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Comment by thebean11 | Hacker News Reader

What's the issue with the dryers? You use them to dry already-washed hands and the dryers themselves aren't very close to the toilets.

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No one washes their hands perfectly (e.g., ready for surgery), so when you dry them there’s still a lot of bacteria present. Dyson dryers aerosolize those particulates, and they do it far more than other dryers.

Think of it this way — they don’t dry your hands, they blow the water off. Where does the water go? All over the bathroom. Dyson dryers disperse fluids up to 3 meters away.

https://arstechnica.com/science/2016/04/dyson-dryers-hurl-60...

To be fair, other hand dryers only do better on this metric because they don't actually remove the water from your hands.

Regular hand dryers (hot/dry airflow) literally make the water evaporate off your hands. How is the water not removed?

Ask my wet pants and the line of people behind me every time waiting to do the same move.

That assumes everyone thoroughly washes their hands, which is unlikely. Dyson hand dryers, specifically, always have a nasty puddle of water at the bottom of their drying "crevice" in busy bathrooms.

The sheer number of people I've seen running their hands through water for a second before moving onto the drier was alarmingly high in 2019 (pre-covid).

I don't know how much that's changed, but I wouldn't expect the change to be particularly meaningful, sadly.

Don't worry, that number hasn't changed

> Dyson hand dryers, specifically, always have a nasty puddle of water at the bottom of their drying "crevice" in busy bathrooms.

That's just a bonus, the main issue with them as other comments have noted is that they shove the water off of your hands using their "air blades".

This aerosolises a significant fraction of that water (the rest goes and collects in the puddle you speak of), spreading it all over the room.

More classic driers primarily work by evaporation, and furthermore direct the air stream downwards (to the floor) rather than sideways (across the room).

Doesn't matter how well you wash your hands, you still have to touch the door handle to get out (they usually open inwards) and some grotty germbags will have poopified that handle 50 times over before you get to touch it.

The bathrooms with Dyson driers near me open inwards but have foot openers,¹ as well as the other bathrooms with paper towels inside and waste baskets just outside (so you can use the towel to open the door before tossing it).

I was hoping that COVID would trigger a contactless revolution in bathrooms where I don't need to touch a pooped up door handle to get out... But sadly seems not a thing

Bacteria -> Your hands

Your hands -> Windstream

Windstream -> Goes everywhere

It's not even about Dyson dryers, but dryers in general

It's meant for hands that were just washed. I understand that not everyone does a great job washing, but I have a hard time believing this poses a real threat..

Let's look at some studies:

> Participants washed their gloved hands with a suspension of MS2 bacteriophage and hands were dried with one of the three hand-drying devices. [...] Over a height range of 0·15–1·65 m, the JAD [jet air dryer] dispersed an average of >60 and >1300-fold more plaque-forming units (PFU) compared to the WAD [warm air dryer] and PT [paper towels] (P < 0·0001), respectively.[1]

Okay, but I'm sure just-washed hands aren't all that dirty, right?

> This observational study was conducted to evaluate [...] hand hygiene practices among college students. [...] Overall, 72.9% of students washed their hands, 58.3% practiced hand hygiene (using either soap or hand sanitizer), and 26.1% washed their hands adequately.[2]

I couldn't find any epidemiological studies, but this feels like good enough of a reason to stick to other options considering these things are a solution in search of a problem anyway.

[1]: https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/jam...

[2]: https://pubmed.ncbi.nlm.nih.gov/18538703/

But you just washed your hands. Where are the bacteria coming from?

"washed"

Have you seen people in the real world?

Even assuming they're washed correctly (entire song thing with all the trimmings), a bathroom sink is not a steriliser.

You’re lucky if people even make a show of washing their hands. If they wash them well, then you have just met a unicorn. And even people who do normally wash their hands well sometimes run into issues like there not being any goddamn soap stocked (in the same bathroom, 3 days in a row).

Don’t use the air blowers; just let your hands air dry if there’s no paper towels. It doesn’t take very long and has been basically my standard practice for about 10 years now.

I cannot even count all the times when I went to use these dryers at always-packed IKEA and immediately got a mouthful of water droplets. No idea if they came from my hands or somebody else’s. TBH I don’t want to know. I just dry my hands on my clothing now.

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