I'm not sure that any town with the south circ running through it is every going to smell that nice, but it would be nice if authorities were taking steps to make the air a little less poisonous - it will kill 10% of us as it stands.

I suspect the worst culprit is the particulates (fine soot) produced by the buses and lorries, so step 1 is to quickly phase out diesel vehicles. I'm afraid we were all lied to that diesel is environmentally friendlier.
Bring the trams back.

Another step would be plant more trees by the sides of busy roads - they are natural filters. The more the merrier - they are saving lives. (What ever happened to the trees promised and paid for on Perry Vale side?)

There need to be controls on traffic volume - those days when the pollution levels are approaching the limit, then through traffic needs to be rerouted.
All vehicles need to be electronically tagged so we can be more selective on any restrictions.

Planting scented flowers is an excellent idea, but they are just covering up a pretty serious problem.