There are anti-oxidants but no anti-oxygen. So, there is not any possibility that you could inhale an atom of anti-oxygen.

Antioxidants are molecules like Vitamin C [ascorbic acid] that get oxidized easily, so they 'reduce' the oxidizing molecules and protect other molecules in the body from getting oxidized. Oxidation and reduction are important things to know about in science.

Antimatter comes in sub-atomic particles, such as positrons which are the antimatter particles of electrons, and antiprotons, which are the antimatter particles of protons. Antimatter is produced in teeny tiny amounts in particle accelerators and some other places, but they are so far apart that they hardly ever find each other to produce antimatter atoms. Check out the Wikipedia article below:

antimatter.