Why can't we breathe O3, aka ozone?

When we breathe air unpolluted by human activities, we usually take in about 10 to 15 parts of ozone per billion parts of air (10-15 ppb). However, pollution from human activities has elevated levels of the ozone we breathe. read more

The Oxygen we breathe is O2, meaning it is a molecule made up of two Oxygen atoms. Ozone is a high energy form of Oxygen with the formula O3, meaning each molecule is made of 3 Oxygen atoms. read more

We are constantly exposed to them and live in an environment where their concentration is essentially fixed: i.e. there is no advantage for us to be able to detect a CHANGE in either of these two things either. As for why we can smell ozone. I don't know. read more