Real-time monitoring of aerosols generated from toilet flushing | Hacker News Reader

Real-time monitoring of aerosols generated from toilet flushing

microbiologyresearch.org

90 pointsthunderbong56 comments

Do we have any data about people actually becoming sick because of toilet flushing aerosols? Everyone enters bathrooms and flushes multiple times per day, but is not constantly sick. So is this actually a problem or just "gross if you think about it"?

I’m guessing the latter.

My gut reaction to this was “why bother.” But even if a pathogen isn’t spread via toilet water aerosol today, it doesn’t mean a new pathogen can’t emerge that could use this transmission vector in the future.

That said, a virus that spreads in this manner should be containable by having some kind of sterilization agent in the toilet water (already commercially available products you can use that adds bleach (or similar) to the water. Typically a slowly dissolving brick of chemical added to the back of your toilet

> My gut reaction

I see what you did there

Maybe it is a bigger issue for people with weak immune systems?

I think the pandemic has taught us that our infrastructure is not well designed to prevent the spread of disease, and that investment in this area can help prevent future pandemics. We used to treat people getting sick as a normal course of life, but obviously people are getting sick from somewhere. The more we can do to prevent that the better quality of life people will have. And more importantly, the harder it will be for potential pandemics to take off. For example we can do a lot to improve building ventilation, which would help reduce transmission of airborne disease like covid.

> I think the pandemic has taught us that our infrastructure is not well designed to prevent the spread of disease, and that investment in this area can help prevent future pandemics.

The only thing the pandemic has taught me is that other people were getting me sick (at work and/or gym, most likely).

I have not been sick with any respiratory sickness (even common cold) since the beginning of COVID, mostly due to going remote.

> The only thing the pandemic has taught me

I bet you have learned more than one thing from the pandemic.

They might have known everything already before ;)

Aren’t we the eternal optimist today! Ah, to have that kind of faith in humanity again.

Shocker- humans are the primary vector for human pathogens.

So, yes, isolation from humans (and animals) will drastically reduce your exposure to pathogens. And probably, joy, fulfilment, and worthwhile experiences as well.

But, you’re not wrong. And for many people, going into work is a bullshit requirement. Remote work FTW.

Maybe we are relatively constantly sick and simply don’t know any different.

Toilets improve hygiene relative to not having them, but it may be that they increase disease in another way which we have not detected yet.

Simple solution is to always put the lid down. Bonus it settles the "seat up vs seat down discussion", with a draw where everybody has skin in the game. I believe it helps keep my immune reserves up stronger by having less busy work. I also keep by toothbrush outside the bath room too.

That is not how the immune system works.

> So is this actually a problem or just "gross if you think about it"?

The latter.

Everyone should have the experience of opening a petri dish literally anywhere and then incubating it.

You can't catch something from crap that the crapper didn't already have, and most people use the bathroom in private if they can, where you're mostly only exposed to stuff from household members.

In public it might be an issue.

If anyone wants a visual example of what happens, do a search for "toilet green laser":

* https://www.youtube.com/watch?v=aDIIhzc-FWg

* https://www.youtube.com/watch?v=hTojTHjUckA

Ignorance is bliss

What kind of toilet is that? If you ever wrapped the toilet seat with cling wrap (no judging of why you would do this), you can see how many droplets are on the wrap after the flush. The toilet in the YT videos looks like it's been modified to prove a point.

Commercial, not residential.

"Commercial toilets emit energetic and rapidly spreading aerosol plumes":

* https://www.nature.com/articles/s41598-022-24686-5

E.g.

* https://www.americanstandard-us.com/Toilets-Commercial/Mader...

* https://www.kohler.com/en/products/commercial/shop-commercia...

Please ignore my ignorance in ... the science of toilets, for lack of a proper term ... but these look like regular US-toilets to me. I believe them to be US-toilets, because the seats are missing the front section.

Can you please explain?

Residential toilets only use gravity to flush. Water flows down from the tank into the bowl.

Commercial toilets use water pressure which helps clean the bowl with a jet of water but will also create much more of a spray outside the bowl.

In many (perhaps most?) countries there is not a distinction between commercial and residential toilets, I rarely see any here that aren't gravity flushed.

I remember the first time going into public toilets in the US (at LAX) and I went into a cubicle and thought I'd picked one with a broken toilet - the bowl was full of water!

Wikipedia provides a good introduction into the many kinds of toilet designs found around the world. The U.S.-american residential style with lots of water floating high ip in the bowl, as well as the high-pressure flushing system straight from the pipe are uncommon in most continents. There DIN-norms about „Flachspüler“ and „Tiefspüler“-style toilets e.g. in Germany.

My favourite: Japanese „tornado flush“ style toilets. Optional with built-in bidet or „washlet“. There seems to be zero aerosols and it flushes clean more consistently than others.

[0] https://en.wikipedia.org/wiki/Flush_toilet

[1] https://eu.toto.com/de/produkte/randlose-wcs

Home toilets have the front section

Kind of looks like you’d need to stick your head on top of the toilet while flushing to be affected.

If you feel that confident about it, move your toothbrush closer to your toilet.

Flushing the toilet is something we do 2-4 times per day for all our lives with no real side effects. This "information" is only scary to people who'd rather live in a sterile capsule (usually people having some heavy psychological fear issues).

Wait till they learn there are all kinds of particles from their shitting in the air too, that's how they can smell it.

I'm jealous of someone only flushing the toilet twice per day.

If it's yellow let it mellow....

I mean, arguably there's all sorts of side effects. Society has improved considerably over the centuries. People used to tolerate all sorts of stuff and could have said "we've bathed in the water we drink for thousands of years, and what's wrong with that!"

> This suggests standard lid usage reduces but does not eliminate flush-related bioaerosols. Lid-use changes their characteristics and apparently prolongs their residence time in room air.

There is another problem with lid: the success rate of toilet flushing is not 100%. If you close the lid, you cannot verify if your flush was unsuccessful and then retry. If you close the lid, flushed and then immediately verify the result opening the lid up again, some amount of aerosol will still escape.

All and all, I'm pretty sure you don't want to see a surprise when you open the lid especially when the toilet is shared.

Transparent lid?

Schrodinger’s toilet flush

I find very few people outside my home who religiously put down toilet seats prior to flushing. I can’t even think about it too much without being unsettled. I can see that it obviously isn’t that dangerous given our daily lives, but it is one of my hang ups.

I once saw a comment online that made me aware of this and ever since keep my toothbrush out of the bathroom.

It's always a dilemma when you find yourself exorcising demons in a public toilet stall with someone else in the room. Should I:

A. Do immediate courtesy flushes to minimise trauma of all those present but potentially put everyone's health at risk.

B. Do a single flush at the end with the lid down.

I always lean to A because I have a robust immune system and I figure by that point if anyone else in the room cares for their well being they would have already left the room or taken measures to shield themselves from the ongoing olfactory assault.

Most public toilets I've seen don't have lids anyway.

I'm guessing that the seal created by ones posterior during the aforementioned exorcism would provide significantly more protection against bioaerosols than any standard lid.

theres also this

> This suggests standard lid usage reduces but does not eliminate flush-related bioaerosols. Lid-use changes their characteristics and apparently prolongs their residence time in room air

It's worth remembering that "olfactory assault" is already caused by particles of your poo flying through the room and entering their body through their nose and mouth. If that's not causing a health risk, I find it unlikely adding some water to the mix will suddenly make it dangerous.

Those are gases, not solid matter like pathogens.

While the smell of farts are primarily gas, I thought the smell of poo was mostly particles of poo. And even farts contain a notable amount of poo particles.

Basically anything you can smell is a gas, not particulates.

I'm curious to know whether the thick sodium hypochlorite that comes in squeeze bottles specially for toilet and bathroom use reduces the bacterial load and if any research has been done on that.

Seems a common practice is to squirt some into the bowl before flushing. Is the mixing in the bowl sufficient to kill bacteria effectively or are people just wasting money using bleach this way?

That sounds like a big waste of money (I don't think the mixing is even close to 5%) and also just more trouble for the sewage processing plants (which rely on bacteria to clean the sewage!)

Reckon so, but I gather the purpose isn't to kill bugs in what's flushed only those in the the airborne aerosols.

I use the spray type for bathroom tiles etc. but seeing every supermarket sells a squirt nozzle variety for toilet use it's worth asking whether it's actually effective at killing the aerosol bugs. If it is then I might consider using it.

Flushometer toilets seem to be the worst, which means there is room for improvement. I wonder if codes could be updated to restrict aerosol production.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666014/

I wonder if you put the cover up will these aerosols escape from the gaps. For sure, using electric hand dryers and toilers enrich your air with all kinds of crap... literally.

A present alternative, of course, is the stoic Port O Let. They only get flushed sometime significantly after critical mass, an affair which even the most adamant patrons may never witness in a lifetime. If not for the Flying Wallendas of wanton incontinence that inevitably, covertly grace them, there would be a stillness of all but scent about them, minus the flies and microscopic. Even more so in the summer heat, that clings to tenant and deposit with a thicker, stickier gravity. Aerosols simply cannot thrive in these potty pulpits. With good marksmanship, these wonder boxes can be the sanitary solution we need.

Basically someone needs to modify the rim of the toilet so air to be pulled in internally and expelled via a duct and automatic fan outside.

This along with the mites that live in your eye lashes is required hypochondriac reading / viewing material.

Evidence that the old argument of who should put the seat down is bogus.

Both men and women both should put the cover down.

Probably these bacteria are good in small quantities... Something for the immune system to practice on.

mythbusters did a pretty thorough study on this:

https://www.youtube.com/watch?v=1pFww_EaLiY&pp=ygUebXl0aGJ1c...

I can't figure out how to actually read this. Is there a pdf or something?

I don't know either. It says it is open access and is CC-BY, but I cannot find how to access the file from that web page.

The URL ends with something with "10." so that would indicate a DOI, so I tried putting that in Sci-Hub but it says not found. I also tried Anna's Archive, which recognizes it as a DOI but also does not have that file, but it links to Sci-Hub (which doesn't have it, as I said) and to the same web page linked from here, which is the same one I could not figure it out.

(If anyone does figure it out, you should put it in Anna's Archive and Sci-Hub; the CC-BY would mean that it would be allowed (not that Sci-Hub cares if it is allowed or not anyways, but in my opinion it ought to be there either way).)

You laugh, but my wife would totally implement this.

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