The effciency of an absolute rated filter is directly related to the Beta ratio.
Beta ratios are given for specific micron ratings. For example, a B10 = 200 means that a filter has a Beta ratio of 200 for a 10 micron size. a B5 = 200 would have Beta ratio of 200 for a 5 micron size.
The efficiency of the filter is determined by taking the Beta ratio minus one, dividing it by the Beta ratio, and then multiplying by 100. An example for a Beta ratio of B10=200 is --> [(200 - 1) / 200] X 100 = 99.5%. So this filter is 99.5% efficient in removing particles of 10 micron size.
