The Astounding Physics of N95 Masks

We’re more than two years into the COVID-19 pandemic and, in general, everyone is much more familiar with the different types of masks that are available. Our Chief Scientific Officer, Professor Munir, breaks down what he sees as the biggest differences between them in this article.

What we’ve come to appreciate over the course of this pandemic is that certain masks provide a much higher degree of protection than others. In particular, the best masks you can use to help protect yourself are N95s or FFP2/FFP3 masks. But, how do they work?

The video below, published by MinutePhysics, offers a great explanation of the physics behind N95 masks. Overall, there are three key elements that add to its effectiveness:

1. The fibres used in the material of the masks are naturally ‘sticky’ for the particles, meaning they get stuck to the external layers.
2. Multiple layers increase the chances that those particles will hit (and stick to) fibres instead of making it through the mask.
3. As well as being sticky, the fibres are electricised and actually attract particles. This is particularly helpful for mid-sized particles which would be more likely to make it through the mask otherwise.

What’s the difference between N95 masks and FFP2 masks?

In essence, N95s and FFP2 masks are actually quite similar. The key difference between them is that N95s must meet the American NIOSH standard and FFP2 must meet the European EN 149 standard. FFP2 masks must filter at least 94% of airborne particles and N95s must filter at least 95%. FFP3 take it up a notch again, filtering at least 99%.