L. Poulain
Leibniz Association
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Atmospheric Chemistry and Physics | 2009
D. Niedermeier; Susan Hartmann; Raymond A. Shaw; D. Covert; Th. F. Mentel; Johannes Schneider; L. Poulain; P. Reitz; C. Spindler; T. Clauss; A. Kiselev; E. Hallbauer; Heike Wex; K. Mildenberger; Frank Stratmann
During the measurement campaign FROST (FReezing Of duST), LACIS (Leipzig Aerosol Cloud Interaction Simulator) was used to investigate the immersion freezing behavior of size selected, coated and uncoated Arizona Test Dust (ATD) particles with a mobility diameter of 300 nm. Particles were coated with succinic acid (C 4H6O4), sulfuric acid (H2SO4) and ammonium sulfate ((NH 4)2SO4). Ice fractions at mixed-phase cloud temperatures ranging from 233.15 K to 239.15 K ( ±0.60 K) were determined for all types of particles. In this temperature range, pure ATD particles and those coated with C 4H6O4 or small amounts of H2SO4 were found to be the most efficient ice nuclei (IN). ATD particles coated with (NH4)2SO4 were the most inefficient IN. Since the supercooled droplets were highly diluted before freezing occurred, a freezing point suppression due to the soluble material on the particles (and therefore in the droplets) cannot explain this observation. Therefore, it is reasonable to assume that the coatings lead to particle surface alterations which cause the differences in the IN abilities. Two different theoretical approaches based on the stochastic and the singular hypotheses were applied to clarify and parameterize the freezing behavior of the particles investigated. Both approaches describe the experimentally determined results, yielding parameters that can subsequently be used to compare our results to those from other studies. HowCorrespondence to: D. Niedermeier ([email protected]) ever, we cannot clarify at the current state which of the two approaches correctly describes the investigated immersion freezing process. But both approaches confirm the assumption that the coatings lead to particle surface modifications lowering the nucleation efficiency. The stochastic approach interprets the reduction in nucleation rate from coating as primarily due to an increase in the thermodynamic barrier for ice formation (i.e., changes in interfacial free energies). The singular approach interprets the reduction as resulting from a reduced surface density of active sites.
Atmospheric Chemistry and Physics | 2012
C. Dolgorouky; V. Gros; R. Sarda-Esteve; V. Sinha; J. Williams; Nicolas Marchand; Sébastien Sauvage; L. Poulain; Jean Sciare; B. Bonsang
Hydroxyl radicals play a central role in the troposphere as they control the lifetime of many trace gases. Measurement of OH reactivity (OH loss rate) is important to better constrain the OH budget and also to evaluate the completeness of measured VOC budget. Total atmospheric OH reactivity was measured for the first time in an European Megacity: Paris and its surrounding areas with 12 million inhabitants, during the MEGAPOLI winter campaign 2010. The method deployed was the Comparative Reactivity Method (CRM). The measured dataset contains both measured and calculated OH reactivity from CO, NOx and VOCs measured via PTR-MS, GC-FID and GC-MS instruments. The reactivities observed in Paris covered a range from 10s to 130s, indicating a large loading of chemical reactants. The present study showed that, when clean marine air masses influenced Paris, the purely local OH reactivity (20s) is well explained by the measured species. Nevertheless, when there is a continental import of air masses, high levels of OH reactivity were obtained (120 – 130 s) and the missing OH reactivity measured in this case jumped to 75%. Using covariations of the missing OH reactivity to secondary inorganic species in fine aerosols, we suggest that the missing OH reactants were most likely highly oxidized compounds issued from photochemically processed air masses of anthropogenic origin. Chapitre 4 : Mesure de la réactivité OH à Paris pendant MEGAPOLI hiver 2010 146 Mesure de la réactivité atmosphérique totale avec les radicaux OH : Développement et applications en Ile-de-France
Environmental Science & Technology | 2015
Anke Mutzel; L. Poulain; Torsten Berndt; Yoshiteru Iinuma; Maria Rodigast; Olaf Böge; Stefanie Richters; Gerald Spindler; Mikko Sipilä; Tuija Jokinen; Markku Kulmala; Hartmut Herrmann
Very recent studies have reported the existence of highly oxidized multifunctional organic compounds (HOMs) with O/C ratios greater than 0.7. Because of their low vapor pressure, these compounds are often referred as extremely low-volatile organic compounds (ELVOCs), and thus, they are able to contribute significantly to organic mass in tropospheric particles. While HOMs have been successfully detected in the gas phase, their fate after uptake into particles remains unclear to date. Hence, the present study was designed to detect HOMs and related oxidation products in the particle phase and, thus, to shed light on their fate after phase transfer. To this end, aerosol chamber investigations of α-pinene ozonolysis were conducted under near environmental precursor concentrations (2.4 ppb) in a continuous flow reactor. The chemical characterization shows three classes of particle constituents: (1) intact HOMs that contain a carbonyl group, (2) particle-phase decomposition products, and (3) highly oxidized organosulfates (suggested to be addressed as HOOS). Besides chamber studies, HOM formation was also investigated during a measurement campaign conducted in summer 2013 at the TROPOS research station Melpitz. During this field campaign, gas-phase HOM formation was found to be correlated with an increase in the oxidation state of the organic aerosol.
Geophysical Research Letters | 2016
Astrid Kiendler-Scharr; A. A. Mensah; E. Friese; David Topping; E. Nemitz; André S. H. Prévôt; Mikko Äijälä; J. D. Allan; F. Canonaco; Manjula R. Canagaratna; Samara Carbone; Monica Crippa; M. Dall’Osto; Douglas A. Day; P. De Carlo; C. Di Marco; H. Elbern; Axel Eriksson; Evelyn Freney; Liqing Hao; Hartmut Herrmann; Lea Hildebrandt; R. Hillamo; Jose L. Jimenez; Ari Laaksonen; Gordon McFiggans; Claudia Mohr; Colin D. O'Dowd; R. Otjes; Jurgita Ovadnevaite
In the atmosphere night time removal of volatile organic compounds (VOC) is initiated to a large extent by reaction with the nitrate radical (NO3) forming organic nitrates which partition between gas and particulate phase. Here we show based on particle phase measurements performed at a suburban site in the Netherlands that organic nitrates contribute substantially to particulate nitrate and organic mass. Comparisons with a chemistry transport model (CTM) indicate that most of the measured particulate organic nitrates are formed by NO3 oxidation. Using aerosol composition data from three intensive observation periods at numerous measurement sites across Europe, we conclude that organic nitrates are a considerable fraction of fine particulate matter (PM1) at the continental scale. Organic nitrates represent 34% to 44% of measured submicron aerosol nitrate and are found at all urban and rural sites, implying a substantial potential of PM reduction by NOx emission control.In the atmosphere nighttime removal of volatile organic compounds is initiated to a large extent by reaction with the nitrate radical (NO3) forming organic nitrates which partition between gas and particulate phase. Here we show based on particle phase measurements performed at a suburban site in the Netherlands that organic nitrates contribute substantially to particulate nitrate and organic mass. Comparisons with a chemistry transport model indicate that most of the measured particulate organic nitrates are formed by NO3 oxidation. Using aerosol composition data from three intensive observation periods at numerous measurement sites across Europe, we conclude that organic nitrates are a considerable fraction of fine particulate matter (PM1) at the continental scale. Organic nitrates represent 34% to 44% of measured submicron aerosol nitrate and are found at all urban and rural sites, implying a substantial potential of PM reduction by NOx emission control.
Geophysical Research Letters | 2015
Qi Chen; Colette L. Heald; J. L. Jimenez; Manjula R. Canagaratna; Qi Zhang; Ling-Yan He; Xiao-Feng Huang; Pedro Campuzano-Jost; Brett B. Palm; L. Poulain; Mikinori Kuwata; Scot T. Martin; Jonathan P. D. Abbatt; Alex K. Y. Lee; John Liggio
A large data set including surface, aircraft, and laboratory observations of the atomic oxygen-to-carbon (O:C) and hydrogen-to-carbon (H:C) ratios of organic aerosol (OA) is synthesized and corrected using a recently reported method. The whole data set indicates a wide range of OA oxidation and a trajectory in the Van Krevelen diagram, characterized by a slope of −0.6, with variation across campaigns. We show that laboratory OA including both source and aged types explains some of the key differences in OA observed across different environments. However, the laboratory data typically fall below the mean line defined by ambient observations, and little laboratory data extend to the highest O:C ratios commonly observed in remote conditions. OA having both high O:C and high H:C are required to bridge the gaps. Aqueous-phase oxidation may produce such OA, but experiments under realistic ambient conditions are needed to constrain the relative importance of this pathway.
Tellus B | 2014
Paul Zieger; R. Fierz-Schmidhauser; L. Poulain; T. Müller; W. Birmili; Gerald Spindler; Alfred Wiedensohler; Urs Baltensperger; E. Weingartner
The influence of aerosol water uptake on the aerosol particle light scattering was examined at the regional continental research site Melpitz, Germany. The scattering enhancement factor f(RH), defined as the aerosol particle scattering coefficient at a certain relative humidity (RH) divided by its dry value, was measured using a humidified nephelometer. The chemical composition and other microphysical properties were measured in parallel. f(RH) showed a strong variation, e.g. with values between 1.2 and 3.6 at RH=85% and λ=550 nm. The chemical composition was found to be the main factor determining the magnitude of f(RH), since the magnitude of f(RH) clearly correlated with the inorganic mass fraction measured by an aerosol mass spectrometer (AMS). Hysteresis within the recorded humidograms was observed and explained by long-range transported sea salt. A closure study using Mie theory showed the consistency of the measured parameters.
Journal of Environmental Management | 2015
E. Boonen; V. Akylas; Fotios Barmpas; A. Boréave; L. Bottalico; Mathieu Cazaunau; H. Chen; Véronique Daële; T. De Marco; Jean-François Doussin; C. Gaimoz; M. Gallus; Christian George; Noël Grand; Benoit Grosselin; G.L. Guerrini; Hartmut Herrmann; S. Ifang; Jörg Kleffmann; Ralf Kurtenbach; M. Maille; G. Manganelli; Abdelwahid Mellouki; K. Miet; F. Mothes; N. Moussiopoulos; L. Poulain; R. Rabe; P. Zapf; A. Beeldens
Within the framework of the European Life+-funded project PhotoPAQ (Demonstration of Photocatalytic remediation Processes on Air Quality), which was aimed at demonstrating the effectiveness of photocatalytic coating materials on a realistic scale, a photocatalytic de-polluting field site was set up in the Leopold II tunnel in Brussels, Belgium. For that purpose, photocatalytic cementitious materials were applied on the side walls and ceiling of selected test sections inside a one-way tunnel tube. This article presents the configuration of the test sections used and the preparation and implementation of the measuring campaigns inside the Leopold II tunnel. While emphasizing on how to implement measuring campaigns under such conditions, difficulties encountered during these extensive field campaigns are presented and discussed. This included the severe de-activation observed for the investigated material under the polluted tunnel conditions, which was revealed by additional laboratory experiments on photocatalytic samples that were exposed to tunnel air. Finally, recommendations for future applications of photocatalytic building materials inside tunnels are given.
Journal of Geophysical Research | 2014
Robert M. Healy; Greg J. Evans; Michael Murphy; Z. Jurányi; Torsten Tritscher; M. Laborde; E. Weingartner; M. Gysel; L. Poulain; Katharina A. Kamilli; Alfred Wiedensohler; Ian P. O'Connor; Eoin McGillicuddy; John R. Sodeau; John C. Wenger
Single particle mass spectral data, collected in Paris, France, have been used to predict hygroscopic growth at the single particle level. The mass fractions of black carbon, organic aerosol, ammonium, nitrate, and sulphate present in each particle were estimated using a combination of single particle mass spectrometer and bulk aerosol chemical composition measurements. The Zdanovskii-Stokes-Robinson (ZSR) approach was then applied to predict hygroscopic growth factors based on these mass fraction estimates. Smaller particles with high black carbon mass fractions and low inorganic ion mass fractions exhibited the lowest predicted growth factors, while larger particles with high inorganic ion mass fractions exhibited the highest growth factors. Growth factors were calculated for subsaturated relative humidity (90%) to enable comparison with hygroscopic tandem differential mobility analyzer measurements. Mean predicted and measured hygroscopic growth factors for 110, 165, and 265 nm particles were found to agree within 6%. Single particle-based ZSR hygroscopicity estimates offer an advantage over bulk aerosol composition-based hygroscopicity estimates by providing additional chemical mixing state information. External mixing can be determined for particles of a given diameter through examination of the predicted hygroscopic growth factor distributions. Using this approach, 110 nm and 265 nm particles were found to be predominantly internally mixed; however, external mixing of 165 nm particles was observed periodically when thinly coated and thickly coated black carbon particles were simultaneously detected. Single particle-resolved chemical information will be useful for modeling efforts aimed at constraining cloud condensation nuclei activity and hygroscopic growth.
Environmental Science & Technology | 2017
Shan Huang; L. Poulain; Dominik van Pinxteren; Manuela van Pinxteren; Zhijun Wu; Hartmut Herrmann; Alfred Wiedensohler
Methanesulfonic acid (MSA) has been widely used as a proxy for marine biogenic sources, but it is still a challenge to provide an accurate MSA mass concentration with high time resolution. This study offers an improved MSA quantification method using high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Particularly, the method was validated based on an excellent agreement with parallel offline measurements (slope = 0.88, R2 = 0.89). This comparison is much better than those using previously reported methods, resulting in underestimations of 31-54% of MSA concentration. With this new method, MSA mass concentrations were obtained during 4 North/South Atlantic cruises in spring and autumn of 2011 and 2012. The seasonal and spatial variation of the particulate MSA mass concentration as well as the MSA to non-sea-salt sulfate ratio (MSA:nssSO4) over the North/South Atlantic Ocean were determined for the first time. Seasonal variation of the MSA mass concentration was observed, with higher values in spring (0.03 μg m-3) than in autumn (0.01 μg m-3). The investigation of MSA:nssSO4 suggests a ubiquitous and significant influence of anthropogenic sources on aerosols in the marine boundary layer.
Scientific Reports | 2018
M. Dall'Osto; David C. S. Beddows; Ari Asmi; L. Poulain; Liqing Hao; Evelyn Freney; J. D. Allan; Manjula R. Canagaratna; Monica Crippa; Federico Bianchi; G. de Leeuw; Axel Eriksson; Erik Swietlicki; H.-C. Hansson; J. S. Henzing; C. Granier; K. Zemankova; Paolo Laj; Timothy B. Onasch; Andre S. H. Prevot; J.-P. Putaud; K. Sellegri; Marta Vidal; Annele Virtanen; Rafel Simó; Douglas R. Worsnop; Colin D. O'Dowd; Markku Kulmala; Roy M. Harrison
The formation of new atmospheric particles involves an initial step forming stable clusters less than a nanometre in size (<~1 nm), followed by growth into quasi-stable aerosol particles a few nanometres (~1–10 nm) and larger (>~10 nm). Although at times, the same species can be responsible for both processes, it is thought that more generally each step comprises differing chemical contributors. Here, we present a novel analysis of measurements from a unique multi-station ground-based observing system which reveals new insights into continental-scale patterns associated with new particle formation. Statistical cluster analysis of this unique 2-year multi-station dataset comprising size distribution and chemical composition reveals that across Europe, there are different major seasonal trends depending on geographical location, concomitant with diversity in nucleating species while it seems that the growth phase is dominated by organic aerosol formation. The diversity and seasonality of these events requires an advanced observing system to elucidate the key processes and species driving particle formation, along with detecting continental scale changes in aerosol formation into the future.