Hate to break it to you, toilets aren’t airtight. The particles go right out the side and tend to last longer in the air when the lid is down. It’s creates a reduction in visible particles as it seems the lid causes bigger particles to form so ergo less “visible particles” but they are just bigger and last longer for some reason versus the smaller ones. As has been demonstrated by the Mythbusters and many other studies, the biggest factor is having proper ventilation otherwise your gonna find shit particles everywhere regardless of if you close the lid or not.
For reducing visible particles, not the nano particles which have a higher concentration. Regardless it’s all kinda moot as neither produce levels of bacteria that could realistically get you sick unless you stick your face above the bowl or to the side openings by the lid while flushing and that person has an infecfion. Just wanted to clarify the science behind it.
The highlighted section of that link reads as follows:
The research found that putting the toilet lid down reduced the number of both visible and smaller droplets during and after flushing by 30-60%. However, use of the lid also increased the diameter and concentration of the bacteria in these droplets.
The article doesn’t indicate whether the total bacteria contained in the now larger and more concentrated droplets is thought to be comparable to that contained in the full spray of open-lid droplets, which means a precise comparison isn’t available, so technically I guess it could go either way. However, common sense tells us that many of those microorganisms will either get stuck to the underside of the lid or fall back into the water, so it seems nearly impossible that closed-lid flushing could spray 100% of the microorganisms that open-lid flushing does, right? So if the best (seemingly unlikely) scenario for open-lid flushing is that maybe it only sprays the exact same number of farticles into the air, then what’s the appeal?
That’s not making sense to me. Would you be willing to find your sources? Larger particles would not spend more time in the air as far as I know. It’s almost like you’re claiming it’s better to sneeze wild straight out everywhere instead of into your elbow, handkerchief, or tissue.
But that applies to most commercial toilets with high flow rate. Most home toilets don’t do much more than let gravity do the work. There’s no aerosolized particles, just a few splashes or droplets that may escape
Home toilets use the bowl filling up to create a siphon through the drain trap. For that to work your toilet must first raise the water level above the top of the trap to create the pressure with its weight to start the siphon. I.e with the lid closed you are forcing more air to compress in a smaller volume generating a pressure difference outside the bowl and internally. Leave the lid open and that volume of air goes directly into the room without much resistance creating less pressure in the bowl compared to the surrounding air in the room. Hence with the lid open the distance, the spray travels is lower as it has a lower velocity.
That air pressure doesn’t mean anything without aerosolized particles. High rate commercial toilets create those particles and spew them out at like 6 ft/sec. Draining the tank into the bowl does not create much except maybe a few larger droplets once the drain takes most of the contents that can’t go as far, and that is mitigated by closing the lid.
Correct which is why in addition studies show that having the lid down increases the concentration of those aerosolized bacteria and increases the distanced traveled while also allowing them to linger in the air for up to 11minutes longer. The lid down causes the particles to break up into nano particles which are not visible, but linger longer and spread farther.
A shared university toilet can still be part of a house or low pressure system. I’ve yet to see public restrooms which had a lid for the toilet itself, outside of low pressure toilets in communal housing. If you can link to where they clarified the shared university toilet was high pressure, I will stand corrected.
The reduced airspeed of the shit particles thanks to the closed lid slows the buildup of shit particles on bathroom surfaces enough for my regular cleaning to be sufficient
This would be a good experiment for Myth busters. I’d imagine that with the lid closed the increase in pressure would not be significant and the air particles would be accelerated more horizontally as opposed to vertically. This would, theoretically, cause them to accumulate more on surfaces below countertop level than above.
How does flushing water create air pressure? Are you using a steam toilet? Are you acoustic?
Did you just try to call me dumb when you don’t understand physics?
Here’s a little science experiment and explanation for you:
Water in a toilet bowl first rises as the flush begins before it over comes the pressure in the drain trap. Close the lid, more air is squeezed out the sides of the toilet for a moment as that happens, leave the lid up and you have a larger volume for the air to be offset in. Don’t believe me, flush the toilet with the lid down, wet a finger with water slightly and put it near the opening between the lid and the bowl, you will feel it cool down from the air escaping. Do the same now with the lid open and you will notice this effect less. Obviously do this with a clean toilet and wash your hands afterwards but you will notice the pressure difference in the beginning.
I just did this experiment with a lighter held next to the seat gap, which is a simple but sensitive test of boundary air displacement, and there was zero movement. This is complete nonsense.
Honestly don’t worry, as Mythbusters pointed out that neither are a health concern due to the low concentration relatively speaking and if anything it helps your immune system build up defenses against E coli and the like. Just know lid up during your flush means the sent lingers less. Then after the flush I would advise closing the lid to keep any lingering sent in the air of the toilet bowl and less likely to be disturbed by any airflow in the room. Just don’t like seeing misleading info spread around as honestly the science behind it is pretty interesting.
I don’t know whether it’s an issue with the website, but currently I can’t see much else besides some text which sounds like an abstract. This makes it currently difficult to see this as a good source or estimate the quality of the work. Judging on this abstract alone, although it mentions that the time particles are detectable is about 10 minutes longer with the lid down, it also reports a 30 to 50 % decreased amount of particles. It also states a lack of research regarding smaller particles.
As far as I can see we could safely say, that this issue, whether it’s better to keep the lid up or down, is still debated and a final verdict is still out:
Hate to break it to you, toilets aren’t airtight. The particles go right out the side and tend to last longer in the air when the lid is down. It’s creates a reduction in visible particles as it seems the lid causes bigger particles to form so ergo less “visible particles” but they are just bigger and last longer for some reason versus the smaller ones. As has been demonstrated by the Mythbusters and many other studies, the biggest factor is having proper ventilation otherwise your gonna find shit particles everywhere regardless of if you close the lid or not.
Every source I can find says that closing the lid is better.
For reducing visible particles, not the nano particles which have a higher concentration. Regardless it’s all kinda moot as neither produce levels of bacteria that could realistically get you sick unless you stick your face above the bowl or to the side openings by the lid while flushing and that person has an infecfion. Just wanted to clarify the science behind it.
https://microbiologysociety.org/news/society-news/does-putting-the-lid-down-when-flushing-the-toilet-really-make-a-difference.html#:~:text=The research found that putting,the bacteria in these droplets.
The highlighted section of that link reads as follows:
The article doesn’t indicate whether the total bacteria contained in the now larger and more concentrated droplets is thought to be comparable to that contained in the full spray of open-lid droplets, which means a precise comparison isn’t available, so technically I guess it could go either way. However, common sense tells us that many of those microorganisms will either get stuck to the underside of the lid or fall back into the water, so it seems nearly impossible that closed-lid flushing could spray 100% of the microorganisms that open-lid flushing does, right? So if the best (seemingly unlikely) scenario for open-lid flushing is that maybe it only sprays the exact same number of farticles into the air, then what’s the appeal?
Hmh, what do we make of that?
Simulation from 2020: https://doi.org/10.1063/5.0013318
Laser supported analysis from 2022: https://doi.org/10.1038/s41598-022-24686-5
That’s not making sense to me. Would you be willing to find your sources? Larger particles would not spend more time in the air as far as I know. It’s almost like you’re claiming it’s better to sneeze wild straight out everywhere instead of into your elbow, handkerchief, or tissue.
But that applies to most commercial toilets with high flow rate. Most home toilets don’t do much more than let gravity do the work. There’s no aerosolized particles, just a few splashes or droplets that may escape
Home toilets use the bowl filling up to create a siphon through the drain trap. For that to work your toilet must first raise the water level above the top of the trap to create the pressure with its weight to start the siphon. I.e with the lid closed you are forcing more air to compress in a smaller volume generating a pressure difference outside the bowl and internally. Leave the lid open and that volume of air goes directly into the room without much resistance creating less pressure in the bowl compared to the surrounding air in the room. Hence with the lid open the distance, the spray travels is lower as it has a lower velocity.
That air pressure doesn’t mean anything without aerosolized particles. High rate commercial toilets create those particles and spew them out at like 6 ft/sec. Draining the tank into the bowl does not create much except maybe a few larger droplets once the drain takes most of the contents that can’t go as far, and that is mitigated by closing the lid.
Correct which is why in addition studies show that having the lid down increases the concentration of those aerosolized bacteria and increases the distanced traveled while also allowing them to linger in the air for up to 11minutes longer. The lid down causes the particles to break up into nano particles which are not visible, but linger longer and spread farther.
https://microbiologysociety.org/news/society-news/does-putting-the-lid-down-when-flushing-the-toilet-really-make-a-difference.html#:~:text=The research found that putting,the bacteria in these droplets.
It appears they studied a shared university toilet, likely not a common household unit. The further study that it references I found here
This is referencing hospitals, again not home toilets. I’ve yet to see any actual info on standard low pressure toilets.
A shared university toilet can still be part of a house or low pressure system. I’ve yet to see public restrooms which had a lid for the toilet itself, outside of low pressure toilets in communal housing. If you can link to where they clarified the shared university toilet was high pressure, I will stand corrected.
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The reduced airspeed of the shit particles thanks to the closed lid slows the buildup of shit particles on bathroom surfaces enough for my regular cleaning to be sufficient
The closed lid increases air speed, not decreases it as you create a higher build up of pressure 🤦♂️
This would be a good experiment for Myth busters. I’d imagine that with the lid closed the increase in pressure would not be significant and the air particles would be accelerated more horizontally as opposed to vertically. This would, theoretically, cause them to accumulate more on surfaces below countertop level than above.
But I have no data to support this hypothesis.
They did test it years ago lol and confirmed that closing the lid did not have a benefit.
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Did you just try to call me dumb when you don’t understand physics?
Here’s a little science experiment and explanation for you:
Water in a toilet bowl first rises as the flush begins before it over comes the pressure in the drain trap. Close the lid, more air is squeezed out the sides of the toilet for a moment as that happens, leave the lid up and you have a larger volume for the air to be offset in. Don’t believe me, flush the toilet with the lid down, wet a finger with water slightly and put it near the opening between the lid and the bowl, you will feel it cool down from the air escaping. Do the same now with the lid open and you will notice this effect less. Obviously do this with a clean toilet and wash your hands afterwards but you will notice the pressure difference in the beginning.
I just did this experiment with a lighter held next to the seat gap, which is a simple but sensitive test of boundary air displacement, and there was zero movement. This is complete nonsense.
Sosca the Science Guy!
☹️ thanks for letting me know
Honestly don’t worry, as Mythbusters pointed out that neither are a health concern due to the low concentration relatively speaking and if anything it helps your immune system build up defenses against E coli and the like. Just know lid up during your flush means the sent lingers less. Then after the flush I would advise closing the lid to keep any lingering sent in the air of the toilet bowl and less likely to be disturbed by any airflow in the room. Just don’t like seeing misleading info spread around as honestly the science behind it is pretty interesting.
I don’t want to step on your toes, so hopefully this doesn’t come across that way:
You mentioned Myth Busters and an article from 2019 on microbiologyresearch.com in another comment .
Let’s just say without further elaboration, that Myth Busters are not a solid scientific source.
I couldn’t really find a paper from the article you linked in another comment. Just this: https://www.microbiologyresearch.org/content/journal/acmi/10.1099/acmi.fis2019.po0192
I don’t know whether it’s an issue with the website, but currently I can’t see much else besides some text which sounds like an abstract. This makes it currently difficult to see this as a good source or estimate the quality of the work. Judging on this abstract alone, although it mentions that the time particles are detectable is about 10 minutes longer with the lid down, it also reports a 30 to 50 % decreased amount of particles. It also states a lack of research regarding smaller particles.
As far as I can see we could safely say, that this issue, whether it’s better to keep the lid up or down, is still debated and a final verdict is still out:
https://doi.org/10.1016/j.jhin.2011.08.010
https://doi.org/10.1063/5.0040310
https://doi.org/10.1063/5.0013318
https://doi.org/10.1038/s41598-022-24686-5
However, to me it seems that there are indications that a combination of proper ventilation and closing the lid might be better than an open lid.
Disclaimer: Not my field of expertise. Feel free to correct, where necessary.
Yeah, but now I’ve lost an argument with my wife… She remembered too…
Not necessarily. See my discussion in the same comment level.