This is bad science. This is not a real thing. Neither does running water nearby, or lighting a candle in the kitchen. None of this affects the root cause of your problem.
Onion tears are caused by 2 different chemicals held apart by the onion's cellular structure. Every time you cut an onion, the cells rupture and mix, aerosolization and making you cry when the acid gets into your eyes. A sharp knife (as mentioning in another comment) would help minimize the amount of cellular damage and therefor the gas produced. You can also wear goggles.
Everything else is bunk. From-A former professional chef and person particularly sensitive to onions. (I just learned to cut onions with my eyes closed)
not EVERYTHING else is bunk. Running water nearby might not help but cutting your onions submerged in water would definitely help. Another one is just simple good ventilation. Set up a fan near you and the chemicals will be blown away instead of gradually increasing in concentration around your eyes.
Or even just contact lenses. At least for me it eliminates onion tears completely. I had been using them for at least a decade before I started to cook my own proper food, I'll never forget that one time I tried cutting up onions wearing my glasses instead...
Some people yes, others no? Contacts would seemingly help, but you're still going to have a build up of acid in your eyes that could eventually become irritating with enough volume.
I've known people who just have seemingly no reaction to onions whatsoever, and others who break into tears the second the first cut happens.
Yeah ymmv, but to me it's night and day - with lenses I'm in your first group, without them I'm in the other. Of course I've never cut more than maybe 20-30 onions at a time, but I never felt much of anything doing that. A single cut without lenses on had my tears flowing instantly. I finally got what all the fuss was about - turns out it's not fussing at all. :)
If you're not a professional, using an onion comb (which costs less than $2 and lasts a lifetime) will change your onion-cutting experience. It lets you go way faster and therefore reduce the time you're exposed to tear-inducing chemicals (assuming you're cutting 1-2 onions and not cooking for a whole army).
It's likely that at least half of the effect of a sharp knife is due to time improvements too.
Did you ever try just breathing through your mouth instead of your nose while cutting? This minimizes the exposure via sinuses and works pretty well for me.
It also changes airflow, so the droplets are not pulled directly up towards your eyes, like breathing through your nose does. I might look like a dopey mouth breather, but no tears as long as I concentrate on my breathing.
Sorry, that's a bit hyperbolic on my part. There's so many old wive's tales out there about how to deal with onions. People try to solve it as though the tears were magical and not caused by (relatively) simple chemical reactions.
If you refrigerate your onions, you might be fine for some amount of time and you'll be lessening damage and it's going to help but not solve it at volume (cut one onion, you're fine. Cut 100, not so much).
