A measurement of total reactive nitrogen, NOy, together with NO₂, NO, and O₃ via cavity ring-down spectroscopy.
A measurement of total reactive nitrogen, NOy, together with NO₂, NO, and O₃ via cavity ring-down spectroscopy.
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DOI：
10.1021/es501896w
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发表时间：
2014
影响因子：
11.4
通讯作者：
R. Wild;P. Edwards;W. Dubé;K. Baumann;E. Edgerton;P. Quinn;J. Roberts;A. Rollins;P. Veres;C. Warneke;E. Williams;Bin Yuan;S. Brown
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文献类型：
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作者：
R. Wild;P. Edwards;W. Dubé;K. Baumann;E. Edgerton;P. Quinn;J. Roberts;A. Rollins;P. Veres;C. Warneke;E. Williams;Bin Yuan;S. Brown
我们提出了一种灵敏、紧凑的探测器，它可以测量总反应氮(NOY)以及NO2、NO和O3。在所有通道中，利用基于激光二极管的腔衰荡光谱(CRDS)在405 nm处直接检测到NO2。对于臭氧测量通道，周围的臭氧在过量的NO中被转化为NO2。同样，在过量的臭氧中，环境中的NO被转化为NO2。在加热的石英进气口中，周围的NOY在∼700C时被热解成NO2或NO。任何存在于环境空气中或由其他活性氮化合物的热解形成的NO在热转换器后被转化为过量的臭氧中的NO2。在犹他州和阿拉巴马州的野外活动中，我们测量了六种主要NOY组分的热解离曲线，并将环境测量与其他仪器进行了比较。阿拉巴马州的测量是在生物排放高的农村地区进行的，犹他州的测量是在冬季的异常条件下进行的，这些条件与石油和天然气生产相关的排放形成了高臭氧水平。在阿拉巴马州，NOY与公认的标准测量方法(钼催化转化器/化学发光仪器)的比较，同意在12%以内，我们将其定义为NOY通道准确度的上限。对于所有测量通道，1σ的精度为<；30 pptv，1 S时为<；4 pptv，时间分辨率为1分钟。对于NO2和O3通道，准确度为3%，对于NO通道，准确度为5%。该仪器的精密度和准确度使其成为标准化学发光NOY仪器的通用替代品。
We present a sensitive, compact detector that measures total reactive nitrogen (NOy), as well as NO2, NO, and O3. In all channels, NO2 is directly detected by laser diode based cavity ring-down spectroscopy (CRDS) at 405 nm. Ambient O3 is converted to NO2 in excess NO for the O3 measurement channel. Likewise, ambient NO is converted to NO2 in excess O3. Ambient NOy is thermally dissociated at ∼700 °C to form NO2 or NO in a heated quartz inlet. Any NO present in ambient air or formed from thermal dissociation of other reactive nitrogen compounds is converted to NO2 in excess O3 after the thermal converter. We measured thermal dissociation profiles for six of the major NOy components and compared ambient measurements with other instruments during field campaigns in Utah and Alabama. Alabama measurements were made in a rural location with high biogenic emissions, and Utah measurements were made in the wintertime in unusual conditions that form high ozone levels from emissions related to oil and gas production. The NOy comparison in Alabama, to an accepted standard measurement method (a molybdenum catalytic converter/chemiluminescence instrument), agreed to within 12%, which we define as an upper limit to the accuracy of the NOy channel. The 1σ precision is <30 pptv at 1 s and <4 pptv at 1 min time resolution for all measurement channels. The accuracy is 3% for the NO2 and O3 channels and 5% for the NO channel. The precision and accuracy of this instrument make it a versatile alternative to standard chemiluminescence-based NOy instruments.