Smoke from burn-offs outside the Illawarra blamed for Wollongong's air quality

Air quality was rated as 'fair' from 4am until 7am on Wednesday, April 24, with authorities urging at-risk people to take precautions.

The number of small particles in the air had spiked, and these can get deep into the lungs and be absorbed into the blood stream, the NSW Government said in an alert.

"Short term impacts include difficulty in breathing and worsening of asthma or chronic bronchitis symptoms. They can also cause irritation of eyes, nose and throat," the alert states.

Controlled burns (also known as hazard reductions) underway in the Blue Mountains and Wollondilly coupled with north-westerly winds, meant smoke drifted into the Illawarra, Weatherzone meteorologist Quincy Tut said.

"There's an inversion layer over the Wollongong area. This creates a stable layer that limits any uplifts to the atmosphere," he said.

"Think of it like a lid ... it'll prevent the smoke from moving away."

By 8am air quality had improved in the Wollongong, with the rating listed as 'good'.

Air quality remained at 'good' in Kembla Grange and Albion Park South during Wednesday morning.

People with asthma or a lung infection, as well as infants, children and pregnant women are urged to reduce outdoor physical activity if you develop symptoms such as cough or shortness of breath.

These people are also urged to consider closing windows and doors until outdoor air quality is better, and follow the treatment plan recommended by your doctor.

If you are concerned about symptoms call the 24-hour HealthDirect helpline on 1800 022 222 or see your doctor. In a health emergency, call triple-0.

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