Jeanneret, F.Kirchner, F.Clappier, A.Van den Bergh, H.Calpini, B.2011-02-012011-02-012011-02-01199910.2495/EURO990621https://infoscience.epfl.ch/handle/20.500.14299/63766Hydroxyl radicals dominate daytime tropospheric chem., responsible for reactive removal of most trace gases (e.g., volatile org. compds.[VOC]), and is an active participant in the NO and NO2 cycle. Pump-and-probe LIDAR was used to examine the OH- chem. in the planetary boundary layer. This method consists of a high OH- concn. prodn. by a first laser beam (pump), including a flash photolysis of O3: O3 + hv (256 nm) -> O(1D) + O2, and the reaction, O(1D) + H2O -> 2OH. Its relaxation is followed by measuring the time evolution of the radical by laser-induced fluorescence (probe beam). A simulation of this expt. showed that in a short delay time, a direct est. of the total hydrocarbon reactivity defined as SVOC was obtained. The pump-and-probe technique allows measurements which can distinguish between locations where O3 formation mainly depends on NOx concns. and those where it mainly depends on VOC concns.10028-15-6 (Ozone) Role: FMU (Formationunclassified)PEP (Physicalengineering or chemical process)POL (Pollutant)FORM (Formationnonpreparative)OCCU (Occurrence)PROC (Process) (in-situ hydroxyl radical kinetics study providing indicator fohydroxyl radical kinetics ozone formation indicatorvolatile org compd precursor ozone formationnitrogen oxide precursor ozone formationair pollution hydroxyl radical ozone formationpump and probe lidar ozone formationtext::journal::journal article::research article