Emissionen von volatilen organischen Komponenten in die Atmosphäre: aus Pflanzen und toter Biomaterie.

The starting point of this project was the recent development at our institute of a new method of gas analysis, the socalled proton transfer reaction - mass spectrometer (PTR-MS). This method allows the identification and quantitative analysis of VOCs in air using a fragmentation free ionization method in conjunction with a mass spectrometer. Thus it is now possible to analyze on-line simultaneously concentrations in air all the way down to about 1ppb. In the course of this project this method was further developed (leading to an improved detection limit of VOCs at mixing ratios of a few pptv) and improved and it use pioneered in various areas such as atmospheric and environmental science, medicine and food processing and control. Results obtained have been published in 42 papers in international journals. Typical results include the following examples: 1. Passive smoking: Using acetonitrile as a leading biomarker, quantitative comparsion between passive smoking and direct smokingwas achieved by performing measurements with a PTR-MS machine. Results obatined demonstarte that staying for a working day (8 hours) in a smoke laden environment, as is typical for pubs where guests are smoking heavily, is equivalent to smokung of one to four cigarettes. 2. Abiological VOC production: Recent atmospheric chenistry studies strongly indicate that partially oxidized volatile organic carbon compounds, POVOCs, may play a substantial role in tropospheric photochemistry. Here we have called attention to the significance of abiological production of these compunds from the decay of dead plant material. Measured relative emission of acetone and methanol can be at least 10-4 gg1 and if these results are extarpolated, global annual emission may be up to 8 Tg of acetone and up to 40 Tg of methanol, thus adding strongly to the total emission of these compounds to teh atmosphere. 3. Traffic emissions: Diurnal variations of the concentrations of isoprene, benzene, and toluene have been measured in 1997 in the outskirts of Innsbruck. While emissions of benzene and toluene nearly only occur due to fossil fuel burning (predominatly traffic), isporene originates mainly from biogenic sources and only a small part due to traffic. Simultaneously occurring short term maxima of the concentrations of these three VOVs due to traffic ecvents allow for calculation of the contribution of isoprene concentration from fossil sources. Besides these examples we have also carried out medical applications by means of breath analysis allowing to monitor metabolic processes in the human body, and in addition the PTR-MS method has been successfully applied to food research on the basis of VOC emissions from fruit, coffee, meat and cheese.