Abstract
This chapter reviews and discusses the World Health Organization (WHO) guidelines related to indoor air quality (IAQ). The WHO IAQ health guidelines are developed and published after systematic reviews of evidence from medical and public health studies, and through extensive panel discussion and expert consultation, which provide an important basis for countries to develop your national indoor air standards. First, a general background is provided for establishing health-based air quality guidelines, followed by a summary of the criteria for the inclusion and exclusion of specific pollutants in these documents and a summary of the values of the numerical guidelines for IAQ. The following is a summary of existing or planned national standards or guidelines for IAQ management, including monitoring, in countries around the world, and discussed in the context of the WHO IAQ guidelines. Globally, only several countries have enacted national indoor air quality standards or health guidelines. The importance of developing a national standard or guideline for indoor air quality based on health evidence is discussed as a measure to reduce indoor exposure.