If it's a car built in the last 10 years and it's been properlly maintained, is running well, the sparkplugs come out in a state suggesting clean and complete combustion, and you're not burning oil, you're good to go. You need not worry. You're good for life.
If you're driving a '64 Fairlane you need not worry. You're putting out some carbon, but there's no cat converter, EGR orafice, MAF sensor, IAC or anything else to get messed up.
If you're worried about your "carbon footprint".....forget it. People obsesssed with their "carbon footprints" will be obsessed with them for the rest of their lives no matter whet happens. There is no cure. Just remember that we are carbon based life forms and perhaps you'll sleep better.