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Atmosphère & environnement

The Atmospheric Reactivity Group of ICARE is equipped with a number of experimental facilities used for the investigation of the kinetics and mechanisms of atmospheric reactions relevant for atmospheric chemistry at different scales including gas phase and heterogeneous chemistry. The studies are performed using the most advanced experimental techniques, including low pressure discharge flow reactor coupled with mass spectrometry, flow tube for organic aerosol formation studies, high pressure turbulent flow reactor coupled with chemical ionisation mass spectrometric analysis, laser pulsed photolysis coupled with laser induced fluorescence, atmospheric simulation chambers.

Atmospheric simulation chambers, made of Teflon foil (cubic, parallelepipedic or hemispheric shapes). They are of different sizes : 200 to 7300 L with artificial light sources ; and, 3.4 and 80 m3, (HELIOS platform) with natural irradiation. To monitor the chemical composition over the course of the reaction, they are coupled with modern analytical techniques such as :

  • Gas Chromatography coupled to Flame Ionisation or Photo Ionisation Detectors, Mass spectrometry
  • PTR-TOF-MS : proton transfer reaction ionisation with a time-of-flight mass analyser
  • Infra Red Spectrometry
  • Specific monitors to analyze a number of atmospheric key species : NO, NO2, O3, HCHO, HONO
  • Instrumentation for particle analysis : particles size distributions can be measured by a SMPS or can be also collected on filters and then analysed by different techniques including GC-MS, HPLC (UV and fluorimetric detections) and ionic chromatography. It can be combined with an aerosol flow reactor for particle specific production.

Turbulent flow reactor – chemical ionisation mass spectrometer (TFR-CIMS). The three components are the TFR with nitrogen as the carrier gas from a liquid nitrogen tank, the ionmolecule reactor with both positive and negative ionisation modes, and the quadrupole mass spectrometer. The working pressure and temperature ranges of the TFR are 50-760 Torr and 220-320 K, respectively.

Low pressure discharge flow reactor – modulated molecular beam quadrupole mass spectrometer (with electron impact ionization). The working pressure and temperature ranges are 0.2 – 10 torr and 220 – 370 K, respectively.

Pyrex double-walled cell (200 cm3), with four optical accesses for laser diagnostic applications (radical production by photolysis coupled to Laser Induced Fluorescence detection technique) is currently used to study elementary reactions involving OH radicals.

UV-visible absorption cell, Pyrex double-walled tube associated with a spectrophotometer, allows measurements of cross sections of atmospheric species.