From the article I posted in this thread:
“For nanometer-sized particles, which can easily slip between the openings in the network of filter fibers, electrostatic attraction predominates the removal of low mass particles which are attracted to and bind to the fibers. Electrostatic filters are generally most efficient at low velocities such as the velocity encountered by breathing through a face mask.”
-—Colbeck, I.; Lazaridis, M. 5 - Filtration Mechanisms. In Aerosol Science: Technology and Applications, 1st ed.; Colbeck, I., Lazaridis, M., Eds.; John Wiley & Sons: New York, 2014; pp 89 118.Google Scholar