Author
Annele Virtanen
Other affiliations: Tampere University of Technology, University of Vienna, VTT Technical Research Centre of Finland
Bio: Annele Virtanen is an academic researcher from University of Eastern Finland. The author has contributed to research in topics: Aerosol & Particle. The author has an hindex of 43, co-authored 154 publications receiving 6977 citations. Previous affiliations of Annele Virtanen include Tampere University of Technology & University of Vienna.
Topics: Aerosol, Particle, Particle size, Cloud condensation nuclei, Diesel fuel
Papers published on a yearly basis
Papers
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Goethe University Frankfurt1, CERN2, University of Helsinki3, Paul Scherrer Institute4, University of Beira Interior5, University of Innsbruck6, Carnegie Mellon University7, California Institute of Technology8, University of Leeds9, University of Eastern Finland10, University of Vienna11, Lebedev Physical Institute12, Finnish Meteorological Institute13, Kyoto University14, Helsinki Institute of Physics15, Stockholm University16, Leibniz Association17
TL;DR: The results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.
Abstract: Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei(1). Aerosols can cause a net cooling of climate by scattering sun ...
738 citations
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TL;DR: The results of this study challenge traditional views of the kinetics and thermodynamics of SOA formation and transformation in the atmosphere and their implications for air quality and climate.
Abstract: Secondary organic aerosol (SOA) particles are formed in the atmosphere from condensable oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs)(1-7). On a global scale, biogenic VOCs account for about 90% of VOC emissions(1,8) and of SOA formation (90 billion kilograms of carbon per year)(1-4). SOA particles can scatter radiation and act as cloud condensation or ice nuclei, and thereby influence the Earth's radiation balance and climate(1,2,5,9,10). They consist of a myriad of different compounds with varying physicochemical properties, and little information is available on the phase state of SOA particles. Gas-particle partitioning models usually assume that SOA particles are liquid(1,5,11), but here we present experimental evidence that they can be solid under ambient conditions. We investigated biogenic SOA particles formed from oxidation products of VOCs in plant chamber experiments and in boreal forests within a few hours after atmospheric nucleation events. On the basis of observed particle bouncing in an aerosol impactor and of electron microscopy we conclude that biogenic SOA particles can adopt an amorphous solid-most probably glassy-state. This amorphous solid state should provoke a rethinking of SOA processes because it may influence the partitioning of semi-volatile compounds, reduce the rate of heterogeneous chemical reactions, affect the particles' ability to accommodate water and act as cloud condensation or ice nuclei, and change the atmospheric lifetime of the particles(12-15). Thus, the results of this study challenge traditional views of the kinetics and thermodynamics of SOA formation and transformation in the atmosphere and their implications for air quality and climate.
688 citations
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Paul Scherrer Institute1, Carnegie Mellon University2, CERN3, Goethe University Frankfurt4, University of Helsinki5, Stockholm University6, ETH Zurich7, Earth System Research Laboratory8, Cooperative Institute for Research in Environmental Sciences9, California Institute of Technology10, Helsinki Institute of Physics11, University of Innsbruck12, University of Eastern Finland13, Finnish Meteorological Institute14, National Center for Atmospheric Research15, Karlsruhe Institute of Technology16, University of Leeds17, University of California, Irvine18, University of Vienna19, University of Beira Interior20
TL;DR: It is shown that organic vapours alone can drive nucleation, and a particle growth model is presented that quantitatively reproduces the measurements and implements a parameterization of the first steps of growth in a global aerosol model that can change substantially in response to concentrations of atmospheric cloud concentration nuclei.
Abstract: About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst of new particles near midday. Atmospheric observations show that the growth rate of new particles often accelerates when the diameter of the particles is between one and ten nanometres. In this critical size range, new particles are most likely to be lost by coagulation with pre-existing particles, thereby failing to form new cloud condensation nuclei that are typically 50 to 100 nanometres across. Sulfuric acid vapour is often involved in nucleation but is too scarce to explain most subsequent growth, leaving organic vapours as the most plausible alternative, at least in the planetary boundary layer. Although recent studies predict that low-volatility organic vapours contribute during initial growth, direct evidence has been lacking. The accelerating growth may result from increased photolytic production of condensable organic species in the afternoon, and the presence of a possible Kelvin (curvature) effect, which inhibits organic vapour condensation on the smallest particles (the nano-Kohler theory), has so far remained ambiguous. Here we present experiments performed in a large chamber under atmospheric conditions that investigate the role of organic vapours in the initial growth of nucleated organic particles in the absence of inorganic acids and bases such as sulfuric acid or ammonia and amines, respectively. Using data from the same set of experiments, it has been shown that organic vapours alone can drive nucleation. We focus on the growth of nucleated particles and find that the organic vapours that drive initial growth have extremely low volatilities (saturation concentration less than 10(-4.5) micrograms per cubic metre). As the particles increase in size and the Kelvin barrier falls, subsequent growth is primarily due to more abundant organic vapours of slightly higher volatility (saturation concentrations of 10(-4.5) to 10(-0.5) micrograms per cubic metre). We present a particle growth model that quantitatively reproduces our measurements. Furthermore, we implement a parameterization of the first steps of growth in a global aerosol model and find that concentrations of atmospheric cloud concentration nuclei can change substantially in response, that is, by up to 50 per cent in comparison with previously assumed growth rate parameterizations.
507 citations
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Goethe University Frankfurt1, CERN2, Helsinki Institute of Physics3, University of Helsinki4, University of Leeds5, Paul Scherrer Institute6, University of Washington7, University of Innsbruck8, University of Lisbon9, ETH Zurich10, California Institute of Technology11, University of Eastern Finland12, Finnish Meteorological Institute13, Lebedev Physical Institute14, Stockholm University15, University of Vienna16, Leibniz Association17, University of Beira Interior18, Carnegie Mellon University19
TL;DR: Ion-induced nucleation of pure organic particles constitutes a potentially widespread source of aerosol particles in terrestrial environments with low sulfuric acid pollution.
Abstract: Atmospheric aerosols and their effect on clouds are thought to be important for anthropogenic radiative forcing of the climate, yet remain poorly understood. Globally, around half of cloud condensation nuclei originate from nucleation of atmospheric vapours. It is thought that sulfuric acid is essential to initiate most particle formation in the atmosphere, and that ions have a relatively minor role. Some laboratory studies, however, have reported organic particle formation without the intentional addition of sulfuric acid, although contamination could not be excluded. Here we present evidence for the formation of aerosol particles from highly oxidized biogenic vapours in the absence of sulfuric acid in a large chamber under atmospheric conditions. The highly oxygenated molecules (HOMs) are produced by ozonolysis of α-pinene. We find that ions from Galactic cosmic rays increase the nucleation rate by one to two orders of magnitude compared with neutral nucleation. Our experimental findings are supported by quantum chemical calculations of the cluster binding energies of representative HOMs. Ion-induced nucleation of pure organic particles constitutes a potentially widespread source of aerosol particles in terrestrial environments with low sulfuric acid pollution.
502 citations
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TL;DR: The results indicate that the nucleation mode particles of a Euro IV heavy-duty diesel vehicle exhaust have a nonvolatile core formed before the dilution process, which was observed to be linked to the total hydrocarbon concentration in the diluted sample.
Abstract: The characteristics of the nucleation mode particles of a Euro IV heavy-duty diesel vehicle exhaust were studied. The NOx and PM emissions of the vehicle were controlled through the use of cooled EGR and high-pressure fuel injection techniques; no exhaust gas after-treatment was used. Particle measurements were performed in vehicle laboratory and on road. Nucleation mode dominated the particle number size distribution in all the tested driving conditions. According to the on-road measurements, the nucleation mode was already formed after 0.7 s residence time in the atmosphere and no significant changes were observed for longer residence times. The nucleation mode was insensitive to the fuel sulfur content, dilution air temperature, and relative humidity. An increase in the dilution ratio decreased the size of the nucleation mode particles. This behavior was observed to be linked to the total hydrocarbon concentration in the diluted sample. In volatility measurements, the nucleation mode particles were obs...
234 citations
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TL;DR: In this article, the authors present a document, redatto, voted and pubblicato by the Ipcc -Comitato intergovernativo sui cambiamenti climatici - illustra la sintesi delle ricerche svolte su questo tema rilevante.
Abstract: Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.
4,187 citations
01 Jan 2007
TL;DR: The Third edition of the Kirk-Othmer encyclopedia of chemical technology as mentioned in this paper was published in 1989, with the title "Kirk's Encyclopedia of Chemical Technology: Chemical Technology".
Abstract: 介绍了Kirk—Othmer Encyclopedia of Chemical Technology(化工技术百科全书)(第五版)电子图书网络版数据库,并对该数据库使用方法和检索途径作出了说明,且结合实例简单地介绍了该数据库的检索方法。
2,666 citations
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TL;DR: A copy of the Guangbo jiemu bao [Broadcast Program Report] was being passed from hand to hand among a group of young people eager to be the first to read the article introducing the program "What Is Revolutionary Love?".
Abstract: A copy of Guangbo jiemu bao [Broadcast Program Report] was being passed from hand to hand among a group of young people eager to be the first to read the article introducing the program "What Is Revolutionary Love?" It said: "… Young friends, you are certainly very concerned about this problem'. So, we would like you to meet the young women workers Meng Xiaoyu and Meng Yamei and the older cadre Miss Feng. They are the three leading characters in the short story ‘The Place of Love.’ Through the description of the love lives of these three, the story induces us to think deeply about two questions that merit further examination.
1,528 citations
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TL;DR: It is found that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies.
Abstract: Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally.
1,340 citations