The NIOSH Science Blog, "Do We Need to Challenge Respirator Filters with Biological Aerosols?" explains what is currently known about an important aspect of respirator filtration. NIOSH is seeking information and comments to assess whether NIOSH should consider additional filter test methods to enhance existing requirements. Are there any important developments in aerosol science or key scientific data that would better inform NIOSH on the filtration of biological aerosols? This request for information was published in a Federal Register Notice on March 14, 2014. Comments may be submitted directly to NIOSH Docket #272 through regulations.gov. Additionally, comments to this blog will be added to the docket. The deadline for comments to the docket is April 14, 2014.