It’s a cliched act of common courtesy to light a match after using the bathroom (or more specifically, after dropping a dirty bomb on Mount Porcelain). But how does that actually combat the stinky memories left behind by our behinds? By producing a smell that’s even more pungent!
During an episode of “Mythbusters,” the hosts pumped hydrogen sulphide and methyl mercaptan (smell-causing compounds that are found in both farts and feces) into a sealed chamber. They then measured the concentrations of these gases before and after lighting a match, and found that the accumulation of gases remained unaffected. This proves that lighting a match doesn’t either consume or eliminate these odorous compounds.
Instead, lighting a match produces sulphur dioxide, a smell-causing compound that’s even more pungent (and way more agreeable) than methyl mercaptan. “Sulphur dioxide smells completely different [than methyl mercaptan] and is much less unpleasant,” Jo Døhl, head of the Department of Chemistry at the University of Oslo, told ScienceNordic.
In other words, the odour-causing compounds found in farts and faeces are still present after lighting a match, but they’re disguised by the potent smell of sulphur dioxide. Most of the time, in fact, that’s enough to cover the smell altogether (and if it’s not, we recommend visiting your doctor in the near future).