The news: The US Centers for Disease Control and Prevention has updated its guidelines to acknowledge that the coronavirus can be spread by tiny particles that linger in the air. The agency said it made the decision because of the mounting evidence that people with covid-19 can infect people even if they are more than six feet away, or shortly after the infected person left the area. These cases all occurred in poorly ventilated and enclosed spaces, and often involved activities that cause heavier breathing, like singing or exercise. However, “the CDC continues to believe, based on current science, that people are more likely to become infected the longer and closer they are to a person with COVID-19,” it said in a statement. The long-coming update could help to finally clarify the situation after the CDC published guidance acknowledging airborne transmission and then suddenly retracted it last month.