Smoke blankets parts of Greater Sydney
Smoke from hazard reduction burns in NSW is affecting parts of Greater Sydney, the Central Coast, Blue Mountains, Snowy Valleys, Southern Highlands and the Illawarra and the Shoalhaven.
NSW Health has reminded people that children, the elderly and people with heart and lung conditions are most susceptible to excessive smoke.
"If you have asthma or a lung condition, reduce outdoor activities if smoke levels are high and if shortness of breath or coughing develops, take your reliever medicine or seek medical advice," it said in a statement.
Health Minister Brad Hazzard says people with conditions such as asthma should stay inside and keep their medication close.
"For someone who suffers asthma I would advise the community to be very cautious because there is a lot of smoke around and it can certainly affect your lungs - as it is me at the moment," he told Nine's Today program on Monday.
"Stay inside if you can and make sure you use your preventers," he said.
The NSW Rural Fire Service said light winds and an overnight inversion had resulted in smoke settling in low lying residential areas.
Smoke is forecast to then begin to lift and clear across Monday as the day begins to warm up.
A number of planned burns had been postponed to contain the smoke.
Sydney Ferries advised that some services had been cancelled on Monday morning, with smoke and fog reducing visibility on the water.
Meanwhile, the Electrical Trades Union has advised its members to down tools if they are affected by smoke.
"Nobody should be forced to compromise their health to do their job," ETU NSW Secretary, Allen Hicks said.
"In large swathes of Sydney today, air quality is a threat to the health of people working outdoors. Those workers need to know if their employer can't protect them from smoke exposure they have the right to stop work.
"Smoke from hazard reduction burns can badly irritate the eyes and throat. Bushfire smoke also contains particles which can affect lung health, particularly for people who already suffer from conditions such as asthma or emphysema."
Under state and federal laws workers had a right to stop work if their employer can't provide a safe workplace, Mr Hicks said.
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