Bildung und Umweltverhalten monofunktioneller Organonitrate - Analytik und Simulation atmosphärischer Belastungsmuster

Abstract

In this thesis, the group of alkyl mono nitrates was investigated in the lower troposphere and in different kinds of precipitation. For the first time a correlation between tropospheric patterns of alkyl nitrates and emissions from both traffic and biogenic sources could be proved by analytical and simulative means. Alkyl nitrate standards were synthesized with high purity and characterized by IR-, NMR-, CHN-analysis and gas chromatography (GC) in combination with different detectors (FID, ECD and MSD). The quantification of nitrate standard solutions was carried out on a HRGC/FID system using carbon response factors and a surrogate system. Alkyl nitrates were preconcentrated of large air volumes by adsorption followed by chemical desorption and HPLC group preseparation. The analysis of environmental samples was carried out on a HRGC/(ECNI-)MSD using relative retention times and selective fragmentation patterns. The used analytical procedure provided low detection limits, good linearity and high reproducibility. Three air sampling series in Europe and the USA were analyzed and compared. Similar and different patterns could be explained by the corresponding source situation. Determined mixing ratios of alkyl mono nitrates ranged up to 50 ppt(v). Unusual high amounts of primary alkyl nitrates could be explained by their selective formation in the photochemical degradation of n-aldehydes. Simulations of alkyl nitrate patterns were carried out under radical and near atmospheric conditions with hydrocarbon mixtures and commercial gasolines. Both simulations provided typical urban alkyl nitrate patterns. This way both the correlation between alkyl nitrate and hydrocarbon patterns and the impact of traffic emissions on atmospheric nitrate patterns could be approved. Finally the atmospheric deposition of alkyl nitrates was investigated. It could be shown that precipitation is negligible for longer chain alkyl mono nitrates in comparison to OH degradation and photolysis.