Author
Markku Kulmala
Other affiliations: Moscow State University, University of Helsinki
Bio: Markku Kulmala is an academic researcher from Nanjing University. The author has contributed to research in topics: Nucleation & Aerosol. The author has an hindex of 6, co-authored 30 publications receiving 299 citations. Previous affiliations of Markku Kulmala include Moscow State University & University of Helsinki.
Topics: Nucleation, Aerosol, Particle, Atmosphere, Ternary operation
Papers
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01 Jan 2007
TL;DR: Kerminen and Kulmala as discussed by the authors derived a simple yet rather accurate formula for this purpose by estimating the particle formation rate, nucleation mode growth rate and scavenging rate onto background particles (coagulation sink) from measured size distribution evolution.
Abstract: Connections between observed particle formation rates (typically at diameter 3 nm or larger) and the actual nucleation rates have important applications in atmospheric science. First, nucleation theories can be evaluated and second, semi-empirical particle formation rates can be developed for large scale models that neglect the cumbersome initial steps of formation and growth. Kerminen and Kulmala, by estimating the particle formation rate, nucleation mode growth rate and scavenging rate onto background particles (coagulation sink) from measured size distribution evolution, derived a simple yet rather accurate formula for this purpose [Kerminen V.-M., Kulmala, M. (2002). Analytical formulae connecting the “real” and the “apparent” 25 nucleation rate and the nuclei number concentration for atmospheric nucleation events, Journal of Aerosol Science 33, 609–622]. The present work reformulates the original theory in a way that two drawbacks are eliminated: (1) the original expression was derived using a slightly inaccurate coagulation sink dependence on particle size and (2) was based on knowing the condensation sink which requires knowledge of the condensing vapors. 2007 Elsevier Ltd. All rights reserved.
152 citations
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TL;DR: In this paper, a ternary nucleation model based on classical nucleation theory was proposed to predict nucleation rates over a larger temperature range (258-303 K) compared with previous work.
Abstract: A new version of a ternary nucleation (sulphuric acid-ammonia-water) model based on classical nucleation theory, but with an improved ability to predict nucleation rates over a larger temperature range (258-303 K) compared with previous work, is presented. The modeled nucleation rates are given as a function of temperature and ambient acid and ammonia concentrations. For the first time the predicted ternary nucleation rates are compared to the observed particle production rates using measured ambient sulphuric acid and ammonia concentrations as input data. The ambient gas concentrations were measured simultaneously to aerosol formation rates during the 1999 New Particle Formation and Fate in the Coastal Environment (PARFORCE) coastal field campaign at Mace Head. According to the results, daytime ambient acid and ammonia concentrations were significantly higher than required by model calculations to induce the formation of new particles by homogeneous ternary nucleation. However, binary nucleation of sulphuric acid-water molecules is not able to predict new particle formation since the binary nucleation rate is far too small. We conclude that all particle formation events observed at coastal sites can be initiated by ternary nucleation of sulphuric acid, ammonia, and water vapor. However, related studies illustrate that ambient sulphuric acid concentrations are, nevertheless, insufficient to explain observed rapid growth of particles from 1 to 3 nm sizes which can be detected by current instrumentation.
68 citations
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TL;DR: Atmospheric aerosols in the earth system: a review of interactions and feedbacks K. S. Carslaw, O. Boucher, D. V. Mann, J. L. Rae, S. Woodward, and M. W.
Abstract: Atmospheric aerosols in the earth system: a review of interactions and feedbacks K. S. Carslaw, O. Boucher, D. V. Spracklen, G. W. Mann, J. G. L. Rae, S. Woodward, and M. Kulmala School of Earth and Environment, University of Leeds, Leeds, UK Met Office Hadley Centre, FitzRoy Road, Exeter, UK University of Helsinki, Department of Physics, Division of Atmospheric Sciences and Geophysics, Helsinki, Finland Received: 7 April 2009 – Accepted: 18 April 2009 – Published: 5 May 2009 Correspondence to: K. S. Carslaw (k.s.carslaw@leeds.ac.uk) Published by Copernicus Publications on behalf of the European Geosciences Union.
29 citations
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TL;DR: In this paper, the feasibility of using wearable low-cost pollution sensors for capturing the total exposure of commuters is analyzed by using extensive experiments carried out in the Helsinki metropolitan region, and they demonstrate that wearable sensors can capture subtle variations caused by differing routes, passenger density, location within a carriage, and other factors.
Abstract: Transit activities are a significant contributor to a person’s daily exposure to pollutants. Currently obtaining accurate information about the personal exposure of a commuter is challenging as existing solutions either have a coarse monitoring resolution that omits subtle variations in pollutant concentrations or are laborious and costly to use. We contribute by systematically analysing the feasibility of using wearable low-cost pollution sensors for capturing the total exposure of commuters. Through extensive experiments carried out in the Helsinki metropolitan region, we demonstrate that low-cost sensors can capture the overall exposure with sufficient accuracy, while at the same time providing insights into variations within transport modalities. We also demonstrate that wearable sensors can capture subtle variations caused by differing routes, passenger density, location within a carriage, and other factors. For example, we demonstrate that location within the vehicle carriage can result in up to 25 % increase in daily pollution exposure – a significant difference that existing solutions are unable to capture. Finally, we highlight the practical benefits of low-cost sensors as a pollution monitoring solution by introducing applications that are enabled by low-cost wearable sensors.
15 citations
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TL;DR: In this article, the reported coefficients in the parameterized equation are numerically inaccurate for the calculation of ternary nucleation rates and critical cluster sizes accurately, and a Fortran code is provided to calculate the reported parameterized nucleation rate.
Abstract: [1] In the paper ‘‘New parameterization of sulfuric acidammonia-water ternary nucleation rates at tropospheric conditions’’ by J. Merikanto et al. (J. Geophys. Res., 112, D15207, doi:10.1029/2006JD007977, 2007) the reported coefficients in the parameterized equation are numerically inaccurate for the calculation of ternary nucleation rates. The coefficients were given with six significant digits. However, this precision is not sufficient. Coefficients with 16 significant digits are given in Table 1. We also provide a Fortran code that calculates the reported parameterized nucleation rates and critical cluster sizes accurately (see auxiliary material). [2] Also, the term containing f15 in equation (8) in paragraph 18 should be multiplied by RH. The correct equation is
11 citations
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TL;DR: In this paper, the formation rate of 3-nm particles is often in the range 0.01-10 cm −3 s −1 in the boundary layer in urban areas and in coastal areas and industrial plumes.
2,028 citations
01 Dec 2006
TL;DR: This paper showed that reactive anthropogenic VOCs (AVOCs) produce much larger amounts of SOA than these models predict, even shortly after sunrise, and a significant fraction of the excess SOA is formed from first-generation AVOC oxidation products.
Abstract: [1] The atmospheric chemistry of volatile organic compounds (VOCs) in urban areas results in the formation of ‘photochemical smog’, including secondary organic aerosol (SOA). State-of-the-art SOA models parameterize the results of simulation chamber experiments that bracket the conditions found in the polluted urban atmosphere. Here we show that in the real urban atmosphere reactive anthropogenic VOCs (AVOCs) produce much larger amounts of SOA than these models predict, even shortly after sunrise. Contrary to current belief, a significant fraction of the excess SOA is formed from first-generation AVOC oxidation products. Global models deem AVOCs a very minor contributor to SOA compared to biogenic VOCs (BVOCs). If our results are extrapolated to other urban areas, AVOCs could be responsible for additional 3–25 Tg yr−1 SOA production globally, and cause up to −0.1 W m−2 additional top-of-the-atmosphere radiative cooling.
947 citations
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University of Leicester1, Earth System Research Laboratory2, Cooperative Institute for Research in Environmental Sciences3, Centre national de la recherche scientifique4, Norwegian Institute for Air Research5, United Kingdom Department for Environment, Food and Rural Affairs6, Japan Agency for Marine-Earth Science and Technology7, International Institute for Applied Systems Analysis8, Danish Meteorological Institute9, Paul Scherrer Institute10, ETH Zurich11, University of California, Irvine12, University of Leeds13, Aristotle University of Thessaloniki14, École Polytechnique Fédérale de Lausanne15, Geophysical Fluid Dynamics Laboratory16, National Center for Atmospheric Research17, Stockholm University18, Swiss Federal Laboratories for Materials Science and Technology19, Forschungszentrum Jülich20, University of Oslo21, Max Planck Society22, University of Helsinki23, Blaise Pascal University24, Joseph Fourier University25, University of York26, University of Toulouse27, University of Urbino28, University of Manchester29, National University of Ireland, Galway30, University of Edinburgh31, Heidelberg University32, University of East Anglia33, Weizmann Institute of Science34, Norwegian Meteorological Institute35, Chalmers University of Technology36, Energy Research Centre of the Netherlands37, University of Stuttgart38, VU University Amsterdam39
TL;DR: A review of the state of scientific understanding in relation to global and regional air quality is outlined in this article, in terms of emissions, processing and transport of trace gases and aerosols.
760 citations
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TL;DR: In this paper, the authors review the impact of natural systems on atmospheric aerosol based on observations and models, including the potential for long term changes in emissions and the feedbacks on climate.
Abstract: . The natural environment is a major source of atmospheric aerosols, including dust, secondary organic material from terrestrial biogenic emissions, carbonaceous particles from wildfires, and sulphate from marine phytoplankton dimethyl sulphide emissions. These aerosols also have a significant effect on many components of the Earth system such as the atmospheric radiative balance and photosynthetically available radiation entering the biosphere, the supply of nutrients to the ocean, and the albedo of snow and ice. The physical and biological systems that produce these aerosols can be highly susceptible to modification due to climate change so there is the potential for important climate feedbacks. We review the impact of these natural systems on atmospheric aerosol based on observations and models, including the potential for long term changes in emissions and the feedbacks on climate. The number of drivers of change is very large and the various systems are strongly coupled. There have therefore been very few studies that integrate the various effects to estimate climate feedback factors. Nevertheless, available observations and model studies suggest that the regional radiative perturbations are potentially several Watts per square metre due to changes in these natural aerosol emissions in a future climate. Taking into account only the direct radiative effect of changes in the atmospheric burden of natural aerosols, and neglecting potentially large effects on other parts of the Earth system, a global mean radiative perturbation approaching 1 W m−2 is possible by the end of the century. The level of scientific understanding of the climate drivers, interactions and impacts is very low.
528 citations
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Paul Scherrer Institute1, Carnegie Mellon University2, CERN3, Goethe University Frankfurt4, University of Helsinki5, Stockholm University6, ETH Zurich7, Cooperative Institute for Research in Environmental Sciences8, Earth System Research Laboratory9, 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