Face Masks standards and what they mean

Did some surfing to try and educate myself today on the various standards of particulate filtration that face mask are certified against.

We of course all now know the infamous N95 or at least heard of it. What does it really mean? Here is what I gathered from several online sources and help from a friend.

In order to obtain certification as an N95, a respirator must pass NIOSH’s test requirements, which include Exhalation Resistance, Inhalation Resistance and Sodium Chloride (NaCl) N95 Filtration.

There are 3 different filter classifications for particulate filters under the AS/NZS 1715 being a P1, P2 and P3.

The filters are tested against a sodium chloride solution with a size range of 0.02 micrometer to 2 micrometer which has a mass medium particle diameter of 0.3 micrometer to 0.6 micrometer.
 
A P1 filter must not have more than 20% penetration (filters at least 80%)
A P2 filter must not have more than 6% penetration  (filters at least 94%)
A P3 filter must not have more than .05% penetration (filters at least 99.95%)


Someone came up with an even more handy chart, reproduced below.

In other words, N95 is somewhat equivalent to a P2 one. Good to know if anyone is buying such stuff over in NZ or Australia or asking their relatives to get from there.

There are a lot of misinformation out there, some websites have items that are evaporative air coolers that are being claimed as air purifiers just because they have a simple mesh dust filter in them! Some people really know how to exploit FUD (fear, uncertainty, doubt) at this period in time!

Also note that the effectiveness of an N95 mask is affected by dirt AND moisture, please do not be cheapskate and try to wash and reuse! Things do not work that way!!!