Development of a Northern Continental Air Standard Reference Material

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• 作者：George C. Rhoderick ; Duane R. Kitzis ; Michael E. Kelley ; Walter R. Miller ; Bradley D. Hall ; Edward J. Dlugokencky ; Pieter P. Tans ; Antonio Possolo ; Jennifer Carney
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：March 15, 2016
• 年：2016
• 卷：88
• 期：6
• 页码：3376-3385
• 全文大小：354K
• ISSN：1520-6882

文摘

The National Institute of Standards and Technology (NIST) recently began to develop standard mixtures of greenhouse gases as part of a broad program mandated by the 2009 United States Congress to support research in climate change. To this end, NIST developed suites of gravimetrically assigned primary standard mixtures (PSMs) comprising carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) in a dry-natural air balance at ambient mole fraction levels. In parallel, the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado, charged 30 aluminum gas cylinders with northern hemisphere air at Niwot Ridge, Colorado. These mixtures, which constitute NIST Standard Reference Material (SRM) 1720 Northern Continental Air, were certified by NIST for ambient mole fractions of CO₂, CH₄, and N₂O relative to NIST PSMs. NOAA-assigned values are also provided as information in support of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Program for CO₂, CH₄, and N₂O, since NOAA serves as the WMO Central Calibration Laboratory (CCL) for CO₂, CH₄, and N₂O. Relative expanded uncertainties at the 95% confidence interval are <±0.06% of the certified values for CO₂ and N₂O and <0.2% for CH₄, which represents the smallest relative uncertainties specified to date for a gaseous SRM produced by NIST. Agreement between the NOAA (WMO/GAW) and NIST values based on their respective calibration standards suites is within 0.05%, 0.13%, and 0.06% for CO₂, CH₄, and N₂O, respectively. This collaborative development effort also represents the first of its kind for a gaseous SRM developed by NIST.