Goulburn's air quality deteriorates to the worst in state

Smoke drifting in from the 89,264 hectare Currowan fire in the Shoalhaven is to blame, says the Bureau of Meteorology.

The air quality index hit 1184 between 6am and 7am Monday, the Department of Planning, Industry and Environment data showed. Anything above 200 is considered 'hazardous' and people with respiratory problems are advised to take precautions.

ALSO READ: Police probe 'suspicious' car fire on rural road

The nearest level was southwestern Sydney, sitting on 450, followed by northwestern Sydney on 165.

The index shot up from 98 between 4am and 5am, which was considered 'fair.

It's the second time in just over a week that the index has reached more than 400. On Monday, December 9, it averaged at 480.

The data, provided on an hourly basis, can be sourced here. It is gauged at a newly installed air quality monitoring station at Leggett Park, off McDermott Drive in Goulburn.

READ MORE: Goulburn and region experience hazardous air quality from fires

Bureau of Meteorology duty forecaster Rob Taggart said a southeasterly wind was sending smoke from the Shoalhaven area up the coast.

"Goulburn will have the southeast winds all day so it's looking like a bad one in terms of smoke," he said.

Tonight, the wind is expected to turn east, sending the smoke to areas east of the city.

Mr Taggart said the situation wasn't expected to ease much on Tuesday, with more easterly winds forecast. By Tuesday afternoon they will turn east-southwest at 20km/h.

The Bureau's 'horizontal' visibility meter guaged visibility at 2km but Mr Taggart said as it was calibrated to also pick up fog, it could be half or a third of this.

The Currowen fire broke containment lines on Sunday and closed the Kings Highway between Nelligen and Braidwood. The Highway remains closed and it's not known when it will re-open.

READ MORE: Kings Highway closed to drivers as crews work to contain South Coast fire

Mr Taggart told The Post that due to a temperature inversion, smoke was being trapped between the ground and warmer air above.

The Bureau is predicting it will disperse more on Wednesday when the wind turns west.

"Wednesday is looking clear unless there are ignitions to the west of Goulburn," Mr Taggart said.

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NSW Health says the smoke for most people will cause mild symptoms like sore eyes, nose and throat. However, people with conditions like asthma, emphysema and angina are at greater risk because the smoke can trigger their symptoms.

"NSW Health continues to recommend that people with these conditions should avoid outdoor physical activity when there's smoke around," NSW Health Director of Environmental Health Richard Broome said.

Meantime, a very high fire danger is in place today for the Southern Ranges.

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