In Frank Breslau’s letter to the editor, “We Should All Be Wearing Masks” (May 21, 2020), he writes that studies have demonstrated that “just talking can launch thousands of droplets that can remain suspended in the air for eight to 14 minutes.” Consequently, he concludes that one should wear a face mask when walking in the street.

Upon further study, I found that The New York Times, (May 15, 2020) states the following:

“Talking can also launch thousands of droplets so small they can remain suspended in the air for eight to 14 minutes. The research…could help explain how people with mild or no symptoms may infect others in close quarters such as offices, nursing homes, cruise ships and other confined spaces…its findings strengthen the case for wearing masks and taking other precautions in such environments to reduce the spread of the coronavirus.”

Subsequently, I accessed the abstract of this study, which was published last Wednesday in the Proceedings of the National Academy of Sciences. Below please find the abstract and note its last sentence:

“Speech droplets generated by asymptomatic carriers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are increasingly considered to be a likely mode of disease transmission. Highly sensitive laser light scattering observations have revealed that loud speech can emit thousands of oral fluid droplets per second. In a closed, stagnant air environment, they disappear from the window of view with time constants in the range of 8 to 14 min, which corresponds to droplet nuclei of ca. 4 µm diameter, or 12- to 21-µm droplets prior to dehydration. These observations confirm that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments.”

In short, Mr. Breslau’s position was based upon this one study, and the conclusion of this study is the need to promote the wearing of masks “in confined environments.”