For another set of data, NIOSH, the official US government agency tasked with certifying respirators and other PPE, has tested and released a large set of data,

For another set of data, NIOSH, the official US government agency tasked with certifying respirators and other PPE, has tested and released a large set of data, including masks that were already in volume production before the pandemic: https://www.cdc.gov/niosh/npptl/respirators/testing/default.html https://www.cdc.gov/niosh/npptl/respirators/testing/default.... https://www.cdc.gov/niosh/npptl/ppecase.html https://www.cdc.gov/niosh/npptl/ppecase.html