International comparison CCQM-K82: methane in air at ambient level (1800 to 2200) nmol/mol
International comparison CCQM-K82: methane in air at ambient level (1800 to 2200) nmol/mol
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国际比较CCQM-K82：环境水平空气中的甲烷（1800至2200）nmol/mol
DOI：
10.1088/0026-1394/52/1a/08001
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发表时间：
2015
期刊：
影响因子：
2.4
通讯作者：
P. Brewer
中科院分区：
文献类型：
--
作者：
E. Flores;J. Viallon;T. Choteau;P. Moussay;Robert I Wielgosz;N. Kang;Byung Moon Kim;E. Zalewska;Adriaan (A M H) van der Veen;L. Konopelko;Hai Wu;Q. Han;G. Rhoderick;Franklin R Guenther;Takuro Watanabe;T. Shimosaka;K. Kato;B. Hall;P. Brewer
CCQM-K82比较旨在评估在（1800至2200）nmol/mol范围内，空气一级参比混合物中甲烷的NMI能力的等效程度。用于标准物的平衡气体是经洗涤的干燥真实的空气或合成空气。许多实验室多年来一直在制定空气中的甲烷标准，最近的发展侧重于大气测量浓度的标准，目的是在独立制定的标准之间取得一致。2003年曾对空气中甲烷的主要气体标准的差异进行过比较（CCQM-P41温室气体。1和2），对于一组更有限的标准品，结果的标准偏差约为30 nmol/mol和10 nmol/mol的参考值。这与世界气象组织（WMO）制定的数据质量目标（DQO）规定的实地实验室常规测量大气甲烷水平所需的一致性水平形成对比，该目标旨在反映全球范围内CH 4测量的科学理想兼容性水平，目前设定为2 nmol/mol（1 sigma）。这一关键比较的测量工作于2012年5月至2012年6月进行。八个实验室参加了由BIPM和NIST协调的这项比较。根据在BIPM进行的腔衰荡光谱测量，结合参与者的重量分析值计算关键比较参考值，以确定一组一致的标准。回归分析允许计算每个标准品的预测值，作为KCRV。在这项比较中，参与者报告的标准不确定度范围为0.50 nmol/mol至2.4 nmol/mol，单个KCRV的不确定度范围为0.68 nmol/mol至0.71 nmol/mol。KCRV值的标准集合的标准偏差为1.70 nmol/mol。这表明，与2003年相比，甲烷在空气标准中的兼容性水平提高了10倍以上。标准兼容性的进一步改进将需要改进平衡气体中痕量甲烷测量的方法和不确定性。正文。要查看本文的正文，请点击最终报告。请注意，此文本出现在BIPM密钥比较数据库kcdb.bipm.org/的附录B中。根据CIPM互认协议（CIPM MRA）的规定，最终报告已由CCQM进行同行评审并批准发布。
The CCQM-K82 comparison was designed to evaluate the degrees of equivalence of NMI capabilities for methane in air primary reference mixtures in the range (1800 to 2200) nmol/mol. The balance gas for the standards was either scrubbed dry real air or synthetic air. CH4 in air standards have been produced by a number of laboratories for many years, with more recent developments focused on standards at atmospheric measurement concentrations and aimed at obtaining agreement between independently produced standards. A comparison of the differences in primary gas standards for methane in air was previously performed in 2003 (CCQM-P41 Greenhouse gases. 1 and 2) with a standard deviation of results around the reference value of 30 nmol/mol and 10 nmol/mol for a more limited set of standards. This can be contrasted with the level of agreement required from field laboratories routinely measuring atmospheric methane levels, set by Data Quality Objectives (DQO) established by the World Meteorological Organization (WMO) to reflect the scientifically desirable level of compatibility for CH4 measurements at the global scale, currently set at 2 nmol/mol (1 sigma). The measurements of this key comparison took place from May 2012 to June 2012. Eight laboratories took part in this comparison coordinated by the BIPM and NIST. Key comparison reference values were calculated based on Cavity Ring Down Spectroscopy Measurements performed at the BIPM, combined with participant's gravimetric values to identify a consistent set of standards. Regression analysis allowed predicted values for each standard to be calculated which acted as the KCRVs. In this comparison reported standard uncertainties by participants ranged from 0.50 nmol/mol to 2.4 nmol/mol and the uncertainties of individual KCRVs ranged from 0.68 nmol/mol to 0.71 nmol/mol. The standard deviation of the ensemble of standards about the KCRV value was 1.70 nmol/mol. This represents a greater than tenfold improvement in the level of compatibility of methane in air standards compared to that demonstrated in 2003. Further improvements in the compatibility of standards will require improved methods and uncertainties for the measurement of trace level methane in balance gases. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).