Figure 5
From: Computational characterization of inhaled droplet transport to the nasopharynx
Quantifying virion transmission to the nasopharynx: (A) Graphical representation of the flow-averaged data on the percentage of droplets of each size undergoing deposition at the nasopharynx. (B) Distribution of droplet sizes ejected each minute during normal speaking, the numbers are calculated from earlier studies on expelled droplet tracking with food coloring7; the reported size distribution is for dehydrated droplets. Also note that the referenced article7 described the size bin limits as \(\alpha - \beta \) (in \(\upmu \)). For consistency, we typically interpreted that as droplet sizes (in \(\upmu \)) that are \(\ge \alpha \) and \(< \beta \); and in this graphic, such a droplet size bin range is represented by \([\alpha ,\beta )\), conforming to set theory notations. (C) Pie diagram showing which droplet sizes are dominant contributors for virion transmission at the nasopharynx, for ejecta size distribution as in (B). Symbol \(\mathbb {D}\) is the inhaled droplet diameter. The numbers assume that the droplets have undergone dehydration before being inhaled into the nasal airspace. (D) Estimated number of virions that are deposited at the susceptible individual’s nasopharynx via dehydrated inhaled droplets, during close-range exposure to a COVID-19 carrier for 5 min. Outputs in (A–D) in the above graphic respectively correspond to the steps marked by labels A–D in Fig. 2. The plots on (A,C) are generated using Microsoft Excel 365; link to software homepage.
