You are comparing very different standards e.g. https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/default.html https://www.cdc.gov/niosh/npptl/topics

You are comparing very different standards e.g. https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/default.html https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part... N95 – Filters at least 95% of airborne particles. Not resistant to oil. Surgical N95 – A NIOSH-approved N95 respirator that has also been cleared by the Food and Drug Administration (FDA) as a surgical mask. N99 – Filters at least 99% of airborne particles. Not resistant to oil. N100 – Filters at least 99.97% of airborne particles. Not resistant to oil. R95 – Filters at least 95% of airborne particles. Somewhat resistant to oil. P95 – Filters at least 95% of airborne particles. Strongly resistant to oil. P99 – Filters at least 99% of airborne particles. Strongly resistant to oil. P100 – Filters at least 99.97% of airborne particles. Strongly resistant to oil. Additionally, see https://www.ecfr.gov/current/title-42/part-84 https://www.ecfr.gov/current/title-42/part-84