Determination of elemental concentrations in small-mass particulate matter aircraft samples by x-ray fluorescence

Aircraft sampling of atmospheric particulate matter often implies small mass collection for subsequent analysis, especially when free tropospheric samples are considered. We present here results of the use of an X-ray fluorescence instrument, specifically designed for small-mass samples, in the determination of free tropospheric and boundary layer elemental concentrations. Based on 1- to 2-h-long samples, ng m⁻³ ambient air concentrations of Ti, Cr, Mn, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, Mo, Cd and Pb may be determined with uncertainties of 5–15% in polluted and even some rural boundary layer samples. In free tropospheric and remote boundary layer samples, concentrations may be determined for many of these elements but with larger uncertainties.