n KLIMA & MILJØ På billedet ses besætningsmedlem med prøveudtagningskit på et skib i Nordatlanten. in situ aerosol-, CO-, CO 2 -, H 2 O-, CH 4 - og HCl-koncentrationer, samt opsamle gasprøver til efterfølgende isotopanalyse og aerosolprøver til elementær analyse. Denne viden er essentiel for at forstå den naturlige mekanisme bedre, men også for at undersøge potentialet for at bruge mekanismen som et klimaindgreb. En af usikkerhederne her er nemlig, om det ville kunne påvirke ozonlaget i stratosfæren, hvilket kun kan besvares ved at undersøge den vertikale profil for processen. Konklusion Fotolysen af jernsalt-aerosoler er den største kilde til klorradikaler i Nordatlanten. Disse aerosoler dannes ved interaktionerne mellem havsalt- aerosoler og jernholdige støvpartikler, men det globale omfang, effekten af støvkompositionen og interaktioner med luftforurening er indtil videre ukendt. ISAMO-projektet har til formål at udfor - ske og kortlægge den naturlige fore - komst, samt at undersøge mekanismens potentiale som klimaindgreb. Dette arbejde er undervejs som en interdisci - plinær kombination af feltkampagner, laboratorieforsøg og modellering verden over. Dataanalyse for alle de igangvæ - rende kampagner er undervejs og vi ser frem til at præsentere dem i kommende artikler. E-mail: Matthew S. Johnson: msj@chem.ku.dk Litteratur 1. van Herpen, M.M.J.W., Li, Q., Saiz-Lopez, A., Liisberg, J.B., Röckmann, T.,871. Cuevas, C.A., Fernandez, R.P., Mak, J.E., Mahowald, N.M., Hess, P., Meidan, D., Stuut, J.-B. W. & Johnson, M., 2023. Photocatalytic chlorine atom production on mineral dust–sea spray aerosols over the north atlantic. Proceedings of the National Academy of Sciences of the USA , 120 (31), p. e2303974120. 2. Mikkelsen, M.K., Liisberg, J.B., van Herpen, M.M.J.W., Mikkelsen, K.V. & Johnson, M.S., 2024. Photocatalytic chloride to chlorine conversion by ionic iron in aqueous aerosols: A combined experimental, quantum chemical and chemical equilibrium model study. Aerosol Research , under review. 3. Wittmer, J., Bleicher, S. & Zetzsch, C., 2015. Iron(III)-Induced Activation of Chloride and Bromide from Modeled Salt Pans. The Journal of Physical Chemistry A, 119 (19), p.4373-4385. 4. Wittmer, J., Bleicher, S., Ofner, J. & Zetzsch, C., 2015. Iron (III)-induced activation of chloride from artificial sea- salt aerosol. Environmental Chemistry , 12 (4), p.461-475. 5. Wittmer, J. and Zetzsch, C., 2017. Photochemical activation of chlorine by iron-oxide aerosol. Journal of Atmospheric Chemistry , 74, p.187-204. 6. Munoz, A., Vera, T., Sidebottom, H., Mellouki, A., Borras, E., Ródenas, M., . & Vazquez, M., 2011. Studies on the atmospheric degradation of chlorpyrifos- methyl. Environmental science & technology , 45(5), p.1880-1886. 7. Munoz, A., Borras, E., Rodenas, M., Vera, T., & Pedersen, H.A., 2018. Atmospheric oxidation of a thiocarbamate herbicide used in winter cereals. Environmental science & technology , 52(16), p.9136-9144. 8. Feigenbrugel, V., Person, A.L., Calvé, S.L., Mellouki, A., Munoz, A., & Wirtz, K., 2006. Atmospheric fate of dichlorvos: photolysis and OH-initiated oxidation studies. Environmental science & technology , 40(3), 850-857. 9. Mak, J.E., Kra, G., Sandomenico, T., & Bergamaschi, P., 2003. The seasonally varying isotopic composition of the sources of carbon monoxide at Barbados, West Indies. Journal of Geophysical Research: Atmospheres , 108(D20). 10. Pennacchio, L., van Herpen, M.M.J.W., Meidan, D., Saiz-Lopez, A & Johnson, M.S., 2024. Catalytic efficiencies for methane removal: Impact of HOx, NOx and chemistry in the high-chlorine regime. Proceedings of the National Academy of Sciences of the USA, under review. n From the 2023 Maersk Sustainability Report: Supporting ocean and climate sci - ence Maersk continues to leverage our vessels and ocean networks in support of ocean and climate sci - ence through long-standing partner - ships with research organisations. In 2023, Maersk supported the Oceans X - Xploration ISAMO pro ject, an exploration of solutions that could one day recreate the natural process of methane oxidation, which removes methane (a greenhouse gas) from the atmosphere. Maersk crew on vessels crossing the Atlantic collected and returned 280 sam - ples for analysis in 2023, helping scientists understand why methane oxidation occurs at an increased rate over the sea and in areas with high iron content, as well as the impact of dust from the Sahara Desert over the Atlantic Ocean. 8 Dansk Kemi, 105, nr. 2, 2024 -
Download PDF fil
Se arkivet med udgivelser af Dansk Kemi her
TechMedias mange andre fagblade kan læses her