Why do Farts Smell Worse in the Shower? – The Real Science
Have you noticed that your farts are extra pungent in the shower? There is a good bit of science behind the reason of why your farts smell worse in the shower. In this article, we are going to take an in-depth look at the science behind this phenomenon and find some of the specific factors that play a role in your shower farts being extra smelly.
Why do farts smell worse in the shower?
The moisture in the air allows the gas particles to travel quicker through the air and the warmer temperatures can increase the amount of gas released from your body. This amplifies the observed smell. The small, enclosed area, of the shower can trap the smell in making it more potent and last longer.
If you have ever wondered why your farts seem to have an extra kick to them while you are showering, read more to discover the surprising reasons that this phenomenon occurs.
Why Do Farts Smell Worse in the Shower?
This is not due to your imagination, your farts really are smellier when you are in the shower. There is real scientific evidence and proof to back this up. Before we get into the specifics behind why your farts smell worse in the shower, we have to first understand exactly what flatulence is and how it works.
The Science of Flatulence:
So, why do farts smell in the first place? Your farts are mostly made of gasses including nitrogen, carbon dioxide, hydrogen, and methane. There are also other gases that are commonly found in lesser amounts such as sulfide and ammonia.
Dimethyl sulfide, methanethiol, and hydrogen sulfide are the main gasses that actually make your farts smell. These gases are produced by bacteria in your colon during the digestion process.
Hydrogen Sulfide (H2S) – This gas is the most common and abundant gas that is associated with the foul smell of your flatulence. It is what is attributed to the “rotten egg” smell of your farts, and is an odor that can last in the air for a particularly long time.
Methanethiol (CH3SH) – This gas is the one that causes the smell of garlic or rotten cabbage. It is produced by the breakdown of sulfur-containing amino acids.
Dimethyl Sulfide (DMS) – Different from the other 2 gasses, this one actually has a musty odor that has been said to smell similar to decaying organic matter. This gas is produced by breaking down choline which is mostly found in foods such as eggs and liver.
In an average middle-aged man, the typical composition of these gasses is generally as follows:
Hydrogen Sulfide 0.05 – 1 PPM
Methanethiol 0.01 – 0.3 PPM
Dimethyl Sulfide – less than 0.1 PPM
If you are interested in learning more on why your farts smell, we actually have a complete write up on the science behind this right here in our Why do Farts Smell article.
Humidity:
When you take a hot shower both the temperature and the humidity in the air increases. The hot water vaporizes and releases water molecules into the air which increases the volume of water vapor available in the surrounding area. This increase in humidity, particularly, has increases your sense of smell as the odorous molecules dissolve easier in this type of environment.
A study done in 2019 by a team of researchers in Austria shows that the presence of water vapor in the air can have an enhancing effect on the detection of odor particles. More specifically, this study showed that there is a strong correlation between the detectability of the odor of butanol, in lower concentrations, and the increase in humidity within the immediate surroundings. This humid environment, as apposed to a dry one, increased the objective measurements of scent reception for this particular molecule.
This is attributed to the fact that odor molecules dissolve easier in water than they do in air. Thus the solubility of the particles increase which makes them more accessible to the olfactory receptors in the nasal cavity.
This overall concept is known as the “odor detection threshold”.
Peer reviewed academic literature reference:
Tauber, C., Brilke, S., Wlasits, P. J., Bauer, P. S., Köberl, G., Steiner, G., & Winkler, P. M. (2019). Humidity effects on the detection of soluble and insoluble nanoparticles in butanol operated condensation particle counters. Atmospheric Measurement Techniques, 12(7), 3659-3671.
Temperature:
It is a well-known scientific fact that an increase in temperature effects chemical reactions. This concept is taught in both general chemistry and biochemistry in the earlier years of college studies.
The volatility of the chemical reactions is increased in direct, and measurable, correlation to an increase in the systems surrounding temperature. This means that an increase in the temperature of either the fart itself, or the environment will both increase the vapor solubility rate. This will lead to the stench being more noticeable to your olfactory receptors as well.
Not only this, but an increase in heat can also cause the gasses that a fart is comprised of to undergo different chemical reactions than they otherwise would. These gasses such as nitrogen, carbon dioxide, oxygen, methane, and hydrogen can further produce odorous compounds from this increase in heat.
Some of these compounds that can cause odor as a resulting product are:
Methanethiol – This is often a product of methane in the presence of heat.
Dimethyl sulfide – This compound can be produced by adding heat to certain sulfur-containing compounds.
Carbon disulfide – If a carbon containing compound is heated in the presence of sulfur, this is often a product.
Ammonia – This is produced when nitrogen-containing compounds are heated. This includes amino acids.
Hydrogen sulfide – This can be produced as the result of a sulfur-containing compound being heated. This includes cysteine, which is found in many foods such as eggs, meat, dairy, and more.
As well as these other factors, an increase in heat may often lead to an increase in bacterial activity. If there is a significant enough increase in temperature the bacteria that call the intestinal tract home will show changes in metabolic activity. An increase in temperature can easily stimulate the growth of many bacterial species within your intestines as well as inhibiting others.
This change in heat within the intestines can also change the pH levels, oxygen saturation, and bioavailability of nutrients within the intestines themselves. This can change the environment that these bacteria live within your intestinal tract. Not to mention the fact that some species of bacteria actually produce toxins in the presence of higher temperatures. I.e. Clostridium difficile is known to produce 2 major toxins that can cause inflammation and damage to the lining of the gut when exposed to high heat for an extended period of time. These toxins can cause diarrhea and other gastrointestinal issues.
Toxin A (TcdA) and Toxin B (TcdB) are the 2 toxins released by the heating of the bacterial species Clostridium. TcdA is a large protein that binds to receptors and triggers inflammation responses from the body. This process can be harmful to the lining of the gut and cause breakdown of the barrier which will, in turn, let other bacteria through. TcdB is another large protein that acts by disrupting the actin cytoskeleton of cells. This hinders the cell from keeping its correct shape and performing its proper functions and can even lead to full cell death.
Not only are these toxins able to make your farts stink worse, but they can also cause diarrhea, abdominal pain, and fever. In some cases, though much more rare and severe, it can actually lead to pseudomembranous colitis, toxic megacolon, or even sepsis. These can be deadly.
Peer reviewed academic literature reference:
Chumbler, N. M., Farrow, M. A., Lapierre, L. A., Franklin, J. L., & Lacy, D. B. (2016). Clostridium difficile toxins TcdA and TcdB cause colonic tissue damage by distinct mechanisms. Infection and immunity, 84(10), 2871-2877.
Close Proximity:
The concentration of odorants increases with the enclosed space and close proximity of a shower. The Volatile Organic Compounds (VOCs) that make up your fart are usually of the sulfur-containing variety. These VOCs generally have a lower molecular weight than the others, which means that the substance will have increased volatility as well as a lowered boiling point. Both of these factors play their own roles in giving the compound the tendency to stay in the surrounding air longer.
These sulfur-containing compounds, such as hydrogen sulfide and sulfur dioxide, have lower molecular weights and similarly weaker intermolecular forces holding them together. This means that it is easier for them to be distributed into the air, stay aerosolized, and reach your nose for an extended period of time.
This is in stark contrast to heavier and more complex molecular compounds that have stronger intermolecular forces. The heavier compounds more readily condense together and settle out of the air at a quicker chronological pace.
The molecular weight of the VOCs:
Hydrogen sulfide (H2S) – 34 g/mol (found in farts)
Methanethiol (CH3SH) – 48 g/mol (found in farts)
Dimethyl sulfide (DMS, (CH3)2S) – 62 g/mol (found in farts)
Sulfur dioxide (SO2) – 64 g/mol (not found in farts)
Benzene (C6H6) – 78 g/mol (not found in farts)
Toluene (C7H8) – 92 g/mol (not found in farts)
Notice the molecular compounds that all have the lowest molecular weights are found in farts, while those at the bottom of the list with the higher molecular weights are not found in farts. This means that’s the actual molecular makeup of your farts provides the perfect vehicle for the smell to stay in the air for as long as possible. This coupled with the fact that the shower is a small location, and often a closed system at that, means that you will smell the fart more significantly and for longer.
Being in a, functionally, closed system such as a shower; there is often a lack of air circulation. This lack of air circulation adds to the stagnation of the odorants in the air which hinders the process of dissipation in comparison to an open environment that is well ventilated.
In addition to the increased time in which you are surrounded by the odors as well as the concentration and lack of ventilation, there is the psychological aspect to take into consideration as well. If you are in close proximity to someone that has just farted, or you have just farted in a small enclosed space, it is likely that your perception of the smell will be more dramatic than if you were able to move or “escape” the smell. It has been proven in studies that smells and other sensory inputs can seem stronger and more pleasant/unpleasant within a closer proximity.
Not only this, but the book entitled ‘Olfaction, taste, and Cognition’ states that there are “Far” senses and “Near” senses. It speaks on how sensory input from our eyes and ears are what we use to obtain special information from a greater distance, and senses such as smell and touch are for closer proximity information. This means that the closer you are to whatever source of the smell is in the air, the stronger the emotional and physiological response will be because of it.
Academic literature reference:
Olfaction, Taste, and Cognition - Google Books
Köster, E. P. (2002). The specific characteristics of the sense of smell. Olfaction, taste and cognition, 27-43.
Increased Relaxation:
Simply put, being more relaxed means, you can fart more. The volume, frequency, and odor of your farts can all increase if you are more relaxed. Even without the direct odor increase, the sheer volume and frequency increase of the farts will increase the odor as well due to the surge of VOCs in the air.
When you are relaxed it allows your digestive system to slow down and take its time throught its process of breaking down foods. This means that the food will stay in your intestines longer, which will likely result in more gas being produced by the bacteria talked about earlier in this article.
This is a good thing, but it can absolutely mean more farts and a smellier time in the shower for you.
Being Naked:
When you fart with clothes on, the fabric that your clothes are made of actually absorb some of the VOCs from your fart. When you are in the shower you are, hopefully, naked. This means that you lack the fabric that generally absorbs some, but not nearly all, of the odor from the fart itself. Clothing, while often times minimal, does play a role in how smelly a fart is to you and the people around you.
How do You Reduce Fart Odors in the Shower?
Use a fan & open a window:
As you saw in one of the earlier sections in this article, a main issue with the smell of farts in the shower is the lowered level of ventilation. To fix this, you should incorporate a fan or open a window. The best thing that you can do is actually open a window and place the fan inside of the window pointing outwards. This will not only pull the VOCs out of the shower room, but it will also lower the humidity which is another major factor as to why farts smell worse in the shower.
Time Your Shower:
This may sound silly to you, but if you time your shower properly around your bowel movements you can actually avoid much of those smelly shower farts. If you take a shower after you have had a bowel movement you will be much less likely to fart while you are in the shower. You will have expelled most of the gas during the bowel movement, thus providing yourself ample time to take your shower with little to no gas expulsion.
Use Candles:
Using scented candles can be a great “two birds with one stone” scenario for you. The fire from the candle wick will aid in breaking down some of the odor-causing compounds within the gasses. Not only this, but the scented aspect to the candle will add a positive smell into the air which will help mask the unwanted odors from the flatulence. This is a really great reason to go to Yankee Candle (not sponsored).
Recap & Summary:
Farts can surely smell bad pretty often, but they can be especially smelly in the shower. While they are a natural part of life and the digestion process, you may feel the desire to avoid the smell of them while you are in a hot relaxing shower. The factors that mainly play a role in the smell of a fart being so bad in a shower is the increased humidity, temperature, relaxation, and close proximity.
Learning these key aspects as to why your farts smell worse in the shower will provide you with the necessary information to help you reduce the smell of your next relaxing bathing session. Make sure you focus on your health and your farts will be exactly how they are supposed to be. Don’t be embarrassed, everyone does it.
Hopefully you learned a lot about farts and you enjoyed this article. If you did, and you want to read more like it, there are actually plenty of other articles just like this right here in our Science Category. If you just want to read about farts some more, we have started an All About Farts Category just for you.
Thank you so much for taking the time out of your day to read this article! : )