Table 3.
Summary of recent studies on expansions of the Wells-Riley model for COVID-19.
| Ref. | Modification | Quanta emission rate () value (quanta/h) | Calculating method for value |
|---|---|---|---|
| Buonanno et al. (2020) | Integrate time-varying quanta concentration | > 100 (asymptomatic, vocalization, light activities) < 1 (symptomatic, resting condition) | Estimate based on the viral load in expiratory particles and the quanta-RNA copies correction factor, which are influenced by different respiratory activities, and different activity levels |
| Sun and Zhai (2020) | Introduce social distance index and ventilation factor | 856.8 (speaking, droplet transmission) | Back-calculate with other known parameters from actual pandemic cases |
| Dai and Zhao (2020) | Introduce filtration effect of masks | 14–48 (asymptomatic, light exercise) | Estimate with the basic reproductive number of COVID-19 based on the fitted equation |
| Zhang and Lin (2020) | 1. Dilution-based | - | - |
| 2. Consider spatially and temporally non-uniform | |||
| Kriegel et al. (2020) | 1. Integrate time-varying quanta concentration | 139 (breathing/ speaking, sitting/ standing) | Estimate with the basic reproductive number of COVID-19 based on the fitted equation, and modify according to human activity levels |
| 2. Consider time-dependent viability of the virus | |||
| Miller et al. (2021) | 1. Integrate time-average quanta concentration | 970 ± 390 (singing/ vocalization) | Back-calculate with other known parameters from actual pandemic cases |
| 2. Consider deposition and virus decay |