MPPS stands for the ‘Most Penetrating Particle Size’. For air filters, this is the size of particle that is easiest to get through the filter. It is a number, typically given in microns or nanometers.<\/p>\n\n\n\n
The EN1822 standard<\/a> defines the MPPS as:<\/p>\n\n\n\n MPPS<\/strong> Most penetrating particle size (= particle size, for which the filtration efficiency is a minimum)<\/p>\n\n\n\n Typically, the most penetrating particle size for an air filter is around 0.3 microns (0.3\u00b5m). That’s why you’ll see many HEPA filters being marketed as capturing 99.97% or 99.95% of 0.3 microns, just like this one:<\/p>\n\n\n\n However, 0.3 microns is not always the MPPS for an air filter or HEPA filter. The MPPS can vary depending on several factors.<\/p>\n\n\n\n The speed of air travelling through a HEPA filter can affect the MPPS. Think of the case where air is travelling faster through a filter. Bigger particles will have more momentum, and be able to push more easily through the filter. As the air speed through a HEPA filter increases, the MPPS decreases.<\/p>\n\n\n\n This graphic from a study on the MPPS of HEPA filters<\/a> shows the effect the air speed has on a filter’s MPPS. The MPPS (marked by the lowest point on the line) increases in size from 0.3 microns to 0.5 microns as the air speed decreases.<\/p>\n\n\n\n Learn more: what is the EN 1822 standard for air filters and HEPA filters?<\/a><\/p>\nWhat is the most penetrating particle size (MPPS) for air filters?<\/h3>\n\n\n\n
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<\/figure><\/div>\n\n\n\nWha affects the most penetrating particle size (MPPS) for air filters?<\/h3>\n\n\n\n
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