I thought brake dust would be drastically decreased due to regenerative braking?

that sounds right. Tire rubber microplastic generation would go way up, though, because of the vehicle weight.

I propose small motor scooters (as is common in asia) as the solution. Cars also take up a godawful amount of space, all the time. Especially in a city. That's the real harm, the tailpipe emissions are trivial compared to the space consumption.

Trivial compared to space consumption... in what sense? That sounds very difficult to compare. I also live in New Mexico, which is a huge state full of next-to-nothing but space, so perhaps I'm missing context.

Small motor scooters are not a good solution in the rain and snow

they're adequate (but less fun) in the rain. I have a good thick waterproof poncho in the scooter.

Snow, obviously, is not great. Cold is fine, though.

I live in Denver, ride the scooter year-round, though obviously don't go out in certain conditions.

There's some offset due to the increased weight from the battery pack. Highway driving is better, city driving is worse. Also, the tires emit more, since wear is also a function of weight.

Looks like it's still expected to a be a big net win for brake wear: https://www.sciencedirect.com/science/article/pii/S026974912...

Yeah but I can just buy a Tesla with hepa filters so I’m not breathing it in