1. 切洋葱前先冷藏或冷冻

According to the Institute, putting onions in the fridge 30 minutes or in the freezer for 10-15 minutes before chopping can prevent the stinging as the cold stops tear-jerking gas from being produced.
根据研究所的说法，在切洋葱之前，先将它们放入冰箱30分钟，或放入冷冻室10到15分钟，便可以防止流泪，因为冷气能阻止其释放催泪气体。

However, do not start storing your onions in the fridge at all times as this will cause them to go off more quickly.
但是，不要一直把洋葱放在冰箱里，这样会让它们坏得更快。

2. 将洋葱浸泡在水中

Another way to reduce the gas released by the onion is to soak in water - although this could compromise the taste.
减少洋葱释放气体的另一种方法是将其浸泡在水中——尽管这样可能会影响它的味道。

Good Housekeeping recommends: ‘Chop the end off the onion and then put it straight into a bowl of water to soak. The water will draw out the acid making you tear up less when you chop it.’
《家政》建议：“切掉洋葱的末端，然后把它们直接放入一碗水中浸泡。水会抽出洋葱中的酸味物质，所以切洋葱时，就能减少流泪。”

3. 最后切洋葱根部

When an onion grows it mixes with sulfur in the soil to create amino acid sulfoxides. These sulfoxides turns into sulfenic acid when the onion is sliced which reacts with the enzymes to create a gas called syn-propanethial-S-oxide.
洋葱生长时，与土壤中的硫混合，从而产生氨基酸亚砜。而洋葱被切成片时，这些亚砜会变成次磺酸，与酶反应后产生名为丙硫醛-S-氧化物的气体。

As it reaches your face, this irritating gas stings and burns, triggering the eyes to produce tears to flush out the gasses.
这种刺激性气体接触面部时，你的眼睛会感到刺痛和灼烧，然后你便会开始流眼泪来排出眼睛内的气体。

The root is where the fumes are most concentrated so it is recommended that this part of the onion is left on as you chop it to avoid stinging eyes.
洋葱的根部是气体最集中的地方，所以杂志建议，在切洋葱时最后切这一部分，以免刺激眼睛。

4. 在通风处切洋葱

Another way to reduce the gas’s effect on your eyes is to chop it next to a window or near a fan so the gas is diluted or blown away from your face.
另一种减少气体刺激眼睛的方法是在窗户边或者风扇旁切洋葱，这样气体就能从你面前被稀释或吹走。

5. 使用锋利的刀具

And take care to use a sharp knife, this will make it easier to glide through the vegetable, causing fewer cells to be broken and less gas to be released as a result.
注意使用锋利的刀具，切开洋葱时更容易，减少对细胞的破坏，从而减少其释放的气体。

The type of onion you use can also make a difference. The enzymes required to create the tear-inducing gas are more concentrated in white, yellow and red onions compared to sweet onions, green onions and spring onions.
洋葱的种类也有影响。与甜洋葱、大葱和小葱相比，刺激流泪的气体所需的酶更集中于白色、黄色和红色的洋葱中。