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  Overview: On the transport and transformation of pollutants in the outflow of major population centres – observational data from the EMeRGe European intensive operational period in summer 2017

Hernández, M. D. A., Hilboll, A., Ziereis, H., Förster, E., Krüger, O. O., Kaiser, K., et al. (2022). Overview: On the transport and transformation of pollutants in the outflow of major population centres – observational data from the EMeRGe European intensive operational period in summer 2017. Atmospheric Chemistry and Physics, 22(9), 5877-5924. doi:10.5194/acp-22-5877-2022.

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Hernández, M. Dolores Andrés, Author
Hilboll, Andreas, Author
Ziereis, Helmut, Author
Förster, Eric, Author
Krüger, Ovid O.1, Author              
Kaiser, Katharina2, Author              
Schneider, Johannes2, Author              
Barnaba, Francesca, Author
Vrekoussis, Mihalis, Author
Schmidt, Jörg, Author
Huntrieser, Heidi, Author
Blechschmidt, Anne-Marlene, Author
George, Midhun, Author
Nenakhov, Vladyslav, Author
Klausner, Theresa, Author
Holanda, Bruna A.1, Author              
Wolf, Jennifer, Author
Eirenschmalz, Lisa, Author
Krebsbach, Marc, Author
Pöhlker, Mira L.1, Author              
Hedegaard, Anna B., AuthorMei, Linlu, AuthorPfeilsticker, Klaus, AuthorLiu, Yangzhuoran, AuthorKoppmann, Ralf, AuthorSchlager, Hans, AuthorBohn, Birger, AuthorSchumann, Ulrich, AuthorRichter, Andreas, AuthorSchreiner, Benjamin, AuthorSauer, Daniel, AuthorBaumann, Robert, AuthorMertens, Mariano, AuthorJöckel, Patrick, AuthorKilian, Markus, AuthorStratmann, Greta, AuthorPöhlker, Christopher1, Author              Campanelli, Monica, AuthorPandolfi, Marco, AuthorSicard, Michael, AuthorGomez-Amo, Jose L., AuthorPujadas, Manuel, AuthorBigge, Katja, AuthorKluge, Flora, AuthorSchwarz, Anja, AuthorDaskalakis, Nikos, AuthorWalter, David1, Author              Zahn, Andreas, AuthorPöschl, Ulrich1, Author              Bönisch, Harald, AuthorBorrmann, Stephan2, Author              Platt, Ulrich, AuthorBurrows, John Phillip, Author more..
1Multiphase Chemistry, Max Planck Institute for Chemistry, Max Planck Society, ou_1826290              
2Particle Chemistry, Max Planck Institute for Chemistry, Max Planck Society, ou_1826291              


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 Abstract: Megacities and other major population centres (MPCs) worldwide are major sources of air pollution, both locally as well as downwind. The overall assessment and prediction of the impact of MPC pollution on tropospheric chemistry are challenging. The present work provides an overview of the highlights of a major new contribution to the understanding of this issue based on the data and analysis of the EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) international project. EMeRGe focuses on atmospheric chemistry, dynamics, and transport of local and regional pollution originating in MPCs. Airborne measurements, taking advantage of the long range capabilities of the High Altitude and LOng Range Research Aircraft (HALO, https://www.halo-spp.de, last access: 22 March 2022), are a central part of the project. The synergistic use and consistent interpretation of observational data sets of different spatial and temporal resolution (e.g. from ground-based networks, airborne campaigns, and satellite measurements) supported by modelling within EMeRGe provide unique insight to test the current understanding of MPC pollution outflows. In order to obtain an adequate set of measurements at different spatial scales, two field experiments were positioned in time and space to contrast situations when the photochemical transformation of plumes emerging from MPCs is large. These experiments were conducted in summer 2017 over Europe and in the inter-monsoon period over Asia in spring 2018. The intensive observational periods (IOPs) involved HALO airborne measurements of ozone and its precursors, volatile organic compounds, aerosol particles, and related species as well as coordinated ground-based ancillary observations at different sites. Perfluorocarbon (PFC) tracer releases and model forecasts supported the flight planning, the identification of pollution plumes, and the analysis of chemical transformations during transport. This paper describes the experimental deployment and scientific questions of the IOP in Europe. The MPC targets – London (United Kingdom; UK), the Benelux/Ruhr area (Belgium, the Netherlands, Luxembourg and Germany), Paris (France), Rome and the Po Valley (Italy), and Madrid and Barcelona (Spain) – were investigated during seven HALO research flights with an aircraft base in Germany for a total of 53 flight hours. An in-flight comparison of HALO with the collaborating UK-airborne platform Facility for Airborne Atmospheric Measurements (FAAM) took place to assure accuracy and comparability of the instrumentation on board. Overall, EMeRGe unites measurements of near- and far-field emissions and hence deals with complex air masses of local and distant sources. Regional transport of several European MPC outflows was successfully identified and measured. Chemical processing of the MPC emissions was inferred from airborne observations of primary and secondary pollutants and the ratios between species having different chemical lifetimes. Photochemical processing of aerosol and secondary formation or organic acids was evident during the transport of MPC plumes. Urban plumes mix efficiently with natural sources as mineral dust and with biomass burning emissions from vegetation and forest fires. This confirms the importance of wildland fire emissions in Europe and indicates an important but discontinuous contribution to the European emission budget that might be of relevance in the design of efficient mitigation strategies. The present work provides an overview of the most salient results in the European context, with these being addressed in more detail within additional dedicated EMeRGe studies. The deployment and results obtained in Asia will be the subject of separate publications.


Language(s): eng - English
 Dates: 2022-05-05
 Publication Status: Published online
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: DOI: 10.5194/acp-22-5877-2022
 Degree: -



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Title: Atmospheric Chemistry and Physics
  Abbreviation : ACP
Source Genre: Journal
Publ. Info: Göttingen : Copernicus Publications
Pages: - Volume / Issue: 22 (9) Sequence Number: - Start / End Page: 5877 - 5924 Identifier: ISSN: 1680-7316
CoNE: https://pure.mpg.de/cone/journals/resource/111030403014016