precipitator

noun

1. One who or that which precipitates (causes something to happen or urges it on with vehemence or rashness).

   “[…] those of that sect […] that call’d themselves by that name of Zealots, and withal, took upon them to be the saviours and preservers of the City, but as it prov’d, the hastners & precipitators of the destruction of that Kingdom […]”

   “Even the most wanton precipitators of war always try to give it, in the eyes of the common people, a defensive character.”

   “Wherever one looks the rate of change on the international scene has achieved dizzying proportions, often with ominous overtones for United States interests. What is frequently overlooked, however, is that American behavior may be one of the greatest precipitators of this growing instability.”

   “[…] the most common precipitator of workplace violence is a layoff or firing.”

2. A person who, or device that, carries out precipitation.
3. An apparatus which removes dust particles from gases by electrostatic precipitation.