This project aims to maximise the uptake of the Certification Protocol for Zero Gas, developed by EMRP JRP ENV01 MACPoll, by converting it into a draft documentary standard under ISO Technical Committee 158 “Gas Analysis”. Zero gases are ultra-high purity gases such as nitrogen or synthetic air, which are used as reference points in the calibration of equipment in ambient air pollution measurements. By application of this standard, there will be no ambiguity in the level of accuracy and traceability of the purity of the zero gas used.
The European Network of Air Quality Reference Laboratories (AQUILA) and its members, the National Reference Laboratories (NRL) of EU member states, aim to provide traceable calibration services to the air monitoring networks within Europe. This project will develop and provide a training course to facilitate the uptake of the Certification Protocol for Zero Gas by these key stakeholders. The endorsement and implementation of the Certification Protocol and later of the ISO standard by AQUILA will improve compliance with EU regulations and allow better reliability of the measurement data generated by EU air monitoring networks.
The air monitoring networks of EU countries are mandated by the EU Directive on ‘Ambient Air Quality and Cleaner Air for Europe’ (2008/50/EC) and Commission Directive 2015/1480/EU to perform and guarantee SI traceable measurements of gas pollutants at high and extremely low (parts per billion) levels. To measure at low levels, the zero gas should be the “anchor point” for the analytical equipment from which minimum changes in instrument response are detected.
The European documentary standards (EN standards), that describe the reference methods for measuring gas pollutants, specify the criteria for the purity of the zero gas but do not give explicit instruction on how to achieve the requirements. For example, when measuring NO2 at the EU Annual Limit Value of 21 nmol/mol with a maximum allowed uncertainty on the measurement result of 15 %, the presence of 1 nmol/mol in the zero gas counts already for one-third of the allowed uncertainty. The standards specify that the content of NO2 in zero gas shall be less than 1 nmol/mol. However, a zero gas with such level of metrological accuracy does not exist on the market. Hence, there is an urgent need for a standardised purity assessment protocol and Zero Gas Calibration Standards to ‘zero’ the gas analysis equipment with greater accuracy.
EMRP JRP ENV01 MACPoll delivered a Certification Protocol for Zero Gas that enables the metrological assessment of the purity of zero gases, and generates SI traceable and ultra-accurate Zero Gas standards down to the nmol/mol.
While the Certification Protocol for Zero Gas is already available it has, at present, no formal standing. International acceptance would be achieved by incorporating it in an ISO standard under TC 158, the Technical Committee involved in the preparation of documentary standards for gas analysis. The Chair of ISO/TC 158 is the primary supporter of this SIP and requires a draft New Work Item Proposal (NWIP) to amend ISO 19229 standard “Gas analysis – Purity analysis and the treatment of purity data” so that it will include the relevant parts of the Certification Protocol for Zero Gas.
A second fundamental output of EMRP JRP ENV01 MACPoll was the successful implementation of the Certification Protocol for Zero Gas by the project partners to test gas purification systems, namely gas filters, zero gas generators and best grade compressed gases in cylinders.
Articles and presentations at symposia given recently by industrial parties demonstrate the challenge and the need for developing Zero Gas Calibration Standards. Currently, industrial producers of zero gases, of gas purification systems and of zero gas generators provide conservative and therefore inaccurate specifications which do not meet the metrological requirements (accuracy and SI traceability) prescribed by the EN standards and the EU Air Quality Directives as above. This situation results in a non-compliance of the EU air monitoring networks with existing legislation and in a lack of confidence in the measurement data provided for policy makers to improve EU Air Quality. There is therefore a need for training events for the EU air monitoring networks and industrial zero gas producers in the correct implementation of the Certification Protocol for Zero Gas in order that they may comply with legislation.
The objectives of the SIP are:
- To incorporate the “Certification Protocol for Zero Gas” and practical case studies developed in EMRP JRP ENV01, into ISO 19229 (to Committee Draft status).
- To facilitate the uptake of the Certification Protocol by direct users of Zero Gas Calibration Standards, namely the AQUILA Network of Air Quality Reference Laboratories and by industrial producers of zero gases, namely gas producers and manufacturers of gas purification systems and zero gas generators. This objective will complement objective 1, by focusing on dedicated training for the correct implementation of the Protocol and of the future ISO standard.
The project results will be twofold:
First, in cooperation with ISO/TC 158 a New Work Item Proposal will be developed covering the incorporation of the “Certification Protocol for Zero Gas” (including practical examples taken from measurement results obtained in EMRP JRP ENV01 MACPoll) into ISO 19229. Partners will work with the Committee to ensure the acceptance of the Working Draft Document to achieve the status of Committee Draft.
Second, dedicated hands-on training courses will be organised for industrial producers of zero gases and members of the AQUILA Network on the use of the procedures and data handling described in the Certification Protocol. This will ensure the correct adoption of the Protocol and of the new draft ISO standard.
The incorporation of the Certification Protocol for Zero Gas into an ISO standard will directly impact gas producers and users of zero gases.
Specifically for gas producers and manufacturers of gas purification systems the new ISO standard will allow the metrological assessment of their zero gases and therefore it will allow the provision of accurate and SI traceable zero gas (Zero Gas Calibration Standards) on the market that will meet the needs of users, in particular the air monitoring networks.
The presence on the market of Zero Gas Calibration Standards and the capability of direct users, such as AQUILA laboratories in applying the ISO standard will enable compliance of the air monitoring networks with the EU Air Quality legislation requirements.
This will further impact on the quality of the measurements carried out by the air monitoring networks, leading to reliable and comparable data in Europe. The indirect environmental impact of the SIP is in terms of cleaner air for European citizens as a result of the effective implementation of the European Directive on ‘Ambient Air Quality and Cleaner Air for Europe’. The route to impact is dependent on the existence and implementation of a formal and internationally recognised documentary standard that will help to improve the measurement of air pollution.