Today the CDC finally made a statement that was obvious to everyone else; that aerosols can spread COVID-19.

The concept that a cloud of virus released into the air from someone singing or speaking loudly could persist for some period of time In a closed space and infect other people has been well accepted. In fact, the CDC seemed at odds with everyone else in not publicly acknowledging that potential.
The CDC’s new guidance indicates that SARS-COV-2, the virus that causes COVID-19, is most frequently spread among people in close contact with one another, through respiratory droplets produced when an infected person coughs, sneezes or talks. But what the agency published Monday on its website also acknowledged that under certain circumstances, people have become infected by smaller particles that can linger in the air in enclosed spaces that are poorly ventilated.
“Sometimes the infected person was breathing heavily, for example while singing or exercising,” the CDC said. In such cases, the CDC said, there’s evidence that the amount of smaller infectious droplets and particles that a contagious person produces “became concentrated enough to spread the virus to other people” – even if they were more than 6 feet away. In some cases, the CDC said, transmission occurred “shortly after the person with COVID-19 had left” the room.

The real impact of this guidance is not that anyone will act differently since most people were wearing respiratory protection. I think it is in understanding the risk involved in being in a closed space with many people. There should be no debate about the importance of using protective measures like masks In these situations.
Remember, this is something we won’t have to do forever. Since a vaccine appears to be on the horizon everyone should stay safe until it is available. We therefore have a good reason not to get infected right now!