“We found that cotton masks, surgical masks, and N95 masks all have a protective effect with respect to the transmission of infective droplets/aerosols of SARS-CoV-2“Effectiveness of Face Masks in Preventing Airborne Transmission of SARS-CoV-2 - PubMed
Guidelines from the CDC and the WHO recommend the wearing of face masks to prevent the spread of coronavirus (CoV) disease 2019 (COVID-19); however, the protective efficiency of such masks against airborne transmission of infectious severe acute respiratory syndrome CoV-2 (SARS-CoV-2)...pubmed.ncbi.nlm.nih.gov
You mean this NIH study?
Your study was published in October, 2020. The one @DriveInDriveOut pointed to was published this month. Seems the NIH has learned some things over the past 11 months.