Before revision:  While the initially near unity infection probability due to droplets (airborne/ballistic) rapidly decays within the first 25s, the small yet persistent infection probability of airborne desiccated nuclei decays appreciably only by  1000s  . Combined with molecular collision theory adapted to calculate frequency of contact between the susceptible population and the droplet/nuclei cloud, infection probabilities are used to define infection rate constants , ab-initio, leading to a SEIR model .
After revision:  While the initially near unity infection probability due to droplets rapidly decays within the first 25s, the small yet persistent infection probability of airborne desiccated nuclei decays appreciably only by 1000s . Combined with molecular collision theory adapted to calculate frequency of contact between the susceptible population and the droplet/nuclei cloud, infection probabilities are used to define infection rate constants , ab-initio, leading to a SEIR model .