Atmosphärische Untersuchungen der Wechselwirkung von Mineralstaub mit den Spurengasen HNO ₃ und SO ₂

The trace gases HNO₃ and SO₂ have an influence on various atmospheric processes concerning the earths climate. Mineral dust, one of the most abundant aerosols in the atmosphere, may have a lasting but almost unexplored effect on their concentrations. Within the scope of this work the interaction of mineral dust with these trace gases was studied in Izana, 2367m asl, Tenerife. During six periods of high atmospheric dustload the HNO₃ concentration decreased below the detection limit, allowing a first calculation of the uptake coefficient based on in-situ measurements: γ _HNO3 = 0.033. In contrast and in contradiction with the results of laboratory experiments from other research teams, a mineral dust-SO₂-anti-correlation was not observed. A lack of information regarding the dust composition and alkalinity which have a decisive influence on the SO₂ uptake allows no profound interpretation of this result yet. The detection of the above trace gases was performed using the highly sensitive CIMStechnique (CIMS = Chemical Ionization Mass Spectrometry). This work included the improvement of calibration, diagnostic measurements and the deployment of a newly designed blower inlet to prevent volatile aerosols from entering the CIMS probe. Finally, a successful comparison of the CIMS technique with several techniques of other research teams regarding the measurement of HNO₃, SO₂ and H2O₂ was performed during various measurement campaigns