What is the difference between Absolute and Nominal micron rating?
Micron rating is the size of particles which are filtered out by filters at a certain efficiency. When this efficiency is at least 98.6%, we speak about absolute micron rating/filtration. Nominal micron rating is just a commercial trick for all efficiencies lower than 98.6%, meaning that for the same micron rating (for ex. 10 ยต) in the case of nominal rating, not all particles will be captured in the filter as in the case of absolute micron rating.
