The N95 respirator is a specialized personal protective device designed to filter at least 95% of airborne particulates, such as dust, aerosols, and biological agents, when worn correctly. This device is classified as a filtering facepiece respirator, meaning that the entire mask acts as the filtering medium for air passing through it. For the N95 to function effectively, it must create and maintain a complete seal against the wearer’s face, ensuring that all inhaled air passes only through the filter material. The two-strap system is a fundamental design element that helps achieve the necessary tight fit around the face, unlike looser surgical or cloth masks. Without a proper fit, the mask offers little more protection than a standard barrier mask, as contaminants can bypass the filter by entering through gaps around the seal.
Preparation and Inspection Before Use
Before attempting to put on the respirator, perform thorough hand hygiene, either by washing hands with soap and water for at least 20 seconds or by using an alcohol-based hand sanitizer. This step minimizes the risk of transferring contaminants to the inner surface of the mask or your face during the donning process. Once your hands are clean, inspect the N95 respirator for any signs of damage. Check the mask material for tears, punctures, or excessive moisture, and confirm the metal nosepiece is intact. The elastic straps must also be examined to ensure they are not broken, frayed, or stretched out, as their tension is responsible for maintaining the seal.
Step-by-Step Donning Procedure
The process of putting on an N95 respirator begins by cupping the mask in one hand, with the nosepiece resting at your fingertips. Allow the two elastic head straps to dangle freely below your hand, ensuring they are not twisted or tangled. Place the cupped mask firmly over your chin and nose so that the material covers both your mouth and nose completely. Continue holding the respirator firmly against your face with one hand to maintain its position.
With your free hand, pull the bottom elastic strap over your head and position it around the back of your neck, securely below your ears. Next, pull the top elastic strap over your head and place it high on the back of your head, resting near the crown. Ensure that both straps lie flat against your head and are not crossed over each other, as crossing can compromise the tension required for a complete seal.
After the straps are positioned, use the fingertips of both hands to mold the metallic nosepiece to the shape of your nose. Start by pressing down firmly at the center, and then work your way outward, pressing inward along both sides to create a tight, customized fit over the bridge of your nose. This shaping step is critical for eliminating the common leak point near the eyes. Adjust the placement of the mask on your face slightly until it feels comfortably snug and secure.
Performing the User Seal Check
Immediately after donning and adjusting the N95, you must perform a user seal check to verify that no air is leaking around the edges of the mask. This check is required every time the respirator is put on, but it is not a substitute for a professional fit test. The procedure involves two methods: the positive pressure check and the negative pressure check.
The positive pressure check is performed by gently exhaling while covering the entire surface of the mask with your hands. If a proper seal is achieved, you should feel a slight increase in pressure inside the mask with no air escaping. For the negative pressure check, cover the mask surface with your hands and inhale sharply. A successful negative pressure check will cause the mask material to pull inward or collapse slightly toward your face. If you detect any air leakage during either test, readjust the nosepiece or the straps and repeat the seal checks until a complete seal is confirmed.
Safe Removal and Disposal
The process of safely removing the N95, known as doffing, must be handled carefully to prevent contamination. Throughout the removal, you should avoid touching the front surface of the mask, as this area is considered contaminated. Only touch the elastic straps when taking the mask off your head. First, pull the bottom strap over your head without touching the mask itself.
Next, remove the top strap by pulling it over your head while holding it away from your face and hair. Once both straps are off, dispose of the N95 immediately into a waste receptacle, still holding it only by the straps. The mask should be discarded if it is dirty, damaged, or if breathing through it becomes difficult. As the final safety step, perform hand hygiene using soap and water or hand sanitizer.