QA QC Framework


As part of their provision of support to 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) as part of their Local Air Quality Management process.

This is aimed at the analytical laboratories that supply and analyse the diffusion tubes and currently comprises:

  • Promotion of the independent AIR-PT scheme, operated by LGC Standards and supported by the Health and Safety Laboratory, with yearly assessment against agreed performance criteria. AIR-PT combines two long running PT schemes: LGC Standards STACKS PT scheme and HSL Workplace Analysis Scheme for Proficiency (WASP) PT scheme. For more information about the AIR-PT scheme, please visit the Air & Stack Emissions (AIR PT) website on the LGC Standards website.
  • Operation of a field inter-comparison exercise, in which diffusion tubes are co-located with an automatic analyser (from January 2006 this is at a roadside site).
  • Provision of quality control standard solutions, free of charge to laboratories that prepare and analyse NO2 diffusion tubes used by local authorities for LAQM purposes.

Summaries of participating laboratories’ performance in the AIR-PT/WASP scheme over the preceding months, prepared by LGC/BV/NPL, are available by clicking on the links below.

Current version


AIR-PT-Rounds 37 to 50 (May 2020 to Jun 2022)

Released: July 2022 (PDF, 169 KB, 5 pages)


The AIR PT scheme uses laboratory spiked Palmes type diffusion tubes to test each participating laboratory’s analytical performance on a quarterly basis and continues the format used in the preceding WASP PT scheme. It should be noted that such tubes are not designed to test other parts of the measurement system e.g. sampling.

Previous versions


AIR-PT-Rounds 30 to 42 (Jan 2019 to Mar 2021)

Released: March 2021 (PDF, 163 KB, 5 pages)

AIR-PT-Rounds 30 to 40 (Jan 2019 to Oct 2020)

Released: October 2020 (PDF, 166 KB, 5 pages)

AIR-PT-Rounds 24 to 34 (Jan 2018 – Nov 2019)

Released: November 2019 (PDF, 320 KB, 5 pages)

AIR-PT-Rounds 22 to 33 (Sep 2017 – Aug 2019)

Released: August 2019 (PDF, 320 KB, 5 pages)

AIR-PT-Rounds 21 to 31 (Jul 2017 to May 2019)

Released: May 2019 (PDF, 320 KB, 5 pages)

AIR-PT-Rounds 19 to 30 (Apr 2017 – Feb 2019)

Released: February 2019 (PDF, 228 KB, 5 pages)

AIR-PT-Rounds 18 to 28 (Jan 2017 – Oct 2018)

Released: October 2018 (PDF, 228 KB, 5 pages)

AIR-PT-Rounds 16 to 27 (Sep 2016 – Aug 2018)

Released: August 2018 (PDF, 228 KB, 5 pages)

AIR-PT-Rounds 13 to 24 (Apr 2016 – Feb 2018)

Released: March 2018 (PDF, 228 KB, 5 pages)

AIR-PT-Rounds 12 to 22 (Jan 2016 – Oct 2017)

Released: November 2017 (PDF, 227 KB, 5 pages)

AIR-PT-Rounds 10 to 21 (Oct 2015 – Aug 2017)

Released: August 2017 (PDF, 227 KB, 5 pages)


To view summaries for previous rounds of the AIR-PT/WASP scheme, please contact the LAQM Helpdesk.

LAQM Helpdesk
Skip to content