CO2 emissions..???

You will need to take this to a state-licensed emission testing facility that uses a "sniffer," which is a tester that hooks up to the exhaust and measures the amount of CO2, NOx, etc., that your vehicle is putting out under various engine loads. THey can print you a sheet showing what your output is.

i would recomend getting a basic tune up if your car has a few miles on it.that way when you get your reading it will be lower than now.