What makes stink bombs stink

The gas expands and ultimately pops the outer bag, releasing the unpleasant odor. Ammonium sulfide and hydrogen sulfide are the most common ingredients in stink bombs, but many other smelly chemicals may be used. Most odoriferous compounds are organic, but some are inorganic:. When used as directed, stink bombs are not dangerous. The small quantities used in a single stink bomb may cause eye or skin irritation, which should resolve within 72 hours 7 days or severe eye exposure. However, the safety relies on the small dose of a single stink bomb and brief exposure.

Stink bomb compounds are toxic at high concentrations or after prolonged exposure at low concentrations. Some chemicals, such as hydrogen sulfide, are flammable. Using too many stink bombs at once can be dangerous.

The safest and easiest stink bomb is the classic rotten egg version. Then, you can either throw the egg or else puncture the shell with a pin and leave it to do its work.

The human body produces small amounts of hydrogen sulfide. However, hydrogen sulfide is toxic and flammable. Rotting seafood is an alternative to the rotten egg. At the other end of the spectrum, the governments of Israel and the United States of America are developing stink bombs for use by their law enforcement agencies and militaries as riot control and area denial weapons.

Using stink bombs for these purposes have advantages over traditional riot control agents : unlike pepper spray and tear gas, stink bombs are believed not to be dangerous, and they are effective at low concentrations.

Typically, lower molecular weight volatile organic compounds are used. Generally the higher molecular weight for a given class of compounds, the lower volatility and initial concentration but the longer persistence. It should be noted that some chemicals typically thiols have a certain concentration threshold over which the smell is not perceived significantly stronger; therefore a lower-volatility compound is capable of providing comparable stench intensity to a higher-volatility compound, but for longer time.

Another issue is the operating temperature, on which the compound's volatility strongly depends. Care should be taken as some compounds are toxic either in higher concentration or after prolonged exposure in low concentartion. Category : Chemical weapons. Read what you need to know about our industry portal bionity. My watch list my. My watch list My saved searches My saved topics My newsletter Register free of charge.

Keep logged in. Cookies deactivated. To use all functions of this page, please activate cookies in your browser. Login Register. The smell activated both amygdalae, but the more revolted and fearful people felt, the more active their left amygdala became. How we perceive and respond to a smell depends on whether we recognise it and what sort of associations it has.

Humans have an extraordinary memory for smells, and just a whiff of something can bring past experiences rushing back. A smell can be enough to revive old terrors. If you can't categorise it you don't know if it's dangerous.

There's little you can do but run away. The perfect stink would trigger an emotional response-preferably one that sets you running-before the reasoning part of the brain can work out what's going on. In theory, it's possible. The hard part is finding one smell that works on everyone. There's little evidence that humans are born with preferences for certain odours, the way they are with tastes.

But even if people are, these preferences can easily be overcome by experience. Some people even like the smell of skunk," says Dalton. People's likes and dislikes also vary enormously between cultures. To people in South-East Asia, for example, the fetid smell of the durian fruit holds the promise of something delicious.

To almost everyone else, it's stomach-churning. At Monell, Dalton and her team have been searching for a stench that transcends any cultural differences. They tested a range of horrible smells on five groups of volunteers of different ethnic origin-whites, African-Americans, Asians and Hispanics from the Philadelphia area, and a group from the township of Grahamstown in South Africa's Eastern Cape province. Dalton's team quizzed the volunteers on the repulsiveness of each stench, how it made them feel and whether they thought it was harmful.

And as the volunteers breathed in the foul odours, the researchers logged their bodies' physiological responses. They found that with the vilest smells, people take shallower breaths, their hearts beat faster, and their stomachs churn more vigorously. Most of the bad odours they tested proved disappointing. Everyone hated the smell of butyric acid-a cross between rancid butter and sweaty feet-but few people thought it was harmful.

Burnt hair, supposed to mimic burnt flesh, turned out to be surprisingly inoffensive. Even the smell of vomit-an off-the-shelf mix called Proprietary Vomit Odor-was only mildly objectionable.

The response to one of Monell's special mixtures revealed a major cultural difference. This odour was developed to mimic the smell around sewage treatment plants and is reminiscent of gently decaying rubbish with a hint of faecal matter. Everyone found it disgusting, but the people from Grahamstown were also afraid of it.

They think breathing it would be harmful. But Dalton did find two loathsome odours that transcend culture.

One is a truly repugnant mixture called US Government Standard Bathroom Malodor, a stink concocted to test the efficiency of deodorant cleaning products. It fills your head. It gets to you in ways that are unimaginable. It's not something you are likely to come across in the real world. Even though the smell is quite harmless, almost everyone thought it would damage their health.

Dalton wasn't surprised. This classic has a bouquet rich with foul-smelling molecules, dominated by a sulphurous pong.