Guidance in Relation to Quality of Air Emissions Data

Air emissions sampling and analysis is a particularly difficult aspect of environmental monitoring and specialist equipment may need to be used to analyse a gas stream in-situ or alternatively potentially complex methods  may need to be employed to extract and concentrate the pollutant of interest from a waste gas stream.  Therefore, both the sampling and analysis stages of air emissions monitoring require a high level of competency and quality control. There may be cases where the use of simpler techniques or measurement of surrogate parameters (i.e. measurement of a different parameter (which is easy to measure) with a known relationship to the parameter under investigation) is justified, once this method is shown to be suitable, providing the required level of accuracy, precision and resolution.

Most licensees will not carry out their own emissions monitoring but will instead employ a contractor to carry out the monitoring and provide a report. The Agency generally supports the approach of using external specialist service providers and would not recommend that licensees attempt to carry out their own air emissions monitoring unless the relevant staff have been properly trained, appropriate and properly maintained and calibrated equipment is used, adequate procedures and quality control measures are in place and all relevant licence conditions are being fully complied with. 

It is important to ensure that both the sampling and analysis (where analysis is carried out subsequent to a sample being collected) is carried out by competent personnel.  Accredited service providers are available for both emissions monitoring and laboratory analysis, and the Agency recommends that accredited service providers should be used in preference to non-accredited contractors.  Further information on the accreditation process for monitoring contractors can be found here.  When employing accredited monitoring contractors or laboratory services it is important to check that the scope of accreditation covers the type of monitoring/analysis which is being sought.

Also, a licensee may choose to audit air monitoring service providers to review items such as personnel competency and training details, quality management systems, equipment maintenance and calibration records and standard operating procedures.  

Some general points to consider in relation to monitoring of air emissions are detailed below:

• Is the monitoring being carried out in compliance with the licence requirements, e.g. using appropriate standards, competent personnel, suitable equipment, suitable procedures and applying a satisfactory level of quality control;(See basic checklist for licensees) 
• Use of an accredited contractor should provide additional confidence that appropriate methods are being used and adequate quality management systems are in place.
• Is the monitoring and reporting being carried out in accordance with the relevant EPA Air Monitoring Guidance Notes? Details of EPA and other best practice guidance on air emissions monitoring can be found here.  It is important that the report contains sufficient information to allow the Agency and the licensee to fully assess the monitoring programme. Reporting requirements for air emissions monitoring are specified in EPA Air Monitoring Guidance Note AG2.
• Have the results of the monitoring been presented in the correct units and at the appropriate reference conditions (e.g. have any required corrections for temperature, pressure, moisture level, oxygen been applied).  Further information on referencing emissions monitoring results can be found here.  This is a common area where errors are made.
• The Agency recommends that licensees operate a system to record and track all emissions monitoring data, and many licences contain a condition specifically requiring such a Data Management System.  This will allow any significant changes or changing trends in emissions to be tracked.
• Does a review of historical monitoring data for a given emission point indicate consistent compliance with the specified emission limit value? If so the Agency may consider reducing the frequency of monitoring, which would reduce monitoring costs to the licensee.  The ability of the licensee to demonstrate that the monitoring was carried out using appropriate methods and by appropriately qualified personnel would also be important in considering any requests of this nature.
• Licensees which are required to operate continuous emissions monitoring systems can find general guidance here.