At 8.45am on Wednesday the numerical air quality rating for Orange was 1011 which ranks as 'hazardous' on the NSW Department of Planning, Industry and Environment (DPIE) website.

The level was far above any other DPIE reading location in NSW.

At this level, the OEH advises that people with heart or lung disease, older adults, and children should avoid exercising outdoors.

"Everyone else should reduce prolonged or heavy exertion," the alert stated.

"If you have symptoms rest and use your reliever medicine. If symptoms persist, seek medical advice."

Meanwhile, there is a very high danger risk and total fire ban in the Central Ranges for Wednesday which includes these council areas: Orange, Bathurst, Blayney, Cabonne, Cowra, Lithgow, Mid-Western and Oberon.

The largest fire currently burning in the region is the 320,000 Gospers Mountain bushfire burning north-east of Lithgow which is listed as being controlled.

The Green Wattle Creek bushfire, buring within 3.5 kilometres of Oberon Correctional Centre is also creating large volumes of smoke.

Stay up-to-date with fires in your area at Fires Near Me.

If you see an unattended fire call triple-0 immediately.

NSW Health say the most common symptoms experienced during a dust storm are irritation to the eyes and upper airways. People who may be more vulnerable than others are:

The following precautions can help you protect yourself and minimise the adverse effects of a dust storm:

For emergency medical assistance call triple-0.

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