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The Air Up There: A New Solution to the Olfactory Scourge of Flying

Even the most experienced scholar is often tempted to slide into social advocacy. I endeavor to maintain strict boundaries between my rigorous scholarship of gastrointenstinal humor and any formal statements weighing in on pressing public policy matters. For instance, I have pointedly refused to comment on the risks and rewards of maritime methane capture, and I have had to resort to the fire escape to avoid journalists seeking comment on Rudolph Giuliani’s diet. (An entirely speculative exercise and wholly without merit—but likely involving spring cabbage.)

Nonetheless, I can no longer remain silent on a matter where my intellectual expertise and public health intersect so dramatically. By now I assume you have already guessed the cause to which I must lend my name: confronting the crisis of commercial airline flatulence—or what my colleague D. Engber refers to as “mile-high miasma.”

Before I jump on the proverbial soapbox, however, let us first consider the science. Obviously, we start with “Flatulence on the Fly: Just Let It Go”(2013) – the groundbreaking study conducted by Kålspiser and her colleagues at the Instituttet Prutter in Copenhagen. As had long been suspected, if not so elegantly demonstrated, pressurized cabins in modern jet airplanes unfortunately create a highly conducive environment for releasing the Kraken. Kålspiser et al. were able to convince nearly 1,200 passengers on flights originating in Copenhagen to wear a series of gasopsamlingsposer – roughly translated as "personal gas collection bag" – during the flight, as well as for two days prior and subsequent to the flight. Further, they were able to substitute 593 in-flight chicken dinners with a mixture of roasted Brussels sprouts and fava beans, with a side of garlic-infused sourdough bread.

The results were stunning in their clarity: during the flight and for the ten hours following it, those who ate the Brussels sprouts mixture released between 30% and 86% more flatus than those who did not—and that flatus scored on average 73% higher on the Lifschitz Scale (a standard measure of pungency). But perhaps the more noteworthy result was the fact that all study participants—regardless of what meal they were given or indeed whether they ate anything on the flight—increased both the volume of their flatus and their Lifshitz score by an average of 23% and 33%, respectively, when compared to the volume and putridity of their thunders-down-under during the two days prior to the flight.

Kålspiser et al. speculate that pressurized cabins are largely the cause of this in-flight epidemic of personal contrails. “Pressure differentials,” they write, “may stimulate the flatutory organs while withholding flatus under pressurized conditions my cause significant discomfort.” The further discomfort of cramped quarters of modern aircraft, they continue, “likely compel air travelers to push through the social complications associated with the release of large quantities of acutely rancid flatus in order to seek a measure of relief.”

Here we should mention Hunfiser’s insight that advances in airliner noise-reduction have only heightened the crisis, as passengers are now more likely to catch wind (both sonically and olfactorally) of their neighbor’s emissions. (The rise of noise cancelling headphones, Igen and Prutt point out, somewhat diminishes the auditory risk.)

One airline memorably took the issue head-on. Finland’s Gaspar Air offered “Frequent Flatus Status” to loyal customers and briefly launched its After-Dinner Express Service from “Helstinki” to “Somewhere in the Netherlands.” Both services took it on the nose; they were soon discontinued.

Air travel may have diminished during the pandemic, but what flight attendants often refer to as “passengering gas” (or just “the gassengers”) has not—and anecdotal reports suggest that incidents of air rage are on the rise (see L. Berk’s editorial in the August issue of Post-Industrial Odors).

We can all point fingers about pulled fingers, but thankfully, a promising solution has emerged. In fact, the solution has been right there, under our very noses, for more than two decades. In 1998, the Minneapolis Veterans Affairs Medical Center identified a potent stench neutralizer: charcoal. Here we can see the methodology and results:

Flatus was quantitatively collected via rectal tube from 16 healthy subjects who ingested pinto beans and lactulose to enhance flatus output. The concentrations of sulfur-containing gases in each passage were correlated with odor intensity assessed by two judges. Odor intensity was also determined after treatment of flatus samples with zinc acetate, which binds sulphydryl compounds (hydrogen sulphide and methanethiol), or activated charcoal. Utilizing gastight Mylar pantaloons, the ability of a charcoal lined cushion to adsorb sulfur-containing gases instilled at the anus of eight subjects was assessed… The cushion absorbed more than 90% of the sulfur gases… Sulfur-containing gases are the major, but not the only, malodorous components of human flatus. The charcoal lined cushion effectively limits the escape of these sulfur-containing gases into the environment.

(For those readers who have not yet tried on gastight Mylar pantaloons, I can highly recommend them. However, I cannot unreservedly recommend serving as an “odor intensity” judge. I was asked to do so once at the Allamakee County All-Bean Festival in Waukon, Iowa, and had to resign my commission halfway through the Over-65 French Bean Soufflé Eating Freestyle.)

As for the public health solution, it lies buried in a footnote in Kålspiser’s brilliant study:

[I]f active charcoal were embedded in the seat cushion, this material may prove capable of neutralizing the most wretched stink. Moreover, active charcoal could be integrated into pants, sheets, and blankets to propagate this effect. Other less practical or politically viable solutions might include i) restricting flatus-prone persons’ access to airplanes by using a methane breath test or ii) permanently altering the fibre content of airline meals in order to reduce their explosive potential..

To which I can only add, “Hear, hear!”

Followed, inevitably, by, “Smell, smell!”


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