I'm writing a fictional story where the protagonist is trapped in a house with the antagonist. The protagonist is going to escape the house, but they need to set off a chemical reaction to prevent the antagonist from following them out. It'll have to be with reactants that would be reasonably found in a home.
I've heard of the bleach and ammonia/vinegar mix, but chlorine gas seems a bit too deadly for this protagonist. I'm looking for something irritating and difficult to pass through, like pepper spray, but not harmful enough to risk fatal consequences.
Please let me know if anyone has any ideas. Since it's just a story, it doesn't need to be 100% realistic, just plausible. Thanks.