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Planning and air quality

Date updated: 11/10/2023

Air Quality Supplementary Planning Document (SPD)

The Air Quality Supplementary Planning Document is for developers to use to ensure construction and demolition works minimise emissions of air pollutants.

The SPD provides detailed guidance relating to the London Plan Air Quality Policies and the City of London Corporation's Local Plan Air Quality Policies

City of London Air Quality SPD PDF (2.3MB)
Date submitted: 11/02/22

 Pre planning air quality checklist 

Requirement Summary Further Detail Relevant Policy and Guidance

Air Quality Positive Statement

Air Quality Positive Statements are required for development sites subject to an EIA. They are encouraged for major developments.

The Air Quality Positive Statement must consider what measures have been taken during the design stages to achieve the best possible outcomes for air quality. These should include design and layout, transport, energy and innovation and future proofing.

Developments subject to an EIA will be required to submit detailed Air Quality Positive Statements.

Policy HL2 of the draft City Plan

Policies SI1 Improving Air Quality (C) and Policy SD4 CAZ (D) of the London Plan

London Plan Guidance: Air Quality Positive

Air Quality Neutral Assessment

All developments, unless specifically excluded in the London Plan Guidance, are required to submit an Air Quality Neutral Assessment.

There is a simplified assessment for minor development.

Both building and transport emission benchmarks should be met to achieve air quality neutral requirements.

Where developments are phased, the entire development should be Air Quality Neutral and at the completion of each phase.

For minor developments applicants should provide a statement that either the development is excluded, or an assessment based on the simplified procedure for the benchmarks has been undertaken.

Policy HL2 of the draft City Plan

Policies SI1 Improving Air Quality Part B(2)(a) and E of the London Plan

London Plan Guidance: Air Quality Neutral

Air Quality Assessment

Major developments which:

are within 50m of sensitive use (if the development itself is a significant source of air pollution e.g., large combustion plant)

create a significant increase in traffic

expose sensitive or a high number of people to air pollution (schools, hospitals and >75 residential properties)

create exposure to poor air quality for long periods of the day

require an EIA

include a process that requires Environmental Permitting, including Medium Combustion Plant



For major developments, a preliminary assessment of local air quality should be carried out before designing the development to inform the design process.

Air quality assessments should: demonstrate that the development will:

not lead to further deterioration of existing poor air quality

not create any new areas that exceed air quality limits

not lead to a delay in compliance with targets

not create unacceptable risk of high levels of exposure

Major developments are defined as 10 or more dwellings or over 1000 square metres floor space or the site area is 1 hectare or more

Policy HL2 of the draft City Plan

London Plan Policy SI1 Improving Air Quality Part B1 B2 (c)

Combustion Plant

Submit details of all combustion plant on site including:



Combined heat and power

Details should include size, fuel, emissions levels, and location of flue.

Policy HL2 of the draft City Plan

London Plan Policy SI2

GLA Energy Assessment Guidance 2020

Standby Generators

All developments proposing generators using carbon-based fuels (generally diesel)

Alternatives to diesel generators, designed to be used in an emergency, should be investigated at the design stage.

Consideration should be given to:

a secondary electrical power supply to negate the need for a generator

battery backup

alternatively fuelled generators such as gas fired or hydrogen.

Testing of generators should be limited.


Policy HL2 of the draft City Plan

Combustion flues, including generators

Minimum requirements:

1m above highest roof

3m above general access areas

Away from air intakes

Location plan required


Furnaces burning liquid or gaseous matter at a rate of 366.4 kilowatts require a Chimney Height Approval.

The calculated chimney height can conflict with requirements of planning control and further mitigation measures may need to be taken to allow installation of the plant.

Policy HL2 of the draft City Plan

Clean Air Act 1993 and Chimney Heights Clean Air Act Memorandum

Non Road Mobile Machinery (NRMM)

Comply with the Non-Road Mobile Machinery Low Emission Zone

Meet the emission requirements for non-road mobile machinery on construction sites and register the equipment on the GLA NRMM register.

Policy SI 1 D of the London Plan

City of London Code of Practice for Construction and Deconstruction

Ventilation inlets

Passive ventilation should be incorporated where possible.

For mechanical ventilation:

Inlets should be located away from source of pollution

Filtration should be provided for particles and nitrogen dioxide

Drawings showing location of inlets should be provided.

Policy HL2 of the draft City Plan

Outdoor space and public realm

Should be located away from high levels of air pollution e.g., busy roads.

Designs incorporated to protect users from high levels of air pollution.

Policies G5 A and D8 I of the London Plan

Policy DE3 of the draft City Plan

Roof gardens for use by people

Plans should be submitted to show the proximity of any flues/ chimneys that extract on the roof from gas boilers, generators, and CHP plant.

Where roof terraces are proposed, users of the roof could be exposed to emissions of air pollutants from any chimneys that extract on the roof.

A design that places a minimum of 3 metres from the point of efflux of any chimney serving combustion plant, to any person using the roof terrace is required.

Policy DE5 of the draft City Plan


Air quality plants can be incorporated in areas of poor air quality.

Greening can be used to screen users of the site from pollution source.

Policies G5 A and D8 I of the London Plan

Policy S14 of the draft City Plan

Contact the Air Quality team