Galloway, Heather, and Javier Salas. 2020. “A room, a bar and a classroom: how the coronavirus is spread through the air.” EL PAÍS, October 28, 2020.
The risk of contagion is highest in indoor spaces but can be reduced by applying all available measures to combat infection via aerosols. Here is an overview of the likelihood of infection in three everyday scenarios, based on the safety measures used and the length of exposure.
Methodology: we calculated the risk of infection from Covid-19 using a tool developed by José Luis Jiménez, an atmospheric chemist at the University of Colorado and an expert in the chemistry and dynamics of air particles. Scientists around the world have reviewed this Estimator, which is based on published methods and data to estimate the importance of different measurable factors involved in an infection scenario. However, the Estimator’s accuracy is limited as it relies on numbers that are still uncertain – numbers that describe, for example, how many infectious viruses are emitted by one infected person. The Estimator assumes that people practice the two-meter social distancing rule and that no one is immune. Our calculation is based on a default value for the general population, which includes a wide range of masks (surgical and cloth), and a loud voice, which increases the amount of aerosols expelled. Videos by Luis Almodóvar.