摘要
A new FAGE setup has recently been built at the University of Lille,France.It permits the quantification of OH and HO 2 in the atmosphere with a detection limit of 3×10 5 molecules/（cm 3 ·min） for OH and 1×10 6 molecules/（cm 3 ·min） for HO 2.Its coupling to a photolysis cell enables the measurement of the total reactivity of the hydroxyl radical in ambient air and kinetic studies in laboratory.Two configurations have been considered：one with the photolysis cell at 90° to the FAGE nozzle,the other on line with the FAGE nozzle.The two configurations have been tested and validated by measuring the well known rate constants of OH with CH 4,C 3 H 8 and CO.The advantages and drawbacks of each configuration have been evaluated.The ＂on line＂ configuration limits losses and permits measurements over a larger reactivity range but is affected by OH formation from the laser beam striking the FAGE nozzle,thus limiting the ability to carry out energy dependence studies which can,in contrast,be successfully performed in the 90° configuration.
A new FAGE setup has recently been built at the University of Lille,France.It permits the quantification of OH and HO 2 in the atmosphere with a detection limit of 3×10 5 molecules/（cm 3 ·min） for OH and 1×10 6 molecules/（cm 3 ·min） for HO 2.Its coupling to a photolysis cell enables the measurement of the total reactivity of the hydroxyl radical in ambient air and kinetic studies in laboratory.Two configurations have been considered：one with the photolysis cell at 90° to the FAGE nozzle,the other on line with the FAGE nozzle.The two configurations have been tested and validated by measuring the well known rate constants of OH with CH 4,C 3 H 8 and CO.The advantages and drawbacks of each configuration have been evaluated.The ＂on line＂ configuration limits losses and permits measurements over a larger reactivity range but is affected by OH formation from the laser beam striking the FAGE nozzle,thus limiting the ability to carry out energy dependence studies which can,in contrast,be successfully performed in the 90° configuration.
基金
supported by the Nord-Pas de Calais region in the frame of the IRENI research program,by the French Research Ministry,by the European Fund for Regional Economic Development (FEDER)
the EU for financial support through project MEST-CT-2005-020659
the French Government for financial aid through an EIFFEL scholarship
