Breakthrough is defined as the percentage of challenge gas that gets through the filter.

Testing was done at AQF Test Facilities as follows:
temp = 72F
humidity = 50% RH
dimensions = 5.25x5.25x1.5"
effective media velocity = 14.8 fpm

Several different filter constructions, challenge gases, and test parameters were used to create these curves.

Breakthrough is defined as the percentage of challenge gas that gets through the filter. Efficiency is defined as the percentage of gas that does not get through the filter.