N95 masks have several clever methods for filtering airborne particles. The most interesting method is the electrostatic charging of N95 masks, which is a major contributor to their filtration efficiency, improving it at least 10-fold over uncharged fabric.

An electret (formed of electr- from “electricity” and -et from “magnet”) is a dielectric material that has a quasi-permanent electric charge or dipole polarisation. An electret generates internal and external electric fields, and is the electrostatic equivalent of a permanent magnet.

The name derives from “electron” and “magnet”; drawing analogy to the formation of a magnet by alignment of magnetic domains in a piece of iron. [source]