Croydon / Planning & development
Air quality assessment in Croydon
From Norbury and Thornton Heath to the town centre, Purley Way and the borough’s southern neighbourhoods, a useful assessment connects the street setting with the actual design.
ACP provides air quality assessment, monitoring and mitigation advice for planning. We assess development emissions and future exposure alongside transport, ventilation, energy and construction.
Discuss your projectPolicy and validation
DM23, DM16 and the updated May 2026 validation list.
Monitoring and local sources
Roadside trends, diffusion tubes and data coverage.
Your assessment brief
Coordinate incoming exposure and effects on neighbours.
01 / Borough context
Start with the road, the receptor and the proposal
Norbury and Thornton Heath
London Road, the Thornton Heath corridors and local junctions feature in the council’s Focus Area context. Check road-facing occupied spaces, school uses, servicing and ventilation against the actual assessment year.
Town centre and Wellesley Road
Bring construction, delivery routes, new homes and commercial plant into one brief. Assess exposure at proposed windows and intakes separately from the development’s effect on existing neighbours.
Purley Way, Purley Cross and the south
The A23 corridor combines traffic with commercial and industrial uses. In other neighbourhoods, check the local roads, heating, extract and construction sources rather than transferring a town-centre baseline across the borough.
The whole borough remains an AQMA
Defra records Croydon’s borough-wide AQMA for annual nitrogen dioxide from 24 April 2003. The designation covers the whole borough; it does not mean every address has the same concentration.
Defra: Croydon AQMA and designation · Council delivery plan and Focus Area context
02 / Annual monitoring evidence
Read the measured trend alongside data coverage
LondonAir’s full-year objective statistics report annual NO₂ at Norbury falling from 44 µg/m³ in 2019 to 25 in 2025. Purley Way A23 has qualifying results for fewer years in the selected series.
Norbury annual NO₂
µg/m³ in the 2025 LondonAir annual table.
Diffusion tubes
The council’s public monitoring overview describes 30 NO₂ tubes.
Borough-wide AQMA
The current Defra designation dates from 24 April 2003.
Measured annual NO₂ / 2019–2025
Norbury and Purley Way A23
Rounded annual means in µg/m³ from the public LondonAir objective tables. The series describe two monitoring positions.
Norbury
CR5 · automatic roadside evidence
25 µg/m³ in 2025
LondonAir annual objective tables; gaps remain unfilled.
Purley Way A23
CR7 · automatic roadside evidence
18 µg/m³ in 2024
LondonAir annual objective tables; gaps remain unfilled.
View annual values and missing years
| Year | Norbury CR5 | Purley Way CR7 |
|---|---|---|
| 2019 | 44 | 29 |
| 2020 | 35 | 24 |
| 2021 | 39 | 26 |
| 2022 | 37 | — |
| 2023 | 32 | — |
| 2024 | 27 | 18 |
| 2025 | 25 | — |
A dash means the annual objective table reports no or insufficient valid results, rather than zero pollution. The service normally excludes results below 90% annual valid data capture. The charts retain those gaps and do not estimate missing years.
Norbury annual statistics and capture rule · Purley Way A23 annual statistics
03 / Monitoring methods and exposure
Use the right measurement for the question
| Evidence | What it tells you | Check before use |
|---|---|---|
| AutomaticNorbury CR5 | 2025 annual NO₂: 25 µg/m³. | Road distance, year, receptor height and the published capture rule. |
| AutomaticPurley Way CR7 / Park Lane CR9 | The selected 2025 tables report no or insufficient valid results. | Do not treat a missing annual value as a compliant result or fill it with a live reading. |
| PassiveDiffusion tubes | Local monthly and annual nitrogen-dioxide evidence. | Location, year, bias adjustment, annualisation and distance to relevant exposure. |
| ParticlesPM₁₀ and PM₂.₅ | Separate particle evidence at suitable instruments, including Park Lane and the Norbury Manor background record. | Pollutant coverage, averaging period and completeness for the chosen year. |
Reference network and sensors
The council overview describes three automatic sites and 30 diffusion tubes. Additional Breathe London sensors offer local NO₂ and PM₂.₅ context. Keep indicative sensor readings separate from reference-method annual statistics.
Traffic is only part of the source mix
The council’s delivery plan also considers building combustion, wood burning, industrial activity and construction. Scope the pollutant suite against the actual process and nearby receptors.
Background and nearby façades
A roadside monitor and an urban-background site serve different purposes. Review the Defra background grid without double-counting explicit sources, then assess windows, outdoor spaces and intakes at the relevant positions.
Use dated annual data and check the local report
Choose the monitoring year and quality-assurance record before model verification or a baseline comparison. Keep recent provisional readings separate from ratified annual evidence and check diffusion-tube results in the council’s current annual report.
Council monitoring overview and annual-report route · Breathe London local sensors · Defra local-authority dashboard
04 / Policy and submission
Use DM23 with the current validation list
Adopted Local Plan 2018
DM23 addresses development causing or affected by air, dust, noise and vibration pollution. It requires Air Quality Neutral development, mitigation and protection of users and neighbours. DM16 provides the wider healthy-community context.
Read DM23 and paragraphs 8.16–8.18 · Adopted Local Plan gateway
May 2026 validation requirements
The updated list identifies an air-quality assessment for major applications. It asks applicants to address emissions and exposure at design stage and identify mitigation. The application inventory should explain how each relevant requirement is met.
Current submission and validation gateway · Published May 2026 list, printed page 20
Local air-quality Interim Policy Guidance
The council still links its guidance on assessment situations and methods. It is older guidance with superseded policy and technical references. Retain the local source-and-receptor questions, using current London policy and technical methods for the report.
Council guidance gateway · Read the published Interim Policy Guidance
Delivery Plan 2024–2029
The current council gateway links this plan for transport, development, construction and exposure actions. Use the actions relevant to the project, while keeping policy requirements and the proposed mitigation evidence distinguishable.
Council action-plan gateway · Air Quality Delivery Plan 2024–2029
London Plan SI1: separate assessment from benchmarks
Impact assessment considers operational and construction effects plus incoming exposure. Air Quality Neutral uses the applicable building and transport benchmarks. Apply Air Quality Positive to the relevant large-scale design approach, rather than treating these as interchangeable labels.
The London air-quality hub and tools help organise the regional policy and borough evidence.
05 / Design and delivery
Assess incoming exposure and outgoing emissions
Place new occupants carefully
Map bedrooms, classrooms, gardens and intake positions against roads, plant and neighbouring activities. Coordinate ventilation and acoustic requirements before the design is fixed.
Assess the submitted operation
Identify traffic, deliveries, combustion plant, restaurant extract and operating hours. Model the relevant pollutants and discharge conditions where needed, using the same equipment and plans as the submission.
Control construction effects
Use the demolition, earthworks, construction and trackout risk assessment to define controls and monitoring. Align the construction logistics plan, access routes, machinery requirements and sensitive-neighbour response.
For commercial kitchens, coordinate odour treatment, air discharge and fan noise in one drawing set. Where a credible pathway reaches an ecological receptor, include the appropriate ecological air-pollution assessment question.
Local delivery / Construction evidence
Make the construction controls usable on site
Croydon’s published delivery plan describes pollution-team review of construction logistics plans and enforcement where required. Its construction actions address fugitive dust, machinery, materials transport and the movement of waste.
For a project, link each assessment recommendation to a control, monitoring approach or drawing. Identify the sensitive neighbours, who reviews the results and the response to a trigger, keeping the obligations consistent with the actual planning condition.
Read the council’s development and construction actions · Local building-development and ventilation guidance
06 / Interactive project checklist
Croydon evidence planner
Answer five questions to organise the assessment brief. Unanswered points remain visible so you can identify the information still needed.
Answers stay in this page. The planner organises evidence and does not decide planning requirements or certify compliance.
Project examples / Scope and design
Connect the proposal with the evidence it needs
Use the local setting and proposed operation to identify the assessment inputs and the decisions they support.
New homes beside London Road or Purley Way
Inputs: road-facing rooms, gardens, intake heights, traffic assumptions and representative baseline evidence.
Design decisions: layout and ventilation options informed by incoming exposure and the development’s own emissions.
A town-centre mixed-use scheme or new plant
Inputs: servicing, traffic, equipment, operating hours, flues and existing neighbouring receptors.
Design decisions: plant and discharge design, transport measures and the applicable Neutral evidence.
Construction near homes or schools
Inputs: demolition and earthworks, access and trackout routes, machinery and the programme.
Design decisions: dust controls, monitoring and logistics commitments tied to the actual construction plan.
07 / Emerging policy and future evidence
Track the Local Plan review without pre-empting adoption
The council is progressing its partial Local Plan review. As checked on 20 October 2026, the forward decision record schedules consideration of adoption for 18 November 2026, dependent on receipt of the Inspector’s report. A scheduled decision does not adopt the plan.
Use the adopted 2018 plan alongside applicable London policy, keeping emerging provisions clearly identified. Check for later monitoring publications, changes to the delivery plan and new guidance when fixing the submission evidence.
Council Local Plan review gateway · Scheduled adoption decision and stated dependency
Distinguish current assessment criteria from consultation proposals, future particle targets and health-based guidelines. Use the relevant Defra background edition, current GLA methods and applicable IAQM guidance for the actual assessment.
08 / Send what you have
Start your Croydon air quality brief
Send the information available now:
- Site address, proposed use and planning reference.
- Plans showing occupied rooms, gardens and air intakes.
- Council comments, validation request and conditions.
- Traffic, servicing, parking and energy information.
- Plant and kitchen-extract equipment details.
- Demolition, construction, access routes and programme.
- Previous reports and changes since their preparation.
We can then identify the assessment workstreams and inputs needed to support the submission.
Questions / Local answers
Croydon air-quality FAQs
Is the whole of Croydon an Air Quality Management Area?
Yes. Defra records the whole borough as an AQMA for annual nitrogen dioxide from 24 April 2003. The designation does not mean every location has the same concentration or the same assessment requirements.
What does Croydon Local Plan DM23 require?
DM23 addresses development that causes or is affected by air, noise, dust or vibration pollution. It requires Air Quality Neutral development, appropriate mitigation and protection of site users and surrounding land uses.
Which validation list should my application use?
The council’s submission gateway links its May 2026 Local Validation List. It identifies an air-quality assessment for major applications and asks for emissions and exposure to be addressed at design stage. Check the current gateway when submitting.
Does Croydon use diffusion tubes as well as automatic monitors?
Yes. The council’s public overview describes 30 nitrogen-dioxide diffusion tubes and three automatic sites. Check the actual measurement year, tube locations, bias adjustment and annualisation in the current annual report before assessment use.
What do the latest full-year Norbury statistics show?
LondonAir’s annual objective table reports a rounded annual NO2 mean of 25 µg/m³ in 2025, compared with 44 in 2019. These results describe the monitor and do not establish exposure at every proposed window or intake.
Why are there gaps in the Purley Way chart?
The public annual objective table reports no or insufficient valid results for the missing years. It normally excludes annual results below 90% valid data capture. A gap is not a zero concentration and has not been interpolated in this chart.
Can I follow every method in the older Interim Policy Guidance?
Use it to identify the local assessment questions, but check its older policy and technical references against current requirements. The report should use appropriate current GLA, Defra and IAQM methods for the agreed scope.
Has Croydon already adopted the reviewed Local Plan?
As checked on 20 October 2026, the forward record schedules an adoption decision for 18 November 2026, dependent on the Inspector’s report. A future scheduled decision is not adoption; keep the emerging review separate from the adopted plan.
Croydon / Your next step
Discuss your air quality project
Send the site, proposal and planning stage. Include any council request and programme constraints so ACP can identify the assessment steps.
Your details are handled under our privacy policy.
Sources / Local and London evidence
Croydon sources and further reading
- Council monitoring network and annual-report route
- LondonAir Norbury annual statistics
- LondonAir Purley Way A23 annual statistics
- LondonAir Park Lane annual statistics
- Defra borough-wide AQMA
- Adopted Local Plan gateway
- Local Plan DM23 and local air-quality context
- Current submission and validation gateway
- May 2026 validation list
- Local air-quality Interim Policy Guidance gateway
- Current air-quality action-plan gateway
- Air Quality Delivery Plan 2024–2029
- Local Plan review gateway
- Scheduled adoption decision
- Breathe London local sensors
- Defra local-authority dashboard
- London air-quality policy, borough finder and tools