We breathe OUT carbon dioxide
Do We Breath Carbon Dioxide?
No, we breathe oxygen and exhale carbon dioxide.
Carbon dioxide (CO2) is considered to be a "standard" component of air, although the concentration of carbon dioxide in air will vary somewhat by location, and by season of the year. Therefore, any "standard" value for the concentration of carbon dioxide in air is an approximation. So to answer your question "Do we breath Carbon dioxide?", it would be yes.