ffp2/pff2 Maskfrombrazil.com What is the difference between the PFF2 respirator and one with N95 certification? Respirators with PFF2 classification follow the Brazilian standard (ABNT / NBR 13698: 1996) and European and have a minimum filtration efficiency of 94%, while respirators with N95 classification follows the American standard and has a minimum filtration efficiency of 95%. Therefore, PFF2 and N95 respirators have equivalent protection levels.