N95 day 2018 NIOSH classifies the filtering media in respirators based on its resistance to oil and its particle filtering efficiency. The resistance to oil is designated as “N”, “R”, or “P”. Particle filtering efficiency is designated “95”, “99”, or “99.97”. NIOSH Respirator Trusted-Source: https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/RespSource.html NIOSH Respirator Selection Logic: https://www.cdc.gov/niosh/docs/2005-100/pdfs/2005-100.pdf Publication date from document properties. N95RespirClassesInfographic-508.pdf

Stephen B. Thacker CDC Library collection