Editor's note. This article is worth reading a couple of times as it explains the extraordinary level of efficiency achieved by IQAir Air Purifiers.
Why are MPPS Tested HyperHEPA filters better than at 0.3 tested filters?
The current 0.3 micron DOP test for particulate filters was developed in the 1950s. While it gives some performance guidelines for the efficiency of particulate filters, it does not tell us anything about which particles the filter is least efficiency at filtering. While an HEPA filter may filter out 99.97% of particles at 0.3 microns, it may filter significantly less at smaller particle sizes.
The EN (European Norm) 1822 is a two part test, which identifies the particle size, which penetrates the HEPA filter most easily, hence the name MPPS (Most Penetrating Particle Size). EN 1822, which was released in the year 2000 is world's most advanced and stringent air filter standard for particulate filters. Many high-tech manufacturers such as Intel already require their filter suppliers to supply them with proof of efficiency at MPPS.
The first part of the test determines which particles penetrate most easily through the HEPA media. Since the efficiency is strongly correlated to the speed with which the air passes through the media, this is done exactly at the speed, which is present under actual conditions of use. When the most penetrating particle size has been determined (e.g. 0.16 microns), this information is used in the second part of the test.
Part 2 of the EN 1822 test uses a test rig in which the HEPA filter is challenged only particles of the most penetrating particle size (e.g. 0.16 microns). This creates an absolutely worst case scenario for the filter.
IQAir's HyperHEPA filter elements are currently the first filters in an air cleaner to have been type-tested inside the IQAir housing by an independent filter testing laboratory (Filtech Laboratories Switzerland).
IQAir's HyperHEPA filter was rated at a worst case efficiency of > 99.95% for airflow rates up to 190 m3/h (112 cfm) and > 99.5% for up to 475 m3/h (280 cfm).
IQAir is the world's only air cleaner manufacturer that certifies and guarantees each and every HealthPro series air cleaner to provide a total certified system efficiency of over 99.97% at 0.3 microns. Each air cleaner is individually tested at the factory and issued a Certificate of Performance to guarantee this minimum efficiency.
While the efficiency at 0.3 micron gives some indication of filter efficiency for particles it doesn't give you a worst case performance scenario. IQAir is at the current edge in determining this for its air cleaners. Independent testing has determined that the absolute worst case efficiency at any particles size is better than 99.5% for speeds 4, 5 and 6 and 99.95% for speeds 1, 2 and 3.