>If you are not using masks in the labs are you discouraging talking as another means of source control? See  https://www.nature.com/articles/s41598-019-38808-z

• speaking (as exemplified by counting aloud) releases about 2-10 times as many total particles as a single cough  
• droplet nuclei generated by singing is 6 times more than that emitted during normal talking and approximately equivalent to that released by coughing 
• counting aloud for 10=E2=80=89seconds followed by 10=E2=80=89seconds of breathing, repeated over two minutes, releases half as many particles as 30=E2=80=89seconds of continual coughing, which in turn releases half as many particles as saying "aah" for 30=E2=80=89seconds. 

> 

I am confused. The third bullet, above is quite specific. The first bullet is less specific but seems to cover the some topical region of speech produced particle emission vs. cough. The information in the two bullets seems inconsistent, or perhaps contradictory would be a better term. Both appear to be based on studies referenced in the above link. Given the contradictory results, what is their value and why relate them in this context?

Peter Zavon, CIH
Penfield, NY

PZAVON**At_Symbol_Here**Rochester.rr.com