Transition metal ion (TMI) organic complexes photochemistry in tropospheric aerosols and clouds

自1992年和第一届地球峰会以来，不同的国家已经认识到气候受到人类活动的强烈影响，并计划根据国际公约解决这个问题。在这种情况下，由联合国领导的缔约方会议（COP）将各国聚集在一起作出承诺。然而，为了采取有意义的行动，世界各地的科学家必须为政策提供有用的数据，作为决策的基础。正是在这一更广泛的背景下提出了REACTE项目，该项目涉及国际公认的法国和德国研究人员，他们在各自的科学领域具有高度互补性。因此，对这一系统及其根据其所接受的不同输入而发生的变化有一个正确的理解是至关重要的。氧化还原反应是大气多相系统的主要转化途径之一，为了更好地理解大气多相系统的发展，应该仔细考虑。过渡金属离子（TMIs）的（光）化学，它是含水气溶胶粒子和对流层云滴中高活性物质的主要来源。事实上，目前关于这些金属的确切作用和反应性的数据非常少，这些金属目前在模型中几乎完全以自由形式存在，而已知它们在自然环境中以络合物形式存在。REACTE旨在回答以下问题：i）TMI的络合如何直接通过金属和/或与H2 O2的“芬顿”型反应影响其光反应性和氧化还原反应; ii）与这些反应相关的活性物质，H2 O2，HxOy自由基及其形成产率？它们将对大气的氧化能力产生什么影响，从而对大气的化学成分产生什么影响？然后将所获得的结果实施在一个多相大气化学模式，包括化学水相自由基机制（CAPRAM），以预测其对有机物的转化，HOx平衡和大气液滴或气溶胶中的TMIs的价态的影响。REACTE项目结合互补的科学能力，将使人们能够更好地了解大气颗粒中存在的TMI复合物的化学性质，从而了解它们在大气多相化学中的作用。

Since 1992 and the first Earth summit, different countries have recognized that climate is strongly impacted by human activity and they planned to tackle it under an international convention. In this context, ledby the United Nations, COPs (Conference of parties) bring together countries to make commitments. However, in order to take meaningful action, it is important that scientists worldwide provide useful data to policy as a basis for decisions. It is in this wider context that the REACTE project, involving internationally recognized French and German researchers in their respective highly complementary scientific fields, is proposed.The atmosphere is a complex and highly reactive system where many bio-physicochemical processes take place. It is therefore crucial to have a sound understanding of this system and its changes according to the different inputs it is subjected to. Redox reactions are one of the major transformation pathways that should be carefully considered in order to better understand the development of the atmospheric multiphase system. The (photo)chemistry of transition metal ions (TMIs) which represents a major source of highly reactive species in water-containing aerosol particles and in tropospheric cloud droplets. Indeed, very little data currently exists on the exact role and reactivity of these metals, which are currently considered almost exclusively in their free form in models, whereas they are known to be present as complexes in natural environments. REACTE intends to answer the following questions: i) How will the complexation of TMIs influence their photo-reactivity and redox reactions directly through the metal and/or with H2O2 as "Fenton" type reactions; ii) What will be the reactive species associated with these reactions, H2O2, HxOy radicals and their formation yields? What will be their impact on the oxidative capacity of the atmosphere and thus on, more generally, its chemical composition? The obtained results will be then implemented in a multiphase atmospheric chemistry model involving the chemical aqueous-phase radical mechanism (CAPRAM) to predict their influence on the organic matter transformation, the HOx balance and the valence states of TMIs in atmospheric droplets or aerosols. The REACTE project, in combining complementary scientific competences, will allow to better understand the chemistry of the TMI complexes present in atmospheric particles and thus to understand their role in atmospheric multiphase chemistry.