A commonly asked question.
Breaking down the table:
Filter performance refers to the reduction in concentration various aerosols in the air that pass through the filter
Test Agent refers to the aerosol that is used for the test, in this case, Salt Water (NaCl)
Total inward leakage is the amount of aerosol that enters the facepiece after 3 minutes in a test chamber.
Pressure Drop is the resistance air is subjected to as it moves through the respirator filter.