Total-reflection X-ray fluorescence analysis (TXRF) is a very sensitive method for the analysis of trace and ultra-trace elements. Currently, TXRF is used over a wide range of applications and is especially suited for the analysis of environmental samples, such as airborne particulate matter (APM). In the frame of this thesis, a new method for the quantitative TXRF analysis of APM, using a three-stage Dekati PM10 cascade impactor, was developed and thoroughly investigated. Samples were directly collected on greased quartz reflectors suited for TXRF. For quantitative analysis, a calibration was established for each stage, as the samples consist of patterns of individual sample spots. The method was compared against routine EDXRF analysis and showed similar results. An outdoor sampling campaign carried out in January 2017 showed the applicability of this method to time-resolved APM analysis. Furthermore, TXRF analysis of APM collected on 1" Si wafers with a Sioutas Personal Cascade Impactor was carried out during a sampling campaign in October 2017. The second major part of this thesis was the redesign of an already existing vacum TXRF spectrometer (WOBISTRAX ), equipped with a Rh anode low-power X-ray tube. The new design makes use of the fact that a multilayer monochromator also acts as a cut-off reflector, transmitting the low-energy part of the tube spectrum. For this concept, the term dual-band excitation is introduced. A newly designed entrance-flange avoids air-absorption of the low-energy part, so that the Rh-L lines (Rh-L at 2.69 keV) can enter the chamber. The Rh-L lines are used to excite low Z elements (S and below), leading to a drastic enhancement of the peak intensities of these elements. Dual-band excitation will allow an extension of the analyzable element range, so that elemental analysis from C to U will be possible. Finally, X-ray absorption near-edge spectroscopy (XANES) of indoor APM was carried out successfully for the K-edges of Cu, Zn and Cr at the BESSY II and ELETTRA synchrotron facilities.