Australia Weather News

Authorities are warning Sydneysiders the dust engulfing their home town can penetrate "deep into your lungs" as air quality in Australia's largest city reaches "hazardous levels".

The dust which has descended on the Harbour City is the by-product of a statewide drought, with dry soil swept up by the strong winds.

Earlier this year, 100 per cent of NSW was declared in drought, or drought affected.

A perfect storm of strong winds and a low pressure trough cold front has helped the dust travel across western parts of the state to highly populated coastal areas like Sydney, the Hunter Valley and Illawarra.

The conditions prompted the Office of Environment and Heritage to declare air quality in parts of Sydney's north-west, the Central Coast and Upper Hunter had reached a "hazardous" level.

How dangerous is it?

According to the NSW Government, the most vulnerable people are the elderly, children, and people with existing respiratory issues such as asthma or chronic bronchitis.

These people should limit their time outside until the dust storm passes and use air conditioners to keep the inside air clean.

Dr Richard Broome, the department's director of environmental health, said some of the dust particles were very small, and could therefore find their way deep into people's lungs.

"That's why we're concerned about people's health," he said.

The particles can cause systemic inflammation or make angina worse.

How can you stay safe?

First for the bad news — Dr Broome said face masks might not protect you.

He said while some people might choose to wear a mask, evidence on whether they were beneficial was limited.

Now for the good news — the dust is not here to stay.

Conditions are expected to be at their worst this afternoon, before steadily clearing.

Dr Broome said health symptoms could still persist for a day or two even after the dust had passed.

He said the greatest protection would be offered by staying in air-conditioned premises, while drivers could reduce the amount of dust entering their vehicles by switching the air intake to recirculate.