Cities tend to have more air pollution, but the difference in CO2 and O2 are neglible. I once ran the numbers for O2, which is proportional, and it came out to

Cities tend to have more air pollution, but the difference in CO2 and O2 are neglible. I once ran the numbers for O2, which is proportional, and it came out to roughly 10m of high in the atthmosphere. I. e. climb a tree in the countryside and you’re at O2 pressure similar to a city.