Vito wrote:

"Martin Baxter" wrote
Hmmm, not sure about your chemistry here Vito, Nitric acid, HN03, you
need hydrogen too, and that's not coming from the air.

Ah, but it is - in the form of water vapor (fog) which mixes with the nitric
oxide to mke acid.

Well, what we are really talking about is the creation/emission of
nitric oxide (NO), nitrogen dioxide (N02) and nitrous oxide (N2O), not
nitric acid (HNO3. The nitric acid thing happens in the atmosphere and
forms acid rain. After doing a little research you are basically
correct, the rate of formation of nitrogen oxides is related to
compression ratios, has to do with heat of the reaction and rate of burn
apparently.

Interestingly the catalytic converter which reduces NO and NO2, both
contributors to smog may actually increase the production of nitrous
oxide. Nitrous oxide is not regulated by the Clean Air Act as it is not
considered to contribute to smog formation. It is however considered to
be nasty greenhouse gas, over 300 times as potent as carbon dioxide.

Cheers
Marty