The topic of endless schoolboy jokes, it can be intensely embarrassing when it happens involuntarily. It caused Nasa some concerns in the 60s, when engineers speculated that the build-up of astronaut gases might cause an explosion in one of the spacecraft. Their research revealed that the average bloke emits about 200ml of gas a day, but that some produce up to two litres.
The gas is produced mainly by bicarbonate in your saliva combining with acids during digestion to produce carbon dioxide gas. The digestion process also produces nitrogen, methane and hydrogen gas, and small amounts of sulphur gas which have a smell out of all proportion to their presence in the gut. Bacteria in the lower bowel thrive on carbohydrate-rich foods, which ferment to produce pungent farts.
To reduce your risk of being a biological hazard:
- Wash all pulses such as beans, peas and lentils thoroughly before cooking them;
- Avoid chewing gum and drinking carbonated drinks, and don’t gulp down hot beverages;
- Get regular exercise;
- Take a charcoal tablet before each meal. Charcoal absorbs the smell and passes through your system without being absorbed;
- Carry a box of matches. Lighting one every time your trousers cough neutralises the smell. We don’t advise this in a spacecraft, but it’s fine at home.
(William Smook, Health24, updated January 2009)