MERV vs. MPR rating
Microparticle Performance Rating, or MPR for short, is a filter rating system developed by 3M to rate a filters ability to cature the smallest airborne particles. The higher the MPR rating the better the filters ability to capture particles from the air. This system helps in comparing 3M filters, but is not directly comparable to the MERV rating system.
If your filter at home is rated by the MPR system, here is a table to show you what the comparable MERV rating would be.
MPR rating Comparable MERV rating
300....................6
600....................8
1000..................11
1200..................11
1500..................12
1900..................12
2200..................12