Christina Bax of the Perelman School of Medicine co-authored a study that found human speech can emit small respiratory droplets that can linger in the air for more than eight minutes, potentially contributing to the spread of the coronavirus.
https://www.washingtonpost.com/health/experiment-shows-human-speech-generates-droplets-that-linger-in-the-air-for-more-than-8-minutes/2020/05/13/7f293ba2-9557-11ea-82b4-c8db161ff6e5_story.html The Washington Post