Gysel, Martin

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Martin Gysel

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  • Vorschaubild
    Publikation
    Contribution of new particle formation to the total aerosol concentration at the high‐altitude site Jungfraujoch (3580 m asl, Switzerland)
    (Wiley, 2016) Tröstl, Jasmin; Herrmann, Erik; Frege, Carla; Bianchi, Federico; Molteni, Ugo; Bukowiecki, Nicolas; Hoyle, Christopher R.; Steinbacher, Martin; Weingartner, Ernest; Dommen, Josef; Gysel, Martin; Baltensperger, Urs [in: Journal of Geophysical Research: Atmospheres]
    Previous modeling studies hypothesized that a large fraction of cloud condensation nuclei (CCN) is attributed to new particle formation (NPF) in the free troposphere. Despite the potential importance of this process, only few long‐term observations have been performed to date. Here we present the results of a 12 month campaign of NPF observations at the high‐altitude site Jungfraujoch (JFJ, 3580 m above sea level (asl)). Our results show that NPF significantly adds to the total aerosol concentration at the JFJ and only occurs via previous precursor entrainment from the planetary boundary layer (PBL). Freshly nucleated particles do not directly grow to CCN size (90 nm) within observable time scales (maximum 48 h). The contribution of NPF to the CCN concentration is low within this time frame compared to other sources, such as PBL entrainment of larger particles. A multistep growth mechanism is proposed which allows previously formed Aitken mode particles to add to the CCN concentration. A parametrization is derived to explain formation rates at the JFJ, showing that precursor concentration, PBL influence, and global radiation are the key factors controlling new particle formation at the site.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    The role of low-volatility organic compounds in initial particle growth in the atmosphere
    (Springer, 2016) Tröstl, Jasmin; Chuang, Wayne K.; Gordon, Hamish; Heinritzi, Martin; Yan, Chao; Molteni, Ugo; Ahlm, Lars; Frege, Carla; Bianchi, Federico; Wagner, Robert; Simon, Mario; Lehtipalo, Katrianne; Williamson, Christina; Craven, Jill S.; Duplissy, Jonathan; Adamov, Alexey; Almeida, Joao; Bernhammer, Anne-Kathrin; Breitenlechner, Martin; Brilke, Sophia; Dias, Antònio; Ehrhart, Sebastian; Flagan, Richard C.; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Gysel, Martin; Hansel, Armin; Hoyle, Christopher R.; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Krapf, Manuel; Kürten, Andreas; Laaksonen, Ari; Lawler, Michael; Leiminger, Markus; Mathot, Serge; Möhler, Ottmar; Nieminen, Tuomo; Onnela, Antti; Petäjä, Tuukka; Piel, Felix M.; Miettinen, Pasi; Rissanen, Matti P.; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Sengupta, Kamalika; Sipilä, Mikko; Smith, James N.; Steiner, Gerhard; Tomè, Antònio; Virtanen, Annele; Wagner, Andrea C.; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M.; Ye, Penglin; Carslaw, Kenneth S.; Curtius, Joachim; Dommen, Josef; Kirkby, Jasper; Kulmala, Markku; Riipinen, Ilona; Worsnop, Douglas R.; Donahue, Neil M.; Baltensperger, Urs [in: Nature]
    About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst of new particles near midday1. Atmospheric observations show that the growth rate of new particles often accelerates when the diameter of the particles is between one and ten nanometres2,3. In this critical size range, new particles are most likely to be lost by coagulation with pre-existing particles4, 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 growth5,6, leaving organic vapours as the most plausible alternative, at least in the planetary boundary layer7,8,9,10. Although recent studies11,12,13 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 afternoon2, and the presence of a possible Kelvin (curvature) effect, which inhibits organic vapour condensation on the smallest particles (the nano-Köhler theory)2,14, 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 shown15 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.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    A European aerosol phenomenology-5. Climatology of black carbon optical properties at 9 regional background sites across Europe
    (Elsevier, 2016) Zanatta, Marco; Gysel, Martin; Bukowiecki, Nicolas; Müller, Thomas; Weingartner, Ernest; Areskoug, Hans; Fiebig, Markus; Yttri, Karl Espen; Mihalopoulos, Nikolaos; Kouvarakis, Giorgos; Beddows, David; Harrison, Roy; Cavalli, Fabrizia; Putaud, Jean; Spindler, Gerald; Wiedensohler, Alfred; Alastuey, Andrés; Pandolfi, Marco; Sellegri, Karine; Swietlicki, Erik; Jaffrezo, Jean-Luc; Baltensperger, Urs; Laj, Paolo [in: Atmospheric Environment]
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Size-dependent particle activation properties in fog during the ParisFog 2012/13 field campaign
    (Copernicus, 2014) Hammer, Emanuel; Gysel, Martin; Roberts, Greg; Elias, Thierry; Hofer, Julian; Hoyle, Christopher R.; Bukowiecki, Nicolas; Dupont, Jean-Charles; Burnet, Frederic; Baltensperger, Urs; Weingartner, Ernest [in: Atmospheric Chemistry and Physics]
    Fog-induced visibility reduction is responsible for a variety of hazards in the transport sector. Therefore there is a large demand for an improved understanding of fog formation and thus improved forecasts. Improved fog forecasts require a better understanding of the numerous complex mechanisms during the fog life cycle. During winter 2012/13 a field campaign called ParisFog aiming at fog research took place at SIRTA (Instrumented Site for Atmospheric Remote Sensing Research). SIRTA is located about 20 km southwest of the Paris city center, France, in a semi-urban environment. In situ activation properties of the prevailing fog were investigated by measuring (1) total and interstitial (non-activated) dry particle number size distributions behind two different inlet systems; (2) interstitial hydrated aerosol and fog droplet size distributions at ambient conditions; and (3) cloud condensation nuclei (CCN) number concentration at different supersaturations (SS) with a CCN counter. The aerosol particles were characterized regarding their hygroscopic properties, fog droplet activation behavior and contribution to light scattering for 17 developed fog events. Low particle hygroscopicity with an overall median of the hygroscopicity parameter, κ, of 0.14 was found, likely caused by substantial influence from local traffic and wood burning emissions. Measurements of the aerosol size distribution at ambient RH revealed that the critical wet diameter, above which the hydrated aerosols activate to fog droplets, is rather large (with a median value of 2.6μm) and is highly variable (ranging from 1 to 5μm) between the different fog events. Thus, the number of activated fog droplets was very small and the non-activated hydrated particles were found to contribute significantly to the observed light scattering and thus to the reduction in visibility. Combining all experimental data, the effective peak supersaturation, SSpeak, a measure of the peak supersaturation during the fog formation, was determined. The median SSpeak value was estimated to be in the range from 0.031 to 0.046% (upper and lower limit estimations), which is in good agreement with previous experimental and modeling studies of fog.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Investigation of the effective peak supersaturation for liquid-phase clouds at the high-alpine site Jungfraujoch, Switzerland (3580 m a.s.l.)
    (Copernicus, 2014) Hammer, Emanuel; Bukowiecki, Nicolas; Gysel, Martin; Jurányi, Zsófia; Hoyle, Christopher R.; Vogt, Roland; Baltensperger, Urs; Weingartner, Ernest [in: Atmospheric Chemistry and Physics]
    Aerosols influence the Earth's radiation budget directly through absorption and scattering of solar radiation in the atmosphere but also indirectly by modifying the properties of clouds. However, climate models still suffer from large uncertainties as a result of insufficient understanding of aerosol-cloud interactions. At the high altitude research station Jungfraujoch (JFJ; 3580 m a.s.l., Switzerland) cloud condensation nuclei (CCN) number concentrations at eight different supersaturations (SS) from 0.24% to 1.18% were measured using a CCN counter during Summer 2011. Simultaneously, in-situ aerosol activation properties of the prevailing ambient clouds were investigated by measuring the total and interstitial (non-activated) dry particle number size distributions behind two different inlet systems. Combining all experimental data, a new method was developed to retrieve the so-called effective peak supersaturation SSpeak, as a measure of the SS at which ambient clouds are formed. A 17-month CCN climatology was then used to retrieve the SSpeak values also for four earlier summer campaigns (2000, 2002, 2004 and 2010) where no direct CCN data were available. The SSpeak values varied between 0.01% and 2.0% during all campaigns. An overall median SSpeak of 0.35% and dry activation diameter of 87 nm was observed. It was found that the difference in topography between northwest and southeast plays an important role for the effective peak supersaturation in clouds formed in the vicinity of the JFJ, while differences in the number concentration of potential CCN only play a minor role. Results show that air masses coming from the southeast (with the slowly rising terrain of the Aletsch Glacier) generally experience lower SSpeak values than air masses coming from the northwest (steep slope). The observed overall median values were 0.41% and 0.22% for northwest and southeast wind conditions, respectively, corresponding to literature values for cumulus clouds and shallow-layer clouds. These cloud types are consistent with weather observations routinely performed at the JFJ.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Evolution of particle composition in CLOUD nucleation experiments
    (Copernicus, 2013) Keskinen, Helmi; Virtanen, Annele; Joutsensaari, Jorma; Tsagkogeorgas, Georgios; Duplissy, Jonathan; Schobesberger, Siegfried; Gysel, Martin; Riccobono, Francesco; Slowik, Jay Gates; Bianchi, Federico; Yli-Juuti, Taina; Lehtipalo, Katrianne; Rondo, Linda; Breitenlechner, Martin; Kupc, Agnieszka; Almeida, João; Amorim, Antonio; Dunne, Eimear M.; Downard, Andrew J.; Ehrhart, Sebastian; Franchin, Alessandro; Kajos, Maija K.; Kirkby, Jasper; Kürten, Andreas; Nieminen, Tuomo; Makhmutov, Vladimir; Mathot, Serge; Miettinen, Pasi; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud; Santos, Felipe D.; Schallhart, Simon; Sipilä, Mikko; Stozhkov, Yuri; Tomé, Antonio; Vaattovaara, Petri; Wimmer, Daniela; Prévôt, André; Dommen, Josef; Donahue, Neil M.; Flagan, Richard C.; Weingartner, Ernest; Viisanen, Yrjö; Riipinen, Ilona; Hansel, Armin; Curtius, Joachim; Kulmala, Markku; Worsnop, Douglas R.; Baltensperger, Urs; Wex, Heike; Stratmann, Frank; Laaksonen, Ari [in: Atmospheric Chemistry and Physics]
    Sulphuric acid, ammonia, amines, and oxidised organics play a crucial role in nanoparticle formation in the atmosphere. In this study, we investigate the composition of nucleated nanoparticles formed from these compounds in the CLOUD (Cosmics Leaving Outdoor Droplets) chamber experiments at CERN (Centre européen pour la recherche nucléaire). The investigation was carried out via analysis of the particle hygroscopicity, ethanol affinity, oxidation state, and ion composition. Hygroscopicity was studied by a hygroscopic tandem differential mobility analyser and a cloud condensation nuclei counter, ethanol affinity by an organic differential mobility analyser and particle oxidation level by a high-resolution time-of-flight aerosol mass spectrometer. The ion composition was studied by an atmospheric pressure interface time-of-flight mass spectrometer. The volume fraction of the organics in the particles during their growth from sizes of a few nanometers to tens of nanometers was derived from measured hygroscopicity assuming the Zdanovskii–Stokes–Robinson relationship, and compared to values gained from the spectrometers. The ZSR-relationship was also applied to obtain the measured ethanol affinities during the particle growth, which were used to derive the volume fractions of sulphuric acid and the other inorganics (e.g. ammonium salts). In the presence of sulphuric acid and ammonia, particles with a mobility diameter of 150 nm were chemically neutralised to ammonium sulphate. In the presence of oxidation products of pinanediol, the organic volume fraction of freshly nucleated particles increased from 0.4 to ~0.9, with an increase in diameter from 2 to 63 nm. Conversely, the sulphuric acid volume fraction decreased from 0.6 to 0.1 when the particle diameter increased from 2 to 50 nm. The results provide information on the composition of nucleated aerosol particles during their growth in the presence of various combinations of sulphuric acid, ammonia, dimethylamine and organic oxidation products.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    CCN activity and volatility of β-caryophyllene secondary organic aerosol
    (Copernicus, 2013) Frosch, Mia; Bilde, Merete; Nenes, Athanasios; Praplan, Arnaud P.; Jurányi, Zsófia; Dommen, Josef; Gysel, Martin; Weingartner, Ernest; Baltensperger, Urs [in: Atmospheric Chemistry and Physics]
    In a series of smog chamber experiments, the cloud condensation nuclei (CCN) activity of secondary organic aerosol (SOA) generated from ozonolysis of β-caryophyllene was characterized by determining the CCN derived hygroscopicity parameter, κCCN, from experimental data. Two types of CCN counters, operating at different temperatures, were used. The effect of semi-volatile organic compounds on the CCN activity of SOA was studied using a thermodenuder. Overall, SOA was only slightly CCN active (with κCCN in the range 0.001–0.16), and in dark experiments with no OH scavenger present, κCCN decreased when particles were sent through the thermodenuder (with a temperature up to 50 °C). SOA was generated under different experimental conditions: In some experiments, an OH scavenger (2-butanol) was added. SOA from these experiments was less CCN active than SOA produced in experiments without an OH scavenger (i.e. where OH was produced during ozonolysis). In other experiments, lights were turned on, either without or with the addition of HONO (OH source). This led to the formation of more CCN active SOA. SOA was aged up to 30 h through exposure to ozone and (in experiments with no OH scavenger present) to OH. In all experiments, the derived κCCN consistently increased with time after initial injection of β-caryophyllene, showing that chemical ageing increases the CCN activity of β-caryophyllene SOA. κCCN was also observed to depend on supersaturation, which was explained either as an evaporation artifact from semi-volatile SOA (only observed in experiments lacking light exposure) or, alternatively, by effects related to chemical composition depending on dry particle size. Using the method of Threshold Droplet Growth Analysis it was also concluded that the activation kinetics of the SOA do not differ significantly from calibration ammonium sulphate aerosol for particles aged for several hours.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Black carbon physical properties and mixing state in the European megacity Paris
    (Copernicus, 2013) Laborde, Marie; Crippa, Monica; Tritscher, Torsten; Jurányi, Zsófia; Decarlo, Peter; Temime-Roussel, Brice; Marchand, Nicolas; Eckhardt, Sabine; Stohl, Andreas; Baltensperger, Urs; Prévôt, André; Weingartner, Ernest; Gysel, Martin [in: Atmospheric Chemistry and Physics]
    Aerosol hygroscopicity and refractory black carbon (rBC) properties were characterised during wintertime at a suburban site in Paris, one of the biggest European cities. Hygroscopic growth factor (GF) frequency distributions, characterised by distinct modes of more-hygroscopic background aerosol and non- or slightly hygroscopic aerosol of local (or regional) origin, revealed an increase of the relative contribution of the local sources compared to the background aerosol with decreasing particle size. BC-containing particles in Paris were mainly originating from fresh traffic emissions, whereas biomass burning only gave a minor contribution. The mass size distribution of the rBC cores peaked on average at an rBC core mass equivalent diameter of DMEV ~ 150 nm. The BC-containing particles were moderately coated (coating thickness Δcoat ~ 33 nm on average for rBC cores with DMEV = 180–280 nm) and an average mass absorption coefficient (MAC) of ~ 8.6 m2 g−1 at the wavelength λ = 880 nm was observed. Different time periods were selected to investigate the properties of BC-containing particles as a function of source and air mass type. The traffic emissions were found to be non-hygroscopic (GF ≈ 1.0), and essentially all particles with a dry mobility diameter (D0) larger than D0 = 110 nm contained an rBC core. rBC from traffic emissions was further observed to be uncoated within experimental uncertainty (Δcoat ~ 2 nm ± 10 nm), to have the smallest BC core sizes (maximum of the rBC core mass size distribution at DMEV ~ 100 nm) and to have the smallest MAC (~ 7.3 m2g−1 at λ = 880 nm). The biomass burning aerosol was slightly more hygroscopic than the traffic emissions (with a distinct slightly-hygroscopic mode peaking at GF ≈ 1.1–1.2). Furthermore, only a minor fraction (≤ 10%) of the slightly-hygroscopic particles with 1.1 ≤ GF ≤ 1.2 (and D0 = 265 nm) contained a detectable rBC core. The BC-containing particles from biomass burning were found to have a medium coating thickness as well as slightly larger mean rBC core sizes and MAC values compared to traffic emissions. The aerosol observed under the influence of aged air masses and air masses from Eastern Continental Europe was dominated by a~more-hygroscopic mode peaking at GF ≈ 1.6. Most particles (95%), in the more-hygroscopic mode at D0 = 265 nm, did not contain a detectable rBC core. A significant fraction of the BC-containing particles had a substantial coating with non-refractory aerosol components. MAC values of ~ 8.8 m2g−1 and ~ 8.3 m2g−1 at λ = 880 nm and mass mean rBC core diameters of 150 nm and 200 nm were observed for the aged and continental air mass types, respectively. The reason for the larger rBC core sizes compared to the fresh emissions – transport effects or a different rBC source – remains unclear. The dominant fraction of the BC-containing particles was found to have no or very little coating with non-refractory matter. The lack of coatings is consistent with the observation that the BC-containing particles are non- or slightly-hygroscopic, which makes them poor cloud condensation nuclei. It can therefore be expected that wet removal through nucleation scavenging is inefficient for fresh BC-containing particles in urban plumes. The mixing-state-specific cloud droplet activation behaviour of BC-containing particles including the effects of atmospheric aging processes should be considered in global simulations of atmospheric BC, as the wet removal efficiency remains a major source of uncertainty in its life-cycle.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Hygroscopic mixing state of urban aerosol derived from size-resolved cloud condensation nuclei measurements during the MEGAPOLI campaign in Paris
    (Copernicus, 2013) Jurányi, Zsófia; Tritscher, Torsten; Gysel, Martin; Laborde, Marie; Gomes, L.; Roberts, G.; Baltensperger, Urs; Weingartner, Ernest [in: Atmospheric Chemistry and Physics]
    Abstract. Ambient aerosols are a complex mixture of particles with different physical and chemical properties and consequently distinct hygroscopic behaviour. The hygroscopicity of a particle determines its water uptake at subsaturated relative humidity (RH) and its ability to form a cloud droplet at supersaturated RH. These processes influence Earth's climate and the atmospheric lifetime of the particles. Cloud condensation nuclei (CCN) number size distributions (i.e. CCN number concentrations as a function of dry particle diameter) were measured close to Paris during the MEGAPOLI campaign in January–February 2010, covering 10 different supersaturations (SS = 0.1–1.0%). The time-resolved hygroscopic mixing state with respect to CCN activation was also derived from these measurements. Simultaneously, a hygroscopicity tandem differential mobility analyser (HTDMA) was used to measure the hygroscopic growth factor (ratio of wet to dry mobility diameter) distributions at RH = 90%. The aerosol was highly externally mixed and its mixing state showed significant temporal variability. The average particle hygroscopicity was relatively low at subsaturation (RH = 90%; mean hygroscopicity parameter κ = 0.12–0.27) and increased with increasing dry diameter in the range 35–265 nm. The mean κ value, derived from the CCN measurements at supersaturation, ranged from 0.08 to 0.24 at SS = 1.0–0.1%. Two types of mixing-state resolved hygroscopicity closure studies were performed, comparing the water uptake ability measured below and above saturation. In the first type the CCN counter was connected in series with the HTDMA and and closure was achieved over the whole range of probed dry diameters, growth factors and supersaturations using the κ-parametrization for the water activity and assuming surface tension of pure water in the Köhler theory. In the second closure type we compared hygroscopicity distributions derived from parallel monodisperse CCN measurements and HTDMA measurements. Very good agreement was found at all supersaturations, which shows that monodisperse CCN measurements are a reliable alternative to determine the hygroscopic mixing state of ambient aerosols.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Mobility particle size spectrometers. harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions
    (Copernicus, 29.03.2012) Wiedensohler, Alfred; Birmili, Wolfram; Nowak, Marta; Sonntag, A.; Weinhold, Kay; Merkel, M.; Wehner, Birgit; Tuch, T.; Pfeifer, S.; Fiebig, Markus; Fjäraa, Ann Mari; Asmi, Eija; Sellegri, Karine; Depuy, R.; Venzac, H.; Villani, P.; Laj, Paolo; Aalto, P.; Ogren, J. A.; Swietlicki, Erik; Williams, P.; Roldin, P.; Quincey, P.; Hüglin, C.; Fierz-Schmidhauser, R.; Gysel, Martin; Weingartner, Ernest; Riccobono, Francesco; Santos, S.; Grüning, C.; Faloon, K.; Beddows, D.; Harrison, Roy; Monahan, C.; Jennings, Stephen G.; O'Dowd, Colin D.; Marinoni, A.; Horn, H.-G.; Keck, L.; Jiang, J.; Scheckman, J.; McMurry, P. H.; Deng, Z.; Zhao, C. S.; Moerman, M.; Henzing, B.; de Leeuw, G.; Löschau, G.; Bastian, S. [in: Atmospheric Measurement Techniques]
    Abstract. Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer. We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data. Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research) and ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30%, which could not be explained. The network reference mobility spectrometers with identical design agreed within ±4% in the peak particle number concentration when all settings were done carefully. The consistency of these reference instruments to the total particle number concentration was demonstrated to be less than 5%. Additionally, a new data structure for particle number size distributions was introduced to store and disseminate the data at EMEP (European Monitoring and Evaluation Program). This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between different networks and sites, and their transparency and traceability back to raw data.
    01A - Beitrag in wissenschaftlicher Zeitschrift