The guidelines are targeted at public health professionals involved in prevent- ing health risks of environmental exposures as well as specialists and authorities involved in the design and use of buildings, indoor materials and products. The guidelines are based on the accumulated scientific knowledge available at the time of their development. They have the character of recommendations. Nev- ertheless, countries may wish to use the guidelines as a scientific basis for legally enforceable standards. The evidence review supporting the guidelines for each of the selected pollut- ants includes an evaluation of indoor sources, current indoor concentrations and their relationship with outdoor levels, as.
