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International HALocarbons in Air Comparison Experiment
Background and Goals
Many halogenated compounds, such as halocarbons, contribute to greenhouse warming, destruction of the ozone layer, some air quality issues, and are important indicators of the oxidizing capacity of the atmosphere. Worldwide measurements of halocarbons and related compounds are being conducted by a number of groups (NOAA/CMDL, AGAGE, UCI, UEA). Many of these measurements are reported on independent calibration scales. Formal, well-established relationships between all major calibration scales have not been determined. There is no international program for inter-laboratory comparison similar to that for carbon dioxide. Recognizing this important gap, the Global Atmospheric Watch (GAW) program of the World Meteorological Organization and agencies responsible for major global networks have organized an international intercomparison.
Short term goal: Establish a calibration matrix that relates the calibration scales of each laboratory to one another. This will enable the creation of an integrated, global halocarbon database.
Establish a quality assurance system for global halocarbons measurements with a calibration standard centre and a system of routinely comparing secondary standards with the primary standard.
Long term goal:
Target Compounds
CFCs, HCFCs, HFCs, Halons, PFCs, short-lived halocarbon, methyl halides (CH3Cl, CH3Br), and other trace gases of interest such as SF6, CH4, N2O, COS.
Experimental design
The experiment is planned as a round robin experiment, i.e. a set of air samples will be prepared and cycled between the participants. The results will be reported to the two co-referees. Each lab will have 3-4 weeks for analysis and shipping to the next participant.
Status of the Experiment