Brief Answer:
It can be a mild allergic response.

Detailed Answer:
Hello,
Thanks for the query.
Harpic vapour may induce an allergic reaction or inflammation of the upper respiratory tract. In most cases the toxicity will be mild and does not lead to major health related problems.
Fresh air is the best treatment, and you have to avoid further exposure and breath in lots of fresh air:
Over the counter antihistamines like cetrezine or levocetrizine can be taken for symptomatic relief. Expectorant cough syrup can also help to reduce the cough and clear the airways.
Generally the symptoms will settle in two to three days.
If symptoms persist better to consult a physician and get evaluated. In that case conditions like pneumonitis must be excluded.
Wishing all the best.
Thanks

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