How Our Friend Ozone Turns on Us
Way up in the stratosphere, ozone (O3) absorbs deadly radiation from the sun, protecting all life on Earth. But don’t get too close! If we breathe ozone, it irritates our tissues, potentially causing respiratory problems.
Because commercial jets fly in the lower stratosphere, some of the “fresh” air flowing into planes contains ozone.
Ozone in cabin air causes some of the familiar discomforts of air travel: itchy eyes, a slight headache, trouble breathing, fatigue.
Your Greasy Skin Makes It So Much Worse
Your skin is constantly churning out fats and oils to keep itself moist. Unfortunately, ozone also reacts with substances in those oils, such as squalene, fatty acids, and cholesterol, creating compounds like aldehydes that are themselves known irritants.
So on planes you form your own personal pollution cloud that scientists call the “Pig-Pen Effect.”
What’s even grosser is that these skin oils rub off of you (and off the passengers that flew before you) onto seat fabrics and other surfaces. Even empty seats emit Pig-Pen pollution clouds for everyone onboard to inhale.
Are We Stuck Breathing Oily Ozone Air When We Fly?
Yes and No. Some planes have catalytic converters that quickly break down ozone into harmless oxygen before it enters the cabin. They work like the converter in your car that turns carbon monoxide and unburned hydrocarbons into oxygen, water vapor, and CO2.
Inbound air passes through a mesh inside the converter that’s coated in the catalyst, which grabs one of ozone’s oxygen atoms, letting a molecule of breathable O2 pass through. When another ozone molecule loses an oxygen atom to the catalyst, the two lone oxygens combine to form another molecule of breathable O2:
2O3 —-- > 3O2
But don’t get too comfortable…
Not every plane has one of these converters. Controlling cabin ozone is only mandated for flights over 4 hours.