Merton / Planning, sources and design
Air quality assessment in Merton
Prepare your Merton air quality assessment around local exposure, the adopted policy and the sources your project introduces. ACP supports planning evidence, monitoring and coordinated mitigation for major schemes, conversions and smaller commercial works.
Connect Merton’s dedicated air-quality guidance with practical design and a clear submission.
Discuss your projectAdopted local requirements
P15.10, the 2021 SPD and updated validation checklist.
Local monitoring context
Town-centre tubes, automatic stations and receptor adjustments.
Combined project evidence
Exposure, kitchens, construction and energy considered together.
01 / Local context
Town centres, new exposure and smaller-site sources
Merton’s town centres and busy roads create different exposure settings from its background and open-space locations. The council’s latest linked annual report highlights Wimbledon Hill, Colliers Wood and Mitcham town-centre sites. An assessment should connect these local sources with the proposed use and occupied façades.
Wimbledon Hill and the town centre
Use the kerbside tube history with its receptor distance. Street-level homes, conversions and ventilation intakes can raise exposure questions even where the proposal adds little traffic.
South Wimbledon and Colliers Wood
Review Merton Road, High Street, local traffic, servicing and relevant commercial sources together. Keep the source inventory consistent with the transport and energy brief.
Morden and Mitcham
Morden Civic Centre provides an automatic NO₂ history, while tubes extend coverage along local roads and near schools. A low urban-background reading does not resolve every roadside façade.
Kitchens and constrained basement works
The dedicated SPD expressly includes smaller sources such as commercial kitchens and basement construction. Coordinate cooking, filtration, extract and fan noise; for excavation, document dust, access and material handling.
Whole-borough AQMA: Defra records Merton’s designation from 17 November 2003 for NO₂ and PM₁₀. Distinguish that designation from Air Quality Focus Areas and the assessment question for the site. Check the Defra register.
02 / Monitoring and trends
Read roadside results at the right position
The report published on 30 May 2025 covers 2024. Both plotted sites were lower than in 2018. Wimbledon Hill remained above 40 µg/m³ at the tube, while Merton Road fell below it. Capture was 92.5% and 90.6% respectively. These observations do not isolate the effect of a single intervention.
Annual NO₂ / 2018–2024
Two roadside histories, with different exposure checks
Annual objective: 40 µg/m³
Wimbledon Hill
Tube 18 · kerbside
41.7µg/m³2024 annual mean
Merton Road
Tube 21 · roadside
34.7µg/m³2024 annual mean
Shared 0–80 µg/m³ scale · reported annual measurements at each monitoring location.
Read the annual values
| Year | Wimbledon Hill tube 18 | Merton Road tube 21 |
|---|---|---|
| 2018 | 66 | 69 |
| 2019 | 65 | 63 |
| 2020 | 57 | 52 |
| 2021 | 58 | 59 |
| 2022 | 52 | 51 |
| 2023 | 44.8 | 44.7 |
| 2024 | 41.7 | 34.7 |
Monitor and receptor are different positions. The distance-calculation table on page 81 predicts 30.7 µg/m³ at the Wimbledon Hill receptor, compared with the measured tube value of 41.7. The report therefore identifies one tube exceedance but no exceedance after its relevant-exposure adjustments. This does not settle exposure at a different proposed façade. Read the results and adjustment table.
03 / Network and interpretation
Keep coverage, capture and new channels clear
| 2024 evidence | Result / capture | Interpretation |
|---|---|---|
| Morden Civic Centre ME9 · NO₂ | 21.3 µg/m³ / 99.1% | Roadside automatic; 2021 has insufficient valid results |
| Merton Road ME2 · PM₁₀ | 20.8 µg/m³ / 73.1% full-year | Annualised; monitoring-period capture 87.1% |
| Urban-background tube 31 | 11.7 µg/m³ / 100% | Background setting; not a substitute for kerbside exposure |
Diffusion-tube coverage
The report describes 62 NO₂ diffusion-tube locations, including school and town-centre settings. Triplicate tubes at the Civic Centre support the local co-location study. Read site-specific capture and the bias-adjustment method.
A changing automatic network
The 2024 results relate to two stations. The report’s May 2025 update lists the wider four-site programme at Merton Road, Civic Centre, Mitcham West and Plough Lane, with Civic Centre then awaiting permission. Keep that update separate from the 2024 results.
The expanded programme includes PM₂.₅ and additional pollutant channels. Check the current station and ratification record before using a new series. Use Defra borough data with representative local observations and backgrounds; preserve the 2021 ME9 and 2023 ME2 gaps rather than inventing a continuous record.
04 / Planning requirements
Connect adopted policy, Positive design and validation
Adopted P15.10: a wider pollution policy
The Local Plan was adopted on 20 November 2024. P15.10 addresses air, noise, odour and other environmental effects, protecting existing and future occupiers. It requires assessment for major schemes and other specified exposure or emissions situations. Policy P15.10, pages 510–512.
Positive and Neutral are distinct
P15.10(5) requires major developments in Merton, and development briefs for large-scale EIA development, to achieve an Air Quality Positive approach. Part (6) requires all development to be at least Neutral. Include design-stage Positive evidence where the local policy applies.
Dedicated Air Quality SPD
Adopted on 22 June 2021, the SPD covers major development, new exposure including conversions, and smaller sources such as kitchens and basement works. Use its local scope with the adopted 2024 policy and current technical guidance. Adoption and document.
Updated validation checklist
Entries 52–53 separate AQA from Neutral evidence. AQA covers major schemes and other potentially significant effects. Neutral has a simplified minor-development route and an assumption for proposals without added emissions sources. Entries 50–51 also address acoustics and kitchen extraction. Pages 31–32.
Use the London air-quality guide and tools for the wider framework, while retaining Merton’s specific Positive policy scope in the project brief.
05 / Assessment and design
Four Merton settings. Four practical briefs.
These illustrative briefs show how local evidence can shape a proposal before the layout, plant and construction programme are fixed.
Wimbledon Hill: street-level homes
For a conversion beside a busy frontage, plot the proposed windows, occupied rooms and air intakes against road distance and height. Use the tube history and receptor calculation as context, then test whether either position represents the new façade. Coordinate ventilation with overheating and acoustic design.
Useful assessment outputA receptor plan and exposure-led layout or ventilation recommendations, with the assumptions recorded.
Colliers Wood: a phased major scheme
Consider homes occupied while later works continue, construction access and servicing along the High Street and Merton Road setting. Record how design choices reduce exposure and emissions under Merton’s Positive requirement. Keep impact modelling and Neutral calculations identifiable alongside that design evidence.
Useful assessment outputA phase-by-phase receptor and emissions brief, linked to the transport, energy and occupation programme.
Mitcham: a kitchen below homes
For an illustrative commercial kitchen beneath flats, establish cooking methods, hours, extract flow, odour control and discharge position before choosing equipment. Map nearby opening windows and intakes. Coordinate fan noise, maintenance access and servicing with the same operating assumptions.
Useful assessment outputAn extract and odour brief coordinated with acoustics and the proposed elevations.
Morden: constrained basement works
For excavation beside occupied houses, identify dust-generating stages, material storage, vehicle movements and nearby receptors. Match proportionate controls to the working space and programme. Carry the same assumptions into the construction method statement and traffic management plan.
Useful assessment outputA construction dust risk assessment and practical controls tied to site access and sequencing.
Different evidence for different planning questions
Merton’s June 2026 validation checklist separates kitchen extraction (entry 51), AQA (52) and Neutral evidence (53). Basement proposals also have specific entries for impact assessment, construction method and traffic management (64–66). Use the relevant combination for the proposal; a Neutral result alone does not resolve new exposure, odour or construction effects.
Council validation checklist, pages 31–32 and 37–38 · Air Quality SPD, assessment, design and construction chapters.
P15.10 also addresses combustion and decentralised energy. Where emissions could affect habitats, coordinate source and traffic assumptions with ecological assessment. Consider greening alongside source and exposure controls.
Coordinate air quality, odour and noise when a proposal needs combined evidence.
06 / Interactive project checklist
Merton evidence planner
Answer five questions to organise the assessment brief. Choose “Not sure yet” where information is missing; those points remain visible in your results.
Answers stay in this page. The planner organises evidence; it does not certify compliance or decide planning requirements.
07 / Current changes
Use the adopted plan and track newer evidence
The adopted 2024 Local Plan is the starting point even though an older council overview still refers to preparing a replacement plan. Use the dated adoption page and adopted chapter, with the updated validation checklist.
The annual report describes a pending 2025–2030 action plan, while the current reporting gateway still links the 2018–2023 plan. Check a successor’s adoption before treating its proposals as current commitments. Keep new monitoring channels, locations and measurement periods clearly labelled. Current report and plan library.
Review current GLA, Defra and IAQM editions for the submission date. Maintain distinct impact, Neutral and locally applicable Positive workstreams, particularly as energy, transport and design assumptions change.
Technical guidance: checked 23 October 2026
The GLA’s adopted Neutral guidance includes a simplified minor-development route. Read it alongside Positive guidance and Merton’s own policy scope. Defra’s PM₂.₅ interim planning guidance asks for design-stage consideration of emissions and exposure.
IAQM lists the 2017 planning guidance and 2024 construction-dust guidance while updates are in progress. Its estimated consultation dates do not establish that a replacement has been published. The March 2026 EOR roadmap targets the end of 2027; current environmental-assessment legislation and guidance continue until the new system is implemented. Recheck published editions and transition provisions when scoping and submitting the project.
Common questions / Local answers
Merton air-quality FAQs
Is all of Merton within an AQMA?
Yes. The whole-borough designation dates from 17 November 2003 and covers NO2 and PM10. AQMA status, Focus Areas and actual receptor exposure are related but distinct checks.
Which Local Plan policy applies?
Use P15.10 in the Local Plan adopted on 20 November 2024. It covers air quality and wider pollution, including effects on existing and future occupiers. Read it with the 2021 Air Quality SPD and current validation checklist.
Does Merton require an Air Quality Positive approach?
P15.10(5) requires major developments in Merton, and development briefs for large-scale development subject to EIA, to achieve an Air Quality Positive approach. Keep that design evidence distinct from the Neutral assessment required under part (6).
Can a small scheme need air-quality evidence?
Yes. The dedicated SPD includes new exposure through conversions and smaller sources such as commercial kitchens and basement works. Match the assessment to the actual emissions, occupied receptors and applicable policy.
What do the latest linked monitoring results cover?
The report published on 30 May 2025 covers 2024. Wimbledon Hill tube 18 recorded 41.7 µg/m³, while Merton Road tube 21 recorded 34.7 µg/m³. Capture was 92.5% and 90.6% respectively.
Why is Wimbledon Hill adjusted below 40 at the receptor?
The tube and receptor are at different distances from the road. The report predicts 30.7 µg/m³ at the assessed receptor from a tube value of 41.7. A different proposed façade needs its own representative exposure check.
Does Merton monitor particles as well as NO2?
Yes. The 2024 report includes PM10 at Merton Road ME2, with an annualised mean of 20.8 µg/m³ and 73.1% full-year capture. Its network expansion update includes PM2.5; check current station and quality records before using a new series.
Can the Neutral calculation replace an impact assessment?
No. Neutral compares building and transport emissions with benchmarks. Impact assessment considers local concentration changes and exposure. The validation checklist permits combined documentation while keeping the evidence for each question identifiable.
Merton / Your next step
Discuss your air quality project
Tell us what you are proposing and where you are in the planning process.
What to include
- Site and proposal. Address or postcode, proposed use and approximate number of homes or floorspace.
- Planning stage. Application reference, any Merton Council request or condition, and your target date.
- Local setting. Road exposure, occupied rooms, ventilation, energy plant and construction phases.
- Existing information. Mention available drawings, previous air quality reports and traffic or plant details.
Start with what you have. You can email drawings or council correspondence using the address below.
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Evidence / sources checked 23 October 2026
Merton guidance and sources
The council gateways, adopted policy, SPD and updated validation checklist were rechecked on 23 October 2026. Detailed monitoring review from 20–21 October is retained; the Wimbledon Hill and Merton Road values and receptor adjustment were cross-checked again. The latest council-linked annual report remains the 2025 report covering 2024 measurements.
- Council action-plan and annual-report gateway
- 2024 monitoring: report published 30 May 2025
- Adopted Local Plan: November 2024
- Policy P15.10: adopted chapter 15, pages 510–512
- Air Quality SPD adoption and scope
- Adopted Air Quality SPD, June 2021
- Current updated validation checklist
- Defra AQMA register: Merton
- Defra local-authority dashboard
- GLA Air Quality Neutral guidance: adopted February 2023
- GLA adoption decision: Neutral and Positive guidance
- IAQM published guidance and update status
- Defra PM₂.₅ interim planning guidance
- Environmental Outcomes Reports: roadmap, updated March 2026