States that maintenance of the microenvironment at desired levels of temperature, humidity and contamination (gaseous and particulate) contributes to the physiological well-being of the animal during routine housing or animal transport. When the physical factors are not properly controlled, physiological and psychological responses may occur and the behaviour and metabolism of the animal may be affected. Points out that much of what is known about the design of heating, ventilation and air conditioning systems in animal facilities is based on experience, as few systematic studies have been completed on this subject. Reviews the current knowledge in this field and demonstrates that additional research is needed to determine the optimum ventilation air quality and quantity for animal facilities.

KEYWORDS: Ventilation, indoor, air quality, animal housing, laboratory animal housing, microclimate