of dust settled over the city this morning.
Sydneysiders woke to a red haze after strong winds brought large amounts of dust from inland NSW and South Australia, and dumped it on the city.
The conditions could trigger asthma attacks and cause problems for people with other respiratory conditions, medical experts said.
Pregnant women, children and the elderly were also urged to do what they could to prevent dust from entering their lungs.
NSW Director of Environmental Health Wayne Smith warned people to avoid outdoor exercise today.
"We know particulate pollution causes problems for people with asthma and other respiratory diseases," said Guy Marks, professor in respiratory medicine at the University of Sydney.
"The most common type of particulate pollution is not this type, but particles from combustion products like motor vehicles or from bushfires.
"This pollution is from surface dust ... just what effects that will have on people's breathing is hard to say.
"But the cautious advice is that people with respiratory disease should probably stay indoors with the windows closed while the haze is around.
"If you do have to go out you should take precautions [such as by wearing a face mask]."
A number of Sydneysiders could be seen wearing masks today.
People without respiratory problems were unlikely to be severely affected by the dust, but might find it unpleasant, Professor Marks said.
"I suspect it will cause discomfort but whether it causes any real respiratory problems is hard to know.
"In rural Australia, dust storms are not that uncommon and they are not associated with major breathing problems for people."
Professor Marks likened this morning's pollution levels to the thick smoky blanket that settled on Sydney after the 2001 bushfires.
"It's quite extraordinary ... I've lived in Sydney for 53 years and never seen anything like this before," he said.
"There were a couple of summers near the start of the decade where there was terrible pollution.
"I haven't heard the exact numbers [today] but I imagine it would be similar to that."
Reports at the time said the number of deaths in Sydney hospitals increased by 2 to 3 per cent on days of high pollution, while the number of people admitted to hospital with asthma attacks rose by 6 per cent.
The Ambulance Service today said it had experienced an increase in calls from asthma sufferers. Some were taken to hospital, a spokeswoman said.
Professor Marks did not predict any long-term effect from today's pollution, as long as asthma sufferers managed to get through the day without major problems.
"The lungs have a good capacity for clearing these sorts of things," he said.
Public schools across the state have opened as normal.
"But given the circumstances if parents are concern about the effects of the high levels of dust in the air and if their children suffer from asthma or other breathing problems then they can keep their children at home," an Education Department spokesman said.
- with AAP
Email a friend
Favourites
Del.icio.us
Facebook
Digg
StumbleUpon
MySpace
Reddit
Newsvine
LinkedIn
Kwoff
Twitter