The TROLAS group has participated in several measurement campaigns within the framework of different national and international projects (FIELDVOC, PRICE, PRICE II, BROK, ALBATROSS, AEROSOLS99, INDOEX, DOMINO). These campaigns have provided ground based in situ measurements of peroxy radicals in different environments: urban, rural and in the marine boundary layer. Based on the gained experience, the initial PeRCA instrument and the corresponding calibration system have been gradually optimized for in situ measurements in different platforms.
Furthermore, TROLAS has been involved in the airborne measurement of peroxy radicals in the free troposhere. In that context and in cooperation with the Institute of Atmospheric Physics of the German Aerospace Center, DLR, a modified PeRCA instrument for the measurement of the total sum of peroxy radicals in airborne platforms was successfully implemented aboard the DLR Falcon research aircraft for the first time in 2002 and participated in the international AMMA campaign in Burkina Faso in 2006. The airborne DUALER (DUal channel Airborne peroxy radicaL chemical amplifiER) was gradually developed and characterized in the laboratory, and in 2010 was successfully implemented in the CASA-212-200 aircraft within the EUFAR project VERDRILLT for the measurement of peroxy radicals in the boundary layer and up to 3 km.
A second generation of airborne PeRCA instruments in combination with optical cavity ring down spectroscopy for the detection of NO2, has been developed at IUP-UB in the framework of the REVOLVER (Peroxy Radical Measurement based on Optical Feedback Cavity Enhanced Absorption Spectroscopy and Chemical Conversion and Amplification) and PEACE (PEroxy rAdicals measured by OF-Cavity Enhanced spectroscopy in the free troposphere with a focus on the upper troposphere / lower stratosphere) DFG projects. The PeRCEAS (Peroxy Radical Chemical Enhancement and Absorption Spectrometer) instrument and its specifications have been described in detail by Horstjann et al., (2014) and George et al., (2020) and has been deployed on-board the High Altitude and Long Range Research Aircraft (HALO) in international campaigns as in OMO(2015) and EMeRGe(2017, 2018).
In addition, the PeRCA and PeRCEAS instruments of the TROLAS group have participated in experiments taken place in outdoor simulation chambers (EUPHORE, SAPHIR) for the study of the transformation of trace gas mixtures of atmospheric relevance. Recently, the ROxCOMP22 campaign was additionally conceived as a international comparison exercise of state- of- the- art instruments for radical measurements.