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首页> 外文期刊>Atmospheric chemistry and physics >Measurements of OH and HOsub2/sub concentrations during the MCMA-2006 field campaign – Part 1: Deployment of the Indiana University laser-induced fluorescence instrument
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Measurements of OH and HOsub2/sub concentrations during the MCMA-2006 field campaign – Part 1: Deployment of the Indiana University laser-induced fluorescence instrument

机译：在MCMA-2006野战期间测量OH和HO 2 的浓度–第1部分：印第安纳大学激光诱导荧光仪器的部署

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Measurements of tropospheric hydroxyl (OH) and hydroperoxy (HO2)radicals were made during the MCMA (Mexico City Metropolitan Area) fieldcampaign as part of the MILAGRO (Megacity Initiative: Local and GlobalResearch Observations) project during March 2006. These radicals weremeasured using a laser-induced fluorescence instrument developed at IndianaUniversity. This new instrument takes advantage of the Fluorescence Assay byGas Expansion technique (FAGE) together with direct excitation and detectionof OH at 308 nm. HO2 is indirectly measured as OH by titration with NOinside the fluorescence cell. At this stage of development, IU-FAGE iscapable of detecting 3.9×105 molecule/cm3 of both OH andHO2, with a signal to noise ratio of 1, an averaged laser power of10-mW and an averaging time of 5-min. The calibration accuracies (1σ) are ±17% for OH and ±18% for HO2 using thewater-vapor photolysis/O2 actinometry calibration technique.OH and HO2 concentrations were successfully measured at an urban sitein Mexico City, with observed concentrations comparable to those measured inother polluted environments. Enhanced levels of OH and HO2 radicalswere observed on several days between 09:30–11:00 a.m. and suggest an intensephotochemistry during morning hours that may be due to elevated sources ofHOx (OH+HO2) and a fast cycling between the radicals under thehigh NOx (NO+NO2) conditions of the MCMA.
机译：作为三月份的MILAGRO（大城市倡议：本地和全球研究观察）项目的一部分，在MCMA（墨西哥城大都市区）野外活动期间对对流层羟基（OH）和氢过氧化物（HO 2 ）自由基进行了测量。 2006年。这些自由基是使用印第安纳大学开发的激光诱导荧光仪测量的。这款新仪器利用了通过气体膨胀技术（FAGE）进行的荧光检测以及在308 nm处直接激发和检测OH的优势。 HO 2 通过在荧光池内用NO滴定间接测定为OH。在此发展阶段，IU-FAGE能够检测到OH和HO 2 的3.9×10 5 分子/ cm 3 噪声比为1，平均激光功率为10 mW，平均时间为5分钟。使用水蒸气光解/ O 2 光度法校准技术，OH的校准精度（1σ）为±17％，HO 2 的校准精度为±18％。 OH和HO 2 的浓度，观察到的浓度与在其他污染环境中测得的浓度相当。在上午09：30–11：00之间的几天中观察到OH和HO 2 自由基的含量增加，这表明早晨时段强烈的光化学反应可能是由于HO x 2 ）和MCMA在高NO x （NO + NO 2 ）条件下自由基之间的快速循环。

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