Dr Tari Haahtela is professor emeritus of clinical allergology from University of Helsinki. He is the former Head of Skin and Allergy Hospital, Helsinki University Hospital. He has chaired the Finnish Asthma Programme 1994-2004 and the Allergy Programme 2008-2018. His group has studied the environmental and lifestyle determinants of allergy and asthma In the Finnish and Russian Karelia. The results led to the biodiversity hypothesis of allergy and health in general. He was Honorary President of the EAACI Helsinki Meeting in 2017.