You often hear HEPA or HEPA filters mentioned in vacuum cleaner advertisements and may have wondered what they mean by that. As HEPA stands for High-Energy Particle Acceleration, a HEPA filter exists to prevent a vacuum cleaner from essentially functioning as a particle accelerator. As is commonly known, accelerated high-energy particles colliding with other particles pelt the surroundings with radiation and electricity, which is considered dangerous to the health of the non-mutant population..