Fire, a natural thing to me, a few years ago I was trying to blame that 'Humans are the cause of wildfire!', but my thought was destroyed after I'd done some research...it turned out that humans have almost nothing to do with wildfire...
Air? To be 200% honest, I think it's perfectly fine now. The reason why I think this way is because I've experienced some 'Real Air Quality Disaster', not like the wildfire smoke which lasts 2 or 3 weeks, but some PM2.5 problem lasts 1 or 2 years straight. To be 300% honest, I am satisfied with the air quality now in Canada (except the smell of weed every night in Richmond, I hate that thing).
However, 'I am satisfied' does not equal 'there's no more air quality problem in the rest of the world' . I wish this situation could remain like this for a little longer in countries that have relatively good air quality, and turn better years later. I also wish these countries could put more effort into increasing global air quality, provide your tech, your money, your people, and stop complaining all day long pretending to work.
Sorry about this dry post, I will just comment more if I have more ideas.