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UP: Umweltphysik

UP 2: Aerosole II

UP 2.2: Fachvortrag

Monday, March 7, 2005, 16:45–17:00, TU HFT101

HIGH DYNAMIC NITROGEN SPECIATION IN SIZE FRACTIONATED ATMOSPHERIC AEROSOLS — •Burkhard Beckhoff¹, Gerhard Ulm¹, Janos Osán², and Szabina Török² — ¹Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany — ²KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest, H-1525, Hungary

The rate of atmospheric turbidity due to aerosols can be estimated from satellite-borne sensors. While compounds in the gas phase can be measured by high temporal and spatial resolution using optical and remote sensing methods, it is crucial to have analytical methods that enable the measurement of aerosols from a short sampling period while retaining the information on the size distribution of the particles. Near edge X-ray absorption fine structure (NEXAFS) investigations in conjunction with total reflection X-ray fluorescence (TXRF) analysis of aerosols impacted on wafer surfaces are able to contribute to the speciation of the atmospherically important low-Z elements (C, N and O). At the PTB monochromator beamline for undulator radiation at BESSY II several TXRF-NEXAFS measurements of aerosol samples of different size fractions were performed. These samples were deposited on silicon wafer surfaces in a May impactor. The experiments demonstrated that the TXRF-NEXAFS sensitivity allows for the nitrogen speciation of nanoscopic amounts of aerosols, ensuring the analysis of size fractionated aerosols collected over very short sampling times.