Design of and initial results from a Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC)

[摘要] The design of a Highly Instrumented Reactor for Atmospheric Chemistry(HIRAC) is described and initial results obtained from HIRAC are presented.The ability of HIRAC to perform in-situ laser-induced fluorescence detectionof OH and HO₂ radicals with the Fluorescence Assay by Gas Expansion(FAGE) technique establishes it as internationally unique for a chamber ofits size and pressure/temperature variable capabilities. In addition tothe FAGE technique, HIRAC features a suite of analytical instrumentation,including: a multipass FTIR system; a conventional gas chromatography (GC)instrument and a GC instrument for formaldehyde detection; NO/NO₂, CO,O₃, and H₂O vapour analysers. Ray tracing simulations and NO₂actinometry have been utilized to develop a detailed model of the radiationfield within HIRAC. Comparisons between the analysers and the FTIR coupledto HIRAC have been performed, and HIRAC has also been used to investigatepressure dependent kinetics of the chlorine atom reaction with ethene andthe reaction of O₃ and t-2-butene. The results obtained are in goodagreement with literature recommendations and Master Chemical Mechanismpredictions. HIRAC thereby offers a highly instrumented platform with thepotential for: (1) high precision kinetics investigations over a range ofatmospheric conditions; (2) detailed mechanism development, significantlyenhanced according to its capability for measuring radicals; and (3) fieldinstrument intercomparison, calibration, development, and investigations ofinstrument response at a range of atmospheric conditions.

[学科分类] 大气科学