Air quality neutral requirements in London

Air quality neutral is a London Plan requirement, not a national one, and it applies to development across Greater London regardless of whether the site sits in an Air Quality Management Area. Policy SI 1 of the London Plan requires development proposals to be at least air quality neutral, which means the emissions associated with the completed development must not exceed published benchmarks. Air quality neutral london compliance is a calculation, submitted as part of the air quality evidence, and it is separate from the assessment of the scheme's effect on local concentrations.

Boroughs check it. Failing to address it is a routine reason for a further information request.

What the policy asks of a scheme

The requirement bites on the finished, operational development rather than on the construction period. Construction dust and emissions are dealt with separately, usually through a dust risk assessment and a construction management plan.

Two emission sources are counted. Building emissions, meaning the combustion plant serving the development, chiefly heating and hot water and any standby generation. And transport emissions, meaning the vehicle movements the completed development generates.

The test compares the scheme's emissions against benchmarks for its use class and location. Where the scheme is below the benchmark it is air quality neutral. Where it is above, the shortfall has to be addressed through design changes, and where that is not possible the borough will look for offsetting or mitigation, with the acceptability of that varying between authorities.

The Greater London Authority publishes London Plan Guidance on air quality neutral setting out the benchmarks and the calculation method. It has been revised since the plan was adopted, so work from the current version rather than from a precedent document on a previous scheme.

Building and transport emissions benchmarks

Benchmarks are expressed per unit of floor area per year, separately for nitrogen oxides and for particulate matter, and separately by use.

For building emissions, the variables that decide the answer are the heating strategy, the fuel and the equipment specification. An all electric scheme with heat pumps has no combustion emissions at all from space heating, which removes most of the building emissions term in one decision. A gas fired scheme has to meet the benchmark through ultra low emission boiler specification, and combined heat and power is difficult to reconcile with the policy on smaller schemes because its emissions per unit of heat are higher.

For transport emissions, the variables are trip generation, mode share and the fleet assumed. The figures come from the transport evidence, so the air quality consultant and the transport consultant have to be working from the same trip rates and the same parking provision. Where they are not, a borough officer will notice.

Two practical points. Standby generators are often forgotten at the calculation stage and then appear on the mechanical drawings, so agree the testing regime and the emissions specification early. And kitchen extract for food and drink uses sits outside the neutral calculation but is assessed in its own right, which is the subject of a separate Ventilation and Extraction Statement.

Running the calculation

The sequence is mechanical once the inputs are fixed.

1. Establish the floor areas by use class, using the same areas as the application form and the schedule of accommodation.
2. Take the benchmark values for those uses from the current guidance.
3. Calculate building emissions from the proposed plant, with the specified emission rates and the assumed operating hours.
4. Calculate transport emissions from the trip generation in the transport evidence, with the fleet and emission factor version stated.
5. Compare each against the benchmark and report the outcome separately for nitrogen oxides and particulates.
6. Where a benchmark is exceeded, set out the design changes considered and the residual position.

State the version of every input. The emission factor toolkit, the benchmark document and the trip rate source all get updated, and a calculation that does not say which version it used cannot be checked by the officer or defended at appeal.

Air quality positive for larger schemes

Air quality positive applies to major development that is subject to the plan's requirements for larger schemes, including masterplans and development in opportunity areas. It is a different exercise, and treating it as air quality neutral with a longer report is the commonest mistake.

Neutral is arithmetic about emissions. Positive is about design decisions that reduce exposure and improve air quality across the site: where the most sensitive uses are placed relative to the busiest roads, where school playgrounds and play space sit, how building massing affects street level dispersion, which routes pedestrians and cyclists are given, and how the scheme's plant and servicing are arranged.

An air quality positive statement should therefore be produced with the design team rather than after them. The useful version explains the options the layout considered and why the chosen arrangement reduces exposure. The useless version lists the same mitigation measures every scheme proposes and attaches them to a completed masterplan.

What to submit at application

Boroughs differ on format, and most want the neutral assessment inside the air quality report rather than as a separate document. A submission that works usually contains:

• an Air Quality Assessment covering local air quality effects and exposure of new occupiers
• the air quality neutral calculation, with the benchmark version and all input assumptions stated
• a short table showing building and transport emissions against the benchmarks for nitrogen oxides and particulates
• the plant specification, including emission rates in the units the benchmarks use
• a dust risk assessment for the construction phase
• an air quality positive statement where the scheme falls within that requirement

Put the results table at the front. An officer who can read the outcome in one table without reconstructing the calculation will process the application faster, and the same table is what ends up quoted in the committee report.

Where boroughs add their own requirements

The London Plan sets the floor. Local plans add to it, and the additions are where schemes get caught.

Several boroughs operate their own air quality planning guidance with tighter expectations: emission specifications below the London-wide figure, restrictions on solid fuel appliances, requirements for electric vehicle charging above the plan minimum, or a local position on offsetting contributions. Air Quality Management Area coverage brings its own local expectations, particularly around exposure of new residential occupiers to roadside concentrations.

Non-road mobile machinery used on London construction sites is subject to emission standards enforced through conditions, with stricter standards in the central zone. That is a condition compliance matter rather than a submission requirement, but the plant hire implications are worth knowing before a programme is priced.

Check the borough's own guidance page as well as the local plan policy. Where an authority has published a validation checklist item for air quality, follow its wording precisely, because that is what the validation officer reads.

Conditions and what happens after completion

Expect conditions tying the development to the emissions specification relied on in the assessment. Typical wording requires plant to be installed with emission rates no higher than those assessed, evidence of compliance before occupation, and commissioning records to be submitted.

Where offsetting was agreed, that usually sits in a planning obligation rather than a condition. Where an air quality positive statement was submitted, some boroughs condition the specific layout and exposure measures relied on.

The gap that causes problems later is substitution. Plant gets value engineered between permission and installation, and a boiler with a higher emission rate than the one assessed is a breach of condition that surfaces at the discharge stage or at handover. Keep the assessed specification in the procurement documents, and if the specification has to change, discharge the condition on the revised figures rather than hoping nobody compares them. Complaints after occupation are a separate matter again, dealt with in our note on statutory nuisance after planning permission is granted.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required, and air quality work of this kind should be prepared or reviewed by a suitably qualified air quality specialist. This is general guidance and not legal advice, so check the position with your local planning authority or a qualified professional before relying on it.