I think they have the most beautiful masks in Venice for masquerade parties.  They are very comfortable to wear too, even the not too fancy few I have.

Here, however, I am talking about the face masks for personal hygiene, be it surgical masks, industrial masks, or everyday masks school children wear daily in some countries.  They can be so refine that they filter out particles less than a micrometer (a micron, or 1 over 10 to the 6th power meter) in size or rough enough for me when I sweep the floor or when I do my woodwork, sanding. A handkerchief or a few layers of clothing can do a rough job. The commercially made ones are usually constructed to fit the face with strings or elastic bands for wearing. 

Rated from bottom up, the lowest in efficiency is of course a hand kerchief or something home made with cloth. Next would be what you buy in hardware stores for wood work, the half spherical thing.  The surgical masks are probably next up.  It is usually blue and is actually pretty good. Doctors and many other health professionals use them in hospitals, clinics as we often see in real life, in news reports, and movies. The design is directional for air flow, effective (not restricted) for one way of flow.  It is like the filters in your air condition unit. The rough outside layer (often colored and often blue) can block out larger particles so they do not clog the refined layer inside.  The inside layers may even have electric static properties making it very effective. 

One grade up would be the one we see often recently, the N95 face mask also called the N95 respirator.  (Apparently, the word “respirator” may refer to the machine that pumps air into a head gear as well as a face mask of N95 quality.) The letter “N” in the name stands for the NIOSH classification meaning “Not resistant to oil” the other two possible letters are “P” for oil Proof, strongly resistant to oil and “R” for oil Resistant, somewhat resistant to oil. The number 95 means it can filter 95% of airborne particles as small as .3 micrometer. The other numbers used are 99 for 99% and 100 for 99.97%. See:




As shown in the above CDC websites and documents, the next one up can be the Elastomeric Half Facepiece Respirator, something probably an overkill .

As indicated by the direction of airflow, these face masks are designed for the wearer, not originally designed for the sick to wear to protect others.  However, it would serve that purpose too to keep the air clean from a sick person’s coughing or breathing. As I indicated in another article (COVID in this issue of Mblem) these face masks are the best tool to help us create our individual quarantine — everyone of us should wear face masks when interact with others.  However, for the time being, while the resources are lean, even the doctors at white house briefings recommend people who have no symptoms not to wear masks. Personally, I think this maybe good intentioned but misleading. For one thing, we do not know who are infected but in the incubation period, who can decide who is to wear a “respirator.”  I think every one still should wear something, say, the cheaper ones or home made cloth ones because anything is better than nothing.  Besides, it help us to bring up our awareness and help us stop touch our faces with hands.  Talking about lack of resources, not like washing hands, I do not think one need to change and throw away a respirator each time he/she sees one patient, say, once a minute.  Of course, I am not a health provider and should not make irresponsible comments.