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    Novel insights on new particle formation derived from a pan-european observing system
    (London : Nature Publishing Group, 2018) Dall’Osto, M.; Beddows, D.C.S.; Asmi, A.; Poulain, L.; Hao, L.; Freney, E.; Allan, J.D.; Canagaratna, M.; Crippa, M.; Bianchi, F.; de Leeuw, G.; Eriksson, A.; Swietlicki, E.; Hansson, H.C.; Henzing, J.S.; Granier, C.; Zemankova, K.; Laj, P.; Onasch, T.; Prevot, A.; Putaud, J. P.; Sellegri, K.; Vidal, M.; Virtanen, A.; Simo, R.; Worsnop, D.; O’Dowd, C.; Kulmala, M.; Harrison, Roy M.
    The formation of new atmospheric particles involves an initial step forming stable clusters less than a nanometre in size (<~1 nm), followed by growth into quasi-stable aerosol particles a few nanometres (~1-10 nm) and larger (>~10 nm). Although at times, the same species can be responsible for both processes, it is thought that more generally each step comprises differing chemical contributors. Here, we present a novel analysis of measurements from a unique multi-station ground-based observing system which reveals new insights into continental-scale patterns associated with new particle formation. Statistical cluster analysis of this unique 2-year multi-station dataset comprising size distribution and chemical composition reveals that across Europe, there are different major seasonal trends depending on geographical location, concomitant with diversity in nucleating species while it seems that the growth phase is dominated by organic aerosol formation. The diversity and seasonality of these events requires an advanced observing system to elucidate the key processes and species driving particle formation, along with detecting continental scale changes in aerosol formation into the future.
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    Interfacial photochemistry at the ocean surface is a global source of organic vapors and aerosols
    ([London] : Nature Publishing Group UK, 2018) Brüggemann, Martin; Hayeck, Nathalie; George, Christian
    The surface of the oceans acts as a global sink and source for trace gases and aerosol particles. Recent studies suggest that photochemical reactions at this air/water interface produce organic vapors, enhancing particle formation in the atmosphere. However, current model calculations neglect this abiotic source of reactive compounds and account only for biological emissions. Here we show that interfacial photochemistry serves as a major abiotic source of volatile organic compounds (VOCs) on a global scale, capable to compete with emissions from marine biology. Our results indicate global emissions of 46.4-184 Tg C yr-1 of organic vapors from the oceans into the marine atmosphere and a potential contribution to organic aerosol mass of more than 60% over the remote ocean. Moreover, we provide global distributions of VOC formation potentials, which can be used as simple tools for field studies to estimate photochemical VOC emissions depending on location and season.