If you found it a little difficult to breathe this morning, you’re not alone. The smoke from 78 bushfires burning on the mid-north coast has drifted south, causing Sydney’s air quality to be deemed “hazardous” by the NSW Office of Environment and Heritage. It’s believed the smoke has been pushed down the coast by strong winds, and it isn’t expected to clear for at least another 24 hours.

The office advises everyone, especially people with heart or lung disease, to avoid exertion outdoors and to stay inside as much as possible. Bushfire smoke is made up of small particles, gases and water vapour, which can affect the respiratory system. The particles can also cause itchy or burning eyes, throat irritation and runny noses, and aggravate conditions such as bronchitis, emphysema and asthma.

It’s recommended that Sydney residents keep their windows and doors closed and avoid vigorous exercise outdoors. If you’re particularly affected by the smoke, consider leaving the area.

Follow the NSW Office of Environment and Heritage’s hourly air quality alerts here.