What we Think we Know about Ventilation

The amount of outdoor air ventilation in buildings is one of the most important determinants of indoor air quality, but many critical questions and misunderstandings exist. First, given the importance of ventilation, how well do we know how much outdoor air is even needed in buildings? While research has been done on ventilation and odour perception and on ventilation and symptom prevalence, is it adequate to support the ventilation requirements in our standards and regulations? While this research and many years of designing and operating buildings have been used to develop ventilation requirements in standards and regulations, these requirements treat all buildings the same. Can we provide understandable and practical ventilation requirements that address the tremendous variability in buildings and occupants? While much time and effort is spent developing and debating ventilation requirements, compliance with these requirements in design and ultimately operation is rarely given the attention that it deserves. Addressing actual ventilation performance in buildings requires measurement, which is more difficult to conduct in the field than often realized and is too often omitted from building management practice as well as indoor air quality research. When ventilation rates are measured, the results often reveal significant gaps between design intent and actual performance, which can have serious implications for both indoor air quality and energy. Given the importance of ventilation, the research that has been done and the many questions that remain, it is reasonable to ask how much we really know about ventilation.