Nitrogen oxides and VOC/Hydrocarbons along with sunlight form ozone, its doesn't come directly out of the exhaust. Carbureted two-stroke engines emit large quan

Nitrogen oxides and VOC/Hydrocarbons along with sunlight form ozone, its doesn't come directly out of the exhaust. Carbureted two-stroke engines emit large quantities of hydrocarbons compared four-stroke even without emissions gear like a cat. This is due to the the intake and exhaust port being open together for a period of time on a two-stroke, certain amount of unburned fuel goes directly out the exhaust, this is why they are so bad. It's the VOC they are emitting that can then form ozone.