Development of WHO guidelines for indoor air quality: dampness and mould

Report on a WHO working group meeting held in Bonn, Germany, 17-18 October 2007

Microbial pollution is one of the key constituents of indoor air pollution. It consists of hundreds of species of bacteria and fungi, and in particular filamentous fungi (moulds) growing indoors when sufficient moisture is available. Health problems associated with moisture and biological agents include increased prevalence of respiratory symptoms, allergies, and asthma as well as
perturbation of the immunological system.

Based on the extensive review of the scientific evidence, this WHO working group identified the main health risks due to excess moisture, associated with microbial growth and contamination of indoor spaces. It also formulated WHO guidelines for protecting public health, recommending that persistent dampness and microbial growth on interior surfaces and in building structures should be prevented (or minimized) as they may lead to adverse health effects.