During the decade of the 30's William Wills published and article commenting the capacity of infection of the flugge drops. Wills also studied the properties of ultraviolet light for air control. In the 60's other investigators reported the air transmission of several infections including tuberculosis, influenza and measles.

Later findings showed that fungus spores, including aspergillus fumigatus can be found on different surfaces.

A study was recently published relating of an investigation which showed that taking several samples in an operating room proved that there was the presence of microorganisms and other elements such as lint, fiber, etc.

Air conditioning in hospitals is fundamental in the prevention of infections inside the hospitals. Not all of the areas of a hospital maintain the same temperature, pressure, and air renovation.

Air conditioning contributes in improving health as a result of controlling the temperature, humidity, cleanliness, and movement of the air. Doctors firmly recommend that areas of patients must have air conditioning.

An efficient air filtration system alleviates the suffering in patients with asma or allergies.