Tracegas analysis in an inneralpine region

Volatile organic compounds (VOCs "volatile organic compounds") largely determine our air quality, although they occur only in very small quantities. VOCs play a crucial role in the formation of tropospheric ozone (O3). In addition VOCs are important precursor gases for aerosol particle formation. On such particles water vapor condenses and clouds can be formed. Therefore VOCs influence cloud cover and climate.

VOCs have a variety of anthropogenic and biogenic sources and due to their reactivity in the atmosphere a limited lifetime. Thus, the concentration of individual VOCs is locally very different and laboratory experiments cannot replace measurements in the real world atmosphere.

The aim of this project was to create a unique dataset about the composition and source strengths of VOCs and investigate the spatial representativeness of VOC measurements in a rural, inner Alpine region.
Therefore a collaboration of scientists of several research institutions from Tyrol and Salzburg and the students and teachers of the BORG Mittersill and the BG/BRG Zell am See carried out measurements in the alpine region Pinzgau in Austria.
The schools turnde into modern air quality monitoring stations, which were equipped with a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) for highly sensitive measurements of VOCs and a weather station including a sonic anemometer. The high time resolution of these high tech instruments allowed the application of the direct eddy-covariance method in order to determine emission fluxes of individual VOCs.

A total of four measurement campaigns took place at the two sites in order to capture the seasonal variety of VOC . The students supervised the monitor station on a daily basis and assist during regular service and maintenance periods of the highly sophisticated instruments.

At least once per measurement period on a "Golden Day" the students started out in teams of two performing a research expedition. Each team filedl an evacuated canister at an appropriate location in their home communities respectively at exactly the same time with outside air. Subsequently the canisters' content was analysed in the laboratory. This will result in a snapshot picture of the air composition in the entire valley and will help to investigate the representativeness of a single point measurement in a complex alpine terrain.

This project has been completed.