Airborne Viral Load Simulator (2D)

Room & Source

Infectors in room 1

Emission rate (breathing → loud talk) 25 q/hr

Ventilation (ACH) 3.0 /hr

Mask filtration (source + inhale) 0%

Room floor area (3 m ceiling) 120 m³

Live Readouts

Aerosol concentration C(t)

0.00 quanta/m³

Exposure time elapsed

0.0 min

Steady-state concentration

0.00 quanta/m³

Susceptible occupant infection risk

0.0%

How it works

This is the Wells–Riley model of airborne viral transmission, treating the room as one well-mixed volume V and infectious aerosol as "quanta" — the dose that infects 1 − e⁻¹ ≈ 63% of exposed people.

Mass balance:  dC/dt = G/V − λ·C
Steady state:  C_ss = G / (V·λ)
Inhaled dose:  D(t) = p·(1−η)·∫C dt
Infection risk: P = 1 − e^(−D)

G = q · I · (1−η)   (source strength, quanta/hr)
λ = ACH + λ_removal  (total 1/hr: ventilation + settling/inactivation)

Infectors I — how many infectious people are exhaling virus-laden aerosol into the room.
Emission rate q — quanta produced per hour per infector; rises sharply from quiet breathing to loud talking or singing.
Ventilation ACH — air changes per hour; higher airflow dilutes and removes quanta faster, pulling the steady state down.
Mask filtration η — reduces both the source term (exhaled quanta) and the susceptible occupant's inhaled dose, so its effect on risk scales roughly as (1−η)².
Room floor area — with ceiling height fixed at 3 m, a bigger room gives the same source more air to dilute into, lowering C for the same G and λ.

Real-world relevance: this is the same model epidemiologists use to size classroom/office ventilation and justify mask mandates — it's why cracking a window or running MERV-13 filtration measurably cuts transmission risk.

Drag inside the floor plan to pan, scroll/pinch to zoom — the top-down view supports the same free navigation as the original 3D room.

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Infector(s) Susceptible occupant Viral aerosol quanta