The new popular varieties of anti-smoking devices, called “Electronic Cigarettes”, contains liquid nicotine in, I believe, a water-base.
When inhaled, the battery-operated sensor flash-evaporates the liquid(s) (a drop at a time) and transforms it instantly to vapor.
This vapor enters the (mouth and) lungs, thus delivering the nicotine.
May this device be “smoked” on Tisha-B’Av?
And in general, may a Jew inhale water-vapor on Tisha-B’Av OR Yom-Kippur? (e.g. While hovering over a boiling tea-pot.)
In general, it is not permitted to inhale water vapor on Tisha Be’Av, and certainly not on Yom Kippur, because the water vapor turns into water on contact, and one ends up drinking water, which is of course forbidden, and a Torah prohibition on Yom Kippur.
There is room to be lenient for the nicotine cigarette on Tisha Be’Av, provided that one does not swallow any liquid. The purpose of the “cigarette” is not to swallow anything, but only to simulate a cigarette, and therefore it can be compared to mouthwash and other liquids that are not supposed to be swallowed. For such liquids, and in particular where one experiences a degree of discomfort, one can be lenient on Tisha Be’Av.
For washing out one’s mouth, on Yom Kippur authorities are stringent (see 467:3; 613:4; 613:6 and Shaar Ha-Zion 20); on Tisha Be’Av, where a person experiences discomfort, one can be lenient.