Auflistung nach Autor:in "Weinhold, Kay"

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Citizen Science - Rußdetektoren fürs Handy?
(2016) Birmili, Wolfram; Pfeifer, Sascha; Alas, Honey D.C.; Müller, Thomas; Wiesner, Anne; Kecorius, Simonas; Weinhold, Kay; Wiedensohler, A.
Intercomparison of 15 aerodynamic particle size spectrometers (APS 3321): uncertainties in particle sizing and number size distribution
(2016) Pfeifer, Sascha; Müller, Thomas; Weinhold, Kay; Ries, Ludwig; Meinhardt, Frank
Aerodynamic particle size spectrometers are a well-established method to measure number size distributions of coarse mode particles in the atmosphere. Quality assurance is essential for atmospheric observational aerosol networks to obtain comparable results with known uncertainties. In a laboratory study within the framework of ACTRIS (Aerosols, Clouds, and Trace gases Research Infrastructure Network), 15 aerodynamic particle size spectrometers (APS model 3321, TSI Inc., St. Paul, MN, USA) were compared with a focus on flow rates, particle sizing, and the unit-to-unit variability of the particle number size distribution. Flow rate deviations were relatively small (within a few percent), while the sizing accuracy was found to be within 10?% compared to polystyrene latex (PSL) reference particles. The unit-to-unit variability in terms of the particle number size distribution during this study was within 10?% to 20?% for particles in the range of 0.9 up to 3 Nano-m, which is acceptable for atmospheric measurements. For particles smaller than that, the variability increased up to 60?%, probably caused by differences in the counting efficiencies of individual units. Number size distribution data for particles smaller than 0.9?Ţm in aerodynamic diameter should only be used with caution. For particles larger than 3?Ţm, the unit-to-unit variability increased as well. A possible reason is an insufficient sizing accuracy in combination with a steeply sloping particle number size distribution and the increasing uncertainty due to decreasing counting. Particularly this uncertainty of the particle number size distribution must be considered if higher moments of the size distribution such as the particle volume or mass are calculated, which require the conversion of the aerodynamic diameter measured to a volume equivalent diameter. In order to perform a quantitative quality assurance, a traceable reference method for the particle number concentration in the size range 0.5-3 Nano-m is needed. Quelle: http://www.atmos-meas-tech.net
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, Klaus
The 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.net
Performance analysis of the NanoScan SMPS and the Mini WRAS Ultrafine Aerosol Particle Size Spectrometers
(2022) Ahlawat, Ajit; Weinhold, Kay; Marval, Jesus; Gerwig, Holger; Birmili, Wolfram
In aerosol science, there is an increasing interest to perform mobile measurements to obtain number size distribution of ultrafine particles (UFP), using portable instruments based on unipolar charging and size segregation by electrical particle mobility. Applications of such measurements range from ambient and indoor aerosol studies to source identification in work environments. However, knowledge on the actual measurement uncertainties of these portable instruments under various conditions has been limited. This investigation presents results from an intercomparison workshop conducted at the World Calibration Center for Aerosol Physics (WCCAP) in Leipzig, Germany, in January 2020. Manufacturers and users were invited to have their portable instruments tested and compared against reference instrumentation for particle number size distributions (PNSD) and total particle number concentration (PNC). In particular, the performances and uncertainties of the NanoScan SMPS (Scanning Mobility Particle Sizer) Model 3910 (TSI Inc.) and the Mini Wide Range Aerosol Spectrometer (WRAS) Model 1371 (Grimm Aerosol Technik) were investigated extensively against the WCCAP Mobility Particle Size Spectrometers (MPSS) and Condensation Particle Counters (CPC). A total of 11 TSI NanoScan SMPS and 4 GRIMM Mini WRAS instruments were characterized for ambient aerosols as well as lab-generated aerosols. © Author(s) 2022
Trends of tropospheric black carbon and sub-(micro)m particle number concentration in the German Ultrafine Aerosol Network (GUAN), 2009-2014
(2015) Sun, Jia; Birmili, Wolfram; Weinhold, Kay; Rasch, Fabian; Sonntag, Andre; Wiedensohler, Alfred; Cyrys, Josef; Felntje, Harald; Löschau, Gunter; Bastian, Susanne; Schladitz, Alexander; Meinhardt, Frank; Bath, Olaf; Schwerin, Andreas; Ries, Ludwig; Gerwig, Holger; Wirtz, Klaus
Ultrafeine Partikel und Ruß
(2017) Birmili, Wolfram; Schwerin Andreas; Sun, Jia; Weinhold, Kay; Rasch, Fabian; Meinhardt, Frank; Bath, Olaf; Ries, Ludwig; Gerwig, Holger; Wirtz, Klaus
Ultrafeine Partikel und Ruß in Deutschland
(2016) Birmili, Wolfram; Weinhold, Kay; Rasch, Fabian; Sonntag, Andre; Sun, Jia; Merkel, Maik; Wiedensohler, Alfred; Bastian, Susanne; Schladitz, Alexander; Löschau, Gunter; Cyrys, Josef; Pitz, Mike; Gu, Jianwei; Kusch, Thomas; Flentje, Harald; Quass, Ulrich; Kaminski, Heinz; Kuhlbusch, Thomas A.J.; Meinhardt, Frank; Schwerin, Andreas; Bath, Olaf; Ries, Ludwig; Gerwig, Holger; Wirtz, Klaus; Fiebig, Markus