# berekening SARS-CoV-2 verspreiding zangkoor

*1*). Certain persons, known as superemitters, who release more aerosol particles during speech than do their peers, might have contributed to this and previously reported COVID-19 superspreading events (

*2*–

*5*). These data demonstrate the high transmissibility of SARS-CoV-2 and the possibility of superemitters contributing to broad transmission in certain unique activities and circumstances. It is recommended that persons avoid face-to-face contact with others, not gather in groups, avoid crowded places, maintain physical distancing of at least 6 feet to reduce transmission, and wear cloth face coverings in public settings where other social distancing measures are difficult to maintain.

Estimation of COVID-19 aerosol transmission: |
|||||||

This is a general spreadsheet applicable to any situation, under the assumptions of this model - See notes specific to this case (if applicable) at the very bottom |
|||||||

Important inputs as highlighted in orange - change these for your situation |
|||||||

Other, more specialized inputs are highlighted in yellow - change only for more advanced applications |
|||||||

Calculations are not highlighted - don't change these unless you are sure you know what you are doing |
|||||||

Results are in blue -- these are the numbers of interest for most people |
|||||||

Environmental Parameters |
|||||||

Value |
Value in other units |
Source / Comments |
|||||

Length of room |
ft |
m |
Can enter as ft or as m (once entered as m, changing in ft does not work) |
||||

Width of room |
ft |
= |
m |
Can enter as ft or as m (once entered as m, changing in ft does not work) |
|||

sq ft |
m2 |
Can overwrite the m2 one. If you want to enter sq ft, enter "=B15*0.305^2" in the m2 cell, where B15 is the cell w/ sq ft |
|||||

Height |
ft |
= |
m |
Can enter as ft or as m (once entered as m, changing in ft does not work) |
|||

Volume |
m3 |
Volume, calculated. (Can also enter directly, then changing dimensions does not work) |
|||||

Pressure |
atm |
Used only for CO2 calculation |
|||||

Temperature |
C |
||||||

Relative Humidity |
50 |
% |
Not yet used, but may eventually be used for survival rate of virus |
||||

Background CO2 Outdoors |
ppm |
See readme |
|||||

Duration of event |
min |
h |
Value for your situation of interest |
||||

Number of repetitions of event |
times |
For e.g. multiple class meetings, multiple commutes in public transportation etc. |
|||||

Ventilation w/ outside air |
h-1 |
||||||

Decay rate of the virus |
h-1 |
See Readme, can estimate for a given T, RH, UV from DHS estimator |
|||||

Deposition to surfaces |
h-1 |
Buonnano et al. (2020), Miller et al. (2020). Could vary 0.24-1.5 h-1, depending on particle size range |
|||||

Additional control measures |
h-1 |
||||||

Total first order loss rate |
h-1 |
Sum of all the first-order rates |
|||||

Ventilation rate per person |
L/s/person |
This is the value of ventilation that really matters for disease transmission. Includes additional control measures |
|||||

Parameters related to people and activity in the room |
|||||||

Total N people present |
Value for your situation of interest |
||||||

Infective people |
person |
Keep this at one unless you really want to study a different cases - see conditional and absolute results |
|||||

Fraction of population inmune |
|||||||

Susceptible people |
people |
Value for your situation of interest |
|||||

Density (area / person) in room |
sq ft / person |
||||||

Density (people / area) in room |
persons / m2 |
||||||

Density (volume / person) in room |
m3 / person |
||||||

Breathing rate (susceptibles) |
m3 / h |
||||||

Relative breathing rate factor |
Ratio between the actual and base breathing rates |
||||||

CO2 emission rate (1 person) |
L/s (@ 273 K and 1 atm) |
||||||

CO2 emission rate (all persons) |
L/s (@ at actual P & T of room) |
Previous, multiplied by number of people, and applying ideal gas law to convert to ambient P & T |
|||||

Quanta exhalation rate (infected) |
infectious doses (quanta) h-1 |
||||||

Q. enhancement due to variants |
1 for the original variant, can be higher for variants of concern. See Readme file. |
||||||

Relative quanta exhalation rate |
Dimensionless (ratio to breathing) |
For calculation of infection risk parameters. See Readme file. |
|||||

Exhalation mask efficiency |
0 if infective person is not wearing a mask. See Readme sheet |
||||||

Fraction of people w/ masks |
Value for your situation. It is applied to everybody for both emission & inhalation. Modify formulas manually if needed |
||||||

Inhalation mask efficiency |
|||||||

Parameters related to the COVID-19 disease |
|||||||

Probability of being infective |
|||||||

Hospitalization rate |
From news reports. Varies strongly with age and risk factors |
||||||

Death rate |
From news reports. Varies strongly with age and risk factors (1% typical - Higher for older / at risk people) |
||||||

CONDITIONAL result for ONE EVENT: we assume the number of infected people above, and get the results under that assumption |
|||||||

More appropriate to simulate known outbreaks (e.g. choir, restaurant etc.), and an worst-case scenario for regular events (if one is unlucky enough to have infective people in attendance of a given event) |
|||||||

Net emission rate |
infectious doses (quanta) h-1 |
Includes the number of infective people present |
|||||

Avg Quanta Concentration |
infectious doses (quanta) m-3 |
Analytical solution of the box model. Equation (4) in Miller et al. (2020) |
|||||

Quanta inhaled per person |
infectious doses (quanta) |
||||||

Conditional Results for A GIVEN PERSON & ONE EVENT (assuming number of infected above, typically 1) |
|||||||

Probability of infection (1 person) |
Applying Wells-Riley infection model to the amount of infectious doses inhaled. Equation (1) in Miller et al. (2020) |
||||||

Prob. of hospitalization (1 person) |
|||||||

Prob. of death (1 person) |
|||||||

Ratio to risk of car travel death |
times larger risk |
See FAQs for rough estimate of death traveling by car on a given day |
|||||

Conditional Results for ALL ATTENDEES & ONE EVENT (assuming number of infected above, typically 1) |
|||||||

Number of COVID cases arising |
Number of people. Multiplies probability of one person, times the number of susceptible people present |
||||||

N of hospitalizations arising |
Number of people |
||||||

N of deaths arising |
Number of people |
||||||

Airborne Infection Risk Parameters (From Peng et al., 2021, submitted) |
|||||||

Infection Risk Parameter (H) |
h2 person / m3 |
||||||

Relative Inf. risk Parameter (Hr) |
h2 / m3 |
||||||

Results for CO2 as an indicator of risk (not needed for infection estimation, can ignore for simplicity) |
|||||||

Avg CO2 mixing ratio |
ppm (including 400 ppm background) |
||||||

Avg CO2 concentration |
g m-3 (excluding 400 ppm background) |
Conversion from Atmos. Chem. Cheat Sheet, plus ideal gas law |
|||||

Exhaled CO2 re-inhaled per person |
grams (excluding 400 ppm background) |
This parameter is the most analogous to risk. See FAQ page for limitations |
|||||

Exhaled CO2 re-inhaled per person |
ppm * h (maybe easier units, excludes 400 ppm background) |
This parameter is the most analogous to risk. See FAQ page for limitations |
|||||

Exhaled CO2 re-inhaled per person |
%CO2 * h (same as above, different unit, for use next) |
||||||

Ratio of prob of infection to Ex_CO2 |
% chance of infection for 1 person per %CO2 * h inhaled |
||||||

CO2 to inhale 1 hr for 1% infect. |
ppm |
This is another metric of risk |
|||||

ABSOLUTE result for ONE EVENT: we use the prevalence of the disease in the community to estimate how many infected people may be present in our event, and calculate results based on that |
|||||||

More appropriate for general risk estimation, e.g. in a college classroom, indoor gathering etc., where often infective people will not be present |
|||||||

N of infective people present |
It has to be interpreted statistically. This would be the average over e.g. 100 repetitions of the event in a given location |
||||||

Absolute results for A GIVEN PERSON & ONE EVENT (using disease prevalence in community) |
|||||||

Probability of infection (1 person) |
|||||||

Prob. of hospitalization (1 person) |
|||||||

Prob. of death (1 person) |
|||||||

Ratio to risk of car travel death |
times larger risk |
See FAQs for rough estimate of death traveling by car on a given day |
|||||

Absolute results for ALL ATTENDEES & ONE EVENT (using disease prevalence in community) |
|||||||

Number of COVID cases arising |
Number of people |
||||||

N of hospitalizations arising |
Number of people |
||||||

N of deaths arising |
Number of people |
||||||

CO2 to inhale 1 hr for 1% infect. |
ppm |
This is another metric of risk |
|||||

ABSOLUTE result for events that are REPEATED MULTIPLE TIMES (e.g. many class meetings during a semester, or a daily commute on public transportation) - Ignore for a single event |
|||||||

Absolute results for A GIVEN PERSON & MULTIPLE EVENTS (using disease prevalence in community) |
|||||||

Probability of infection (1 person) |
|||||||

Prob. of hospitalization (1 person) |
|||||||

Prob. of death (1 person) |
|||||||

Ratio to risk of car travel death |
times larger risk (than traveling same N of days) |
See FAQs for rough estimate of death traveling by car on a given day |
|||||

Absolute results for ALL ATTENDEES & MULTIPLE EVENTS (using disease prevalence in community) |
|||||||

Number of COVID cases arising |
Number of people |
||||||

N of hospitalizations arising |
Number of people |
||||||

N of deaths arising |
Number of people |
||||||

Specific notes for this case |
|||||||

Probability of death is set higher because of the higher age of choir members (75% of those ill were >= 65 yr old). Suggest changing to 1% for general applications |
|||||||

Probability of being infective calculated from prevalence of the disease in the county at the time (7 cases * 2 to account for undetected cases / 129000 population of county), see Miller et al. 2020 |