You're arguing a point I didn't make. I didn't bring up air quality or pollution policy at all. I brought up a very specific, lived experience: my wife walking our newborn and being exposed to a strong, pervasive cannabis smell in our own neighborhood.
These two issues can coexist, but they're in completely different universes. Long-term air quality and vehicle pollution are systemic public-health problems. This is about basic courtesy and reasonable behavior in shared public spaces, especially around infants. One does not negate or diminish the other.
I could make the point that pollution by vehicles is also about basic courtesy and reasonable behaviour in shared public spaces, but it has become so normalised that I don't think you'll be convinced.
However, I do agree that people should be more wary around children and not subject them to second-hand smoke. The problem is that cannabis has such a strong smell that the smell is noticeable even when the amount of smoke exposure is likely not measurable.
These two issues can coexist, but they're in completely different universes. Long-term air quality and vehicle pollution are systemic public-health problems. This is about basic courtesy and reasonable behavior in shared public spaces, especially around infants. One does not negate or diminish the other.