Respirable droplets from whirlpools: measurements of size distribution and estimation of disease potential.

Droplets generated from water surfaces have been implicated in a number of diseases such as Legionnaires' disease and Pontiac fever. These droplets can be inhaled by people and can deposit in the respiratory system. The physical size of the droplets is critical in determining whether the droplets can contain the bacteria, reach the breathing zone of the subject, and deposit in the respiratory tract. The present study establishes the presence of water droplets above the surface of health club whirlpools. These droplets are of the appropriate size for causing respiratory disease. Several factors including pool temperature, bubbling action during operation, and height above the water surface have been investigated. The results are related to the deposition of the droplets, and hence bacteria, in the various regions of the respiratory tract.