I-EN 149 iyindinganiso yaseYurophu yokuhlola kanye nezidingo zokumaka zokuhlunga imaski ewuhhafu. Izifihla-buso ezinjalo zivala ikhala, umlomo nesilevu futhi zingase zibe namavalvu okuphefumulayo kanye/noma okukhipha umoya. I-EN 149 ichaza amakilasi amathathu anjalo imaski eyingxenye yezinhlayiyana, ebizwa ngokuthi i-FFP1, i-FFP2 ne-FFP3, (lapho i-FFP imele ukuhlunga ubuso) ngokuya ngokusebenza kahle kokuhlunga. Iphinde ihlukanise imaski ibe 'ukusetshenziswa kweshifu eyodwa kuphela' (ayisebenziseki kabusha, ephawulwe ngokuthi i-NR) noma 'ingasetshenziswa kabusha (i-shift engaphezu kweyodwa)' (ephawulwe ngokuthi R), kanye nohlamvu olwengeziwe lokumaka D lubonisa ukuthi imaski iphumelele ukuhlolwa kokuvala okungakhethwa kusetshenziswa uthuli lwe-dolomite. Izihlungi ezinjalo zokuphefumula zivikela ekuhogeleni izinhlayiya ezinjengezinhlayiya zothuli, amaconsi, nama-aerosol.
