Air quality across parts of NSW has reached hazardous levels and people have been warned to take care outdoors, as a large dust storm engulfs the coast.
Sydney's north-west, the Central Coast and the upper Hunter region recorded hazardous air quality levels - and the storm is forecast to get worse before it gets better.
NSW Health has warned that air quality in the Sydney basin could be poor today and possibly extending into Friday.
Director of environmental health Dr Richard Broome said it was especially important for children, older people, and people with chronic respiratory and cardiovascular conditions such as asthma, chronic bronchitis, emphysema and heart disease to limit their time outside and not engage in vigorous exercise during a dust storm.
Last time a major dust storm hit Sydney, in 2009, the SES received more than 500 calls for help, mostly from people with breathing difficulties.
