Table 1 Exposure of elderly residents in nursing homes to Legionella bacteria in water and aerosols while showering: five tested exposure scenarios
 Description Exposure calculation Scenario 1 (water quality) For each subject, exposure (E1) was the greatest Legionella concentration (Cwater) among the showers (s) he/she utilized (not more than four have been recorded)E1 represents the worst case exposure to water Legionella for s = 1–4 Scenario 2 (water quality) For each subject, exposure (E2) was the greatest average of Legionella concentrations (Cwater) across all the showers (s = 1–4) he/she utilized, based on the mean of water samples duplicatesE2 represents the average maximal exposure to water Legionella for s = 1 to 4 Scenario 3 (water quality) For each subject, exposure (E3) was the weighted average of Legionella concentrations (Cwater) (mean of water samples duplicates) across the different showers (s), where weighs are the number of showers (N) taken with each showerE3 represents the frequency-weighted exposure to water Legionella Scenario 4 (Aerosol quality) For each subject, exposure (E4) was the maximum Legionella concentration (Caerosol) across the showers (s) he/she utilizedE4 represents the worst case exposure to airborne Legionella for s = 1 to 4 Scenario 5 (Aerosol quality) For each subject, exposure (E5) was the weighted average of airborne Legionella concentrations (Caerosol), where weighs are the number of showers (N) taken with each showerE5 represents the frequency weighted exposure to airborne Legionella