Sulphur dioxide (SO2)
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Sulphur dioxide (SO2) is a colourless gas that has a strong smell. It is mainly produced by the burning of fossil fuels containing sulphur however it can also be produced by some industrial processes.
SO2 is harmful when inhaled at high concentrations and acts directly on the upper airways (nose, throat and lungs) producing a response within minutes. It is particularly harmful to people with existing respiratory problems, such as asthmatics or people suffering from lung disease. Symptoms of SO2 inhalation include wheezing, chest tightness, shortness of breath and coughing.
In Northland, the most significant industrial source of SO2 is the New Zealand Refining Company Limited, located at Marsden Point. The prevailing wind in this area frequently blows emissions from the refinery towards the Whāngārei Heads, a largely rural, residential area. The Council monitors ambient SO2 concentration using a continuous monitor stationed at Taurikura Bay.
In 2009-2010, results from the monitoring station at Taurikura indicated 100% compliance of SO2 concentrations with the National Environmental Standard of 350 µg/m3 one hour average and also well below the current 24-hour ambient air quality standard of 120 µg/m3.