AIR QUALITY MONITORING - UK EQUIPMENT STUDY PUBLISHED

13 Jun 2006 09:45 AM

A study of the equipment used across the UK to monitor particle matter in the air has been published today by Defra.

The Equivalence Programme for monitoring particulate matter is an EU requirement of all Member States where they are not using the standard 'reference' method. It ensures that the data produced by any Member State can be interpreted alongside the data produced by others to achieve a framework for comparison of air quality across Europe. Particulate matter poses a public health risk in the UK, with 2005 levels reducing average life expectancy by up to about 8 months and at an estimated cost of up to £9.1 to 21.4 billion per annum.

Unlike the standard 'reference' method of the EU first Daughter Directive used by some countries, which produces data several days after particles are collected, the majority of monitors in the UK's network allow near real-time dissemination of information to the public and gives sensitive individuals the opportunity to take appropriate action should particulate levels increase.

The report published today is one of the first to be completed, and one of the most extensive studies undertaken to date. It has been reviewed by independent experts before publication. Findings indicate that:

* The equivalence criteria are met by three of the monitor types (Partisol 2025 Sequential Sampler; Tapered Element Oscillating Micro-balance (TEOM) retrofitted with Filter Dynamic Measurement System (FDMS) for PM10 and PM2.5; and the OPSIS SM200 by Beta) without correction for slope and/or intercept.
* Two further monitor types (OPSIS SM200 by Mass, and Met One Beta Attenuation Monitor (BAM)) meet the criteria after correction for slope and/or intercept; and
* The TEOM method do not meet the equivalence criteria with or without a correction factor. This result is consistent with preliminary investigations carried out for Defra and the devolved administrations.

Despite the TEOM's non-equivalence with the first Daughter Directive reference method, the conclusions from its data corrected using the current 1.3 factor would be broadly the same as those from the reference method. Any difference would not provide under-estimated readings but may actually over-estimate particulate levels in some places.

The findings also indicate that most TEOMs retrofitted with FDMS would achieve equivalence with the first Daughter Directive requirements. TEOMs are widely used by local authorities in their Local Air Quality Management regimes and information on what they should do with data from TEOMs will be provided by Defra via their local authority monitoring helpline (0870 190 6050;
www.laqmsupport.org.uk/).

The full report is published online at www.airquality.co.uk.

Notes for Editors

1. European Directive 96/62/EC sets out the current framework for the assessment of twelve different pollutant species across the EU. In order to achieve harmonisation of measurements across the member states the Directive provides for the setting of European standards for monitoring and analysis.

2. The First Daughter Directive 1999/30/EC (DD1) sets Limit Values for particles within the PM10 fraction, based on measurements made using the reference method EN12341 - a filter-based gravimetric measurement method. In the UK, measurements of PM10 are largely founded on the use of the Tapered Element Oscillating Microbalance. More recently, the EU Commission has proposed a Concentration Cap and an Exposure Reduction Target for particles less than 2.5Um in diameter and the European Standards Institute (CEN) has published the standard reference method in EN14907.

3. Where a Member State chooses to employ monitoring methods outside of the reference method, a programme of 'equivalence' must be undertaken. In recognising the need for further guidance on such programmes - the approach to be taken, the assessment criteria and the methods of reporting - the European Commission has produced the Guidance for the Demonstration of Equivalence of Ambient Air Monitoring Methods, which sets out whether a candidate method can be considered equivalent to the EU reference method.

4. This report summarises the results of the UK Particulate Monitoring Programme, which has included the operation of seven candidate instruments collocated with the EU reference method (Low Volume Samplers for PM10 and PM2.5). Instruments included in the programme are: Tapered Element Oscillating Micro-balance (TEOM); TEOM retrofitted with Filter Dynamic Measurement System (FDMS); Partisol 2025 Sequential Sampler; OPSIS SM200 (Beta and Mass configurations); Met-One Beta Attenuation Monitor (BAM), and Met-One BAM retrofitted with a heater (herein referred to as a "Smart BAM").

5. The programme has included operation of the monitoring equipment across eight studies that collectively represent particulate conditions typically encountered across the United Kingdom. Field campaigns have been undertaken during summer and winter periods at Teddington (SE England); Birmingham (Midlands); East Kilbride (Scotland) and Bristol (SW England). All instruments were operated in duplicate in order to determine the 'between-sampler' uncertainty.

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