Determining how to identify and manage indoor-air problems may appear straightforward. Instrumentation is nowadays capable of detecting pollutant concentrations at levels far below those considered to be a health hazard. Sophisticated, computer-controlled “smart” building systems are also available that enable parameters within large, multi-zone buildings to be set and maintained at required levels and that control other variables related to operating the buildings in response to outdoor climate. Buildings can also be designed so that indoor-air problems are prevented initially. Nevertheless, the frequency of media headlines on the consequences of indoor-air and indoor-environment problems indicates that much is still to be done in identifying and managing indoor-air deficiencies. This paper explores the causes behind indoor-air problems, particularly when measurements do not identify any problems and everything has been done properly. On the basis of the given illustrations, options for ensuring good air quality in complex and ever-changing indoor environments are discussed in this paper.

Key terms building system; health guideline; indoor air; indoor-air problem; infection; occupational environment; submicrometer particle; ventilation