Viability of Long-Storaged Airborne Bacterial Aerosols

Radioactive tagged Escherichia coli cells were aerosolized from distilled water suspension and stored for 4 hr in a storage chamber where temperature and relative humidity were under control. It was found that increase of air temperature and or decrease of relative humidity increased the death rate. The death rate was proportional to the rate of water evaporation. The presence of chemical additives such as 0.85% sodium chloride solution, 0.20% glucose solution or nonradioactive growth medium all decreased the death rate. It is believed that the viability of airborne bacteria is affected by the presence of chemical additives due to their effect upon water evaporation. Bacterial aerosols from sewage treatment plants can survive a long time due to the presence of chemical additives. This should be considered as a potential hazard to public health.