The map above shows hourly average data for all parameters, i.e., PM10, PM2.5, NO2, SO2, NH3, wind speed and wind direction values. Here's how to manage the risks.Dr Cowie said while some studies were underway, there was limited research looking into when a city is blanketed in smoke for weeks like Sydney. In three weeks time who knows. "If their respiratory symptoms worsen, it's important that they seek medical advice. ... New South Wales Health rated Tuesday's air quality … "When it's really hot and quite still, we can get a built up of some pollutants, and in this case it's ozone," he said. Sydney's air quality is already three times worse than at any moment in the past five years, but research is limited about the health effects of prolonged exposure to bushfire smoke. Not bad today. "It's important that people with respiratory diseases, such as asthma, follow their action plan and use their relieving medication if necessary," he said. High ozone in the Sydney basin and Illawarra can However, the smoke appears to be clearing with AQI numbers across Sydney dropping. "The gas serves an important purpose for humans when it occurs in the stratosphere — commonly known as the ozone layer — where it inhibits harmful ultraviolet light from the sun.Temperatures in the city are forecast to soar on Wednesday, with a top of 38C expected on the coast and 40C in Penrith.Bureau of Meteorology duty forecaster David Berry, who is asthmatic, said he would be carrying his puffer in his pocket. New South Wales Health has issued a warning for people with respiratory conditions as a toxic gas lingers in Sydney.A combination of hot, still weather and pollution is being blamed for an excess of harmful ozone in the city's western suburbs.New South Wales Health rated Tuesday's air quality as "poor" and said people with respiratory conditions, such as asthma, should take care.Ozone is a colourless, but pungent gas that is a respiratory hazard and can damage the lungs, and cause chest pain, coughing and throat irritation when inhaled.The gas is formed when nitrogen oxides from things like car exhausts and air conditioner fumes react with oxygen in the air on hot days.Normally, the wind blows pollution away, but the problem is exacerbated on still days.Dr Ben Scalley, director of NSW Health's Environmental Health Branch, said ozone levels would be high in western Sydney. These additional data provide a baseline for understanding the smoke incidents which occurred at these locations. 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