Modelling the Impact of Reactive Halogens on Tropospheric Ozone

Naturally emitted halogen species (chlorine, bromine and iodine) are known to play an important role in the chemistry and oxidizing capacity of the troposphere. Halogens participate in catalytic reaction cycles that efficiently destroy ozone, change the HO_x and NO_X partitioning, affect the oxidation of volatile organic compounds (VOCs) and mercury, reduce the lifetime of methane, and take part in new particle formation. Numerical models predict that reactive halogen compounds account for 30% of O₃ destruction in the marine boundary layer and 5-20% globally. This communication will explore the impact of halogens on tropospheric ozone as modelled at different spatial scales and over different environments, from the tropics to the polar regions.