No, it won't be correct. There are various processes that alter the composition of the gases (here CO2 and O2) in the atmosphere. Burning of coal, oil, wood and other such things like that vary the Carbondioxide (actually carbon) concentration by a lot degree. Then the animal respiration also adds to the change in the level. The oxygen given by the plants also varies, at night oxyen level drops and Carbondioxide level increases because oxygen is not given at night.

So, not always there is a balance between the two.

View the original article here