Comparing the effect of Natural Halogens on Tropospheric Ozone Chemistry between Pre-Industrial and Present-Day

JAVIER A. BARRERA; DOUGLASS KINNISON; ALFONSO SAIZ-LOPEZ

Boulder, CO, USA

Congreso; Atmosphere Model, Chemistry Climate & Whole Atmosphere Working Group Meeting 2023; 2023

National Center for Atmospheric Research

Reactive halogens (X+XO, X= I, Br or Cl) catalytically destroy a fraction of tropospheric ozone under present-day (PD) conditions, however, their distribution and potential impact on tropospheric ozone under pre-industrial (PI) conditions remain largely unexplored. This study uses the Community Atmospheric Model with Chemistry (CAM˗Chem) to compare the effect of natural halogens on tropospheric ozone between PI and PD. Model results show that the impact of halogens on ozone changes with the increase in anthropogenic ozone precursor emissions from PI to PD, which drives an enhancement in the inorganic halogen budget, as well as a change in the partitioning of inorganic halogens. As a result, the global tropospheric ozone depletion due to natural halogens is more sensitive in PI than PD