I have no idea why they would report the percent O2 in the ambient air. It's not directly relevent to emission testing and it's pretty constant at most places on earth. IIRC air is about 20 percent O2, 78 percent N2, and two percent other gases - CO2, argon, etc. Our CA test reports list percent O2 in the exhaust, which is a useful diagnositic tool for evaluating emission system performance.

You might want to check with your state emission test authorities to check out this claim. I doesn't make any sense to me.

Let us know if you find out anymore about this. It's rather odd.

Duke