4 ms·Why Do We Get Sick at Altitude?2 points by todsul 15y agobigiain 15y ago"each molecule of air still contains about 21% oxygen" Errmm, no. ("air" doesn't have homogenious "molecules", there are N2 molecules in air which are 100% nitrogen and 0% oxygen, and O2 molecules which are 100% oxygen...)todsul 15y agoFixed. Thanks.