This book collects the main scientific contributions presented at a NATO Advanced Research Workshop entitled "Ventilation and Indoor Air Quality Requirements in Hospitals" that was held in Milan, Italy, from September 13-16, 1995. The workshop was made possible through the funding support of the NATO Scientific and Environmental Affairs Division and was sponsored and supported in part by the International Centre for Pesticide Safety, the Institute of Occupational Health ofthe University ofMilano, the Politecnico of Milano, and the United States Environmental Protection Agency. The workshop was held in the frame ofthe program ofthe NATO/CCMS Pilot Study on Indoor Air Quality and in conjunction with the international conference Healthy Buildings'95, whichwas attended by more than 500 delegates. The contents ofthe book are arranged in sixmainsections. The first section deals with the major issues related to indoor air quality in hospitals, that are reviewed from the North-American, Scandinavian, Italian and Russian perspective. The second section discusses the ventilation requirements in hospitals, with particular focus on design and maintenanceofthe ventilation systemsand provisionofclean air to critical areas, such as infectious disease wards, surgicaltheatres, etc. The third section is directed to chemical and biological air pollution in hospitals and collects papers from surveys carried out invarious countries. Airborne allergens in hospitals is the subject of section 4. New problems have arisen for the health care personnel from exposure to allergens and they are illustrated with studies performed in North­ America and England.