Air quality reports

Improving air quality on and around our network

We are supporting the government’s delivery of the UK Nitrogen Dioxide (NO₂) Plan.

The government’s Pollution Climate Mapping (PCM) model identifies sections of road where there is the potential for pollution levels to exceed the legal annual mean nitrogen dioxide (NO₂) limit values.

This includes a number of locations on our strategic road network (SRN) in England.

The government has commissioned us to:

carry out more detailed examination of these locations
develop measures to improve air quality for those links confirmed as exceeding the limit value in the shortest possible time

We were initially commissioned to consider 101 PCM links (Commission 1) and subsequently a further seven PCM links (Commission 2).

Air Quality – Annual Evaluation Report 2022 (published February 2024)

This evaluation report provides a summary of the latest compliance status for sections of the SRN that have been assessed for air quality by National Highways up to the end of 2022.

This report also provides an update on the progress of measures that have been implemented to improve air quality on these links during this time.

Evidence in the report shows that speed limits that have been in place to help manage air quality at two locations on the motorway network can be removed.

Air Quality – Annual Evaluation Report 2022 (published February 2024)

Appendix A – PCM link summary

Appendix B – Air quality monitoring

Appendix C – PCM link maps

Appendix D – New developments

Appendix E – Air quality modelling techniques

Appendix F – Vehicle emissions from the emission factor toolkit

Appendix G – Distance corrected concentrations

Appendix H – Maps of SRN PCM links above the annual mean NO2 limit value

Appendix I – Traffic data review

Air Quality – Annual Evaluation Report 2021 (published December 2022)

This evaluation report provides a summary of the compliance for all sections of the SRN that have been assessed for air quality by National Highways up to the end of 2021.

This report also provides an update on the progress of measures that have been implemented to improve air quality on these links during this time.

Air Quality – Annual Evaluation Report 2021 (published December 2022)

Appendix A - PCM link summary
Appendix B - Monitoring
Appendix C - PCM link changes
Appendix D - New development
Appendix E - Elevated roads
Appendix F - EFT v9-v11 NOx emissions
Appendix G - Distance corrected concentrations
Appendix H - Commissioning and assessment
Appendix I - NVM location maps - images compressed

Air Quality Progress Update Report (July 2021)

Our assessment for each commission is summarised in this Air Quality Update Progress Report.

The report explains:

the outcome of the phased assessment approach
which links we assessed as meeting the NO2 limit value
the actions to achieve compliance on those sites exceeding the NO2 limit value.

Commission 1 Progress Update Report

National Highways Air Quality Monitoring Network (NHAQMN) reports

These reports give summary results from our air quality monitoring network since its creation in 2016.

We operate a network of automatic monitoring stations across the Strategic Road Network.

Data from these monitors helps us understand Nitrogen Dioxide and, more recently, particulate matter around our network.

Particulate matter (PM) means microscopic solid or liquid particles suspended in the air. These particles are categorised by size - for example, PM_2.5 means particles with a diameter of less than 2.5 micrometres (µm). PM caused by road traffic includes exhaust emissions as well as tyre and brake wear.

This data informs our programme of activity to improve air quality.

If you need help interpreting this information, or more detailed data from a specific monitor, please contact us at Airquality@highwaysengland.co.uk.

NHAQMN Annual 2022 Network Report

NHAQMN Annual 2021 Network Report

Appendix A - NHAQMN locations 2021 part 1

Appendix A - NHAQMN locations 2021 part 2

NHAQMN Annual 2020 Network Report

NHAQMN Annual 2018 Network Report

NHAQMN Annual 2017 Network Report

NHAQMN Annual 2016 Network Report

Supporting technical information

Here are the technical reports covering our assessment of the PCM links on our network.

As we progress through each phase we update baseline maps and audit reports to include our findings from earlier phases.

If you need help interpreting this information, or to track down a particular document, please contact us at Airquality@highwaysengland.co.uk.

Commission 1

Commission 1 Phase 1 Air Quality Report

Front Cover

Recommend to stop at Phase 1

PCM Link Details 36656 - Gateshead
PCM Link Details 38230 – Stoke-on-Trent
PCM Link Details 46015 – West Midlands
PCM Link Details 73526 - Newcastle
PCM Link Details 75418 – Stoke-on-Trent
PCM Link Details 84040 - Solihull
PCM Link Details 99833 – Manchester

Joint Air Quality Unit (JAQU) to provide advice on whether to progress to Phase 2

PCM Link Details 17793 – Test Valley
PCM Link Details 18626 – Newcastle Upon Tyne
PCM Link Details 38107 - Southampton
PCM Link Details 73208 - Calderdale
PCM Link Details 75421 – Stoke-on-Trent
PCM Link Details 76076 - Tameside
PCM Link Details 84041 – Solihull and North Warwickshire

Audit Summary Reports – Recommend to stop at Phase 1

Audit Summary Report – 6480
Audit Summary Report – 17793
Audit Summary Report – 18487
Audit Summary Report – 18626
Audit Summary Report – 36656
Audit Summary Report – 38107
Audit Summary Report – 73197
Audit Summary Report – 73208
Audit Summary Report – 73526
Audit Summary Report – 75418
Audit Summary Report – 75421
Audit Summary Report – 76076
Audit Summary Report – 84040
Audit Summary Report – 84041
Audit Summary Report – 99833

Commission 1 Phase 2 Air Quality Report

Going through to Phase 3 - indicative modelling suggests compliance

Indicative modelling suggests compliance (without monitoring support)

Audit Summary Report – 8147
Audit Summary Report – 17961
Audit Summary Report – 26051
Audit Summary Report – 38230
Audit Summary Report – 46062
Audit Summary Report – 48707
Audit Summary Report – 56062

Indicative modelling suggests exceedance

Nottingham compliant – stop at Phase 2

Audit Summary Report – 17304 Nottingham
Audit Summary Report – 37416 Nottingham
Audit Summary Report – 56557 Nottingham

Going through to Phase 3 - indicative modelling suggests compliance

PCM Link Details_8348 - Leeds
PCM Link Details_16237 – East Hampshire
PCM Link Details_18061 - Plymouth
PCM Link Details_ 26064 - Kirklees
PCM Link Details_ 28018 - Southampton
PCM Link Details_28445 - Haslingden
PCM Link Details_36296 - Havant
PCM Link Details_47243 – Newcastle Under Lyme
PCM Link Details_47964 - Haslingden
PCM Link Details_56009 - Leeds
PCM Link Details_56058 – Test Valley
PCM Link Details_57783 – Stoke-on-Trent
PCM Link Details_70007 – Stockton on Tees
PCM Link Details_73998 - Wiltshire
PCM Link Details_74456 - Derby
PCM Link Details_74590 - Oldham
PCM Link Details_ 75235 - Manchester
PCM Link Details_75258 - Southampton
PCM Link Details_75259 - Southampton
PCM Link Details_75290 - Sefton
PCM Link Details_75422 – Stoke-on-Trent
PCM Link Details_77419 - Northampton
PCM Link Details_77484 - Stafford
PCM Link Details_80428 - Gateshead
PCM Link Details_81006 - Durham
PCM Link Details_81374 - Plymouth
PCM Link Details_81388 - Leeds
PCM Link Details_99331 – Stoke-on-Trent
PCM Link Details_99332 – Stoke-on-Trent
PCM Link Details_99333 – Stoke-on-Trent
PCM Link Details_99335 – Stoke-on-Trent

Indicative modelling suggests compliance (without monitoring support)

PCM Link Details_8147 – Stoke-on-Trent
PCM Link Details_17961 – Stockton on Tees
PCM Link Details_26051 - Bolton
PCM Link Details_38230 – Stoke-on-Trent
PCM Link Details_46062 - Durham
PCM Link Details_48707 – Newcastle Upon Tyne
PCM Link Details_56062 – Cheshire West and Chester

Indicative modelling suggests exceedance

PCM Link Details_6046 - Manchester
PCM Link Details_26017 - Dudley
PCM Link Details_27711 – West Midlands
PCM Link Details_28015 - Salford
PCM Link Details_28361 - Hull
PCM Link Details_28772 – Newcastle upon Tyne
PCM Link Details_36045 - Manchester
PCM Link Details_36063 – Cheshire West and Chester
PCM Link Details_56063 - Leeds
PCM Link Details_57832 - Hull
PCM Link Details_70230 - Birmingham
PCM Link Details_73318 - Rugby
PCM Link Details_73424 - Sandwell
PCM Link Details_73773 - Stockport
PCM Link Details_73920 - Sandwell
PCM Link Details_77006 - Oldham
PCM Link Details_77007 - Oldham
PCM Link Details_81007 - Durham
PCM Link Details_81008 - Durham
PCM Link Details_81178 – Stockton-on-Tees
PCM Link Details_99614 - Manchester
PCM Link Details_99631 - Portsmouth

Nottingham compliant – stop at Phase 2

PCM Link Details – 17304 Nottingham
PCM Link Details – 37416 Nottingham
PCM Link Details – 56557 Nottingham

Phase 2 appendix A: Regional traffic model technical note

The Phase 3 (Commission No. 1) report builds on the work completed to date. The report presents updated air quality modelling, new air quality monitoring data and comes to a conclusion for each section of the Strategic Road Network (SRN) whether they exceed the annual mean nitrogen dioxide (NO₂) limit value or not and the date compliance would be achieved. For those sections which have been identified as above the annual mean NO₂ limit value a range of measures have been considered and where they can be delivered the report sets out the anticipated reduction in NO₂ concentrations.

Commission 1 Phase 3 Air Quality Report

Following completion of the Phase 3 assessment (Commission No. 1), the Joint Air Quality Unit (JAQU) asked National Highways to undertake a sensitivity analysis for 37 sections of the Strategic Road Network (SRN) using a different air quality model and the latest vehicle emission factors. The sections of road identified by JAQU had previously been modelled as just below the annual mean nitrogen dioxide (NO2) limit value of 40ug/m3. The purpose of the sensitivity test was to check if the previous modelled outcomes remain below the limit value and JAQU could be confident in approving all the findings in the Phase 3 assessment.

The report showed the updated modelling had very similar outcomes to the air quality assessment previously shared in the original Phase 3 assessment (Commission No. 1) with JAQU. This meant there was no change to the original findings set out in the repor

Final Phase 3 Addendum Report - 37 links

Monitoring data

Analytical assurance statement 1
Analytical assurance statement 2

Speed distribution

ADMS verification graphs
DMRB verification graphs

Background maps - monitoring
Background maps - PCM receptors

Audit Summary Report — 36045 — M56 Manchester — NQF
Audit Summary Report — 47964 — A56 Haslingden — NQF
Audit Summary Report — 56058 — M271 Test Valley — NQF
Audit Summary Report — 77006 — M60 Oldham — NQF
PCM Link Details_36045 - M56 Manchester NQF
PCM Link Details_47964 - A56 Haslingden NQF
PCM Link Details_56058 - M271 Test Valley NQF
PCM Link Details_77006 - M60 Oldham NQF

A1 Dunston Gateshead Traffic Management Scheme
A34 Oxford Traffic Management Scheme
A38 Plymouth Traffic Management Scheme
A50 Stoke-on-Trent Traffic Management Scheme
A66 Surtees Bridge Traffic Management Scheme
M11 Redbridge Traffic Management Scheme
M32 Bristol Traffic Management Scheme
M5 West Midlands Traffic Management Scheme

Commission 2

Commission 2 Phase 1 Air Quality Report

PCM Link Details_8280 - M4 Hillingdon

Commission 2 Phases 2 and 3 Combined Air Quality Report

PCM Link Details_16321 - M3 Southampton
PCM Link Details_26010 - M3 Blackwater Valley
PCM Link Details 48064 - M27 Southampton
PCM Link Details 70234 – M6 Birmingham
PCM Link Details 75258 – M27 Southampton
PCM Link Details 77743 – A69 Tyneside

Monitoring data

Analytical assurance statement

Receptor Location Map 16321 - M3 Southampton
Receptor Location Map 26010 - M3 Blackwater Valley
Receptor Location Map 48064 - M27 Southampton
Receptor Location Map 75258 – M27 Southampton
Receptor Location Map 77743 – A69 Tyneside

PCM qualifying feature traffic
Monitoring sites 2017 traffic

Background maps

Audit Summary Report - 16321 - M3 Southampton
Audit Summary Report - 26010 - M3 Blackwater Valley
Audit Summary Report - 48064 - M27 Southampton
Audit Summary Report - 70234 – M6 Birmingham
Audit Summary Report - 75258 – M27 Southampton
Audit Summary Report - 77743 – A69 Tyneside

Commission 3

Commission 3 Phase 1 Report

Draft SRN PCM Link Review v1
PCM Link Details _48086 - A3, Guildford
PCM Link Details _56044 - M61, Bolton
PCM Link Details_57227 - M11, Redbridge
PCM Link Details_86048 - A282, Dartford
PCM Link Details_89200 - A1, Gateshead
PCM Link Details_89315 - M621, Leeds

Commission 3 Phase 3 Report

PCM Link Details_16056 Trafford
PCM Link Details_17377 Oldham
PCM Link Details_26047 Manchester
PCM Link Details_6053 Bury
PCM Link Details_7701 Manchester
PCM Link Details_16050 Salford
PCM Link Details_26051 Bolton
PCM Link Details_26575 Tameside
PCM Link Details_27854 Tameside
PCM Link Details_ 28015 Salford
PCM Link Details_36007 Rotherham
PCM Link Details_37913 Sheffield
PCM Link Details_38230 Stoke on Trent
PCM Link Details_38661 Trafford
PCM Link Details_46583 Tameside
PCM Link Details_47243 Newcastle Under Lyme
PCM Link Details_48011 Stockport
PCM Link Details_48086 A3 Guildford
PCM Link Details_56044 M61 Bolton
PCM Link Details_57227 M11 Redbridge
PCM Link Details_57783 Stoke on Trent
PCM Link Details_6046 Manchester
PCM Link Details_73379 Manchester
PCM Link Details_73575 Portsmouth
PCM Link Details_73909 Sheffield
PCM Link Details_77007 Oldham
PCM Link Details_8340 Stoke on Trent
PCM Link Details_86048 A282 Dartford
PCM Link Details_89052 Thurrock
PCM Link Details_89200 A1 Gateshead

Phase 3 Appendix B: Monitoring

Analytical Assurance Statement 1
Analytical Assurance Statement 2

Phase 3 Appendix G: Phase 3 traffic data and emissions

Phase 3 Appendix H: Phase 3 background

PCM Link Details _6047 - Manchester
PCM Link Details_28052 - Sheffield
PCM Link Details_36045 - Manchester
PCM Link Details_60026 - Stoke-on-Trent
PCM Link Details_70271 - Manchester
PCM Link Details_77006 - Oldham

Phase 3 Appendix L: ADMS Model Networks

Phase 3 Appendix M: Wind Roses

Phase 3 Appendix N: Verification

Phase 3 Appendix O: Verification graphs

Phase 3 Appendix P: EFT v9-v10 NOx emissions

Appendix Q: Comm 3 SRN PCM link location maps

Phase 3 Appendix R: Tameside AQ study
Phase 3 Appendix R: Tameside AQ study - Annex B

PCM Link Evaluation Strategy

Following the agreement with the Joint Air Quality Unit (JAQU), a number of links have been identified as above the permissible levels.

We have developed an evaluation strategy to:

understand and report when each link is compliant
determine whether any mitigation is delivering the improvements
confirm when any mitigation can be removed whilst ensuring the section of the SRN remains compliant

Evaluation approach

Air quality monitoring to be deployed for all links confirmed as non-compliant and assessed within 10% of the limit value, i.e. (36-40µg/m³).

Monitoring to be deployed to at least one site as a minimum, but ideally three, alongside the SRN representative of qualifying feature(s).

Monitoring will continue for at least two years after the respective section of the SRN is modelled to come into compliance.

Monitored concentrations will be evaluated at 6 month intervals, (allowing 2 months for tube analysis by the labs):

mid-year review - end Aug year – covering first 6 months
annual review and report - end Feb year – calendar year annual average

Removing mitigation will be recommended when concentrations are reported below 36µg/m³.