Test method to measure the efficiency of air filtration media against spherical nanomaterials from 3 to 500 nm

The filtration of airborne nanoparticles is becoming an important issue as they are produced in large quantities from material synthesis and combustion emission. Current international standards dealing with efficiency test for filters and filter media focus on measurement of the minimum efficiency at the most penetrating particle size. The available knowledge and instruments provide a solid base for development of test methods to determine the effectiveness of filtration media against airborne nanoparticles down to single-digit nanometer range. An interlaboratory evaluation is performed under the Technical Committee 195 of European Committee for Standardization (CEN/TC195) for the development of the methodology to determine effectiveness of filtration media against air-borne particles in the 3 – 500 nm range. Five different laboratories, ETH/Empa, University of Minnesota (UMN), Politecnico di Torino (Polito), Unifil and Camfil participate in the round robin test in order to ensure the accuracy of the test method and provide a characterization of the filter media filtration efficiency by performing statistical analysis according to ISO 5725-2.