What to Know About Coronavirus and Air Conditioning, According to Medical Experts

As confirmed coronavirus cases in several former U.S. hotspots have begun to come down, cases are rising sharply in a number of states, a trend that's expected to with less social distancing protocols in place. Now, as the heat of the summer starts to settle in, there are concerns over how air conditioning could affect exposure.

Manish Butte, Ph.D. and associate professor in the department of microbiology, immunology, and molecular genetics at the University of California, spoke to Health about the matter. They believe that public settings with air conditioning might could be risky. The way air conditioning works is by circulating the air rapidly, removing the humidity. "Less humidity in the air promotes evaporation, which causes droplets in the air to dry up and disappear," Butte explains. So, given that water vapor holds onto heat, when there's less of it in the air, the room cools down.

The droplets themselves are mostly water, but they also can contain any pathogens, which includes coronavirus. A single cough can release about 3,000 droplets and a single sneeze can release up to 30,000 or more. These droplets can vary in size and distance traveled, and when an AC is turned on, airflow from the vent pushes these droplets through the air and potentially into other people. As Butte puts it, "the airflow direction is what matters."

Essentially, since air conditioning is recycled air, it can help the droplets — and the contagions therein — spread farther. Which, in turn, could result in more infections. Recent studies also suggest that the influx of new coronavirus cases are due directly to the rollbacks of social distancing protocols, which began to lift significantly around Memorial Day. There are currently more than two million cases in the U.S., an unfortunate milestone that has yet to be addressed by the White House.


Despite the spike in cases, U.S. Treasury Secretary Steve Mnuchin asserted in an interview with CNBC that similar actions won't be taken by the government in the future. "We can't shut down the economy again. I think we've learned that if you shut down the economy, you're going to create more damage," Mnuchin said. "And not just economic damage, but there are other areas and we've talked about this: medical problems and everything else that get put on hold."

As of Friday, Johns Hopkins University reports that there have been more than 114,000 deaths from COVID-19 in the U.S. More than 423,000 cases have been reported across the globe.