The HEPA filter traps particles as small as .3 microns with an efficiency of 99.97%.
To give you an idea of the size of a micron, it takes 24,500 microns to equal 1 inch ( 2.54cm ).
A particle of 10 microns is invisible to the naked eye. Pollen ranges between 5-100 Microns. Human hair is between 70-100 microns.
The rating for a HEPA filter is based on capturing nearly all microns 0.3 in size because 0.3 microns are the hardest size to trap and the optimal size for passing into the human respiratory system. Therefore the 0.3 micron efficiency rating sets the highest standard.
A HEPA filter is so efficient that for every 10,000 particles that enter the filter within its filtering range, only 3 particles will get through.
Surprisingly, HEPA filters become even more efficient the longer they are in use. For this reason HEPA filters are used in environments that rely on high clean-air standards. |
