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For those not reading closely note that Hydrocarbons != Carbon. A New vehicle will burn fairly completely (if you include the cat as part of the process), leav

For those not reading closely note that Hydrocarbons != Carbon. A New vehicle will burn fairly completely (if you include the cat as part of the process), leaving a miniscule amount of hydrocarbons (incompletely burned fuel) and a small amount of CO. The catalytic converter will oxidize hydrocarbons, CO and NO2 leaving almost entirely N2 CO2 and H2O (and in fuels with significant sulfer, hydrogen sulfide which has its own issues).

Gordonjcp 3y ago
> New vehicle will burn fairly completely (if you include the cat as part of the process), leaving a miniscule amount of hydrocarbons (incompletely burned fuel) and a small amount of CO So will old ones, if you run them on the right fuel. My 25-year-old Range Rover has a 4.6 litre engine adapted to run on propane which is - under the right circumstances - a *negative* emission vehicle. It can have measurably less CO and HC in the exhaust than in the intake air (city air heavily contaminated with CO and HC for example from bus engines).