Exhaled Oxygen

Most recent answer: 10/22/2007

Q:
Is there any oxygen left in the air which we breathe out of our lungs?
- Chong Wee Lic (age 12)
Jiemin Primary, Singapore
A:
Hi Chong Wee,

Yup, we usually exhale at least half of the oxygen we inhale. It depends of course on if we have been exercising, and whether or not we have held our breaths and for how long. Mouth-to-mouth resucsitation works mainly because there is still lots of oxygen in the air we breathe out.

Tom

(published on 10/22/2007)