Harrison's work has been recognised by award of the John Jeyes Medal and Environment Prize of the Royal Society of Chemistry and the Fitzroy Prize of the Royal Meteorological Society.  He has served for many years as a chair and/or member of advisory committees of the Department for Environment, Food and Rural Affairs (Defra) and the Department of Health.  He was appointed Order of the British Empire OBE in the 2004 New Year Honours for services to environmental science and elected a Fellow of the Royal Society (FRS) in 2017.