They work by removing nitrogen from room air to make 94-98 percent oxygen.

"I've been that way all my life, at twenty percent oxygen."

There's a little over twenty-two percent oxygen in the air, which is close enough.

A planet like Venus has less than one percent oxygen.

In fact, it was about 40 percent oxygen by weight.

The air today is about 21 percent oxygen.

And 94 percent oxygen - you'd feel the difference.

The air is a little over thirty percent oxygen.

Their air is twenty-eight percent oxygen instead of twenty, but they could do very well on Earth.

After exercising, the athletes were provided with either room air or 100 percent oxygen.