Professor Kelly holds the chair in Environmental Health at King's, where he is Director of the Environmental Research Group, Director of the NIHR Health Protection Research Unit on Environmental Hazards and Deputy Director of the MRC-PHE Centre for Environment & Health.

Professor Kelly leads a substantial research activity which spans all aspects of air pollution research from toxicology to science policy. He has led studies of the urban airshed within London including the impact of the introduction of London’s Congestion Charging Zone and Low Emission Zone. During his leadership the London Air Quality Network has developed into a 1st class dissemination and education resource for London residents.