An entrainment-based filtering system for use in connection with a facemask or respirator that includes: a filter housing defining an interior volume comprising at least one airflow pathway having an airflow pathway length that is longer than the length of the interior volume and spaced within the interior volume; and a plurality of entrainment substrates. The plurality of entrainment substrates is positioned within the at least one airflow pathway and the plurality of substrates and the dimensions of the at least one airflow pathway together function to entrain particles on the surface of the chemically coated entrainment substrates and prevent at least 95% of particles traveling through the at least one airflow pathway from exiting the entrainment-based filter.