It is true that local sources of pollution travel around the world. That's a given. We see it every day with our satellite data. If you start with the Montreal Protocol, where they took baselines from the 1990 level, you can establish who is adding more anthropogenic substances into the air compared to who is not. It is clear that China and India are hitting way above the numbers that they should be.
Canada's numbers? Canada only has 2% of the total substance that is being injected into the atmosphere. If Canada were to clean up its 2%, it wouldn't change anything in the world at all. I think we should still meet our targets, but it wouldn't change anything. The space data tells you who is emitting and who has cleaner numbers.
That's about the best I can do.