Does this video of an air quality monitor’s danger signal prove it is unhealthy to wear one of the surgical masks recommended to slow the spread of COVID-19? No, that’s not true: The screen on the gadget in the video, according to the user manual and an instructional video for the Honeywell device, indicates either a fault with the device or that the man in the video was breathing directly into the air monitor intake tube. The Centers for Disease Control and Prevention (CDC) has published multiple scientific studies indicating surgical masks are safe. Tens of thousands of surgeons, nurses, and operating room staff wear them daily. The consensus of public health research is that mask-wearing protects the mask-wearer from breathing in viruses carried through the air by tiny water droplets and reduces the spread of disease by curtailing droplets breathed out.