Wear is inversely related to speed because the wear comes from acceleration, not from rolling at a steady speed. Starting and stopping and turning in urban driving wears tires more than cruising down a motorway.
Rolling also incurs wear. Going at a constant speed still requires shear stress on the tires like acceleration does (to counter air resistance, etc). So reduction in air resistance can also help reduce tire wear.
EV drivers typically brake a little more gradually to maximize regeneration compared to conventional braking. Having each wheel be driven by electric motors with careful traction control can minimize tire wear as well.
If tire wear is the problem we’re trying to address, it might be a good idea to include a specific fee to address it. Related to tire composition and regular annual inspection of tires. That way wear can be minimized in an effective way. Or we develop tire tread whose wear particulates are not a major problem.
Which brings up a point: we have little to no evidence that tire particulates DO pose an actual problem, unlike PAHs, which we do have evidence for. Rubber is somewhat biodegradable already. And the wear particles may be of a size distribution that isn’t so problematic. Detection or extrapolation of existence is not evidence for a problem.
We are multiple levels removed from EVs theoretically having higher weight to actual known health problems here, and likely due to better control and lower rolling resistance, it’s likely EVs are superior.
Why would you require annual inspection of tires instead of just adding an environmental tax to new tires?
If you're worried about people dodging the tax by over-wearing the tires (I doubt this would be a significant thing), you could arrange for taxes that lead to refunding less money when people recycle tires that have less tread left.