The enveloped virus, Φ6, was generally more susceptible than the non-enveloped one, MS2. Thus, the relative viability of Φ6 is shown on a log scale, whereas that of MS2 is shown on a linear scale. The relative viability of Φ6 was less than 10% in droplets containing NaCl at all RHs after 1 h (Fig 2B and 2D). At 20% RH, the relative viability was significantly lower in droplets containing NaCl, at concentrations of both 1 and 35 g/L compared to 0 g/L. At 50% RH, the relative viability was lowest in 1 g/L NaCl droplets, while it was significantly higher in droplets containing 0 and 35 g/L NaCl. At 80% RH, the relative viability was significantly higher in droplets containing 1 g/L NaCl compared to 35 g/L NaCl.