The letters H-E-P-A represent the words High Efficiency Particulate Air.

VOA: special.2009.07.14

And if you put this in the well-ventilated area, if you prepare this outside, the h c n gas will actually be released into the air, so you're safe, you can eat it later.

而如果你把它们放在通风良好的地方，在室外处理，那么氰化氢气体,将会被释放到空气中，这样你就安全了，过后就可以吃了。

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