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Tuukka Petäjä

Bio: Tuukka Petäjä is an academic researcher from University of Helsinki. The author has contributed to research in topics: Aerosol & Particle. The author has an hindex of 82, co-authored 526 publications receiving 30572 citations. Previous affiliations of Tuukka Petäjä include Helsinki Institute of Physics & National Center for Atmospheric Research.


Papers
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Journal ArticleDOI
TL;DR: A recently developed atmospheric pressure interface mass spectrometer (APi-TOF) measured the negative and positive ambient ion composition at a boreal forest site as mentioned in this paper, where the negative ions were dominated by strong organic and inorganic acids (eg malonic, nitric and sulfuric acid), whereas the positive ions consisted of strong bases (eg alkyl pyridines and quinolines) Several new ions and clusters of ions were identified based on their exact masses.
Abstract: A recently developed atmospheric pressure interface mass spectrometer (APi-TOF) measured the negative and positive ambient ion composition at a boreal forest site As observed in previous studies, the negative ions were dominated by strong organic and inorganic acids (eg malonic, nitric and sulfuric acid), whereas the positive ions consisted of strong bases (eg alkyl pyridines and quinolines) Several new ions and clusters of ions were identified based on their exact masses, made possible by the high resolution, mass accuracy and sensitivity of the APi-TOF Time series correlograms aided in peak identification and assigning the atomic compositions to molecules Quantum chemical calculations of proton affinities and cluster stabilities were also used to confirm the plausibility of the assignments Acids in the gas phase are predominantly formed by oxidation in the gas phase, and thus the concentrations are expected to vary strongly between day and night This was also the case in this study, where the negative ions showed strong diurnal behavior, whereas the daily changes in the positive ions were considerably smaller A special focus in this work was the changes in the ion distributions occurring during new particle formation events We found that sulfuric acid, together with its clusters, dominated the negative ion spectrum during these events The monomer (HSO4−) was the largest peak, together with the dimer (H2SO4 · HSO4−) and trimer ((H2SO4)2 · HSO4−) SO5− also tracked HSO4− at around 20% of the HSO4− concentration at all times During the strongest events, the tetramer and a cluster with the tetramer and ammonia were also detected Quantum chemical calculations predict that sulfuric acid clusters containing ammonia are much more stable when neutral, thus the detection of a single ion cluster implies that ammonia can be an important compound in the nucleation process We also believe to have made the first observations of an organosulfate (glycolic acid sulfate) in the gas phase This ion, and its cluster with sulfuric acid, correlates with the HSO4−, but peaks in the early afternoon, some hours later than HSO4− itself A list of all identified ions is presented in the supplementary material, and also a list of all detected masses not yet identified

169 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the diameter growth rate of nucleation mode particles and compared it to an extensive set of ambient meteorological parameters and trace gas concentrations to investigate the processes/constituents limiting the aerosol growth.
Abstract: . The condensational growth rate of aerosol particles formed in atmospheric new particle formation events is one of the most important factors influencing the lifetime of these particles and their ability to become climatically relevant. Diameter growth rates (GR) of nucleation mode particles were studied based on almost 7 yr of data measured during the years 2003–2009 at a boreal forest measurement station SMEAR II in Hyytiala, Finland. The particle growth rates were estimated using particle size distributions measured with a Differential Mobility Particle Sizer (DMPS), a Balanced Scanning Mobility Analyzer (BSMA) and an Air Ion Spectrometer (AIS). Two GR analysis methods were tested. The particle growth rates were also compared to an extensive set of ambient meteorological parameters and trace gas concentrations to investigate the processes/constituents limiting the aerosol growth. The median growth rates of particles in the nucleation mode size ranges with diameters of 1.5–3 nm, 3–7 nm and 7–20 nm were 1.9 nm h−1, 3.8 nm h−1, and 4.3 nm h−1, respectively. The median relative uncertainties in the growth rates due to the size distribution instrumentation in these size ranges were 25%, 19%, and 8%, respectively. For the smallest particles (1.5–3 nm) the AIS data yielded on average higher growth rate values than the BSMA data, and higher growth rates were obtained from positively charged size distributions as compared with negatively charged particles. For particles larger than 3 nm in diameter no such systematic differences were found. For these particles the uncertainty in the growth rate related to the analysis method, with relative uncertainty of 16%, was similar to that related to the instruments. The growth rates of 7–20 nm particles showed positive correlation with monoterpene concentrations and their oxidation rate by ozone. The oxidation rate by OH did not show a connection with GR. Our results indicate that the growth of nucleation mode particles in Hyytiala is mainly limited by the concentrations of organic precursors.

165 citations

Journal ArticleDOI
Katrianne Lehtipalo1, Katrianne Lehtipalo2, Katrianne Lehtipalo3, Chao Yan1, Lubna Dada1, F. Bianchi1, Mao Xiao2, Robert Wagner1, Dominik Stolzenburg4, Lauri Ahonen1, António Amorim5, Andrea Baccarini2, Paulus Salomon Bauer4, Bernhard Baumgartner4, Anton Bergen6, Anne-Kathrin Bernhammer7, Martin Breitenlechner7, Sophia Brilke4, Angela Buchholz8, Stephany Buenrostro Mazon1, Dexian Chen9, Xuemeng Chen1, A.A. Dias5, Josef Dommen2, Danielle C. Draper10, Jonathan Duplissy1, Mikael Ehn1, Henning Finkenzeller11, Lukas Fischer7, Carla Frege2, Claudia Fuchs2, Olga Garmash1, Hamish Gordon12, Jani Hakala1, Xucheng He1, Liine Heikkinen1, Martin Heinritzi6, Johanna Helm6, Victoria Hofbauer9, Christopher R. Hoyle2, Tuija Jokinen1, Juha Kangasluoma1, Juha Kangasluoma13, Veli-Matti Kerminen1, Changhyuk Kim14, Jasper Kirkby15, Jasper Kirkby6, Jenni Kontkanen1, Jenni Kontkanen16, Andreas Kürten6, Michael J. Lawler10, Huajun Mai14, Serge Mathot15, Roy L. Mauldin11, Roy L. Mauldin9, Ugo Molteni2, Leonid Nichman17, Wei Nie1, Wei Nie18, Tuomo Nieminen8, Andrea Ojdanic4, Antti Onnela15, Monica Passananti1, Tuukka Petäjä1, Tuukka Petäjä18, Felix Piel7, Felix Piel6, Veronika Pospisilova2, Lauriane L. J. Quéléver1, Matti P. Rissanen1, Clémence Rose1, Nina Sarnela1, Simon Schallhart1, Simone Schuchmann15, Kamalika Sengupta12, Mario Simon6, Mikko Sipilä1, Christian Tauber4, António Tomé19, Jasmin Tröstl2, Olli Väisänen8, Alexander L. Vogel6, Alexander L. Vogel2, Rainer Volkamer11, Andrea Christine Wagner6, Mingyi Wang9, Lena Weitz6, Daniela Wimmer1, Penglin Ye9, Arttu Ylisirniö8, Qiaozhi Zha1, Kenneth S. Carslaw12, Joachim Curtius6, Neil M. Donahue9, Neil M. Donahue1, Richard C. Flagan14, Armin Hansel7, Armin Hansel1, Ilona Riipinen16, Ilona Riipinen20, Annele Virtanen8, Paul M. Winkler4, Urs Baltensperger2, Markku Kulmala1, Markku Kulmala21, Markku Kulmala13, Douglas R. Worsnop1 
TL;DR: How NOx suppresses particle formation is shown, while HOMs, sulfuric acid, and NH3 have a synergistic enhancing effect on particle formation, elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.
Abstract: A major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NOx) and sulfur oxides (SOx) from fossil fuel combustion, as well as ammonia (NH3) from livestock and fertilizers. Here, we show how NOx suppresses particle formation, while HOMs, sulfuric acid, and NH3 have a synergistic enhancing effect on particle formation. We postulate a novel mechanism, involving HOMs, sulfuric acid, and ammonia, which is able to closely reproduce observations of particle formation and growth in daytime boreal forest and similar environments. The findings elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.

165 citations

Journal ArticleDOI
Mingyi Wang1, Weimeng Kong2, Ruby Marten3, Xu-Cheng He4, Dexian Chen1, Joschka Pfeifer5, Arto Heitto6, Jenni Kontkanen4, Lubna Dada4, Andreas Kürten7, Taina Yli-Juuti6, Hanna E. Manninen5, Stavros Amanatidis2, António Amorim8, Rima Baalbaki4, Andrea Baccarini3, David M. Bell3, Barbara Bertozzi9, Steffen Bräkling, Sophia Brilke10, Lucía Caudillo Murillo7, Randall Chiu11, Biwu Chu4, Louis Philippe De Menezes5, Jonathan Duplissy4, Jonathan Duplissy12, Henning Finkenzeller11, Loic Gonzalez Carracedo10, Manuel Granzin7, Roberto Guida5, Armin Hansel13, Victoria Hofbauer1, Jordan E. Krechmer, Katrianne Lehtipalo14, Katrianne Lehtipalo4, Houssni Lamkaddam3, Markus Lampimäki4, Chuan Ping Lee3, Vladimir Makhmutov15, Guillaume Marie7, Serge Mathot5, Roy L. Mauldin11, Roy L. Mauldin1, Bernhard Mentler13, T. Müller7, Antti Onnela5, Eva Partoll13, Tuukka Petäjä4, M. V. Philippov15, Veronika Pospisilova3, Ananth Ranjithkumar16, Matti P. Rissanen4, Birte Rörup4, Wiebke Scholz13, Jiali Shen4, Mario Simon7, Mikko Sipilä4, Gerhard Steiner13, Dominik Stolzenburg4, Dominik Stolzenburg10, Yee Jun Tham4, António Tomé17, Andrea C. Wagner7, Andrea C. Wagner11, Dongyu S. Wang3, Yonghong Wang4, Stefan K. Weber5, Paul M. Winkler10, Peter Josef Wlasits10, Yusheng Wu4, Mao Xiao3, Qing Ye1, Marcel Zauner-Wieczorek7, Xueqin Zhou3, Rainer Volkamer11, Ilona Riipinen18, Josef Dommen3, Joachim Curtius7, Urs Baltensperger3, Markku Kulmala, Douglas R. Worsnop4, Jasper Kirkby7, Jasper Kirkby5, John H. Seinfeld2, Imad El-Haddad3, Richard C. Flagan2, Neil M. Donahue 
14 May 2020-Nature
TL;DR: Measurements in the CLOUD chamber at CERN show that the rapid condensation of ammonia and nitric acid vapours could be important for the formation and survival of new particles in wintertime urban conditions, contributing to urban smog.
Abstract: A list of authors and their affiliations appears at the end of the paper New-particle formation is a major contributor to urban smog1,2, but how it occurs in cities is often puzzling3. If the growth rates of urban particles are similar to those found in cleaner environments (1–10 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles. Here we show, through experiments performed under atmospheric conditions in the CLOUD chamber at CERN, that below about +5 degrees Celsius, nitric acid and ammonia vapours can condense onto freshly nucleated particles as small as a few nanometres in diameter. Moreover, when it is cold enough (below −15 degrees Celsius), nitric acid and ammonia can nucleate directly through an acid–base stabilization mechanism to form ammonium nitrate particles. Given that these vapours are often one thousand times more abundant than sulfuric acid, the resulting particle growth rates can be extremely high, reaching well above 100 nanometres per hour. However, these high growth rates require the gas-particle ammonium nitrate system to be out of equilibrium in order to sustain gas-phase supersaturations. In view of the strong temperature dependence that we measure for the gas-phase supersaturations, we expect such transient conditions to occur in inhomogeneous urban settings, especially in wintertime, driven by vertical mixing and by strong local sources such as traffic. Even though rapid growth from nitric acid and ammonia condensation may last for only a few minutes, it is nonetheless fast enough to shepherd freshly nucleated particles through the smallest size range where they are most vulnerable to scavenging loss, thus greatly increasing their survival probability. We also expect nitric acid and ammonia nucleation and rapid growth to be important in the relatively clean and cold upper free troposphere, where ammonia can be convected from the continental boundary layer and nitric acid is abundant from electrical storms4,5. Measurements in the CLOUD chamber at CERN show that the rapid condensation of ammonia and nitric acid vapours could be important for the formation and survival of new particles in wintertime urban conditions, contributing to urban smog.

156 citations

Journal ArticleDOI
TL;DR: In this paper, the formation and growth of fresh atmospheric aerosol particles was investigated using a condensation particle counter battery (CPCB), which is a matrix of four separate CPCs, which differ in the combination of both cut-off size and working liquid (water; n-butanol).

155 citations


Cited by
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Journal ArticleDOI
TL;DR: Results of older bio-kinetic studies with NSPs and newer epidemiologic and toxicologic studies with airborne ultrafine particles can be viewed as the basis for the expanding field of nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices.
Abstract: Although humans have been exposed to airborne nanosized particles (NSPs; < 100 nm) throughout their evolutionary stages, such exposure has increased dramatically over the last century due to anthropogenic sources. The rapidly developing field of nanotechnology is likely to become yet another source through inhalation, ingestion, skin uptake, and injection of engineered nanomaterials. Information about safety and potential hazards is urgently needed. Results of older bio-kinetic studies with NSPs and newer epidemiologic and toxicologic studies with airborne ultrafine particles can be viewed as the basis for the expanding field of nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices. Collectively, some emerging concepts of nanotoxicology can be identified from the results of these studies. When inhaled, specific sizes of NSPs are efficiently deposited by diffusional mechanisms in all regions of the respiratory tract. The small size facilitates uptake into cells and transcytosis across epithelial and endothelial cells into the blood and lymph circulation to reach potentially sensitive target sites such as bone marrow, lymph nodes, spleen, and heart. Access to the central nervous system and ganglia via translocation along axons and dendrites of neurons has also been observed. NSPs penetrating the skin distribute via uptake into lymphatic channels. Endocytosis and biokinetics are largely dependent on NSP surface chemistry (coating) and in vivo surface modifications. The greater surface area per mass compared with larger-sized particles of the same chemistry renders NSPs more active biologically. This activity includes a potential for inflammatory and pro-oxidant, but also antioxidant, activity, which can explain early findings showing mixed results in terms of toxicity of NSPs to environmentally relevant species. Evidence of mitochondrial distribution and oxidative stress response after NSP endocytosis points to a need for basic research on their interactions with subcellular structures. Additional considerations for assessing safety of engineered NSPs include careful selections of appropriate and relevant doses/concentrations, the likelihood of increased effects in a compromised organism, and also the benefits of possible desirable effects. An interdisciplinary team approach (e.g., toxicology, materials science, medicine, molecular biology, and bioinformatics, to name a few) is mandatory for nanotoxicology research to arrive at an appropriate risk assessment.

7,092 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provided an assessment of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice.
Abstract: Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr−1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m−2 with 90% uncertainty bounds of (+0.08, +1.27) W m−2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m−2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m−2 with 90% uncertainty bounds of +0.17 to +2.1 W m−2. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m−2, is the second most important human emission in terms of its climate forcing in the present-day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short-lived species that may either cool or warm climate. Climate forcings from co-emitted species are estimated and used in the framework described herein. When the principal effects of short-lived co-emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy-related sources (fossil fuel and biofuel) have an industrial-era climate forcing of +0.22 (−0.50 to +1.08) W m−2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all short-lived emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial-era climate forcing by all short-lived species from black-carbon-rich sources becomes slightly negative (−0.06 W m−2 with 90% uncertainty bounds of −1.45 to +1.29 W m−2). The uncertainties in net climate forcing from black-carbon-rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co-emitted organic carbon. In prioritizing potential black-carbon mitigation actions, non-science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near-term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black-carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.

4,591 citations

Book ChapterDOI
01 Jan 2014
TL;DR: Myhre et al. as discussed by the authors presented the contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) 2013: Anthropogenic and Natural Radiative forcing.
Abstract: This chapter should be cited as: Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Coordinating Lead Authors: Gunnar Myhre (Norway), Drew Shindell (USA)

3,684 citations

Journal ArticleDOI
TL;DR: In this article, an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and analytical techniques used to determine the chemical composition of SOA is presented.
Abstract: Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

3,324 citations