Airplane Oxygen Mask
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We’ve all heard the warning: “In case there is a loss in cabin pressure, yellow oxygen masks will deploy from the ceiling compartment located above you ... Please make sure to secure your own mask before assisting others.”

The same script is repeated on airlines around the world, often ignored passengers listening to music, reading a magazine, or texting on the phones they're about to have to switch to airplane mode.

But understanding how these masks work may one day save your life.

The first thing to note, however, is that crashes from pressure issues on an airplane are exceedingly rare, even if an airplane cabin is punctured, Patrick Smith, a pilot and author of Cockpit Confidential, recently explained to The Telegraph.

“If cabin pressure falls below a certain threshold, the masks will deploy from the ceiling, exposing everybody to the so-called ‘rubber jungle’” Smith said. “Should you be confronted by this spectacle, strap your mask on and try to relax. The plane will be at a safe altitude shortly, and there are several minutes of backup oxygen for everybody.”

Because although oxygen masks and an emergency landing are frightening to passengers, pilots are trained to handle just such situations.

But just how much time will those oxygen masks buy you? According to io9, each plane carries enough oxygen to last each passenger up to 20 minutes. Moreover, it’s not exactly oxygen you’re breathing in, but rather a chemical compound that becomes oxygen once it’s burned. As the Telegraph explained, most planes carry a concoction of barium peroxide, sodium chlorate, and potassium chlorate.

While it may not sound ideal to breathe in chemicals, it’s most certainly a better alternative to losing consciousness or even dying. If you refuse to put on the mask you’ll likely suffer from hypoxia, or a lack of oxygen, in under 30 seconds.

According to Airbus, passengers have about 18 seconds of “useful consciousness” if a plane loses pressure at 37,000 feet. That makes it incredibly important to do exactly as the instructions say: Pull down on the mask, place it over your nose and mouth, and only then assist others around you.