ABSTRACT
Introduction Indoor environmental quality (IEQ) plays an important role for human health, comfort and performance. One of the main reasons is that humans in developed parts of the world spend 85 to 95 per cent of their time indoors (at home, at work, at school or when commuting). Indoor environmental issues received much attention in the mid-19th century and a renaissance of indoor environmental sciences was observed after the energy crisis during the 1970s when the tightening of buildings, use of new building materials and dramatic reductions of energy use resulted in numerous complaints from occupants of indoor spaces. A similar situation is likely to occur in the 2000s as the issue of climate change is reflected in the trend to, again, reduce energy used to create indoor environments, since it constitutes 30 to 40 per cent of the total energy use in buildings. To overcome this threat, emphasis is placed on maintaining IEQ as high as possible when energy reductions have been implemented (EPBD, 2002). This chapter will describe how IEQ can affect humans, without discussing the energy consequences of creating high-quality indoor environments. Emphasis will be placed on the thermal environment and air quality and their effects on health, comfort and performance. Although light and noise are also important constituents of IEQ, they will not be discussed here. Health is understood very broadly, reflecting the basic definition of the World Health Organization (WHO, 1948), which states that health is
