One thing that struck me of interest was a while ago I attended a Shell seminar on their products.... they i am sure said that because of the PC'ness against leaded fuels they had been trying various cocktails to try to produce a lead free Avgas but they were not getting anywhere close to the power output, even though they had calculated the amount of lead released into the atmosphere per year for the total world piston fleet was about 4 tonnes.......... now that is a block about the size of a coffee table.
Odd thing was, when we had unleaded car fuel any Avgas that failed to meet the Octane rating would be blended with motor fuel and sold that way....... Now because they do not have leaded car fuel they have to pay a company to come and burn the stuff for them preventing the lead from entering the atmosphere......go figure.
And as for electric cars, the "greener cleaner approach", you still have somewhere down the line a coal powered power station or such like chucking out pollution to produce your "cleaner greener electricity" for your car........