10.26165/JUELICH-DATA/GK7PJQCho, ChangminChangminCho0000-0002-5977-2705Forschungszentrum Jülich GmbH, IEK-8Hofzumahaus, AndreasAndreasHofzumahaus0000-0003-2876-0880Forschungszentrum Jülich GmbH, IEK-8Fuchs, HendrikHendrikFuchs0000-0003-1263-0061Forschungszentrum Jülich GmbH, IEK-8Dorn, Hans-PeterHans-PeterDorn0000-0001-5945-7708Forschungszentrum Jülich GmbH, IEK-8Glowania, MarvinMarvinGlowania0000-0001-5434-531XForschungszentrum Jülich GmbH, IEK-8Holland, FrankFrankHolland0000-0002-2278-4761Forschungszentrum Jülich GmbH, IEK-8Rohrer, FranzFranzRohrer0000-0003-3436-3419Forschungszentrum Jülich GmbH, IEK-8Vardhan, VaishaliVaishaliVardhanForschungszentrum Jülich GmbH, IEK-8Kiendler-Scharr, AstridAstridKiendler-Scharr0000-0003-3166-2253Forschungszentrum Jülich GmbH, IEK-8Wahner, AndreasAndreasWahner0000-0001-8948-1928Forschungszentrum Jülich GmbH, IEK-8Novelli, AnnaAnnaNovelli0000-0003-2077-7573Forschungszentrum Jülich GmbH, IEK-8Jülich DATA2021Earth and Environmental SciencesInstrument characterizationFuchs, HendrikHendrikFuchsForschungszentrum Jülich GmbH, IEK-82021-02-172022-03-162019-01-01/2019-12-3110.5194/amt-14-1851-20214808469515503765549085798753application/octet-streamapplication/octet-streamapplication/octet-streamapplication/octet-stream1.1CC0 WaiverLaser-induced fluorescence (LIF) is a widely used technique for the measurement of ambient hydroxyl (OH) radicals and was used for the majority of field campaigns and chamber experiments. Recently, most LIF instruments in use for atmospheric measurements of OH radicals introduced chemical modulation to separate the ambient OH radical concentration from possible interferences by chemically removing ambient OH radicals before they enter the detection cell. This data contains the application and characterization of a chemical modulation reactor (CMR) applied to the Forschungszentrum Jülich LIF (FZJ-LIF) instrument in use at the SAPHIR (Simulation of Atmospheric PHotochemistry In a Large Reaction Chamber) atmospheric simulation chamber. Besides dedicated experiments in synthetic air, the new technique was extensively tested during the yearround Jülich Atmospheric Chemistry Project (JULIAC) campaign, in which ambient air was continuously flowed into the SAPHIR chamber. The four files include measurements during winter, spring, summer and fall 2019.EC Horizon2020 ERC681529