Arup                                          ESH0052

Arup - Response to Environmental Audit Committee ‘Call for Evidence’ on Environmental sustainability and housing growth (December 2024)

Introduction

Arup is a global collective of designers, engineers and consultants dedicated to sustainable development who operate across 33 countries, collaborating with clients and partners to help shape a more sustainable world.

Climate change is also central to Arup’s group strategy, and Arup has committed to reaching net zero across our global operations by 2030. We are pursuing ambitious 1.5⁰C aligned science-based targets for our full value chain emissions and compensating residual hard-to-decarbonise emissions with certified greenhouse gas removals.

We respond to questions 4 and 5 of the Call for Evidence, bringing in Arup’s expertise on building retrofit and air quality. Our response has been supported by Arup’s RTPI accredited town planners.

Arup response

Question 4: How will the revised NPPF work to deliver the social and environmental objectives of the planning system? To what extent will it promote outcomes which deliver sustainable social and environmental benefits together, such as access to essential amenities, to public transport and to active travel routes?

The revised National Planning Policy Framework (NPPF), published in December 2024, was limited in updating guidance relating to social and environmental objectives of the planning system. It predominantly focused on creating the conditions for delivering growth at pace, by increasing land capacity for development, increasing housing need requirements and unblocking major infrastructure projects.

We therefore consider that there are many opportunities for national Planning Practice Guidance (or other planning policy mechanisms) to achieve better outcomes for communities and the environment.

Our response to this question will specifically focus on improving air quality, widely understood as a key indicator for local standards of public health, amenity and the environment. Neighbourhoods of poorer air quality have persistently been shown to intersect with areas of deprivation and lower socio-economic outcomes. This trend has been reinforced by research published in December 2024 by the Institute for Fiscal Studies (further details here), funded by the Economic & Social Research Council. It was found that those in the 20% most deprived areas experience 8% higher average PM2.5 concentrations than those in the 20% least deprived areas in England.

Additionally, from a climate change perspective, pollutants including ozone and black carbon particulate matter (a component of PM10 and PM2.5) act as short-lived climate pollutants, contributing to climate change.

NPPF guidance on air quality is currently limited to paragraph 110, where plan-makers are encouraged to actively direct development to locations that reduce transport emissions and thus improve air quality. Separately, NPPF paragraph 199 stipulates that planning policies and decisions “sustain and contribute towards compliance with relevant limit values or national objectives for pollutants”.

In Arup’s experience on projects with developers, planning decisions are often limited to meeting minimum legal thresholds for pollutants. Air quality is also often addressed through reactive interventions at a late stage of the design and development process.

In our work, we seek to encourage our clients to go beyond the minimum requirements and encourage good practice, with the goal of reducing pollution and minimising ‘introduced exposure’ of poor air quality through new development. We consider that there are many opportunities to integrate upfront design interventions in buildings that minimise pollution and introduced exposure, such as determining where developed is sited, especially for people vulnerable to the health impacts of air pollution (children, pregnant and elderly people, and those with existing health conditions), and ventilation. This has already been showcased in London through the Air Quality Positive approach. Further integration of climate and air pollution measures in design and mitigation would allow the benefits for both to be optimised in new development and retrofitted buildings, which would provide both local and global benefits.

At a neighbourhood level, we support the NPPF’s approach on averting poor air quality arising from new development, by promoting sustainable transport, including connections to public transport, walking and cycling routes and facilities. We feel this approach could be strengthened by adopting best practice, as set out in the Environmental Policy Implementation Community (previously Environmental Protection UK) and Institute of Air Quality Management guidance, and various local and regional authority Supplementary Planning Guidance documents.

In addition, we consider that there is a gap in national policy, guidance and Parliamentary scrutiny: interventions to reduce carbon emissions are typically not considered in the context of their air quality impacts.

We feel that this is a key consideration for the planning system to improve both public health and achieve the Government’s statutory net zero targets. Arup recently undertook a Carbon & Climate Study for Milton Keynes City Council, as evidence for the MK City Plan 2050. In developing growth options for the Plan, our analysis illustrated where measures were positive for both climate and air quality, and where there were tensions or more complicated interactions. For example, electric vehicles have zero emissions at point of use for carbon and NOx, but still have negative air quality impacts on PM10 and PM2.5 from tyre and break wear. This encouraged us to consider and lend additional weight to alternative ways of reducing the City’s transport emissions, such as active travel and public transport links.

At a building level, we would highlight that using combustion as a heating source, requires closer scrutiny from an air quality perspective in planning policy and decisions, even where it uses a zero carbon fuel. For example, the combustion of hydrogen in heating can lead to NOx emissions, a pollutant dangerous to public health. This can be averted by implementing hydrogen fuel cells instead.

Additionally, where new (often commercial) buildings have ‘fossil fuel free’ heating, we have observed that they are designed with back-up generators (for when there are power cuts) powered by diesel. This is often where they are regarded as critical infrastructure, such as data centres and hospitals, as well as offices. In planning applications, where an Energy Statement is required, back-up generators do not need to be accounted for, in order to meet energy and emissions reduction targets. While back-up generators are used on a temporary basis, they can incur acute health impacts. They may be required more frequently in light of climate change and the increased frequency of extreme weather events, such as flooding, which can lead to power outages.

Indoor air quality is also important, as people spend most of their time indoors. Heating, cooking and products all give rise to air pollution, and where the building is inadequately ventilated, this can build up to harmful levels. Modern technologies enable buildings to be heat and energy efficient, using a variety of measures, such as insulation and air tightness (when used correctly by occupiers), bringing both climate and air pollution benefits through reduced need for heating and energy production. This may therefore be a consideration for both planning applications and Building Regulations.

Question 5. What contribution can the NPPF make to meeting Government targets for the reduction of greenhouse gas emissions? What account does the NPPF take of advice from the Climate Change Committee on reducing the use of embodied carbon as well as operational carbon in the built environment?

The revised National Planning Policy Framework (NPPF), published in December 2024, did not comprise updates related to the Government’s statutory net zero carbon standards. It also did not include any guidance on reducing embodied and operational carbon emissions.

In 2023, the building sector was reported to emit 81 MtCO2e, as the second greatest source of carbon emissions in the UK. As a result, the Climate Change Committee’s latest Report to Parliament (2024) highlighted building emissions reduction as a priority for policy, requiring rapid acceleration in decarbonisation to meet the UK statutory net zero target by 2050.

With the Government’s growth-focused agenda, we consider that the retrofit of existing buildings could play a pivotal role in unlocking opportunities to both reduce carbon emissions and accelerate housing delivery. It provides opportunities for densification, such as through the addition of floor to existing buildings, making effective use of existing materials and infrastructure. This approach not only reduces the carbon emissions associated with new housing delivery but also aligns with the principles of sustainable development and resource efficiency. It also presents a significant opportunity to drive economic growth through job creation and the development of innovative technologies.

Retrofit can bring vacant buildings back into use, offering a more cost- and carbon-efficient alternative to new builds. This creates opportunities to regenerate neighbourhoods, particularly where there are historic buildings that can be revitalised. Furthermore, prioritising the retrofitting of vacant high-street assets offers a strategic opportunity, with existing datasets already available to support the identification of these sites.

Homes England, the Government’s Housing & Regeneration Agency, has recently commissioned Arup to develop guidance aimed at supporting evidence-based decision-making for both new build and retrofit projects. This recognises the significant co-benefits of retrofit for housing delivery, whole life carbon reduction and regeneration.

Additionally, Arup, Dark Matter Labs, UCL IIPP and Rising Tide are collaborating on a research project funded by Laudes to identify a set of appropriate and impactful tactics which could fulfil housing needs without overshooting planetary boundaries, whilst supporting a just transition of the built environment. Further information can be found here, and the project team have submitted a separate response to this consultation.

We acknowledge that there has been some nervousness on retrofit including through change of use. We consider that the NPPF and associated planning guidance can provide a framework for ensuring we deliver high-quality retrofit. Retrofit can deliver a holistic range of environmental and social benefits, but there are risks in scaling rapidly in an absence of appropriate regulation and policy. We propose that the NPPF could both incentivise and provide appropriate checks and balances whilst also facilitating a degree of flexibility to suit local needs.

December 2024