Trace metals acting as catalysts in a marine cloud: a box model study

A marine cloud includes a limited number of reactive compounds. Major speci es are hydrogen peroxide and ozone which are activated by photochemistry an d RedOx cycling with trace metals. If we put the trace metals into the reac tivity scheme, catalytic cycles appear and completely drive the reactivity even at the very low concentrations found in non polluted areas. This incre ases the speed of the reactions involving OH, HO2 and O-2(-) radicals. Unde r these conditions, the reaction of an added dissolved reactive species can be well fitted by a first order law decrease of the degraded compound. Thi s leads to significant simplifications in a reaction mechanism which is sui table for modelling aqueous phase chemistry in unpolluted marine clouds. (C ) 1999 Elsevier Science Ltd. All rights reserved.