Electronic structure calculations are used to survey possible reactions that HOI and I2
could undergo at night in the lower troposphere, and hence reconcile measurements and models. The reactions NO3
+ HOI and I2
are included in two models to explore a new nocturnal iodine radical activation mechanism, leading to a reduction of nighttime HOI and I2
. This chemistry can have a large impact on NO3
levels in the MBL, and hence upon the nocturnal oxidizing capacity of the marine atmosphere.