Combined aircraft measurements and model simulations show that dust is a source of reactive iodine. The added dust iodine leads to significant regional tropospheric ozone depletion. The results are reported in Science Advances

Ozone depletion in airborne dust layers has been frequently measured but it remains poorly understood. This study shows that dust is a source of active iodine, indicated by aircraft observations of iodine oxide (IO) radicals inside lofted dust layers from the Atacama and Sechura Deserts that are up to a factor of 10 enhanced over the background. The resulting iodine concentrations lead to efficient ozone destruction inside the dust layer (up to 75% depleted). This ozone depletion can potentially affect surface air quality in urban regions exposed to dust intrusions. This previously unrecognized aeolian source of iodine is thought to result from the reduction of iodate to form volatile iodine species although the underlying mechanism still remains elusive.   Theodore K. Koenig, Rainer Volkamer, Eric C. Apel, James F. Bresch, Carlos A. Cuevas, Barbara Dix, Edwin W. Eloranta, Rafael P. Fernandez, Samuel R. Hall, Rebecca S. Hornbrook, R. Bradley Pierce, J. Michael Reeves, Alfonso Saiz-Lopez and Kirk Ullmann. Ozone depletion due to dust release of iodine in the free troposphere, Science Advances, DOI: 10.1126/sciadv.abj6544