SI-0. List of Supporting Information Items

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SI-1. Basic Terminology and Reference Data

SI-1.a. Definitions & Measurements

SI-1.b. Reference Data for Modelling

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SI-2. Spreadsheet Model for SARS-CoV-2 Pneumonia Development

Development towards SARS-CoV-2 pneumonia has a minimum starting infection which expands exponentially with a speed depending on the general defenses of the person involved. Lowest exposure is on day 1. High exposures imply a start as would be reached by the minimum starting infection days later. As soon as SARS-specific defenses build up, or medicines are given, the exponential rise diminishes and may reverse in a decline.

Basic input data may easily be varied: on speed of replication; share of intact virions towards new alveoli infection or to airways; share swallowed or exhaled.

SI-2.a. Spread sheet on exponentially rising SARS-2 virion production and emissions in an unconstrained alveolar infected person.

 

SI-3. Spaces with Special Ventilation

Some spaces have highly irregular forms, such as the inside of person cars and passenger airplanes. We specify the airplane room here based on industry data for a two-ails widebody. Ventilation in the airplane is not fully mixed and more flow oriented. We approach it with the fully mixed model.

SI-3.a. Airplane Person Density and Ventilation

 

SI-4. Model Description Closed Spaces

The model as described is applied in two steps, first the concentrations and next the potential exposures resulting.

SI-4.a. Model Description Closed Spaces

 

SI-5. Stocks Development and Concentration Development per m3, with different Emission Times and HalfLifes

SI-5.a. Stock and Concentration Development with HalfLife 15 Minutes

SI-5.b. Stock and Concentration Development with HalfLife 30 Minutes

SI-5.c. Stock and Concentration Development with HalfLife 60 Minutes

SI-5.d. Stock and Concentration Development with HalfLife 120 Minutes (Standard)

SI-5.e. Stock and Concentration Development with HalfLife 180 Minutes

SI-5.f.  Room Concentrations compared to those of Lednicky et al. (2020)

 

SI-6. Exposures in Closed Spaces, depending on Time of Emission Start and Period of Stay.

The tables are derived from the model as described in SI-4.a. The duration times of emission when a person enters varies from 1 minute to 48 hours. The period of stay varies between 1 minute and 2880 minutes (2 days). The exposures are quantified for a standard space of 20m3 with one standard person emitting 100,000 virions per hour and rising. This is equivalent to five emitting standard persons in a space of 100m3 and five standard emitters. The second variable is the Ventilation Rate, with VRs ranging from VR0 to VR60.

Exposures are potential exposures, without any SARS-2 control measures in place.

 

SI-6.a. Exposures under HalfLife 15

SI-6.b. Exposures under HalfLife 30

SI-6.c. Exposures under HalfLife 60

SI-6.d. Exposures under HalfLife 120 (standard)

SI-6.e. Exposures under HalfLife 180

 

SI-6.Table 1 Exposures all times-all periods-all half-lives and all VRs

With color indication of risk levels at durations of stay

SI-6.Table 2 Exposures HL120-all times-periods and VRS

With color indications per risk level

 

 

SI-7. Spreadsheet Model for Concentrations & Exposures

The spreadsheet is open for easy changes in input data. It is a not-continuous step model, per minute, see the barrel visualization

SI-7.a. Spreadsheet model for concentrations and exposures

SI-7.b. Modelling structure of SI-7a visualized as barrels

 

SI-8. Droplets with Virions and Mass Relations by Size

Virions concentrations tend to be given per watery volume, as per ml. We compute the number of virions per spherical droplet, their sizes measured in diameter. As volume goes by the cube of the radius, the volume size differences towards single virion size are extreme, see SI-8.a. Droplets below 5 micrometer evaporate before inhaling or touching the ground, and between 5 and 10 micrometer evaporation depends on circumstances. Measurement of such small sized droplets is possible in lab situations only. Real-life measurements of the number of viable virions in these small droplets are nearly fully lacking but see Lednicky, also in the main text.

SI-8.a. Virion Content of Droplets and Mass Relations

 

SI-9. Virions in Stool

Virions concentrations  in stool as measured in PCR-type tests can be very substantial. However, they might not all be viable. We use the numbers as an extreme exercise, indicating the need for better measurement of viable virions. There are a few studies finding viable SARS-2 virions in stool but without relevant quantification.

SI-9.a. Virions in Stool

 

SI-10. Exhales Modelling Options in Closed and Open Spaces

Exhales diffuse due to the composition and kinetics of the exhales. The resulting dilution is covered in an expanding cone, in the literature mostly set at 40 degrees, with speed reduced to low levels within half a meter. Inside diffusion is covered by these measurements and – limited – modelling. These data have been used in the main text.

Outside, even a low level of wind transports the virions while diluting them further. Empirical measurements close to our scale level of up to 15m are scanty. There is one exception covering the distance of over 100 meter. From these data it could be concluded that dilution is constant per distance, though faster winds result in this dilution faster. This corresponds to a constant opening dilution cone outside as well. It has been set at a much smaller cone opening of 10 degrees. A more detailed description in s SI-10.a.

SI-10.a. Exhales Diluted Inside & Outside

SI-10.b. Exhales Exposures-4 Cone models & 1 Virtual Room Model

SI-10.c. Concentration Reductions by Distance after Wu et al. (2018)

SI-10.d. Wu Concentrations measured at three points 60m apart

 

SI-11. Situations and Scenarios Quantified and Assessed

Common situations are combined with exposures resulting from time of stay, distance from exhalers, and other options for exposure. In SI-11.a. each situation is combined with relevant exposure scenarios. In SI-11.b. all situations with exposure levels are ordered as to level of potential exposure. Each situation is very shortly evaluated as to the quantified results, in SI-11.c.

SI-11.a. Situations quantified with their scenarios

SI-11.b. Scenarios ordered as to potential exposures

SI-11.c. Exposure situations evaluated

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