[ad_1] Many people wear masks in public to slow the spread of COVID-19, as recommended by the Centers for Disease Control and Prevention (CDC). However, masks with exhalation valves do not slow the spread of the disease, and now new videos from the National Institute of Standards and Technology (NIST) …
Read More »New airflow videos show why exhalation valve masks don’t slow the spread of COVID-19 – ScienceDaily
