Why do onions smell even through a plastic bag after you leave them in the refrigerator? Something with gases?

Question

I dont want solutions I just would like to know the chemistry behind it! Please help! Need answer

Answer 1

some plastic bags used for fresh food products are actually designed to be breathable - they let air through, but not water - which is meant to keep food more fresh
The odour causing molecules in the onion are released when the skin of the onion is cut and these molecules diffuse through the plastic into the air in the fridge

Answer 2

I agree that the molecules are small enough to diffuse through the plastic of the bag.
I would like to know why the same onion odor sticks to my hands when I cut an onion for several days.
You probably noticed that people get onion breath, because the same gas molecules first are absorbed into the blood after we eat them and then diffused out of our blood into the air in the lungs.

Answer 3

The molecules of the onion's "scent" are small enough to diffuse through the plastic bag. More of the molecules go out of the bag than into it; the net movement is from high to low concentration.