Person: Wirtz, Klaus
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Veröffentlichung A metrological approach to improve accuracy and reliability of ammonia measurements in ambient air(2016) Pogány, Andrea; Balslev-Harder, David; Braban, Christine F.; Cassidy, Nathan; Ebert, Volker; Ferracci, Valerio; Hieta, Tuomas; Leuenberger, Daiana; Martin, Nicholas, A.; Pascale, Céline; Peltola, Jari; Persijn, Stefan; Tiebe, Carlo; Twigg, Marsailidh M.; Vaittinen, Olavi; van Wijk, Janneke; Niederhauser, Bernhard; Wirtz, KlausThe environmental impacts of ammonia (NH3) in ambient air have become more evident in the recent decades, leading to intensifying research in this field. A number of novel analytical techniques and monitoring instruments have been developed, and the quality and availability of reference gas mixtures used for the calibration of measuring instruments has also increased significantly. However, recent inter-comparison measurements show significant discrepancies, indicating that the majority of the newly developed devices and reference materials require further thorough validation. There is a clear need for more intensive metrological research focusing on quality assurance, intercomparability and validations. MetNH3 (Metrology for ammonia in ambient air) is a three-year project within the framework of the European Metrology Research Programme (EMRP), which aims to bring metrological traceability to ambient ammonia measurements in the 0.5-500 nmol mol-1amount fraction range. This is addressed by working in three areas: (1) improving accuracy and stability of static and dynamic reference gas mixtures, (2) developing an optical transfer standard and (3) establishing the link between high-accuracy metrological standards and field measurements. In this article we describe the concept, aims and first results of the project.Quelle: http://iopscience.iop.orgVeröffentlichung International comparison CCQM-K10.2018: BTEX in nitrogen at 5 nmol mol-1(2022) Cecelski, Christina E; Rhoderick, George C.; Possolo, Antonio M; Stummer, Volker; Wirtz, KlausVeröffentlichung Variability of black carbon mass concentrations, sub-micrometer particle number concentrations and size distributions: results of the German Ultrafine Aerosol Network ranging from city street to high alpine locations(2019) Sun, Junying; Birmili, Wolfram; Gerwig, Holger; Hermann, Markus; Ries, Ludwig; Schwerin, Andreas; Sohmer, Ralf; Meinhardt, Frank; Wirtz, KlausThis work reports the first statistical analysis of multi-annual data on tropospheric aerosols from the German Ultrafine Aerosol Network (GUAN). Compared to other networks worldwide, GUAN with 17 measurement locations has the most sites equipped with particle number size distribution (PNSD) and equivalent black carbon (eBC) instruments and the most site categories in Germany ranging from city street/roadside to High Alpine. As we know, the variations of eBC and particle number concentration (PNC) are influenced by several factors such as source, transformation, transport and deposition. The dominant controlling factor for different pollutant parameters might be varied, leading to the different spatio-temporal variations among the measured parameters. Currently, a study of spatio-temporal variations of PNSD and eBC considering the influences of both site categories and spatial scale is still missing. Based on the multi-site dataset of GUAN, the goal of this study is to investigate how pollutant parameters may interfere with spatial characteristics and site categories. © 2019 The AuthorsVeröffentlichung Sensorsysteme zur Messung der Luftqualität(VDI-Verlag, 2021) Brauer, Hannes; Bastian, Susanne; Conrad, Thorsten; Travnicek, Wilma; Wirtz, KlausAuf dem Markt sind heutzutage sehr einfach aufgebaute und daher zum Teil vergleichsweise preisgünstige Sensorsysteme verfügbar. In der Öffentlichkeit stoßen diese Sensorsysteme zur Messung der Luftqualität auf großes Interesse. Sie werden häufig abseits der behördlichen Messstationen in der Fläche eingesetzt, um dort ortsbezogen die Luftqualität zu ermitteln. Zum Vergleich der Ergebnisse werden sie mitunter auch direkt neben diesen Messstationen betrieben. Aber sie erfüllen die gesetzlichen Anforderungen an die Güte von Luftqualitätsmessungen für sich nicht und können derzeit nicht zur gesetzlichen Überwachung von Grenzwerten der Luftqualität eingesetzt werden. Sie sind aktuell keine Alternative zu den in den Messnetzen der Bundesländer eingesetzten Referenzmessverfahren, können allerdings in bestimmten Situationen eine sinnvolle Ergänzung darstellen. Die Nutzung von geeigneten Sensorsystemen in Kombination mit Ausbreitungsmodellen kann das Vertrauen in vorhandene Ausbreitungsmodellierungen stärken. Maßnahmen zur Produktzertifizierung seitens der Hersteller und regelmäßige unabhängige Prüfungen auf Basis technischer Standards können wesentlich dazu beitragen, die Nutzung von Sensorsystemen zu fördern und das Vertrauen in die Verlässlichkeit der damit gewonnenen Messwerte zu erhöhen. Quelle: https://www.vdi.de/Veröffentlichung Messung ultrafeiner Partikel im Umfeld eines Großflughafens(2016) Gerwig, Holger; Jacobi, Stefan; Travnicek, Wilma; Wirtz, KlausVeröffentlichung Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN)(2016) Weinhold, Kay; Bath, Olaf; Rasch, Fabian; Birmili, Wolfram; Sonntag, Andre; Sun, Jia; Merkel, Maik; Wiedensohler, Alfred; Gerwig, Holger; Bastian, Susanne; Schladitz, Alexander; Löschau, Gunter; Cyrys, Josef; Pitz, Mike; Gu, Jianwei; Kusch, Thomas; Flentje, Harald; Quass, Ulrich; Kaminski, Heinz; Kuhlbusch, Thomas A.J.; Ries, Ludwig; Meinhardt, Frank; Schwerin, Andreas; Fiebig, Markus; Wirtz, KlausThe German Ultrafine Aerosol Network (GUAN) is a cooperative atmospheric observation network, which aims at improving the scientific understanding of aerosol-related effects in the troposphere. The network addresses research questions dedicated to both climate- and health-related effects. GUAN's core activity has been the continuous collection of tropospheric particle number size distributions and black carbon mass concentrations at 17 observation sites in Germany. These sites cover various environmental settings including urban traffic, urban background, rural background, and Alpine mountains. In association with partner projects, GUAN has implemented a high degree of harmonisation of instrumentation, operating procedures, and data evaluation procedures. The quality of the measurement data is assured by laboratory intercomparisons as well as on-site comparisons with reference instruments. This paper describes the measurement sites, instrumentation, quality assurance, and data evaluation procedures in the network as well as the EBAS repository, where the data sets can be obtained. Quelle: http://www.earth-syst-sci-data.netVeröffentlichung Supplement of Decreasing trends of particle number and black carbon mass concentrations at 16 observational sites in Germany from 2009 to 2018(2020) Sun, Jia; Bath, Olaf; Birmili, Wolfram; Hermann, Markus; Gerwig, Holger; Ries, Ludwig; Schwerin, Andreas; Meinhardt, Frank; Sohmer, Ralf; Wirtz, KlausAnthropogenic emissions are a dominant contributor to air pollution. Consequently, mitigation policies have attempted to reduce anthropogenic pollution emissions in Europe since the 1990s. To evaluate the effectiveness of these mitigation policies, the German Ultrafine Aerosol Network (GUAN) was established in 2008, focusing on black carbon and sub-micrometer aerosol particles, especially ultrafine particles. In this investigation, trends of the size-resolved particle number concentrations (PNC) and the equivalent black carbon (eBC) mass concentration over a 10-year period (2009-2018) were evaluated for 16 observational sites for different environments among GUAN. The trend analysis was done for both, the full-length time series and on subsets of the time series in order to test the reliability of the results. The results show generally decreasing trends of both, the PNCs for all size ranges as well as eBC mass concentrations in all environments, except PNC in 10-30 nm at regional background and mountain sites. The annual slope of the eBC mass concentration varies between -7.7% and -1.8% per year. The slopes of the PNCs varies from -6.3% to 2.7%, -7.0% to -2.0%, and -9.5% to -1.5% per year (only significant trends) for 10-30 nm, 30-200 nm, and 200-800 nm particle diameter, respectively. The regional Mann-Kendall test yielded regional-scale trends of eBC mass concentration, N[30-200] and N[200-800] of -3.8%, -2.0% and -2.4%, respectively, indicating an overall decreasing trend for eBC mass concentration and sub-micrometer PNC (except N[10-30]) all over Germany. The most significant decrease was observed on working days and during daytime in urban areas, which implies a strong evidence of reduced anthropogenic emissions. For the seasonal trends, stronger reductions were observed in winter. Possible reasons for this reduction can be the increased average ambient temperatures and wind speed in winter, which resulted in less domestic heating and stronger dilution. In addition, decreased precipitation in summer also diminishes the decrease of the PNCs and eBC mass concentration. For the period of interest, there were no significant changes in long-range transport patterns. The most likely factors for the observed decreasing trends are declining anthropogenic emissions due to emission mitigation policies of the European Union. © Author(s) 2020Veröffentlichung Ursache für maximale Partikeloberflächenkonzentrationen in Langen bei Frankfurt(2014) Gerwig, Holger; Pecher, Werner; Wirtz, KlausVeröffentlichung Long-term UFP measurements in the urban background in the Rhine-Main area(2023) Gerwig, Holger; Unglert, Sabrina; Wirtz, KlausVeröffentlichung Decreasing trends of particle number and black carbon mass concentrations at 16 observational sites in Germany from 2009 to 2018(2020) Sun, Jia; Bath, Olaf; Birmili, Wolfram; Hermann, Markus; Gerwig, Holger; Ries, Ludwig; Schwerin, Andreas; Meinhardt, Frank; Sohmer, Ralf; Wirtz, KlausAnthropogenic emissions are a dominant contributor to air pollution. Consequently, mitigation policies have attempted to reduce anthropogenic pollution emissions in Europe since the 1990s. To evaluate the effectiveness of these mitigation policies, the German Ultrafine Aerosol Network (GUAN) was established in 2008, focusing on black carbon and sub-micrometer aerosol particles, especially ultrafine particles. In this investigation, trends of the size-resolved particle number concentrations (PNC) and the equivalent black carbon (eBC) mass concentration over a 10-year period (2009-2018) were evaluated for 16 observational sites for different environments among GUAN. The trend analysis was done for both, the full-length time series and on subsets of the time series in order to test the reliability of the results. The results show generally decreasing trends of both, the PNCs for all size ranges as well as eBC mass concentrations in all environments, except PNC in 10-30 nm at regional background and mountain sites. The annual slope of the eBC mass concentration varies between -7.7% and -1.8% per year. The slopes of the PNCs varies from -6.3% to 2.7%, -7.0% to -2.0%, and -9.5% to -1.5% per year (only significant trends) for 10-30 nm, 30-200 nm, and 200-800 nm particle diameter, respectively. The regional Mann-Kendall test yielded regional-scale trends of eBC mass concentration, N[30-200] and N[200-800] of -3.8%, -2.0% and -2.4%, respectively, indicating an overall decreasing trend for eBC mass concentration and sub-micrometer PNC (except N[10-30]) all over Germany. The most significant decrease was observed on working days and during daytime in urban areas, which implies a strong evidence of reduced anthropogenic emissions. For the seasonal trends, stronger reductions were observed in winter. Possible reasons for this reduction can be the increased average ambient temperatures and wind speed in winter, which resulted in less domestic heating and stronger dilution. In addition, decreased precipitation in summer also diminishes the decrease of the PNCs and eBC mass concentration. For the period of interest, there were no significant changes in long-range transport patterns. The most likely factors for the observed decreasing trends are declining anthropogenic emissions due to emission mitigation policies of the European Union. Quelle: https://www.atmos-chem-phys-discuss.net/