You know that CO2 concentration is at 421 ppm, (0.0421%) up from 280 ppm in 1850? That change is negligible compared to the 21% oxygen. Standing in a crowd or being inside causes a much higher variation of the oxygen concentration. Even moving up 2 meters changes the amount of oxygen molecules per volume by more than that.
You know that CO2 concentration is at 421 ppm, (0.0421%) up from 280 ppm in 1850? That change is negligible compared to the 21% oxygen. Standing in a crowd or being inside causes a much higher variation of the oxygen concentration. Even moving up 2 meters changes the amount of oxygen molecules per volume by more than that.