|Abstract Title:||Comparable mercury vapour measurement results|
|Presenter Name:||Ms Iris de Krom|
|Session Choice:||Standards & Quality Assurance|
Abstract Information :
Within the "Traceability for mercury measurements" project (MeTra; European Metrology Research Programme) a mercury vapour generator was developed to establish traceability of mercury vapour measurement results, based upon a gravimetric approach, for ambient air levels as well as higher concentrations.
Current measurement capabilities are maintained at levels of 0,25 - 350 µg Hg/m3, whereas the aim of the novel gravimetric primary standard was to realize metrological traceability for the range 5 ng Hg/m3 - 60 µg Hg/m3, with a target measurement uncertainty of 1 %. This to cover key requirements for ambient air monitoring (1 - 2 ng Hg/m3), health-based exposure standards (50 ng Hg/m3), concentrations relevant to stationary source emissions (upwards of 1 µg Hg/m3) and the minimum alveolar concentration value (20 µg Hg/m3).
The development and characterization of the primary mercury vapour generator will be presented. Furthermore the results will be presented of two comparisons held to demonstrate the robustness and comparability of the novel primary standard. One comparison was performed against the Dumarey vapour pressure equation, while another comparison was performed against current calibration facilities present at national metrology institutes.
The novel primary mercury vapour generator will contribute to comparable measurement results of mercury vapour at ambient and background air levels, and also to higher safety standards and cost reductions in e.g. the LNG field, where aluminium main cryogenic heat exchangers are used which are particular prone to corrosion caused by mercury.
Furthermore the newly developed primary standard will be used within the just started "Metrology for oxidised mercury" project (MercOx; European Metrology Programme for Innovation and Research) to establish and implement a traceable calibration methodology for the most important oxidised Hg species, especially for HgCl2. An overview, and the first results, of this new project will also be presented.