Sulphur dioxide concentrations
Sulphur dioxide levels in all regions except for Mount Isa have met the National Environmental Protection Measures (NEPM) Air Quality Standards. Occasional 1-hour and 24-hour NEPM standard exceedances in Mount Isa are due to smelting operations.
Sulphur dioxide originates mainly from industries such as smelting of mineral ores, oil refining and coal-fired power generation. Motor vehicle fuels in Australia have low sulphur content and are of less concern than industry as a source of sulphur dioxide. The last South East Queensland (SEQ) coal-fired power at Swanbank closed in 2012.
Higher concentrations of sulphur dioxide are observed in the Gladstone and Mount Isa regions due to industrial emissions.
Since 2008, maximum 24-hourly ambient concentrations in SEQ, Gladstone and Townsville have been less than 35% of the NEPM Air Quality Standard. Maximum hourly concentrations in SEQ and Gladstone have rarely exceeded half the 1-hour standard since 2009: Townsville levels have been less than 10% of the standard.
While smelting operations adjacent to the city in Mount Isa have resulted in 1-hour and 24-hour sulphur dioxide concentrations occasionally exceeding NEPM standards, annual concentrations have been consistently below 30% of the annual average standard. The number of exceedances in any given year depends on a number of factors including weather conditions, smelter production levels and the extent of sulphur dioxide capture for sulphuric acid production.
Indicator: Trends in number of exceedances of NEPM air quality standards for sulphur dioxide concentrations, and annual average concentrations
Trends in number of exceedences of National Environmental Protection Measures (NEPM) Air Quality Standards for sulphur dioxide concentrations, and annual average concentrations, by airshed for 2000-2017.