Tech Ingredients did a fantastic video on the subject recently, I love everything from this guy and the recent series in response to COVID-19 is great stuff.
from the article
"the FE (filtration efficiency) of these masks is influenced by the electrostatic charges embedded within the fibers of the filtration layer(s) in the interior part of the masks."
"... using alcohol will erase the charges. However, exposing the masks to air at elevated temperatures such as 70℃ for 30 minutes allows the charges to be retained."