Wells-Riley Airborne Transmission Model

Indoor CO₂ & Expected Infections
COVID-19 vs Influenza

60 people, 1 infectious person, 4-hour exposure. Each person talks ~2.5 minutes total; quiet and seated otherwise. Quanta emission rates are time-weighted averages of talking and resting.

COVID-19 (SARS-CoV-2)

q̅ = 28.4 q/hr · CI: 14.2 – 56.8 q/hr

Central estimate

95% confidence interval

Influenza

q̅ = 13.6 q/hr · CI: 7.1 – 21.5 q/hr

Central estimate

95% confidence interval

Occupants

1 infector · 59 susceptible

Exposure Time

4 hours

Continuous shared room

Activity Mix

~1% talking

2.5 min talk / 237.5 min quiet

COVID q (central)

28.4 q/hr

25 rest + 330 talk, weighted

Flu q (central)

13.6 q/hr

13 rest + 72 talk, weighted

Breathing Rate

0.30 m³/hr

Sedentary / seated

Outdoor CO₂

420 ppm

Background ambient

MODEL: P = 1 − exp(−I·q·p·t / Q) | VENTILATION: Q = n · 0.018 m³/hr / ΔPPM (fraction) | QUANTA SOURCES: Buonanno et al. 2020; Miller et al. 2021; Prentiss et al. 2022 | CI: ×0.5 / ×2 on central q — reflects strain, individual & measurement uncertainty. Not clinical guidance.