CLOUD-16 subproject of Goethe University Frankfurt/Main

The main research focus of this part of the project is the identification and quantification of nucleation processes by use of high-resolution mass spectrometry. The CI-APi-LTOF-MS (Chemical Ionisation - Atmospheric Pressure interface – Long Time Of Flight - Mass Spectrometer), acquired for this purpose, uses chemical ionization through various primary ions, such as nitrate or acetate ions, to detect various gaseous precursors of the nucleation process. In order to analyze the newly formed particles, a particle collector developed during a previous project is used and further developed.

Objectives of the CLOUD-16 project are

(A) Improvement of the identification and the quantification of essential highly-oxidized low volatile organic compounds involved in new particle formation,

(B) The quantification of the role of the ions in the nucleation process,

(C) The determination of the composition of clusters and nano-aerosol particles and

(D) The determination of nucleation and growth rates. In collaboration with international project partners, the climate efficiency of these new aerosol processes will be assessed.

The project includes the procurement and commissioning of the APi-LTOF-MS as well as setting up a new ion source.

  • A first CLOUD measurement campaign on aerosol nucleation and growth,
  • A CLOUD measurement campaign on ice formation and cloud chemistry,
  • And another CLOUD measurement campaign on aerosol nucleation and growth.

Already within the first six month of the project, the APi-LTOF mass spectrometer was procured and the setup of the ion source was completed. Furthermore, the CI-APi-LTOF mass spectrometer was successfully used during the first CLOUD measurement campaign. The nucleation and growth of biogenic precursors such as isoprene, monoterpenes and sesquiterpenes were investigated. The second focus was on the study of anthropogenic precursors, in this case aromatic systems, which are mainly present in urban environments. The high resolution and high sensitivity of the new mass spectrometer allows a significantly improved separation and thus unambiguous identification of many organic substances involved in the nucleation process.

The Chemical Ionisation - Atmospheric Pressure interface – Long Time Of Flight Mass Spectrometer (CI-APi-LTOF-MS) operating at the CLOUD chamber.