A mask only protects you if it fits snugly against your face with no gaps around the edges. The most common mistake isn’t choosing the wrong mask; it’s wearing the right one poorly. Whether you’re using a cloth mask, a surgical mask, or an N95 respirator, the steps below will help you get a proper seal and the most protection out of whichever type you choose.
How Different Mask Types Compare
Not all masks filter equally. N95 respirators, which are approved by the National Institute for Occupational Safety and Health, sit at the top of the protection scale. KN95 masks (the international equivalent) are more variable: some achieve 80 to 90 percent fitted filtration efficiency, while poorly made versions test as low as 53 percent. Surgical or disposable masks fall in the middle. Cloth masks offer the least filtration, typically around 26 percent of airborne particles.
Fitted filtration efficiency measures the percentage of particles that a mask actually blocks while on your face, not just what the fabric can filter in a lab. That means fit matters as much as material. A loosely worn N95 can perform worse than a well-fitted surgical mask. The CDC recommends wearing the most protective mask you can comfortably keep on for an extended period, with a fit that completely covers your nose and mouth.
Step-by-Step: Putting On an N95 or KN95
Start with clean, dry hands. Before touching the mask, inspect it for damage. If it looks dirty, damp, or torn, use a new one.
Hold the respirator in one hand with the metal nose piece (or foam strip) at your fingertips. Place the mask under your chin so the nose piece sits at the top. Pull the top strap over your head and position it near the crown of your skull. Then pull the bottom strap over your head and let it rest at the back of your neck, below your ears. Don’t crisscross the straps, and make sure they lie flat without any twists.
Now mold the nose piece. Place your fingertips from both hands along the top of the metal strip and press down on both sides, shaping it to your nose. This step is critical for eliminating the gap where most air leaks through.
Finally, check the seal. Cup both hands over the mask and exhale firmly. If you feel air escaping from the edges, or if you’re wearing glasses and they fog up, the fit isn’t tight enough. Readjust the nose piece and straps, then test again. If you still can’t get a seal, try a different size or style.
Putting On a Surgical or Cloth Mask
Ear-loop masks are simpler but follow the same principles. Place the mask over your nose and mouth, loop the bands behind each ear, and press the nose wire (if there is one) snugly against the bridge of your nose. Pull the bottom of the mask down so it covers your chin completely.
To check for gaps, cup your hands around the edges of the mask and breathe. With a good fit, you’ll feel warm air pushing through the front of the mask and may see the material move in and out with each breath. If air streams out the sides or top, tighten the ear loops (some have adjustable sliders or toggles) or try tying small knots near where the loops meet the mask to pull the fabric closer to your face.
Facial Hair and Mask Fit
Beards create gaps between the mask and your skin, and even short growth can make a difference. Research testing respirator fit across different beard lengths found that stubble up to about 1/16 of an inch (roughly one day’s growth for most people) performed no differently than a clean shave. At 1/8 of an inch, 98 percent of fit tests still passed. But performance dropped sharply beyond that: only 81 percent of tests passed at 1/4 inch, and just 58 percent passed at 1/2 inch.
The thickness of individual hairs didn’t matter. What mattered was length and how densely the hair covered the sealing area. If you need reliable protection from a tight-fitting respirator, keeping facial hair trimmed to stubble length preserves the seal. For longer beards, a loose-fitting powered respirator or a hood-style covering is a better option than trying to force an N95 over the hair.
Preventing Foggy Glasses
Fogging happens when your warm breath escapes upward through gaps at the nose and hits the cooler surface of your lenses. The fix is closing that gap. Molding the nose wire carefully is the first line of defense. If that’s not enough, try one of these approaches:
- Tape the gap. A strip of medical tape or athletic tape across the bridge of your nose seals the top edge. An adhesive bandage works in a pinch.
- Rest your glasses on top of the mask. Pull the mask up higher on your nose and set your glasses over the mask fabric. This blocks the upward airflow.
- Treat your lenses. Washing them with soap and water before putting them on leaves a thin film that resists fogging. Anti-fog sprays and wipes do the same thing.
- Slide your glasses forward slightly. Moving them a few millimeters down your nose allows more air to circulate around the lenses, though this trades some visual comfort for less fog.
When Wearing a Mask Helps Most
Masks are most useful in specific situations rather than as an all-day-every-day habit. The CDC highlights several scenarios where masking adds a meaningful layer of protection: when respiratory viruses are surging in your community, when you or the people around you were recently exposed to an illness or are currently sick, and when you or someone close to you has risk factors for severe illness. Crowded indoor spaces during a local outbreak are a practical example.
Fitting Masks for Children
Kids need masks sized for smaller faces, and the range of sizes available has expanded significantly. KF94 masks, regulated by the South Korean government, come in toddler sizes (ages 2 to 5), small children’s sizes (ages 4 to 9), and older children’s sizes (ages 5 to 12). KN95 masks for children are typically labeled for ages 5 and up.
If you’re unsure which size to buy, flat-fold masks and masks with adjustable ear loops tend to adapt better to different face shapes. Buying small packs in a few different styles lets your child try them on and pick what feels comfortable. Middle-school-age kids who’ve outgrown children’s masks but swim in adult ones often do well with a small adult size. The same seal check applies: cup your hands around the edges and look for air leaking out the sides.
Storing and Reusing Masks
Disposable surgical masks are designed for single use and should be thrown away after wearing. N95 and KN95 respirators can be reused if they’re still in good shape. Between uses, store the respirator in a labeled paper bag rather than a plastic one. Paper allows moisture to evaporate, which discourages bacterial and mold growth. Let the mask air out for at least a day before wearing it again. If you rotate between several respirators, each one gets time to dry completely between wears.
Replace any mask that becomes visibly dirty, damp, stretched out, or hard to breathe through. If the nose piece no longer holds its shape or the straps have lost their elasticity, the mask can’t form a reliable seal.