Unless you’ve been living under a rock (and we’re a little jealous if you were), you have probably worn an N95 this year. This is because your hospital team rapidly deployed them at the beginning of the pandemic. In many areas, there weren’t enough to go around.

So few, in fact, that OSHA let people re-use their masks, healthcare communities found some creative ways to clean them, and your new badge was actually your N95 with your name written on it.

Thankfully, supply and demand has evened out a little bit, but you are probably stuck wearing one of these bad boys at least some of the time.

Did you wonder what an N95 is and why it’s important to get fit tested through all of that action?

We tend to understand the value of the N95. After all, it’s in the name that the mask filters out up to 95% of contaminants when worn correctly. However, N95 masks aren’t meant to prevent poisonous gases from getting to the wearer, and they aren’t breathing devices. Instead, they simply protect the wearer from things like dust, viruses, and bacterial contaminants.

The way the mask works is through positive and negative pressure. When you breathe in, the mask sucks up against your face, preventing the entry of particulates. When you breathe out, the forced air means particulates would be going against the airflow to get into the mask.

These masks don’t have carbon filters (usually). So that’s why it’s normal to smell through them. Because the air is exiting the mask, it’s also normal to have some dreaded glasses fogging while breathing out.

The key here, though, is fit, which is often ignored.

We all have different size faces and features. A poor-fitting N95 is no better at protecting you than a surgical mask.

A fit test is a procedure used to make sure the mask fits right. There are different versions.

• Saccharin testing uses a sweet aerosolized solution in a hood
• Bitters testing uses a bitter aerosolized solution in a hood
• Smoke testing uses a type of smoke that makes the user cough if it enters the mask.
• Electronic testing– uses a really expensive machine to test pressure gradients without the need for a test solution.

In all fit tests, you will be asked to perform various motions meant to simulate movements you would perform during your shift, like walking in place, moving your head, and speaking to your patient.

It’s essential to take this test seriously and, to be honest, if you start tasting some of the solution. If you are tasting it, the mask isn’t protecting you in a controlled environment. It definitely isn’t going to protect you out in the wild.

Another important note: strap placement matters. If you usually wear a pony, make sure you fit test with one. Beards often interfere with the mask’s ability to suction closely to the face during inhalation. Therefore, N95’s should never be worn with a beard, even if you passed your fit test with one.

Finally, things change. Weight gain or loss, pregnancy, or injury may result in a change of your facial features. What worked for you before may not work right for you now.

Some sure signs things aren’t working include feeling air rush into the mask during inhalation, broken or stretched out straps that make the mask not sit tightly on your face, or if your N95 gets wet.

Regardless of whether you are still rationing N95’s or getting a new one with every patient encounter, the fit is what matters. OSHA requires fit testing to be performed annually. However, that recommendation was briefly on hold during the beginning of the pandemic due to increased need. So make sure you keep up with your appointments to protect yourself!