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Risico verspreiding covid19 via aerosolen in een klaslokaal

Plasmamade-Aorsolen-berekening-klaslokalen-en-retail
Estimation of COVID-19 aerosol transmission in a university classroom

Input Parameters

Value

Value in other units

Source

Surface area

sq ft

=

m2

Typical value

Height

ft

=

m

Typical value

Volume

m3

Faculty / instructors

person

Typical value - Assumed constant

Surface area per student

sq ft

=

m2

CU-Boulder: 60-120 sq ft / person. UNC = 36 sq ft / person. See Readme

Students

people

You can change this number directly, then the previous input of area per student is not used

Breathing rate (instructor)

m3/h

Estimated from Miller et al. (2020), for someone talking a lot

Breathing rate (students)

m3 / h

Estimated from Miller et al. (2020), for someone occasionally talking

Duration of class period

min

h

Typical value

Ventilation w/ outside air

h-1

L/s/per

First value is the same as "air changes per hour". Second is used in most guidelines now

Decay rate of the virus

h-1

Average of literature values (0 and 0.62), Miller et al. (2020)

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

E.g. UV disinfection, personal HEPA air cleaner, etc.

Total first order loss rate

h-1

CONDITIONAL RESULT: Case in which instructor is infected, students are susceptible

Quanta emission rate (instructor)

q h-1

Mask efficiency for emission

See readme sheet

Net emission rate

q h-1

Avg Quanta Concentration

q m-3

Equation (4) in Miller et al. (2020)

Mask efficiency for intake

Quanta inhaled per student

quanta

Probability of infection (1 student)

Equation (1) in Miller et al. (2020). This assumes instructor was infected. See "Campus" sheet for more general case

Number of COVID cases arising

CONDITIONAL RESULT: Case in which student is infected, other students and instructor are susceptible

Quanta emission rate (student)

h-1

Mask efficiency for emission

See readme sheet / Assume potentially different masks types for students and instructor

Net emission rate

q h-1

Avg Quanta Concentration

q m-3

Equation (4) in Miller et al. (2020)

Mask efficiency for intake

Quanta inhaled per person

quanta

Using instructor breathing rate

Probability of infection (1 person)

Equation (1) in Miller et al. (2020). This assumes 1 student was infected. See "Campus" sheet for more general case

Number of COVID cases arising

This is for one lecture only, of the length specified above. For a whole semester, see "Campus" sheet