Saphir simulation chamber
25 Sep 2023

In September 2023, the SAPHIR chamber at the Forschungszentrum Jülich, Germany, was for the first time involved in a series of experiments that included a component of remote access to the chamber.

The project was funded by ATMO-ACCESS and was led by a young post-doc from Peking University (PKU), Mengdi Song, together with Professor Li Xin in collaboration with the scientist working at the SAPHIR chamber.

The focus of the campaign was the investigation of the photo-oxidation of two aromatic compounds, toluene and m-xylene, at different nitrogen oxide levels. Aromatics compounds remain a large fraction of anthropogenic volatile organic compounds in particular in Chinese cities and they contribute to secondary pollutants such as ozone and particles. In particular, the goal of the experiments was to observe the changes in yield and time behavior of different products following the oxidation by the hydroxyl radical  for different chemical regimes. Our PKU colleagues brought in their expertise in operating and calibrating the chemical ionization mass spectrometer (CIMS) which was the key instrument to measure the various low concentration products formed. The advantages of performing the experiments at the SAPHIR chamber were the availability of radical measurements, the possibility to reach low levels of nitrogen oxide (< 100 ppbv) and to work at atmospheric like concentrations of reagents. Overall, 11 experiments were successfully performed and a calibration routine for the CIMS instrument was established.