Air Emission monitoring in the UK

By Dave Curtis, Source Testing Association
The Source Testing Association, established in 1995, has been committed to improving quality, health & safety and providing a technical base for its members.

Reliable source testing is a key element of regulatory control of industrial processes. It can provide evidence of compliance with legislative limits, information on actual releases to the environment and plant optimisation information. From the introduction of the MCERTS scheme for manual stack emission monitoring, the industry and personnel have realised the advantages of the certification scheme. Nearly two hundred personnel have passed the exams at various levels with many hundreds on the register to sit exams.

MCERTS for manual stack-emissions monitoring has been developed in collaboration with the Source Testing Association (STA), the Scottish Environment Protection Agency (SEPA) and the Environment and Heritage Service, Department of Environment, Northern Ireland.

The scheme is split into two components – the certification of personnel and the accreditation of organisations. The term ‘organisation’ is used generically. It includes commercial ‘test houses’, laboratories and industrial operators’ in-house monitoring arrangements.

The MCERTS personnel competency standard enables stack-emission monitoring personnel to be formally certified as competent, based on experience, training and examination. Sira Certification Service (SCS) is the certification body which operates the personnel competency scheme on behalf of the Environment Agency and is accredited by the United Kingdom Accreditation Service (UKAS) to European Standard EN45013: General Criteria for Certification Bodies Operating Certification of Personnel.

MCERTS also requires stack-emission monitoring organisations to be accredited by UKAS to ISO/IEC 17025 for the MCERTS performance standard for organisations. The standard provides an application of ISO/IEC 17025 in the specific field of measurement of industrial emissions from stacks and covers the following:

  • ethical requirements for independence and environmental awareness;
  • use of MCERTS certified personnel;
  • selection of appropriate methods following international standards;
  • method implementation;
  • estimation of measurement uncertainty;
  • use of appropriate equipment;
  • planning of a sampling measurement campaign, including: site review; risk assessment and site-specific protocol
  • reporting of results;
  • participation in proficiency testing schemes.

The stack testing industry has seen the introduction of the scheme as a means of improving the quality to their clients and providing a firm footing for the future of the industry.

Benefits to the process operator

For many years many process operators have viewed stack testing as a necessary evil, which was required to satisfy the regulators. Quality and comparability of the data were jeopardised by downward pressure on prices. Partly as a result of this approach, and a resulting lack of consistency, we have seen many examples of reports of monitoring with very dubious data thus creating distrust within the industry.

In the last couple of years, there has been evidence that some industry sectors are grasping the problem. By installing correct equipment, suitable access platforms and commissioning quality monitoring, they are reaping the benefits of better process control, lower emissions and subsequent compliance with the European Directives.

As time goes by, we are beginning to see the MCERTS schemes become mandatory within certain sectors and in the future we can look forward to increased comparability of data.

What does the future hold in store?

We would all like to gaze into a crystal ball to see how the industry is going to develop but we do know of forthcoming standards and legislation which will affect the way we operate. European standards developed by CEN have a mandatory requirement and must be adopted by all states within the European Union. Within the Air Quality field, the standards developed by CEN technical committee TC264 are underpinned by various EU directive viz.:

  • Integrated Pollution Prevention and Control (IPPC) Directive (96/61/EC)
  • Waste Incineration Directive (2000/76/EC)
  • Large Combustion Plant Directive (2001/80/EC)
  • Solvent Emissions Directive (1999/13/EC)
All these have requirements for either continuous or periodic monitoring or both. These two elements are soon to be interlinked by the introduction of a new standard EN14181. The Standard describes the quality assurance procedures needed to assure that Automated Measurement Systems (AMS) installed to measure emissions to air are capable of meeting the uncertainty requirements on measured values given by legislation, e.g. EU Directives or national legislation. Three different Quality Assurance Levels (QAL 1, QAL 2, and QAL 3) are defined. These cover the suitability of an AMS for its measurement task, QAL 1; the validation of the AMS following its installation, QAL 2; and the control of the AMS during its ongoing operation on an industrial plant, QAL 3. An Annual Surveillance Test (AST) is also defined.

The suitability evaluation of the AMS and its measurement procedure are described in EN ISO 14956 (QAL 1) where a methodology is given for calculating the total uncertainty of AMS measured values. This total uncertainty is calculated from the evaluation of all the uncertainty components arising from its individual performance characteristics. In the UK, QAL 1 procedures are covered by certification under the MCERTS scheme for Continuous Emission Monitoring Systems.

EN14181 specifies procedures for establishing quality assurance levels QAL 2, QAL 3 and AST for an AMS installed on industrial plant for the determination of the flue gas components and other flue gas parameters. It supports requirements in EU Directives 2000/76/EC and 2001/80/EC and within the scope states it “may also be applicable for other purposes”.

This standard specifies:

  • a procedure (QAL 2) to calibrate the AMS and determine the variability of the measured values obtained by an automated measurement system which is suitable for the validation of an AMS following its installation.
  • a procedure (QAL 3) to maintain and demonstrate the required quality of the measurement results during the normal operation of an AMS, by checking that the zero and span characteristics are consistent with those determined during QAL 1.
  • a procedure for the annual surveillance tests (AST) of the AMS in order to evaluate (i) that it functions correctly and its performance remains valid and (ii) that its calibration function and variability remain as previously determined.

This standard is designed to be used after the AMS has been accepted according to the procedures specified in EN ISO 14956 (QAL 1).

The procedures for calibration that have to be employed must be in accordance with CEN Standard Reference Methods (SRM) which are either already in use or are currently under development and include;

  • Particulate: EN13284 Stationary source emissions: Determination of low range mass concentration of dust — Part 2: Automated measuring systems (under development);
  • HCl: BS EN1911:1998 Stationary source emissions: Manual method of determination of HCl parts 1 to 3 (published);
  • TOC: BS EN12619:1999 Stationary source emissions: Determination of the mass concentration of total gaseous organic carbon at low concentrations in flue gases – Continuous flame ionization detector method. (published);

    BS EN13526:1998 Stationary source emissions: Determination of the mass concentration of total gaseous organic carbon in flue gases from solvent using processes - Continuous flame ionisation detector method. (published);

  • O2: EN 14789 Stationary Source Emissions: Determination of volume concentration of oxygen (O2) - Reference metho: Paramagnetism (under development);
  • Water Vapour: EN 14790 Stationary source emissions: Determination of the water vapour in ducts (under development);
  • SO2: EN 14791 Stationary source emissions: Determination of mass concentration of sulphur dioxide (SO2) - Reference method (under development);
  • NOx: EN 14792 Stationary source emissions: Determination of mass concentration of nitrogen oxides (NOx) - Reference method: Chemiluminescence. (under development);
  • CO: Stationary source emissions: Reference method for the determination of carbon monoxide in emission by means of the non-dispersive infrared method. (under development);

These new challenges that we face will make for an interesting time for all involved in emission monitoring.

The Source Testing Association


air quality | gas | incineration | planning | SEPA | training


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