The Unfortunate Science of Gas at Altitude

When flying, you can’t blame the dog for flatus – but you can blame the laws of physics

Bodies are annoying. It’s just the truth. Yeah, yeah: Each is a miraculous machine operating at a level so close to perfection it may as well be magic, but also they’re awful; always having to pee or needing to eat; stubbing toes and demanding attention.

And for reasonable human beings with healthy amounts of shame, there’s no place where these annoyances are more apparent than on a plane. The way your body’s enormousness blocks the aisle as you try to shove your unco-operative backpack into the overhead compartment. The way it has to pee in the exact second your poor aisle-seated companion has settled down with a book. The length of your legs, the curve of your back, the weight of your head, all of it so painfully noticeable on a plane.

The worst one of all is feeling your guts suddenly fill with so much potent, embarrassing gas, you feel like you might actually be dying, the kind of pain that reminds you that you really should make a will, even if it’s just right now on an airplane napkin. Then you realize you have nothing of value to write down, so you wipe away a single tear and quietly decide that maybe it’s fine if you die of farts after all. Thanks for the reminder, body.

If you’re one of these people who expands like a matzo ball at high altitudes, know that you’re not alone. According to a study in The New Zealand Medical Journal, modern airplanes aim to maintain a pressure of around 565 mmHg, and though this pressure regulation helps prevent things like, you know, suffocating to death, it can’t prevent the increased volume of gas that accompanies decreased air pressure. Because that’s science. If you didn’t inflate with gas as the plane’s air pressure dropped, you’d be breaking the ideal gas law, a nearly two-century old scientific observation. It effectively tells us that as the pressure drops – which is what happens in an ascending airplane – volume increases. If you break this law you go to science jail, and while science jail is something I’ve just made up, I can tell you it’s not pretty.

“If you’re one of these people who expands like a matzo ball at high altitudes, know that you’re not alone.”

According to the New Zealand study, the real consequences of holding in this gas aren’t pretty either, with indigestion, discomfort and heartburn on the milder end of the spectrum, and elevated blood pressure and reduced oxygenation of the blood on the more serious end – a particular problem for passengers with pre-existing heart conditions. The study even suggests that regular gas retention can lead to other, more serious diseases in the intestines, and that for pilots, holding in gas can be a dangerous distraction.

All of that essentially means one thing: If you feel some unfriendly flatus (which is the high-falutin’ book learner’s name for an air biscuit) pawing at your back door, you better open up and let it scamper out. Luckily, your scientist friends in New Zealand knew you would wonder: “But how do I just brazenly pass gas on an airplane? The sound will be drowned out by the plane, but the smell, dear god, the smell! I can’t take the humiliation!” And that’s why science also offers solutions.

The main, and most reasonable solution, is active carbon, also known as charcoal: a super porous, odour-absorbing material that is in fact already in use on many airlines, incorporated into the filters in the plane’s air conditioning system, helping to refresh all that recycled air that would otherwise be just lousy with flatus. Many, including those cheeky New Zealand researchers, believe that incorporating more charcoal on the plane would help solve the shame associated with serving unsolicited bean bombs in public; charcoal blankets and cushions for example, or charcoal airline seats, which is apparently already something of an urban myth.

Another study, found via the U.S. National Center for Biotechnology Information, actually put some of these potential products to the test. After conducting what appears to have been a very thorough but also extremely unpleasant experiment on willing but perhaps insane subjects, using, shall we say, strategically placed tubes of sulphide gas to simulate flatulence, it was found that cushions absorbed less than 20% of the gas, blankets absorbed slightly more at 50%, but to those within smelling distance, neither could really be called a solution. There was one product however, that the study deemed “highly effective,” absorbing almost 100% of the sulphide gas. That product is charcoal underwear.

And lucky for the flatulent, there is a company producing just such a product: Gas B Gon ( makes an array of gas absorbing products, like the less effective but more reasonably priced personal cushions (because laying down a gas absorbing pillow before you sit is definitely less embarrassing than letting a few SBDs slip, right?) as well as the “highly effective” charcoal-infused “nether garments” which look just as flattering as they sound, and start at around US$65 per pair. Positive testimonials abound, and come from all over the world, written by long-suffering spouses, desk mates and children, as well as the flatulent themselves.

Other solutions suggested by the Kiwi researchers include limiting dairy intake before a flight, or increasing consumption of foods high in fermented soy, such as soy sauce because it helps fight gas-producing microbes, so now you know that.

Which is important. Because it seems that one thing all of the surprisingly plentiful literature on this topic can agree on is that, at least right now, the onus is on the flatulent to deal with their excess gasses, and not the airline. So though the studies confirm that your flatulence is not your fault, and that, in theory, everyone is suffering as you are, if you aren’t prepared to suffer the pain and discomfort of holding it in but you’re also tired of watching unassuming strangers scowl at your stench,  then it’s time to start exploring other options beyond simply offering up your barf bag.

The Unfortunate Science of Gas at Altitude
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