I don't think you understand what they are measuring here. There are a lot of interest groups dedicated to selling oil until there is no more oil to sell, and t

I don't think you understand what they are measuring here. There are a lot of interest groups dedicated to selling oil until there is no more oil to sell, and they have no interest in being transparent about what they mean when they say that tires are worse than internal combustion. It's pretty clear that the authors are redefining pollution pretty extraordinarily to justify their claims. Only "particulate" counts as pollution, and the lifetime of that particulate, both chemically, and the airborne lifetime, is not even considered. Probably by this measure, the dominant source of pollution on earth is the winds from Africa depositing silt in the Amazon basin.