It is said that cutting onions under water or chilling them before cutting will retard the enzymes that generate the noxious chemicals.
So you can try to cut onions under water or chilling them before cutting, may it works.
And you can cut the onions in a well-ventilated place and cut fast, and while cutting,you can burn a candle immediately adjacent to where you're cutting since the tear-causing gas is drawn toward the heat source.
After the cutting, you may run cool tap water over your hands to remove the smell.
May it helps you.
The onion would release a kind of gas in air when cutting it thus it would stimulate your eyes. There are some tips that can help you to avoid tears when cutting onions. One simple and effective way is cutting the onion under water. It can dissolve the gas into water thus avoid it comes into air. Or you can utilize fan when you cutting an onion to blow off the gas to prevent it enter your eyes. Another way is placing the onion in freezer until the enzymes are chilled without any activation.
The chemical particles evaporate in the air will irritate our eyes. But we prevent our eyes from crying when we cut onions. What you need to do is just put the unions in the refrigerator for few hours and then takes them out and cut into pieces. Usually the crying will gone after a while but it is hard to bear. You can apply some artificial tears to wash out the chemical articles in your eyes.