Oxygen masks are critical because they provide vital supplemental oxygen when the surrounding air pressure is too low to get enough oxygen naturally, preventing unconsciousness, brain damage, or death.
At high altitudes, such as those flown by commercial aircraft, the atmospheric pressure is significantly lower than at sea level. This lower pressure means there are fewer oxygen molecules available in the air you breathe, even though the percentage of oxygen remains the same. Breathing this thin air leads to a condition called hypoxia, which is a deficiency of oxygen reaching the body's tissues.
Hypoxia is particularly dangerous at high altitudes. Without supplemental oxygen, the body cannot function properly. Symptoms can include dizziness, confusion, headache, nausea, and a false sense of well-being or euphoria. Crucially, the time someone can remain conscious and take action (known as "useful consciousness") is severely limited at high altitudes if they are not breathing supplemental oxygen.
The Danger of Decompression at High Altitude
A sudden loss of cabin pressure, known as rapid decompression, is a critical scenario where oxygen masks are essential. According to Airbus, if a plane loses pressure at 40,000 feet, those on board have as little as 18 seconds of “useful consciousness” without supplemental oxygen.
This is an extremely short window. Once the initial feeling of euphoria passes, hypoxia quickly sets in, rendering a person unconscious. Prolonged lack of oxygen due to hypoxia can cause brain damage or death. Therefore, in such emergencies, immediately putting on the oxygen mask and ensuring it is functioning correctly is a matter of survival. The mask delivers a breathable oxygen mixture at a sufficient pressure to counteract the effects of the thin ambient air, restoring the supply of oxygen to the brain and vital organs.
Key Reasons Oxygen Masks are Important
- Preventing Unconsciousness: They supply the oxygen needed to maintain consciousness when ambient air pressure is too low.
- Allowing Time for Action: They give individuals the useful consciousness needed to follow safety procedures and for the flight crew to descend to a safe altitude.
- Protecting Brain Function: By preventing severe hypoxia, they protect against potential brain damage.
- Ensuring Survival: Ultimately, wearing the mask in a low-pressure environment, like a depressurized aircraft cabin, is vital for preventing death.
In summary, oxygen masks are life-saving devices that provide necessary oxygen in environments where the air pressure is too low to sustain consciousness and life, such as during an aircraft depressurization event at high altitude. This prevents the severe consequences of hypoxia, including unconsciousness, brain damage, and death. So, as the guidance often states, wear the mask.
