Halogens impacting atmospheric chemistry: An old story with a new twist
Prof. dr. Lucy Carpenter
Wolfson Atmospheric Chemistry Laboratories
University of York
In addition to their role in stratospheric chemistry, it emerged several decades ago that halogens also play a role in the chemistry of the troposphere, as indicated from the observation of sudden
decreases in surface ozone in the Arctic during spring. More recently, it has been shown that halogens have a pervasive impact on tropospheric ozone across the world’s oceans. The majority
of halogen-related surface ozone destruction is attributable to iodine chemistry. For several decades the main source of iodine was considered to be oceanic emission of volatile halogenated
organic compounds. More recently, laboratory studies established that inorganic iodine is emitted from ocean waters following the reaction of O 3 with iodide at the air-sea interface. This reaction also directly removes O 3 from the atmosphere, representing a negative feedback mechanism for tropospheric ozone. This presentation discusses advances made in understanding the chemistry and exchange of halogenated gases across the ocean surface and the subsequent impacts on the
atmosphere.
Lucy Carpenter is a Professor and Deputy Head of Department (Research) in Chemistry at the University of York. Lucy studied Chemistry at the University of Bristol and then carried out her PhD in experimental atmospheric chemistry at the University of East Anglia. She moved to York as a lecturer in 2000 and was promoted to Professor in 2009. After having children she worked part-time from 2003 -2016. Her group studies the complex interaction between the oceans and the atmosphere, in particular the chemistry of reactive halogens, organic carbon, and reactive nitrogen. She helped establish and is Director of the Cape Verde Atmospheric Observatory and was a lead chapter author of the WMO/UNEP 2014 and 2018 Scientific Assessments of Ozone Depletion. In 2006 she was awarded a Philip Leverhulme Prize, in 2015 the Royal Society Rosalind Franklin Award, in 2017 a Royal Society of Chemistry Tilden Prize and in 2018 a Royal Society Wolfson Merit Award.