2.7. Dose-response modeling and risk characterizationThe risk for L. pneumophila infection was estimated for each of the sampling points. Average concentrations were calculated for each of the seasons,using the dose–response relationship for Legionnaire's disease and the estimated inhalation exposure. For disease transmission modeling, infection as the endpoint is considered more protective and useful over other endpoints such as illness and death (Buse et al., 2012). Infection risk estimation was calculated using the exponential model presented in Table 3 Eq. (3) (Armstrong and Haas, 2007b). Rw (d) is the predicted risk given the weekly dose d (cfu) multiplied by the model parameter for Legionella infection risk γ = 0.06 (1/cfu)