INDOOR VERSUS OUTDOOR CLIMATE

Investigations in this field have been carried out before. Some of them will be mentioned in conjunction with this investigation. The previous investigations were about pollutants that infiltrate a building or come in with the ventilation air. This was one of the reasons that so-called natural ventilation began to be abandoned in the 1950s. Prior to that, ventilation air was taken directly from the street. In fact, the conditions that will be investigated here received attention long ago. One of the reasons that the outdoor conditions have been considered is because of the transition from older ventilation systems to current ones, where air may be taken from roof level and subjected to some treatment and cleaning. Although the subject is understood at least qualitatively, it can be interesting to look at it again. Modern calcualtion methods make it easier to study the problem quantitively, i.e., to calculate the indoor concentrations that can arise as a result of pollutants in the outdoor air. Such calculations can also give an idea of how long high levels of pollutants can be maintained under various circumstances.