Search Results
A phenomenology of new particle formation (NPF) at 13 European sites
2021, Bousiotis, Dimitrios, Pope, Francis D., Beddows, David C. S., Dall'Osto, Manuel, Massling, Andreas, Nøjgaard, Jakob Klenø, Nordstrøm, Claus, Niemi, Jarkko V., Portin, Harri, Petäjä, Tuukka, Perez, Noemi, Alastuey, Andrés, Querol, Xavier, Kouvarakis, Giorgos, Mihalopoulos, Nikos, Vratolis, Stergios, Eleftheriadis, Konstantinos, Wiedensohler, Alfred, Weinhold, Kay, Merkel, Maik, Tuch, Thomas, Harrison, Roy M.
New particle formation (NPF) events occur almost everywhere in the world and can play an important role as a particle source. The frequency and characteristics of NPF events vary spatially, and this variability is yet to be fully understood. In the present study, long-term particle size distribution datasets (minimum of 3 years) from 13 sites of various land uses and climates from across Europe were studied, and NPF events, deriving from secondary formation and not traffic-related nucleation, were extracted and analysed. The frequency of NPF events was consistently found to be higher at rural background sites, while the growth and formation rates of newly formed particles were higher at roadsides (though in many cases differences between the sites were small), underlining the importance of the abundance of condensable compounds of anthropogenic origin found there. The growth rate was higher in summer at all rural background sites studied. The urban background sites presented the highest uncertainty due to greater variability compared to the other two types of site. The origin of incoming air masses and the specific conditions associated with them greatly affect the characteristics of NPF events. In general, cleaner air masses present higher probability for NPF events, while the more polluted ones show higher growth rates. However, different patterns of NPF events were found, even at sites in close proximity (<ĝ€¯200ĝ€¯km), due to the different local conditions at each site. Region-wide events were also studied and were found to be associated with the same conditions as local events, although some variability was found which was associated with the different seasonality of the events at two neighbouring sites. NPF events were responsible for an increase in the number concentration of ultrafine particles of more than 400ĝ€¯% at rural background sites on the day of their occurrence. The degree of enhancement was less at urban sites due to the increased contribution of other sources within the urban environment. It is evident that, while some variables (such as solar radiation intensity, relative humidity, or the concentrations of specific pollutants) appear to have a similar influence on NPF events across all sites, it is impossible to predict the characteristics of NPF events at a site using just these variables, due to the crucial role of local conditions. © Author(s) 2021.
A full year of aerosol size distribution data from the central Arctic under an extreme positive Arctic Oscillation: insights from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition
2023, Boyer, Matthew, Aliaga, Diego, Pernov, Jakob Boyd, Angot, Hélène, Quéléver, Lauriane L. J., Dada, Lubna, Heutte, Benjamin, Dall'Osto, Manuel, Beddows, David C. S., Brasseur, Zoé, Beck, Ivo, Bucci, Silvia, Duetsch, Marina, Stohl, Andreas, Laurila, Tiia, Asmi, Eija, Massling, Andreas, Thomas, Daniel Charles, Nøjgaard, Jakob Klenø, Chan, Tak, Sharma, Sangeeta, Tunved, Peter, Krejci, Radovan, Hansson, Hans Christen, Bianchi, Federico, Lehtipalo, Katrianne, Wiedensohler, Alfred, Weinhold, Kay, Kulmala, Markku, Petäjä, Tuukka, Sipilä, Mikko, Schmale, Julia, Jokinen, Tuija
The Arctic environment is rapidly changing due to accelerated warming in the region. The warming trend is driving a decline in sea ice extent, which thereby enhances feedback loops in the surface energy budget in the Arctic. Arctic aerosols play an important role in the radiative balance and hence the climate response in the region, yet direct observations of aerosols over the Arctic Ocean are limited. In this study, we investigate the annual cycle in the aerosol particle number size distribution (PNSD), particle number concentration (PNC), and black carbon (BC) mass concentration in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. This is the first continuous, year-long data set of aerosol PNSD ever collected over the sea ice in the central Arctic Ocean. We use a k-means cluster analysis, FLEXPART simulations, and inverse modeling to evaluate seasonal patterns and the influence of different source regions on the Arctic aerosol population. Furthermore, we compare the aerosol observations to land-based sites across the Arctic, using both long-term measurements and observations during the year of the MOSAiC expedition (2019-2020), to investigate interannual variability and to give context to the aerosol characteristics from within the central Arctic. Our analysis identifies that, overall, the central Arctic exhibits typical seasonal patterns of aerosols, including anthropogenic influence from Arctic haze in winter and secondary aerosol processes in summer. The seasonal pattern corresponds to the global radiation, surface air temperature, and timing of sea ice melting/freezing, which drive changes in transport patterns and secondary aerosol processes. In winter, the Norilsk region in Russia/Siberia was the dominant source of Arctic haze signals in the PNSD and BC observations, which contributed to higher accumulation-mode PNC and BC mass concentrations in the central Arctic than at land-based observatories. We also show that the wintertime Arctic Oscillation (AO) phenomenon, which was reported to achieve a record-breaking positive phase during January-March 2020, explains the unusual timing and magnitude of Arctic haze across the Arctic region compared to longer-term observations. In summer, the aerosol PNCs of the nucleation and Aitken modes are enhanced; however, concentrations were notably lower in the central Arctic over the ice pack than at land-based sites further south. The analysis presented herein provides a current snapshot of Arctic aerosol processes in an environment that is characterized by rapid changes, which will be crucial for improving climate model predictions, understanding linkages between different environmental processes, and investigating the impacts of climate change in future Arctic aerosol studies.
Global analysis of continental boundary layer new particle formation based on long-term measurements
2018, Nieminen, Tuomo, Kerminen, Veli-Matti, Petäjä, Tuukka, Aalto, Pasi P., Arshinov, Mikhail, Asmi, Eija, Baltensperger, Urs, Beddows, David C. S., Beukes, Johan Paul, Collins, Don, Ding, Aijun, Harrison, Roy M., Henzing, Bas, Hooda, Rakesh, Hu, Min, Hõrrak, Urmas, Kivekäs, Niku, Komsaare, Kaupo, Krejci, Radovan, Kristensson, Adam, Laakso, Lauri, Laaksonen, Ari, Leaitch, W. Richard, Lihavainen, Heikki, Mihalopoulos, Nikolaos, Németh, Zoltán, Nie, Wei, O'Dowd, Colin, Salma, Imre, Sellegri, Karine, Svenningsson, Birgitta, Swietlicki, Erik, Tunved, Peter, Ulevicius, Vidmantas, Vakkari, Ville, Vana, Marko, Wiedensohler, Alfred, Wu, Zhijun, Virtanen, Annele, Kulmala, Markku
Atmospheric new particle formation (NPF) is an important phenomenon in terms of global particle number concentrations. Here we investigated the frequency of NPF, formation rates of 10 nm particles, and growth rates in the size range of 10–25 nm using at least 1 year of aerosol number size-distribution observations at 36 different locations around the world. The majority of these measurement sites are in the Northern Hemisphere. We found that the NPF frequency has a strong seasonal variability. At the measurement sites analyzed in this study, NPF occurs most frequently in March–May (on about 30 % of the days) and least frequently in December-February (about 10 % of the days). The median formation rate of 10 nm particles varies by about 3 orders of magnitude (0.01–10 cm−3 s−1) and the growth rate by about an order of magnitude (1–10 nm h−1). The smallest values of both formation and growth rates were observed at polar sites and the largest ones in urban environments or anthropogenically influenced rural sites. The correlation between the NPF event frequency and the particle formation and growth rate was at best moderate among the different measurement sites, as well as among the sites belonging to a certain environmental regime. For a better understanding of atmospheric NPF and its regional importance, we would need more observational data from different urban areas in practically all parts of the world, from additional remote and rural locations in North America, Asia, and most of the Southern Hemisphere (especially Australia), from polar areas, and from at least a few locations over the oceans.