Black carbon emissions from traffic contribute substantially to air pollution in Nairobi, Kenya

2022 | Commun. Earth Environ.

Rapid urbanization and population growth drives increased air pollution across Sub-Saharan Africa with serious implications for human health, yet pollutant sources are poorly constrained. Here, we analyse fine particulate aerosol concentrations and radiocarbon composition of black carbon over a full annual cycle in Nairobi, Kenya. We find that particle concentrations exceed the World Health Organisation’s recommended safe limit throughout the year, with little seasonal variability in particle concentration or composition. Organics (49 ± 7%) and water-soluble inorganic ions, dominated by sulfates (13 ± 5%), constitute the largest contributors to the particle loadings. Unlike large cities on other continents, the fraction of black carbon in particles is high (15 ± 4%) suggesting black carbon is a prominent air pollutant in Nairobi. Radiocarbon-based source quantification indicates that fossil fuel combustion emissions are a dominant source of black carbon throughout the year (85 ± 3%). Taken together, this indicates that black carbon emissions from traffic are a key stressor for air quality in Nairobi.

Tropical and Boreal Forest – Atmosphere Interactions: A Review

Paulo Artaxo; Hans-Christen Hansson; Meinrat O. Andreae; Jaana Bäck; Eliane Gomes Alves; Henrique M. J. Barbosa; Frida Bender; Efstratios Bourtsoukidis; Samara Carbone; Jinshu Chi; Stefano Decesari; Viviane R. Després; Florian Ditas; Ekaterina Ezhova; Sandro Fuzzi; Niles J. Hasselquist; Jost Heintzenberg; Bruna A. Holanda; Alex Guenther; Hannele Hakola; Liine Heikkinen; Veli-Matti Kerminen; Jenni Kontkanen; Radovan Krejci; Markku Kulmala; Jost V. Lavric; Gerrit de Leeuw; Katrianne Lehtipalo; Luiz Augusto T. Machado; Gordon McFiggans; arco Aurelio M. Franco; Bruno Backes Meller; Fernando G. Morais; Claudia Mohr; William Morgan; Mats B. Nilsson; Matthias Peichl; Tuukka Petäjä; Maria Praß; Christopher Pöhlker; Mira L. Pöhlker; Ulrich Pöschl; Celso Von Randow; Ilona Riipinen; Janne Rinne; Luciana V. Rizzo; Daniel Rosenfeld; Maria A. F. Silva Dias; Larisa Sogacheva; Philip Stier; Erik Swietlicki; Matthias Sörgel; Peter Tunved; Aki Virkkula; Jian Wang; Bettina Weber; Ana Maria Yáñez-Serrano; Paul Zieger; Eugene Mikhailov; James N. Smith; Jürgen Kesselmeier
2022 | TELLUS B | 74 (24-163)

This review presents how the boreal and the tropical forests affect the atmosphere, its chemical composition, its function, and further how that affects the climate and, in return, the ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observatory in Central Amazonia, the Zotino Tall Tower Observatory in Siberia, and the Station to Measure Ecosystem-Atmosphere Relations at Hyytiäla in Finland. The review is complemented by short-term observations from networks and large experiments.

The review discusses atmospheric chemistry observations, aerosol formation and processing, physiochemical aerosol, and cloud condensation nuclei properties and finds surprising similarities and important differences in the two ecosystems. The aerosol concentrations and chemistry are similar, particularly concerning the main chemical components, both dominated by an organic fraction, while the boreal ecosystem has generally higher concentrations of inorganics, due to higher influence of long-range transported air pollution. The emissions of biogenic volatile organic compounds are dominated by isoprene and monoterpene in the tropical and boreal regions, respectively, being the main precursors of the organic aerosol fraction.

Observations and modeling studies show that climate change and deforestation affect the ecosystems such that the carbon and hydrological cycles in Amazonia are changing to carbon neutrality and affect precipitation downwind. In Africa, the tropical forests are so far maintaining their carbon sink.

It is urgent to better understand the interaction between these major ecosystems, the atmosphere, and climate, which calls for more observation sites, providing long-term data on water, carbon, and other biogeochemical cycles. This is essential in finding a sustainable balance between forest preservation and reforestation versus a potential increase in food production and biofuels, which are critical in maintaining ecosystem services and global climate stability. Reducing global warming and deforestation is vital for tropical forests.

Earth observation: An integral part of a smart and sustainable city

Gerasopoulos, E.; Bailey, J.; Athanasopoulou, E.; Speyer, O.; Kocman, A.; Raudner, A.; Tsouni, A.; Kontoes, H.; Johansson, C.; Georgiadis, C.; Matthias, V.; Kussul, N.; Aquilino, M.; Paasonen, P.
2022 | Environmental Science and Policy | 132 (296-307)

Performance characteristics of a small scale cyclone separator operated in different flow regimes

D. Misiulia; G. Lidén; S. Antonyuk
2022 | J Aerosol Sci | 163
Cut-size , Cyclone sampler , large eddy simulation , penetration , Penetration slope , Pressure drop

The flow pattern, cyclone pressure drop and particle penetration through a sampling cyclone have been studied at a wide range of flow rate 0.22–7.54 LPM using the LES simulations that have been validated based on experimental penetration data. The cyclone performance has been described by three dimensionless characteristics, the Euler number, cut-size and slope of the transformed penetration curve. Three main flow regimes and four sub-regimes have been revealed. The effects of the flow rate (Reynolds number) on the dimensionless cyclone performance characteristics have been described and a one-term power series model has been proposed. Additionally, the effect of the aspiration efficiency on the cyclone cut-size has been determined.

Atmospheric composition in the European Arctic and 30 years of the Zeppelin Observatory, Ny-Ålesund

Platt, S. M.; Hov, Ø.; Berg, T.; Breivik, K.; Eckhardt, S.; Eleftheriadis, K.; Evangeliou, N.; Fiebig, M.; Fisher, R.; Hansen, G.; Hansson, H.-C.; Heintzenberg, J.; Hermansen, O.; Heslin-Rees, D.; Holmén, K.; Hudson, S.; Kallenborn, R.; Krejci, R.: Krognes, T.; Larssen, S.; Lowry, D.; Lund Myhre, C.; Lunder, C.; Nisbet, E.; Nizzetto, P. B.; Park, K.-T.; Pedersen, C. A.; Aspmo Pfaffhuber, K.; Röckmann, T.; Schmidbauer, N.; Solberg, S.; Stohl, A.; Ström, J.; Svendby, T.; Tunved, P.; Tørnkvist, K.; van der Veen, C.; Vratolis, S.; Yoon, Y. J.; Yttri, K. E.; Zieger, P.; Aas, W.; Tørseth, K.
2022 | Atmos. Chem. Phys. | 22 (3321-3369)

The Zeppelin Observatory (78.90∘ N, 11.88∘ E) is located on Zeppelin Mountain at 472 m a.s.l. on Spitsbergen, the largest island of the Svalbard archipelago. Established in 1989, the observatory is part of Ny-Ålesund Research Station and an important atmospheric measurement site, one of only a few in the high Arctic, and a part of several European and global monitoring programmes and research infrastructures, notably the European Monitoring and Evaluation Programme (EMEP); the Arctic Monitoring and Assessment Programme (AMAP); the Global Atmosphere Watch (GAW); the Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS); the Advanced Global Atmospheric Gases Experiment (AGAGE) network; and the Integrated Carbon Observation System (ICOS). The observatory is jointly operated by the Norwegian Polar Institute (NPI), Stockholm University, and the Norwegian Institute for Air Research (NILU). Here we detail the establishment of the Zeppelin Observatory including historical measurements of atmospheric composition in the European Arctic leading to its construction. We present a history of the measurements at the observatory and review the current state of the European Arctic atmosphere, including results from trends in greenhouse gases, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), other traces gases, persistent organic pollutants (POPs) and heavy metals, aerosols and Arctic haze, and atmospheric transport phenomena, and provide an outline of future research directions.

Highly Active Ice-Nucleating Particles at the Summer North Pole

Grace C. E. Porter; Michael P. Adams; Ian M. Brooks; Luisa Ickes; Linn Karlsson; Caroline Leck; Matthew E. Salter; Julia Schmale; Karolina Siegel; Sebastien N. F. Sikora; Mark D. Tarn; Jutta Vüllers; Heini Wernli; Paul Zieger; Julika Zinke; Benjamin J. Murray
2022 | J. Geophys. Res.-Atmos. | e2021JD036059

The amount of ice versus supercooled water in clouds is important for their radiative properties and role in climate feedbacks. Hence, knowledge of the concentration of ice-nucleating particles (INPs) is needed. Generally, the concentrations of INPs are found to be very low in remote marine locations allowing cloud water to persist in a supercooled state. We had expected the concentrations of INPs at the North Pole to be very low given the distance from open ocean and terrestrial sources coupled with effective wet scavenging processes. Here we show that during summer 2018 (August and September) high concentrations of biological INPs (active at >−20°C) were sporadically present at the North Pole. In fact, INP concentrations were sometimes as high as those recorded at mid-latitude locations strongly impacted by highly active biological INPs, in strong contrast to the Southern Ocean. Furthermore, using a balloon borne sampler we demonstrated that INP concentrations were often different at the surface versus higher in the boundary layer where clouds form. Back trajectory analysis suggests strong sources of INPs near the Russian coast, possibly associated with wind-driven sea spray production, whereas the pack ice, open leads, and the marginal ice zone were not sources of highly active INPs. These findings suggest that primary ice production, and therefore Arctic climate, is sensitive to transport from locations such as the Russian coast that are already experiencing marked climate change.

An outdoor aging study to investigate the release of per- and polyfluoroalkyl substances (PFAS) from functional textiles

Schellenberger, S.; Liagkouridis, I.; Awad, R.; Khan, S.; Plassmann, M.; Peters, G.; Benskin, J.P.; Cousins, I.T.
2022 | Environ. Sci. Technol. | 56 (6) (3471-3479)

Influence of climate change on Persistent Organic Pollutants and Chemicals of Emerging Concern in the Arctic: State of knowledge and recommendations for future research.

de Wit, C.A.; Vorkamp, K.; Muir, D.
2022 | Environ. Sci.: Processes Impacts | 24 (1530-1543)

Airborne and marine microplastics from an oceanographic survey at the Baltic Sea: an emerging role of air-sea interaction?

Luca Ferrero; Lorenzo Scibetta; Piotr Markuszewski; Mikolaj Mazurkiewic; Violetta Drozdowska; Przemyslaw Makuch; Patrycja Jutzenka-Trzbiatowska; Adriana Zaleska-Medynska; Sergio Ando; Franscesco Seliu; ; E. Douglas Nilsson; Ezio Bolzacchini
2022 | Sci. Total Environ. | 824 (153709) (1-16)
air-sea interaction , atmosphere , baltic salmon , Microplastic , sea

Microplastics (MPs) pollution is one of the most important problems of the Earth. They have been found in all the natural
environments, including oceans and the atmosphere. In this study, the concentrations of both atmospheric and
marine MPs were measured over the Baltic along a research cruise that started in the Gdansk harbour, till the Gotland
island, and the way back. A deposition box (based on a combination of active/passive sampling) was used to collect
airborne MPs while, marine MPs concentrations were investigated during the cruise using a dedicated net. Ancillary
data were obtained using a combination of particle counters (OPC, LAS and CPC), Aethalometer (AE33 Magee Scientific),
spectrofluorometer (sea surface samples, Varian Cary Eclipse), and meteorological sensors. Results showed airborne
microplastics average concentrations higher in the Gdansk harbour (161 ± 75 m−3) compared to the open
Baltic Sea and to the Gotland island (24± 9 and 45 ±20 m−3). These latter values are closer to the ones measured
in the sea (79±18m−3). The MPs composition was investigated using μ-Raman (for the airborne ones) and FTIR (for marine ones); similar results (e.g. polyethylene, polyethylene terephthalates, polyurethane) were found in the two environmental

<compartments. The concentrations and sd<dimilar composition in air and sea suggested a linkag e between
the two compartments. For this purpose, the atmospheric MPs' equivalent aerodynamic diameter was calculated (28
±3μm) first showing the capability of atmospheric MPs to remain suspended in the air. At the same time, the computed
turnover times (0.3–90 h; depending on MPs size) limited the transport distance range. The estimated M-^Ps sea emission fluxes (4–18 ∗ 10^-6 μm^3 m−2 s−1 range) finally showed the contemporary presence of atmospheric transport
together with a continuous emission fromthe sea surface enabling a grasshopper long-range transport ofmicroplastics
across the sea.

Sediment Remediation Using Activated Carbon: Effects of Sorbent Particle Size and Resuspension on Sequestration of Metals and Organic Contaminants

Rämö, Robert; Bonaglia, Stefano; Nybom, Inna; Kreutzer, Anne; Witt, Gesine; Sobek, Anna; Gunnarsson, Jonas, S.
2022 | Environ. Toxicol. Chem. (1-15)

Outside the safe operating space of the planetary boundary for novel entities.

Persson, L.; Carney Almroth, B.; Collins, C.; Cornell, S.E.; de Wit, C.A.; Diamond, M.L.; Fantke, P.; Hassellöv, M.; MacLeod, M.; Ryberg, M.; Søgaard Jørgensen, P.; Villarrubia-Gómez, P.; Wang, Z.; Hauschild, M.Z.
2022 | Environ. Sci. Technol. | 56 (1510-1521)

The Distribution of pCO2W and Air-Sea CO2 Fluxes Using FFNN at the Continental Shelf Areas of the Arctic Ocean

Wrobel-Niedzwiecka Iwona; Kitowska Małgorzata; Makuch Przemysław; Markuszewski Piotr
2022 | Remote Sens.
Air-Sea CO2 flux , air-sea exchange , feed-forward neural network , partial pressure of CO2

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