London ULEZ Air Quality Assessment
Specialist air quality consultants for planning applications across the London Ultra Low Emission Zone. Defensible assessments for developments in all 32 boroughs and the City of London, built on the most current TfL and DEFRA evidence.
Planning in the ULEZ — What the Evidence Shows
Since the August 2023 expansion, the London Ultra Low Emission Zone covers the whole of Greater London out to the M25 boundary — every London borough, every postcode inside the M25, every kerbside on which a sensitive receptor might face traffic emissions from a new development. The implications for planning applications are real but often misunderstood. ULEZ does not waive the need for an air quality assessment; it changes the baseline assumptions that the assessment is built on.
Malcolm Pounder CEnv MIAQM has prepared air quality assessments for planning applications across central London, inner London and outer London boroughs. We use the most recent DEFRA PCM background maps, calibrate against TfL roadside and London Air Quality Network (LAQN) monitoring stations, and reflect the steep decline in roadside NO2 that has followed each phase of ULEZ rollout — the 2019 inner ULEZ, the 2021 North/South Circular extension, and the 2023 London-wide expansion. Where appropriate we present opening-year and future-year scenarios so that decision-makers see how the development sits in a trajectory of improving air quality.
We work directly with planning consultants, architects, developers and EIA teams across London, and we engage early with borough environmental health officers when the project warrants it. From a single residential infill scheme in Camden to a major mixed-use development in Tower Hamlets or an industrial allocation in Hounslow, we deliver assessments that London local planning authorities accept.
ULEZ-Aware Air Quality Assessments
Each of these elements is set up specifically for London planning — reflecting current TfL evidence, GLA policy and borough-level validation requirements.
ULEZ-Calibrated Baseline
Baseline NO2, PM10 and PM2.5 built from the most recent DEFRA PCM background maps and calibrated against nearby London Air Quality Network (LAQN) monitoring sites. We document the trend evidence from each ULEZ rollout phase so the baseline holds up to scrutiny.
AQMA & ULEZ Overlay Mapping
Every London borough has at least one declared AQMA, and most cover the whole borough. We map your site against borough AQMA boundaries, ULEZ boundary, GLA Focus Areas and any local air quality SPD designations to set the policy context with no ambiguity.
Opening-Year & Future-Year Modelling
ADMS-Roads dispersion modelling for opening-year and a defensible future-year scenario, reflecting projected fleet turnover under ULEZ. We are careful not to over-claim improvements and present results conservatively against the AQS objectives.
Borough-Tailored Reporting
Reports tailored to the specific borough's validation checklist and SPD — whether that's a Westminster or Camden air quality SPD, an Islington Air Quality Positive expectation, or a Hounslow construction dust assessment requirement. We have read every London borough's policy framework.
All 32 London Boroughs Covered
ULEZ covers the entire administrative area of Greater London, so every planning application across the 32 boroughs and the City of London is potentially affected. We routinely work across all of them.
Common triggers are residential schemes within an AQMA, developments on or near a busy classified road, mixed-use schemes generating significant trip numbers, hospitality with combustion or kitchen extract, and any scheme where the borough SPD requires Air Quality Neutral or Air Quality Positive.
- Residential within an AQMA
- Mixed-use on classified roads
- Hospitality with kitchen extract
- Combustion plant (CHP, gas boilers)
- Logistics and last-mile depots
- Student accommodation
- Build-to-rent developments
- EIA-scale regeneration schemes
Frequently Asked Questions
How does ULEZ affect my planning application's air quality assessment?
ULEZ has changed the air quality baseline for planning applications across all 32 London boroughs. Since the August 2023 London-wide expansion to the M25 boundary, the vehicle fleet across Greater London has shifted progressively towards lower-emission Euro 6 diesel and Euro 4 petrol vehicles. This means NO2 background concentrations are on a downward trajectory, and your assessment needs to reflect that. We use the most recent DEFRA PCM background maps and TfL monitoring data to set defensible baselines that London local planning authorities and environmental health officers accept.
Does a development inside ULEZ still need an air quality assessment?
Yes. ULEZ reduces vehicle emissions but does not remove the need for an air quality assessment. London planning policy — particularly the GLA London Plan 2021 Policy SI 1 and SI 8, plus borough-level Local Plan policies — still requires assessments for residential development on busy roads, developments within or adjacent to an AQMA, schemes generating significant trip numbers, and any proposal involving combustion plant. ULEZ changes the assumptions in the assessment; it doesn't waive the requirement.
How does ULEZ affect background NO2 concentrations?
ULEZ has accelerated the decline in roadside NO2 concentrations across London. TfL's monitoring shows roadside NO2 in central London fell sharply after the 2019 inner ULEZ launch, and inner-ring boroughs saw further reductions after the 2021 North/South Circular expansion. Background NO2 across most of Greater London now sits below the 40 µg/m³ annual mean objective, and DEFRA's PCM background projections continue to show year-on-year reductions. We always use the most current PCM dataset and cross-check against local diffusion tube and AURN data.
Should my air quality assessment assume declining trends because of ULEZ?
Assessments should reflect the most up-to-date DEFRA PCM background projections, which already incorporate national fleet turnover and the impact of clean air zones including ULEZ. However, planning officers in London expect a precautionary approach — we typically present results for both the opening year and a future scenario, and we are careful not to claim unrealistic future reductions that depend on uncertain policy continuation. The IAQM/EPUK 2017 guidance on land-use planning air quality remains the leading methodology document.
Do all London boroughs treat air quality the same way?
No — although the GLA London Plan provides a consistent strategic framework, each of the 32 London boroughs and the City of London applies its own Local Plan, validation checklist and supplementary planning guidance. Boroughs like Westminster, Camden, Islington, Hackney, Tower Hamlets and Southwark have particularly detailed air quality SPDs and validation requirements, including Air Quality Neutral and Air Quality Positive expectations. We tailor every assessment to the specific borough's requirements and engage early with their environmental health team where helpful.