defined as the extent to which human requirements are met. But what requirements
do people have in relation to indoor air? The desire is that the air be
perceived as fresh and pleasant, that it has no negative impact on their health,
and that the air is stimulating and promotes their work, i.e. it increases their
productivity and the learning of their children in the classroom at school. Present
ventilation standards and guidelines do not care about productivity and learning
and have the very modest requirement that the indoor air shall be acceptable,
meaning that the most sensitive group of persons (usually 20%) perceive the air
as unacceptable while the remaining less sensitive persons may find the air barely
acceptable. With such a modest aim it&n
