The best way to win a war is to know your enemy.  This is particularly important in the medical field. The more we know about an illness, the more effective we can be in fighting it.

As COVID-19  spreads across the globe, scientists have been racing to learn as much about it as possible. While there is still much to learn, there are some facts that are beginning to emerge:

Shape: CoVs are positive-stranded viruses that have a crown-like appearance under an electron microscope (coronam is the Latin term for crown). The spikes are what allows the virus to bind to human cells and cause infection.

Size: The size of a virus is very important because it tells you what type of filter you will need to keep it out. One of the trickiest things about protecting against COVID-19 is that it is extremely small, with a diameter of approximately 60–140 nm.

That’s 100 times smaller than the diameter of a hair! 

So, now that we know what size it is… what can we use to keep it out of our bodies?

By now you’ve probably seen pictures of doctors, nurses, and everyday people wearing masks to keep from getting sick. Perhaps you’ve also read that many of the masks do little to provide real protection. So, what’s the real story?

Do masks give any protection?

It depends…

Masks are classified by their Filtering Face Piece (FFP) class.  They are typically classified as either FFP 1, FFP 2 or FFP 3. The higher the number, the lower the percent of particles that can penetrate the masks… the better the protection.

So, a mask with FFP1 would keep out 80% of particles, FFP2 would keep out 94% of particles, and FFP3 would keep out 99% of particles.

But that’s not the whole picture…

The efficiency of each mask shows the worst-case scenario, meaning that it shows which size particles the mask is weakest at filtering out.  And, in this case, each classification of masks show the same performance… They’re all weakest at filtering particles between 30nm and 60nm.

The good news is…

The coronavirus is around 120 nm in diameter, which means that FFP1, FFP2, and FFP3 masks are all able to filter them out.

What about air purifiers?

Yes!   High-quality air purifiers will filter out particles as small as 1 nm. Because of this, the CDC recommends that hospitals use HEPA filtration systems when dealing with patients with coronavirus. Viruses don’t typically stay in the air for very long, so it’s unlikely that an air purifier will give your home complete protection.  But, during uneasy times like these, any measure of protection is helpful, especially if someone in your home is sick.