Sulphur dioxide (SO2)

What is sulphur dioxide?

Sulphur dioxide (SO2) is a colourless gas with a pungent odour. The largest sources of SO2 emissions are from fossil fuel combustion at power plants and other industrial facilities. Other sources of SO2 emissions include industrial processes such as extracting metal from ore, large ships, and non-road equipment.

What are the health effects of SO2?

In general, inhalation of levels of sulphur dioxide in ambient air will not produce adverse effects in healthy individuals. Asthmatics are particularly susceptible to the respiratory effects of SO2 and may experience bronchoconstriction from short term exposure levels while exercising. Other health effects from exposure to SO2 and related acid aerosols are eye irritation, shortness of breath and reduced lung function.

Who is most at risk?

Effects are more severe or frequent in people with underlying pulmonary or cardiac disease, as well as infants and the elderly. Increases in hospital admissions and emergency room visits have also been associated with exposure to high levels.

Adverse health effects are directly related to the amount of SO2 the individual is exposed to, as well as length of exposure.

What is Public Health Sudbury & Districts role?

The Ministry of the Environment and Climate Change (MOECC) has issued an order to local mining operations to reduce sulphur dioxide concentrations at both ground level and total annual SO2 emissions from their Sudbury area operations.

Public Health Sudbury & Districts issued a news release supporting the MOE initiative, but urged further sulphur dioxide emission reductions. This is due to increased evidence of the health-related effects of short-term exposure to SO2 as low as 0.1 ppm, particularly among those with underlying pulmonary or cardiac disease, and a desire to reduce heavy metals deposition and acid rain as much as possible.

Who is monitoring levels?

The MOECC and industry presently monitor air quality in the City of Greater Sudbury at numerous locations. Real time SO2 results for Sudbury can be found at the Science North – Bestech webpage. The main government air monitoring site is the air quality index (Ministry of the Environment and Climate Change) station located on the south shore of Ramsey Lake.

We continue to respond to complaints related to human health effects. If you would like to speak to a public health inspector about SO2, you can submit your question or complaint electronically or call 705.522.9200, ext. 464 (toll-free 1.866.522.9200).

This item was last modified on August 16, 2019