I’m working out the logistics for trialing triethelyne glycol for pathogen control at a contra dance, and I need something to put the liquid glycol into the air. I’d initially been thinking of using a fog machine, but after discussion with friends who work in the area it sounds like an ultrasonic humidifier would work better. Instead of using heating and cooling, these use vibration, and put out much smaller droplets.
I got a random cheap humidifier on Amazon ($30) but (a) TEG is more viscous than the water its designed for and (b) its output is probably higher than I need. I decided I’d dilute the TEG to resolve both of these.
First I tested with just water, and I used distilled water because these humidifiers can turn the minerals in tap water into a fine dust it’s better not to breathe. I filled the humidifier, weighed it, ran it for an hour on high, and weighed it again. I measured it losing 122g (2g/min), though this is likely an overestimate: instead of weighing the whole device before and after (like I did later) I weighed how much water I poured in (accurate) and then weighed what was left (inaccurate, due to not all the water coming out).
My goal is a concentration of about 1mg/m3 in a stream of 8,000 CFM of incoming air. Converting 8,000 CFM to m3/min I get 227 m3/min, so to put out 1mg/m3 I need 227 mg/min.
If TEG+water behaves similarly to water I should combine six parts water with one part TEG by mass. But the higher viscosity of TEG means it vaporizes more slowly, and after some trial and error I landed on three parts water to one part TEG. In a 60min test I measured mass decreasing by 56g, which is 0.233g/min (56g / 60min * 25% TEG).
This is way closer to my target (0.233g/min vs 0.227g/min) than I had any right to expect, and I don’t expect it to be quite this close in practice.
For the 2025-09-07 dance I’m planning to mix up 3:1 TEG to distilled water at home, where I have a scale. I’ll want about 300g, so I can turn it on as soon as we turn on the fan and not worry about running out.
Note that these figures are all for a large dance hall with thousands of cubic feet of air coming in every minute. So literally don’t try this at home: this is way too high a concentration for your living room.
on page 2 of the PDF / page 153 of the uploaded book at https://www.jefftk.com/harris-and-stokes-1943.pdf, it specifies that they vaporized the glycol by heating it. Maybe I’ve missed this in your writeups on the topic, but did you rule out just putting it in a slow cooker or similar at an appropriate temperature and using a fan like the original experiment? It seems superficially as if heating it into evaporation would be both much easier to do and also a more accurate replication of the original work? Ultrasonic humidifiers put water in the air by emitting tiny droplets, which then evaporate if the air is dry enough. It seems like the pathogen control impact of having lots of little drops of TEG would probably be different from having the TEG actually evaporated as it was in the original research?
This rabbit hole leads me to https://en.wikipedia.org/wiki/Triethylene_glycol where they mention that it’s still a disinfectant when aerosolized, so maybe my concern about evaporation vs making droplets is irrelevant. The other interesting hint there is its use in fog machines—is your current build basically a DIY fog machine for low volumes of party fog? I wonder whether fog machines that are already installed in crowd-gathering venues could be used for infection control!
Are you planning any measurements of how far the TEG travels or how effectively the humidifier-generated droplets clean the air? The settling plate count technique described in the pdf seems shaped like a great science fair type project for kids to help out with!
I think that’s the case—if you look at more recent work they’ve used a wide range of ways of getting glycol into the air.
It’s more than that: fog machines used today (when used with glycols, which is the normal fog juice) are already performing infection control!
I’m not, though if anyone wanted to come test efficacy I’d be happy for them to measure the effect of us having it on sometimes and off other times.