A HEPA filter which utilizes spun bond scrim material and ePTFE membrane for use in an aseptic pharmaceutical filtration air handling system for installation and testing is provided. The installation and testing configuration includes the ePTFE filter with a low or ultra-low concentration of challenging aerosol in the upstream side of the filter along with a scanning device for determining the upstream concentration, all completed in situ within a pharmaceutical air handling system. At the downstream side of the ePTFE filter is positioned another scanner which may be a discrete particle scanner for calculating the penetration percentage of the aerosol through the filtering media of ultra-low concentrations. The system and configuration allows for exposure to ePTFE filtration media for certification by low or ultra-low concentrations of oil based challenging compounds.