Surgical
masks 医用外科口罩 yī yòng wài kē kǒu zhào are often simply
called face masks.
Note:
The photo shown are not N95 masks.
N95 masks filter out 95% particles 粒
子 lì zǐ larger than 0.3
microns in size. One micron is equal to one micrometer (1 μm).
See also
SI
Prefixes
If
this knol is helpful, please Like and Share it. Thanks.