Firstly, and this is a big point, no agency has provided technical specification requirements to the public in terms of a masks construction, fit, and filtration efficiency, let alone air intake and exhaust restrictions. N95s masks, as an example, have different intake and exhaust flow characteristics. A recent trip to the local Ace hardware store and grocery store showed a gentleman sporting a mask made from fishing net. It complied with the law as a “mask” and got him in the door. Another great example was the lady wearing a leather embroidered small black fishnet mask with fake stones which obviously came from Victoria’s Secret or some other place that sells things for purposes other than health care.
The average diameter of a single bacterium is 4.25 micrometers. A micrometer is one thousandth of a meter. A meter is 39.37 inches. The average diameter of a coronavirus is 90 nanometers. A nanometer is a billionth of a meter. There are roughly two orders of magnitude (100 times) difference between a single bacterium and a virus. We can see a single bacterium with a very powerful optical microscope. We cannot see viruses with optical microscopes. We need very powerful electron microscopes to resolve a virus. No mask can trap viruses without significant restrictions of airflow. Now some will claim the objective is to simply trap droplets of water containing the viruses. As a matter of aerosol physics this simply does not work. It is an emotional feel-good measure. It is not a scientific block to the contraction or spread of a viral disease.
The “like chicken soup it can’t hurt” rationale used by some doctors and the CDC rests on a masks ability to trap water droplets containing a viral load held effectively in a colloidal suspension. However a large percentage of that load becomes detached from the droplet through inelastic collisions inside the mask when agitated (coughs and sneezes) and becomes resident in an aerosol. The aerosol travels freely in the air at the whim of convections and airflows. Thus masks are ineffective for viruses due to the physics involved.
Masks are used in the operating room by doctors and all attendant medical personnel to eliminate the possibility of infecting a patient with a bacterial infection through the blood system during the operating procedure. Viruses are not considered in that instance for several reasons. Masks are necessary and most prudent in the operating room.
Most doctors are very good in medicine but have very little understanding of physics. The same holds true for virologists and other researchers in the field.
Masks for the masses are not about health per se. They are political statements to make the population think the leaders are acting in the best interests of the public. This is an election year. To be straightforward, the mask “orders” and their compliance by pedestrians, indicates the lack of science understanding and the gullibility of the masses. Gullibility is a strong word but when it comes to science most people are gullible as illustrated by the Las Vegas comedy team of Penn and Teller in their ban of water.