Southwest Environmental Limited

Air Quality Neutrality Assessment

Air Quality Neutrality is a relatively recent, and seemingly simple concept. That is no being applied to Planning Application within London.

The Mayor of London's Guide Document (Air Quality Neutral - November 2022) is quite a short document, at 33 pages.  And introduces an assessment method, that differs dependent on the size of the project.

Benchmarking

Whether a Building Emissions Benchmark (BEB) or a Transport Emissions Benchmark (TEB), benchmarking features heavily within the guide.

Building Emissions Benchmark (BEB)

Transport Emissions Benchmark (TEB)

Minor Development

Building Emissions Benchmark (BEB) for Minor Development

Air Quality Neutrality in Minor Developments is given a simplified process, with a short cut to Building Emissions Benchmarking:

Where minor developments include new heating systems, they can be assumed to meet the BEB if:

• the new heating system is a heat pump or other zero emission heat source;
• the new heating system is a gas boiler with NOx emissions rated at less than 40 mg/kWh; or
• the development is connecting to an existing heat network.

Transport Emissions Benchmark (TEB) for Minor Development

Car free developments and those with no additional car parking spaces (provided similar use is maintained) then could qualify as exempt.

• Where minor developments include new parking, they can be assumed to meet the TEB if the maximum parking standards set out in policies T6 and T6.1 to T6.5 of the London Plan are not exceeded. 
• Where major developments meet the definition of ‘car-free’2 , they can be assumed to meet the TEB and the rest of Section 4 does not apply.

Air Quality Neutrality Assessment Report

For minor developments we can typically cover neutrality requirements with a chapter in an Air Quality Assessment. However, for Major Developments we can provide a Standalone Air Quality Neutrality Assessment Report. Please contact us for a quotation.

The below section was written by a machine.

Technical Insight: Navigating London's Air Quality Neutral Policy

The "Air Quality Neutral" requirement is a key pillar of the London Plan, designed to ensure that new developments do not contribute to a further decline in the capital's air quality. For developers and architects, this means that a standard air quality assessment must now include a specific demonstration that the project meets or exceeds the designated emission benchmarks for both buildings and transport. This policy applies to all major developments across Greater London, requiring a rigorous evidence-based approach to secure planning consent.

Building and Transport Emission Benchmarks

To achieve neutrality, a project must be evaluated against established benchmarks that cap the allowable emissions of Nitrogen Oxides (NOx) and Particulate Matter (PM10). This evaluation is often a core component of a wider Environmental Impact Assessment (EIA). Compliance is measured across two primary streams:

• Building Emissions: Assessing the impact of onsite heating and energy plant. Developments are encouraged to move away from combustion-based systems toward ultra-low emission technologies.
• Transport Emissions: Evaluating the trip generation associated with the site. Projects located in areas with high public transport accessibility (PTAL) are held to stricter standards to minimize vehicle-related pollutants.
• Mitigation Strategies: Where benchmarks cannot be met through design alone, developers may need to implement onsite mitigation or, as a last resort, provide financial contributions toward local air quality improvements.

Integration with Sustainable Design

The pursuit of air quality neutrality often overlaps with broader sustainability goals. By prioritizing fabric energy efficiency and low-carbon heat sources, developers can simultaneously satisfy the London Plan's energy hierarchy and air quality mandates. For complex industrial or agricultural sites, this may also involve specialized atmospheric modelling or ammonia emissions assessments to understand the wider dispersion of pollutants and their impact on sensitive receptors.

Professional Guidance for London Developers

Securing approval in the London planning system requires the technical authority to interpret complex benchmarks and provide defensible data. At Southwest Environmental Limited, we leverage over 15 years of industry experience to guide projects through these regulatory hurdles. Whether you are addressing odour impact assessments or detailed air quality reports, our team provides the professional accreditation (IAQM/IES) and local knowledge required for a successful outcome. With a portfolio of 900+ projects, we ensure your development meets the highest environmental standards while navigating the specific demands of the London Boroughs.