Lowering of SO2 Air Quality Standards

On October 27, 2017, the MOECC announced its regulatory proposal to change the sulphur dioxide (SO2) air standards. The new standards would be phased-in over a five year period but the MOECC is considering whether to apply these new standards to Northern Ontario.

The changes would lower the regulatory standard for SO2 from the current 1 hour standard of 690 µg/m3 to 100 µg/m3, while the current 24 hour standard (275 µg/m3) would be eliminated. However, there would be the introduction of a new, annual standard of 10 µg/m3.

In relation to SO2, the MOECC is also clarifying that equipment start-up/shut-down operating scenarios are to be included in the assessment for regulatory modelling. Sources of most concern tend to be flaring stacks at petroleum refineries.

For more information on the possible implications of the change in the air standard and your air compliance status, contact:

Jessica Knox

Senior Air Quality Modeller

rsabino[at] 905-890-6957 ext. 107