how small is one micron
Micron. A unit of measure for the smallest of the small, One Micron is 0.001 mm or 0.00004 inch. A micron is really, really small. The width of a human hair is about 70 microns. Our eyes can see no smaller than 40 microns, and youâll need a decent microscope to see a particle 20 microns wide. Allergens like dust, smoke and bacteria are particulates that are often .3 microns or less. At that size, they can get deep into your lungs, because they arenât filtered well by your nose and throat.