When the world was flung into chaos by the global pandemic known as the Corona virus or COVID-19, medical suppliers and mask manufacturers greatly increased production of sanitation equipment and surgical masks to minimize the spread of the virus. Masks have become a vital part of our wardrobes when we leave our houses each day. Something that is arguably more important is the proper information and knowledge about the equipment being used and worn out in public. This article will provide a brief explanation of a few common terms used by the medical industry as well as some information about harmful airborne particles such as viruses and bacteria and mask ratings.


Mask Ratings

If you turn on the news or read articles online, you will hear a lot about N95 respirators and other such masks. But what does N95 mean? What are the specifications? Does it actually help prevent the spread of the virus?


The “N” in N95 stands for “Not Oil Resistant.” Typically, there are three letter designations for these kinds of masks. The other two designations are “R” and “P.” These letters mean “Resistant to Oil” and “Oil Proof.” Normally, you do not have to worry about anything other than the “N” unless you are working with or near oil related substances that may be harmful to your body. Mask Ratings

The “95” stands for 95% efficient at 0.3 microns. This means that the filter media is effective at filtering 95% of airborne particles as long as they are larger than 0.3 microns in diameter. Along with N95 masks, there are also N99 and N100. Since it is virtually impossible to completely filter out all the harmful particles in the air, if a mask demonstrates an efficiency of 99.97% at 0.3 microns, it is rated as N100. Keep in mind, these types of respirators are not recommended for use by the public. Non-patient civilians have been instructed to wear cloth masks or disposable surgical masks.


You will not see mask ratings like these on standard disposable masks because they are not able to achieve 95% effectiveness at 0.3 microns. Most masks are only able to achieve a rating of PM2.5 (Particulate Matter 2.5) or lower. This means that these masks are only effective at 2.5 microns or larger. Here at Filti, we have been able to design and create a patent pending filter material that uses nano fiber to match the N95 standard without having to sacrifice breathability or comfort. 

Particle Sizes

Particle Sizes

Microns, or micrometers (µm), are a common unit of measurement when talking about exceedingly small objects such as strands of thread, dust particles, and molecules. One micron is equal to 0.000001 meters. Another way to think about it is that there are 10,000 microns in 1 centimeter. On average, a single strand of human hair can be anywhere from 17 to 180 microns in diameter.

As for the Coronavirus, these molecules tend to be about 0.1 microns in diameter. The following chart displays various particles along with their respective sizes in order to show just how many things masks and filters prevent from entering our airways.

Particle Sizes


Many people are probably thinking “If the virus is that small, what’s the point in wearing masks that can’t even filter it?” A common misconception is that virus molecules float through the air by themselves, but in reality, the virus is transported from person to person on droplets of fluid created by bodily functions such as sneezing and coughing. These droplets are typically 5 microns or larger. Stopping these molecules is an easy task for our Filti material and N95 equivalent masks. The important thing to remember is that these masks help prevent sick people from spreading the virus as well as preventing healthy people from contracting it. Are masks guaranteed to prevent someone from getting sick? Of course not. Will they substantially reduce the risk of transmitting or receiving the disease? Absolutely.



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