Australia commonly experiences extensive wildfires, mostly during its hot dry summers. These often lead to significant loss of life and property. The October 2013 Blue Mountains Fire burnt through more than 100,000 hectares and generated a large amount of fire dust which was transported to the downwind community residing in the Sydney metropolitan area, which is the largest city in Australia. Record-breaking temperatures in New South Wales and strong winds worsened the wildfire danger index and the extensive fires that broke out by 17th October lasted for more than a week. Analysis of the particulate matter monitored by the New South Wales Environmental Protection Authority around the fire zone showed that the concentrations of PM10 and PM2.5 increased by more than two fold (> 200%) and remained high for a week. During the peak fire period SOx, NOx and O3 concentrations increased by 52%, 29% and 42%, respectively, above the usual levels recorded in metropolitan Sydney. The increase in the concentrations of these air contaminants in the Sydney metropolitan region over such an extended period may have caused increased human health risks, and these are also examined in the paper.