And they laughed at Reagan when he said that trees cause pollution. . . .
I remember that, lol! Regan was right after all.
Background: Reagan was repeating a joke going around in scientific circles at the time. In fact the whole Idea of reducing emission of NO's (ie... the catalytic converter) is based on this. And of course the catalytic coverter was first adopted by CA, thus RR was well aware of the science.
Anyway, trees and other vegetation account for 99.9% of the free hydrocarbons in the atmosphere. These hydrocarbons react with the NO coming out of the tailpipe to create air pollution. NO's react with any hydrocarbon, thus reducing hydrocarbon emissions in cars is completely inaffective. You need to either destroy all vegetation (trees cause smog) or eliminate the No's.