The filtration efficiency of N95 masks on particles with aerodynamic diameter of 0.075 m±0.02 m was above 95%. The aerodynamic diameters of airborne bacterial and fungal spores vary mainly between 0.7 and 10 m, and are also within the range of the N95 mask. Therefore, N95 mask can be used for respiratory protection of some particulate matter, such as dust generated by grinding, cleaning and handling minerals, flour and some other materials. It is also suitable for liquid or non-oily particulate matter generated by spraying, which does not produce harmful volatile gas. Effective filtration and purification of inhaled odors (other than toxic gases) helps reduce exposure to certain inhalable microbiological particles (such as molds, bacillus anthracis, bacillus tuberculosis, etc.), but does not eliminate the risk of contact transmission, illness, or death.
N95 masks are one of nine types of particulate matter respirators certified by NIOSH, the National Institute for Occupational Safety and Health. N95 is not a specific product name. As long as the product meets the N95 standard and passes the NIOSH inspection, it can be called N95 mask. The filtration efficiency of particles with an aerodynamic diameter of 0.24±0.6 living m (physical diameter of 0.075 m±0.020 m) can reach more than 95%.
The N95 mask is one of nine NIOSH certified particle respirators. "N" stands for not resistant to oil. "95" means the concentration of particles in the mask is more than 95% lower than that outside the mask when exposed to a specified number of specialized test particles. 95% of these values are not averages, but minimums. N95 is not a specific product name, as long as it meets the N95 standard and is approved by NIOSH. The protection level of N95 means that the filtration efficiency of mask filter material for non-oily particulate matter (such as dust, acid mist, paint mist, microorganism, etc.) can reach 95% under the testing conditions stipulated by NIOSH standard.
The U.S. department of labor has recommended that health care workers use N95 masks to protect against airborne infections such as influenza and tuberculosis.
Safety standards
Other levels of anti-particulate masks certified by NIOSH include: N95, N99, N100, R95, R99, R100, P95, P99 and P100. These levels of protection are capable of covering the protection range of the N95.
"N" stands for not resistant to oil, suitable for non-oily particles.
"R" stands for oil resistant to oil, suitable for oily or non-oily particles. If it is used for protection of oily particles, it should be used for no more than 8 hours.
"P" stands for oil proof, suitable for oily or non-oily particulate matter. If used for oily particulate matter, the use time should follow the manufacturer's recommendations.
"95", "99" and "100" refer to the filtration efficiency level when testing with 0.3 micron particles. "95" means that the filtration efficiency is above 95%, "99" means that the filtration efficiency is above 99%, and "100" means that the filtration efficiency is above 99.7%.
