Development and validation of a SI-traceable certification protocol for elemental mercury gas generators used in the field
The aim of this work package is to develop and validate a SI-traceable certification protocol for elemental mercury (Hg0) gas generators used in the field based on (1) direct comparison and (2) indirect comparison with the primary mercury gas standard. The project will use the primary mercury gas standard and a calibration infrastructure for mercury concentration measurement in emission sources and the atmosphere produced in the projects EMRP ENV02 PartEmission and EMRP ENV51 MeTra. To ensure the uptake of these traceable calibration methods, a metrologically sound certification protocol for Hg0 gas generators used in the field will be developed by the project.
The specific aims of each task are:
Task 1.1. The aim of this task is to develop a traceable certification protocol for elemental mercury gas generators used in the field traceable to SI.
Task 1.2. The aim of this task is to validate the traceable certification protocol developed in A1.1.4 for Hg0 gas generators, through direct comparisons at concentration levels, which are valid for mercury measurements from emission sources.
Task 1.3. The aim of this task is to validate through indirect comparisons the certification protocol for elemental mercury gas generators developed in A1.1.4, at concentration levels which are relevant for atmospheric mercury measurements in the sub ng/m3 range.
Task 1.4. The aim of this task is to determine the consistent quality of mercury measurements during a comparison. Participants will perform field measurements using elemental gas generators and methods for the simultaneous determination of the mercury concentration at the Monte Curcio Climatic-Environmental Observatory, an official European GMOS mercury speciation site.
| Activity number | Activity description | Partners (Lead in bold) |
| A1.1.1 M03 | PSA, with input from VSL and Lumex, will compile a list of performance characteristics (e.g. repeatability, reproducibility, accuracy, linearity, drift, bias and robustness) and uncertainty sources of 3 commercially available gas generators used in the field with different working principles (e.g. Bell-jars, gas generators). | PSA, VSL, Lumex |
| A1.1.2 M05 | VSL, in collaboration with PSA, will set up an uncertainty calculation for the commercially available gas generators used in the field listed in A1.1.1. | VSL, PSA |
| A1.1.3 M07 | VSL and VTT, in collaboration with TÜV Rheinland, PSA and Lumex, will develop experimental approaches to assess the performance characteristics listed in A1.1.1, thereby taking into consideration existing standards such as ISO 10723, EN 14211, ISO 12963, ISO 6143 and ISO 15796 and the US EPA and NIST interim protocols for establishing traceability of Hg0 evaporative gas generators and HgII evaporative gas generators. The metrological requirements will also be defined by VSL and VTT in consultation with the project SC (A4.1.1) | VSL, VTT, TÜV Rheinland, PSA, Lumex |
| A1.1.4 M12 | Using input from A1.1.1 – A1.1.3, VSL, in collaboration with TÜV Rheinland, VTT, PSA and Lumex, will develop a certification protocol for elemental mercury gas generators used in the field. | VSL, TÜV Rheinland, VTT, PSA, Lumex |
| A1.1.5 M34 | Based on the results of A1.2.4, A1.3.3, A1.3.4 and A3.1.5, VSL, in collaboration with VTT, TÜV Rheinland, PSA and Lumex will finalise the certification protocol developed in A1.1.4 and include relevant validation data such as repeatability, reproducibility, bias and uncertainty evaluation. | VSL, VTT, TÜV Rheinland, PSA, Lumex |
| A1.1.6 M36 | VSL, with support of PSA, Lumex, TÜV Rheinland, JSI, VTT, CNR and LGC will review the certification protocol from A1.1.5 and will send it to the coordinator. The coordinator will then submit it to EURAMET as D1 “Protocol for the SI-traceable certification of elemental mercury (Hg0) gas generators used in the field“. | VSL, PSA, Lumex, TÜV Rheinland, JSI, VTT, CNR, LGC |
The aim of this task is to validate the traceable certification protocol developed in A1.1.4 for Hg0 gas generators, through direct comparisons at concentration levels, which are valid for mercury measurements from emission sources. The directly certified gas generator is used for the indirect comparison to certify other gas generators. As part of this, the repeatability, reproducibility, bias and uncertainty of the gas generators will be evaluated.
| Activity number | Activity description | Partners (Lead in bold) |
| A1.2.1 M15 | VSL, with support from and PSA, will certify an elemental mercury gas generator from PSA using the primary mercury gas standard at VSL, from EMPR ENV02 PartEmission and ENV51 MeTra, according to the protocol developed in A1.1.4. A direct comparison will be performed in the range from 100 till 0.1 ug/m3. | VSL, PSA |
| A1.2.2 M19 | PSA and TÜV Rheinland, with support from VSL, will use the gas generator certified in A1.2.1 for the certification of other gas generators used in the field according to the protocol developed in A1.1.4. | PSA, VSL, TÜV Rheinland |
| A1.2.3 M20 | From the data obtained in A1.2.1 and A1.2.2, VSL, TÜV Rheinland and PSA will perform a repeatability, reproducibility, bias and uncertainty evaluation for the gas generators. | VSL, TÜV Rheinland, PSA |
| A1.2.4 M22 | Using the results from A1.2.1, A1.2.2, and A1.2.3, a validation report will be compiled by VSL, in collaboration with TÜV Rheinland and PSA, describing information on repeatability, reproducibility and uncertainty evaluation at emission and ambient levels extended to the sub ng/m3 level. VSL will send the final validation report to the coordinator. The coordinator, using the final validation report will then submit it to EURAMET as D2 “Validation report for the certification of elemental mercury gas generators including information on repeatability, reproducibility and uncertainty evaluation at emission and ambient levels extended to the sub ng/m3 level. | VSL, TÜV Rheinland, PSA |
The aim of this task is to validate through indirect comparisons the certification protocol for elemental mercury gas generators developed in A1.1.4, at concentration levels which are relevant for atmospheric mercury measurements in the sub ng/m3 range. In contrast to the validation at emission levels, for the validation of a certification protocol for atmospheric mercury measurements, transfer gas standards will be used. Such transfer gas standards can be prepared on-site at sub ng/m3 levels. The repeatability, reproducibility, bias and uncertainty evaluation of gas generators will be evaluated.
| Activity number | Activity description | Partners (Lead in bold) |
| A1.3.1 M21 | JSI, with input from CNR, Lumex, PSA and VSL will investigate performance characteristics and uncertainty sources of different sorption materials which can be used to obtain transfer gas standards (e.g. gold traps and carbon traps) as used in EMRP ENV02 PartEmission and EMRP ENV51 MeTra projects and EMPIR ENV01 MercOx project. This will be done for the indirect certification of Hg0 gas generators at concentration levels which are relevant for atmospheric mercury measurements in the sub ng/m3 range. Based on this review, 2-3 sorption materials with the best features (e.g. recovery, sampling volume) will be selected for other tests. | JSI, CNR, Lumex, PSA, VSL |
| A1.3.2 M23 | JSI, with support of CNR and VSL, will certify an elemental mercury gas generator according to the protocol developed in A1.1.4 and the sorption materials selected in A1.3.1 to obtain transfer standards with the primary mercury gas standard. | JSI, CNR, VSL |
| A1.3.3 M25 | CNR, with support from JSI, will use the gas generator certified in A1.3.2 for the certification of other gas generators (e.g. from CNR) used in the field with sorption materials selected in A1.3.1 to obtain transfer standards. | CNR, JSI |
| A1.3.4 M27 | Using the data obtained in A1.3.2 and A1.3.3 JSI, with support from CNR and VSL will perform a repeatability, reproducibility, bias and uncertainty evaluation for the gas generators and write a validation report and guidance document on how to use the protocol (developed in A1.1.4) in practice. | JSI, CNR, VSL |
The aim of this task is to determine the consistent quality of mercury measurements during a comparison. This will help to ascertain whether using SI-traceable certified gas generators will produce mercury measurement results that agree with each other. Participants will perform field measurements using elemental gas generators and methods for the simultaneous determination of the mercury concentration at the Monte Curcio Climatic-Environmental Observatory, an official European GMOS mercury speciation site. The equipment used by the participants will be calibrated with Hg0 and HgII gas generators certified according to the protocols developed in Task 1.1 and Task 2.3.
| Activity number | Activity description | Partners (Lead in bold) |
| A1.4.1 M12 | CNR, with input from VSL, VTT and JSI, will set up a protocol for the comparison of mercury measurements in air using equipment calibrated with certified Hg0 and HgII gas generators. The protocol shall contain the time schedule of the comparison exercise, details on the measurements performed and instructions on the reporting of the results and their evaluation using statistical analysis. In addition, VSL and VTT will contribute to the preparation of a protocol for the certification of the Hg0 and HgII gas generators used to calibrate the equipment of the participants. | CNR, VSL, JSI, VTT |
| A1.4.2 M20 | CNR, with support of JSI, VTT and VSL, will invite companies regularly performing mercury measurements at air monitoring sites, in contact with regional and global monitoring programmes. 2-5 participants will be selected for the comparison exercise in A1.4.3 according to the protocol set up in A1.4.1. | CNR, JSI, VTT, VSL |
| A1.4.3 M30 | CNR will invite the participants selected in A1.4.2 to the Monte Curcio Climatic‑Environmental Observatory (CNR) for the comparison exercise. CNR, with support from VTT, VSL and JSI will host and conduct the comparison exercise for mercury measurements in air based on the protocol set up in A1.4.1. | CNR, VTT, VSL, JSI |
| A1.4.4 M32 | The measurement results obtained during A1.4.3 will be evaluated by CNR, with support from VTT and VSL, using the protocol from A1.4.1. A report regarding the quality of mercury measurements during a comparison will be written by CNR, with support from VTT and VSL. | CNR, VTT, VSL |