Respirator and Mask Fit Guide
Filtration media is only part of respiratory protection. For tight-fitting respirators, air should pass through the filter rather than leak around the edges.
How to check the fit
Position the respirator over your nose and under your chin, shape the nosepiece if present, and check the perimeter for obvious gaps. NIOSH advises checking for leaks each time a respirator is put on.
Common causes of gaps
Wrong size, incorrect positioning, facial hair, glasses or jewelry can interfere with the seal. If a model will not seal, try a different size or style.
Workplace fit testing is different
A casual user seal check is not a substitute for required occupational fit testing. Follow employer and OSHA/NIOSH requirements when respirators are used for workplace hazards.
Safety note: Fit, product standard, intended use and individual circumstances matter. For occupational respiratory protection, follow your employer's program and applicable NIOSH/OSHA requirements. This site is educational, not medical advice.