This note from the Spanish newspaper el Pais. Part of a long analysis of how COVID-19 propagates via aerosols. They don’t directly mention the ‘Trump shouting’ implications though.
speaking in a loud voice releases 50 times more virus-laden particles than when we don’t speak at all. These aerosols, if not diffused through ventilation, become increasingly concentrated, which increases the risk of infection. Scientists have shown that these particles –which we also release into the atmosphere when simply breathing and which can escape from improperly worn face masks – can infect people who spend more than a few minutes within a five-meter radius of an infected person, depending on the length of time and the nature of the interaction.
Five meters is sixteen feet four and a bit inches. The whole analysis of three scenarios (a social gathering in a private house, a bar, and a schoolroom) is a sobering read. Recommended.