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M. W. Koller, C. Effenberger, G. Schauer, A. Kranabetter, A. Kasper-Giebl:
"The Lab above the clouds: Particle Number Concentration at the Sonnblick Observatory";
Poster: 4th Symposium of the Hohe Tauern National Park for Research in Protected Areas, Kaprun; 17.09.2009 - 19.09.2009; in: "4th Symposium of the Hohe Tauern National Park for Research in Protected Areas - Documentation", Printing office of the federal state government of Salzburg, (2009), ISBN: 978-3-9502062-1-0; S. 183 - 184.

Atmospheric aerosols (particulate matter) are a complex mixture of particles of different size, shape and chemical composition. Consequently various methods for the characterization of atmospheric aerosols exist and have to be used to tackle different problems.
Since daily average mass concentrations are given as limit values in air, quality standards set for particulate matter (PM10; particulate matter smaller than 10 µm a.d.) measurements in monitoring networks often are based on the gravimetric determination of aerosol mass. A further advantage of this method is the possibility to do chemical analysis subsequent to the actual sampling process on filters. If higher time resolution is needed, other procedures yielding data representative for mass concentrations (e.g. TEOM, β-gauge) are used.
The size of particles ranges across several orders of magnitude starting from several nanometers up to several tenth of micrometers. Obviously single large particles contribute more significantly to aerosol mass than small particles. Consequently even a strong increase of small particles might not influence aerosol mass severely. Thus the determination of aerosol mass does not necessarily reflect changes in particle number concentrations. The number concentration of aerosol particles can be determined as an overall number or segregated in different sizes classes, in an ideal case in terms of size distributions.
Small particles are generated during combustion events and thus can be used as a tracer for freshly contaminated air masses. Thus the CP-count has already been used to classify the `air status´ for other measurements more than twenty years ago (Galasyn et al. 1987). Furthermore elevated concentrations of small particles can also be found during nucleation events in background environments induced by photochemistry.

Here we describe the data set of particle number concentrations measurements conducted at the Sonnblick Observatory and show selected results to demonstrate how these measurements can be used for further investigations.

Aerosols, particulate matter, condensation particle concentrations, Sonnblick Observatory