NO2 Quality Assurance

As part of their provision of support to UK Local Authorities for air quality management, Defra and the Devolved Administrations provide a set of centralised QA/QC services, to assist Local Authorities using diffusive samplers for monitoring of ambient nitrogen dioxide (NO₂) concentration, as part of their Local Air Quality Management (LAQM) process. These services are managed by Bureau Veritas UK. One of the services provided is the co-ordination of a quality assurance/quality control (QA/QC) framework, aimed at the analytical laboratories that supply and analyse the diffusion tubes. This service currently comprises

• Promotion of the WASP NO₂  PT scheme operated by the Health and Safety Laboratory
• Operation of a NO₂ field intercomparison exercise, managed by the National Physical Laboratory , in which diffusion tubes are co-located with an automatic analyser 

Participation is recommended for any laboratory that prepares or analyses NO₂ diffusion tubes used by Local Authorities for LAQM purposes.

Contract details for further information

For further details of the LAQM helpdesk please email LAQMHelpdesk@uk.bureauveritas.com or phone 0800 0327953

WASP NO2  PT SCHEME

Scheme overview

The Workplace Analysis Scheme for Proficiency (WASP) NO₂  PT scheme the performance of laboratories undertaking the analysis of Palmes type diffusion samplers for ambient air NO₂ monitoring.  The scheme is operated by HSL, which oversees management, registration, and membership matters together with distribution of the samples and processing the participant data.

 Analytes in the scheme

Who should participate?

Laboratories undertaking the analysis of Palmes type diffusive air samplers for atmospheric nitrogen dioxide concentrations. Scheme is open to worldwide participants. Scheme may be of benefit to laboratories analysing alternative diffusive air sampler designs but where the analytical procedures are similar.

What analytical methods should be used?

A Working Group, comprising representation from Defra and the Devolved Administrations, end user UK laboratories, HSL, the Environment Agency, SEPA and other stakeholders, have produced analytical guidance aimed at harmonising the methodology used in preparing, utilising and analysing diffusion tubes as used in the  WASP NO₂  PT scheme and the companion NO₂  field intercomparison exercise and this can be found here on the Defra website.

Operation of the scheme

Four samples are sent to participants every 3 months. Laboratories have a minimum of a month to analyse the sample and to report the results. Upon completion of the round HSL issues a performance report to each participant. 

There is a requirement that performance of participants that analyse NO₂ diffusion tubes used by UK Local Authorities for LAQM purposes is also reported to the project officer in charge of the QA/QC services mentioned above.

Scheme schedule

see WASP page for details.

Contract details for further information

For further details of the  WASP NO₂  PT scheme please email proficiency.testing@hsl.gov.uk or contact:

The Proficiency Testing Team
Health and Safety Laboratory
Harpur Hill
Buxton
Derbyshire
SK17 9JN

Tel: 00 44 (0)1298 218553
Fax: 00 44 (0)1298 218572

Nitrogen Dioxide Field Intercomparison Study

Scheme overview

This ongoing intercomparison study involves the monthly co-location of diffusive samplers supplied by participants with a real time analyser at a UK urban road site sampling location.  This study is now managed by the National Physical Laboratory (NPL). In advance, participants supply three prepared diffusive samplers plus ttavel blanks to NPL for deployment. At the end of the month, the samplers are recovered and NPL ships them back to the participants for analysis. Participants have one month to analysis the samples and submit results to NPL. NPL compares these results against a target reference value from the real time analyser. A monthly summary report is then dispatched to participants.

Contract details for further information

For further details of the  NO₂  field intercomparison study please email nick.martin@npl.co.uk or contact:

Dr Nick Martin

National Physical Laboratory
Analytical Sciences Division
Hampton Road
Middlesex
TW11 0LW

Tel: 00 44 (0)20 8943 7088