The particulate pollution of 2-stroke engines is really, really bad. https://phys.org/news/2014-05-two-stroke-scooters-super-polluters.html https://phys.org/ne

The particulate pollution of 2-stroke engines is really, really bad. https://phys.org/news/2014-05-two-stroke-scooters-super-polluters.html https://phys.org/news/2014-05-two-stroke-scooters-super-poll... (Lead is arguably worse, but only because lead is unbelievably bad for you, not merely very bad for you)