Mobility particle size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions A. Wiedensohler1, W. Birmili1, A. Nowak1, A. Sonntag1, K. Weinhold1, M. Merkel1, B. Wehner1, T. Tuch1, S. Pfeifer1, M. Fiebig2, A. M. Fjäraa2, E. Asmi3, K. Sellegri4, R. Depuy4, H. Venzac4, P. Villani4, P. Laj5, P. Aalto6, J. A. Ogren7, E. Swietlicki8, P. Williams9, P. Roldin8, P. Quincey10, C. Hüglin11, R. Fierz-Schmidhauser12, M. Gysel12, E. Weingartner12, F. Riccobono12, S. Santos13, C. Grüning13, K. Faloon14, D. Beddows14, R. Harrison14, C. Monahan15, S. G. Jennings15, C. D. O'Dowd15, A. Marinoni16, H.-G. Horn17, L. Keck18, J. Jiang19, J. Scheckman19, P. H. McMurry19, Z. Deng20, C. S. Zhao20, M. Moerman20, B. Henzing21, G. de Leeuw3,6,21, G. Löschau22, and S. Bastian22 1Leibniz Institute for Tropospheric Research, Permoserstr. 15, 04318 Leipzig, Germany 2Norwegian Institute for Air Research, 2027 Kjeller, Norway 3Finnish Meteorological Institute, Research and Development, 00101 Helsinki, Finland 4Laboratoire de Météorologie Physique, Observatoire de Physique du Globe de Clermont-Ferrand, Université Blaise Pascal, 24 avenue des Landais, 63177 Aubière, France 5Laboratoire de Glaciologie et Géophysique de l'Environnement Université Joseph Fourier – Grenoble 1/CNRS, 38400 St Martin d'Hères, France 6Department of Physics, University of Helsinki, 00014 Helsinki, Finland 7NOAA ESRL GMD, 325 Broadway, Boulder, CO 80305, USA 8Division of Nuclear Physics, Lund University, 221 00 Lund, Sweden 9National Centre for Atmospheric Science, University of Manchester, Manchester, UK 10Environmental Measurements Group, National Physical Laboratory, Teddington, Middlesex, UK 11EMPA Dübendorf Air Pollution/Environmental Technology, Überlandstraße 129, 8600 Dübendorf, Switzerland 12Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland 13European Commission – DG Joint Research Centre, IES/CCU, Ispra, Italy 14National Centre for Atmospheric Science, Division of Environmental Health & Risk Management, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK 15School of Physics & Centre for Climate and Air Pollution Studies, Environmental Change Institute, National University of Ireland, Galway, Ireland 16Institute of Atmospheric Sciences and Climate, Via Gobetti 101, 40129 Bologna, Italy 17TSI GmbH, Neuköllner Straße 4, 52068 Aachen, Germany 18GRIMM Aerosol Technik GmbH & Co. KG, Dorfstraße 9, 83404 Ainring, Germany 19Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE Minneapolis, MN 55455, USA 20Department of Atmospheric Sciences, School of Physics, Peking University, Beijing, 100871, China 21TNO Built Environment and Geosciences, 3508 TA Utrecht, The Netherlands 22Saxon State Office for Environment, Agriculture and Geology, Pillnitzer Platz, 01326 Dresden, Germany
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.
Citation: Wiedensohler, A., Birmili, W., Nowak, A., Sonntag, A., Weinhold, K., Merkel, M., Wehner, B., Tuch, T., Pfeifer, S., Fiebig, M., Fjäraa, A. M., Asmi, E., Sellegri, K., Depuy, R., Venzac, H., Villani, P., Laj, P., Aalto, P., Ogren, J. A., Swietlicki, E., Williams, P., Roldin, P., Quincey, P., Hüglin, C., Fierz-Schmidhauser, R., Gysel, M., Weingartner, E., Riccobono, F., Santos, S., Grüning, C., Faloon, K., Beddows, D., Harrison, R., Monahan, C., Jennings, S. G., O'Dowd, C. 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., and Bastian, S.: Mobility particle size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions, Atmos. Meas. Tech., 5, 657-685, doi:10.5194/amt-5-657-2012, 2012.