N95 respirator is one of nine NIOSH certified particle respirators. "N" means not resistant to oil. "95" means that the particle concentration in the mask is more than 95% lower than that outside the mask when exposed to a specified number of special test particles. 95% is not the average, but the minimum. N95 is not a specific product name. As long as the product meets N95 standard and passes NIOSH review, it can be called "N95 mask". The degree of protection is N95, which means that under the test conditions specified in NIOSH standard, the filtering efficiency of the filter material of the mask for non oily particles (such as dust, acid mist, paint mist, microorganism, etc.) reaches 95%.

The filtration efficiency of N95 respirator for particles with aerodynamic diameter of 0.075 μ m ± 0.02 μ m is over 95%. The aerodynamic diameter of air bacteria and fungal spores mainly varied between 0.7-10 μ m, which was also within the protection range of N95 respirator. Therefore, N95 respirator can be used for respiratory protection of some particles, such as dust generated in the process of grinding, cleaning and handling minerals, flour and some other materials. It can also be used for liquid or non oil particles that do not produce harmful volatile gases due to spraying. It can effectively filter and purify the abnormal smell inhaled (except toxic gas), help reduce the exposure level of some inhalable microbial particles (such as mold, anthrax, tuberculosis, etc.), but it does not eliminate the risk of contact infection, disease or death.

The U.S. Department of labor has recommended N95 masks for medical staff to prevent microbial air borne diseases such as influenza and tuberculosis.

Wash your hands before wearing the mask, or avoid touching the inner side of the mask during wearing, so as to reduce the possibility of contamination of the mask.

Distinguish the inside and outside, up and down of the mask.

Do not use your hands to squeeze the mask. N95 mask can only isolate the virus on the surface of the mask. If you use your hands to squeeze the mask, the virus will soak through the mask with the droplets, which is easy to cause virus infection.

Try to make the mask and face have a good fit. The simple test method is: after wearing the mask, exhale hard, and the air can't leak from the edge of the mask.

The protective mask must be close to the user's face, and the user must shave off his beard to ensure that the mask can close to the face. The beard and anything between the mask gasket and the face will cause the mask to leak.

After adjusting the position of the mask according to the face shape, press the nose clip with the index finger of both hands along the upper edge of the mask to make it close to the face [4] anchor point.

In case of the following conditions, the mask shall be replaced in time:

When respiratory impedance increased significantly;

When the mask is damaged or damaged;

When the mask and the face cannot fit tightly;

The mask is contaminated (such as blood stains or droplets, etc.);

The mask has been contaminated (used in individual ward or patient contact);

If the mask contains activated carbon, there is peculiar smell in the mask;

Use the mask longer than recommended.