This Innovation project for impact will bring together policy and practice leaders concerned with how planning decisions affect urban air quality. The overarching aim is to make a software platform for the quantitative assessment of Green Infrastructure as an aid to the improvement of roadside air quality. We call this platform GI4RAQ. Our particular objectives can be summarised as: 1. to provide a consolidated, open-source, computer modelling code for roadside air pollution in urban settings based on our existing research code. 2. to co-design of a fit-for-purpose, simple, and attractive GI4RAQ platform for urban practitioners as a front-end to the consolidated model code. 3. to demonstrate that the GI4RAQ platform can unlock a critical impasse in current planning policy and so enable capacity-building on the regulatory and consultancy sides of the planning process. We will work with major influencers in the private and public sectors, which offers a rapid and cost-effective route to meaningful impact. Specifically, we will work with Transport for London and the Greater London Authority to influence the next issue of the London Plan. To be released towards the end of 2019, a proposed new policy requiring larger-scale developments to be 'Air Quality Positive' may be implemented, but only if tools exist to evidence such a result at planning. We will work with the UK's leading air quality consultants, Cambridge Environmental Research Consultants (CERC) and Ricardo Energy & Environment, to ensure that the GI4RAQ platform is fit for operational use and that it can be used alongside current Air Quality tools. London's 33 Local Authorities must ensure their Local Plans conform to the London Plan, and Authorities across the UK look to the London Plan in preparing their own Local Plans, both of which provide cascading impact for our proposed work. The project is designed to dovetail with 'WM Air', a large multi-partner programme focused on West Midlands' air quality led by the University of Birmingham. The GI4RAQ Principal Investigator leads the work stream on green infrastructure in WM Air alongside GI4RAQ partner Birmingham City Council, thereby ensuring rapid knowledge transfer between research and practice in London and Birmingham. The project will establish a robust approach to 'GI4RAQ' interventions to deliver reliable improvements in roadside air quality, based on quantitative computer modelling but avoiding the time and expense of full fluid flow simulations. The approach develops directly out of a NERC Innovation Pathfinder, which established that a strong demand for quantitative GI4RAQ exists, but also identified the policy impasse, and a placement of the researcher co-Investigator in Transport for London.

The 2019 Climate Change Act committed the UK to reducing its emissions of greenhouse gases to net zero by 2050. The 2019 UK Clean Air Strategy, sees "air pollution as one of the UK's biggest public health challenges", aims to secure clean growth whilst tackling air pollution through reducing emissions. Achieving these reductions in greenhouse gas and air pollutant emissions will entail substantial reductions in use of fossil fuels and changes to the transport fleet over coming years as we make the transition to a 'low carbon economy'. This will also have an important benefit for health of improving levels of outdoor air pollution by reducing emissions from power plants, motor vehicles, wood/coal burning at home and other sources. However, another important climate change action is to improve energy efficiency in homes. Those measures typically entail reducing levels of ventilation to cut down heat losses from escape of heated air. In addition to helping improve winter indoor temperatures, this can be beneficial for human health because it reduces the penetration into the home of air pollutants from the outdoor environment. But it will increase indoor levels of air pollutants derived from sources inside the home - such as particles and gases generated by cooking, volatile organic compounds (VOCs) given off from fabrics and furnishings, cleaning and personal care products. The changes to indoor pollution levels from improved home energy efficiency may thus be overall positive or negative for the health of building occupants depending on the balance of effects on pollutants entering and leaving the indoor environment. That balance is likely to depend on the levels of outdoor pollutants, indoor air pollutant sources and activities that generate these, the form of the energy efficiency improvements, the behaviour of occupants and their vulnerability to air pollutants. People at particular risk are young children, the elderly, those with pre-existing illnesses, and those experiencing social deprivation. To improve understanding of these issues, we have created a new research network (acronym 'HEICCAAM'). This network brings together experienced and early career researchers from nine universities from disciplines as diverse as air quality measurement and modelling, building physics, behavioural science, health and health inequalities, education and policy. The network will also include representatives of the public, as well as stakeholders from the public sector, business/industry and non-government bodies - including Public Health England, Health Protection and NHS Scotland, Scottish Environment Protection Agency, Age UK, the Passivhaus Trust, Good Homes Alliance, Edinburgh City Council, the Chartered Institution of Building Services Engineers and the UK Met Office. The network will build evidence on the consequences for exposure to air pollution of actions aimed at tackling climate change and poor air quality, with particular focus on the home environment. Its aim is to provide underpinning research that can inform and influence policy and practice to safeguard human health. The network will include activities by six Working Groups tasked with generating a series of papers on relevant issues of science and policy. It will also undertake four small research projects aimed at improving understanding of key issues where there are knowledge gaps. It will have a particular focus on protecting the health of vulnerable groups and reduction of health inequities. Network members will have multiple interactions through electronic meetings, webinars, discussion groups and an annual meeting and workshop with a wider group of stakeholders. Through its activities, the network will help build long-term capability in interdisciplinary research in this area, including through the interactions with early career researchers, the development of new research plans, and linkage to other networks and existing research programmes.

Local and global consequences of climate change (enhanced urban heat islands, worsening environmental conditions) affect most of the world's urban population, but only recently have cities been represented, albeit crudely, in weather forecast models. To manage and develop sustainable, resilient and healthy cities requires improved forecasting and observations that cross neighbourhood-influenced scales which the next generation weather forecast models need to resolve. ASSURE addresses the critical issue of which processes need to be parameterised, and which resolved, to capture urban heterogeneity in space and time. We will advance understanding to develop new approaches and parameterisations for larger-scale urban meteorological and dispersion models by combining the results of field observations, high-resolution numerical simulations and wind tunnel experiments. Field work and modelling will focus on Bristol, as its physical geography provides suitably high levels of complexity and allows whole-city approaches. With mid-sized cities being large sources of greenhouse gases, and where large numbers of people live, it is critical agencies can provide predictions of weather and climate variability across cities of this scale as they need this information to manage and provide their services. ASSURE will include idealised simulations and theoretical analyses to ensure generic applicability. The ASSURE objectives are: * To understand how sources of urban heterogeneity (physical setting, layout of buildings and neighbourhoods, human activities) combine to influence the urban atmosphere in space and time. * To quantify effects of urban heterogeneity at different scales (street to neighbourhood, to city and beyond) on flow, temperature, moisture and air quality controlling processes and to determine how these processes interact. * To develop a theoretical framework that captures key processes and feedbacks with reduced complexity to aid mesoscale and larger model parameterisations. * To inform the development priorities of current weather and climate models that have meso-scale capabilities and are used in decision-making processes (e.g. integrated urban services). The ASSURE high-fidelity simulations and carefully designed experiments will allow us to explore implications of urban heterogeneity in isolated and combined configurations; interpret and integrate field observations (e.g. 3D meteorological and city-scale tracer dispersion experiments); integrate different approaches to understand the magnitude, source, and geographical extent of uncertainties in process models at different scales; synthesize the new knowledge to conduct theoretical analyses; develop algorithms reflecting this analysis. Novel in ASSURE are simulations resolving street to city-scale features that are linked to mesoscale models; field observations capturing vertical and horizontal variations in the urban boundary- and canopy-layers, including novel multi-source gas tracer experiments; and wind tunnel simulations across atmospheric stabilities and model resolution. New insights will be gained on the role of variations in the building morphology (or form), local topography, and human activities (e.g. waste heat, and AQ emissions). ASSURE will produce detailed datasets; in-depth understanding across the scale of atmospheric processes involved; high-fidelity multiscale urban modelling tools; theoretical models taking account of multiscale effects; improved assessment of current meso-scale model skill and the data used by practitioners to explore future urban scenarios as city form and function change. We will work with local and international organisations and companies to ensure the project benefits a broad range of society. They include: Avon Longitudinal Study of Parents and Children, CERC, COWI, ECMWF, Met Office, Delft University of Technology, Stanford University, University Hannover, RWDI, Surrey Sensors and UKCRIC.

Air pollution is the most significant environmental risk in the UK, leading to economic costs of £20b/y and significant health inequalities. Quantifying the changing causes of air pollution motivated NERC investment in three fixed air quality supersites - located in urban background locations within London, Birmingham and Manchester, operated via the UKRI SPF project OSCA. In parallel, the forthcoming (early 2021) revision of WHO guidelines will inform new national air quality targets, within the new Environment Bill, which are likely to reflect population-averaged exposure. Poor air quality arises from the interaction of emissions, meteorology and atmospheric processes, affecting the loading and toxicity of the species present. Two key uncertainties are 1 The balance between traffic and urban emissions, and pollutants already present in the air arriving from upwind, key to the regional and national policy responsibility for improving air quality. 2 The interaction between spatially varying emissions and chemical processing affecting air quality, including the role of agricultural emissions and transport shifts for Net Zero. Here, we will develop new UK community capability to address these uncertainties: Flexibly configurable air quality supersite triplets, spanning upwind, roadside and urban observational capability. UK-AQST comprises the existing fixed supersites (urban), augmented by two mobile "supersites" to study (for example) upwind rural and roadside air composition. The two units will be located within sustainable mobile platforms (one electric van, one trailer for maximum flexibility) operated to national standards and producing open-access data. The supersites are not traditional monitoring stations - they will comprise highly sophisticated instruments which monitor key species in atmospheric processes such as ammonia (key to aerosol formation), VOCs (key to ozone, secondary organic aerosol and new particle formation), as well as trace metals, nanoparticles and particle composition in near-real time, in addition to regulated gas pollutants. By using a triplet site configuration (rural, urban, roadside), not only can urban and roadside concentration increments be measured, the processing of polluted air to form key secondary pollutants such as nitrate and secondary organic particles, and freshly formed nanoparticles can be viewed in unprecedented detail to yield process understanding. The triplet observations will generate a step-change in scientific capability for quantifying air pollution sources and processes at a fundamental level, thus consolidating UK's world-leading position in this field. It will produce policy relevant science with significant impact, particularly in informing air quality policy including the validation of approaches accounting for imported emissions, with applications across the UK and for analogous challenges globally.

The challenge articulated in this proposal is: how to develop cities with no air pollution and no heat-island effect by 2050? It is difficult to predict with precision the future of cities, but there will be significant adaptations and changes by 2050, due to advances in technology, changing populations, social expectations and climate change. A roadmap is needed to ensure that decisions taken as the city evolves lead towards a sustainable future. Approximately half of the energy use, carbon dioxide emissions and exposure to air pollution in cities is due to either buildings or transportation, and this total energy use is increasing. Air pollution is projected to be the leading global cause of mortality by 2050. Therefore the question posed here in terms of air quality and temperature rise is important in its own right. However, these quantities together also provide, perhaps uniquely, specific measurable physical properties that cover an entire city and provide a metric for assessing the sustainability of system-wide decisions. Traditional approaches to urban environmental control rely on energy-consuming and carbon/toxics-producing heating, ventilation and air conditioning (HVAC) systems. These traditional approaches produce an unsustainable cycle of increasing energy use with associated emissions of carbon dioxide and pollutants leading to rising temperatures implying, in turn, greater use of HVAC. Breaking this vicious cycle requires a completely different engineered solution, one that couples with natural systems and does not depend solely on mechanical systems. This project will develop a facility consisting of an integrated suite of models and an associated management and decision support system that together allow the city design and its operation to manage the air so that it becomes its own HVAC system, with clean, cool air providing low-energy solutions for health and comfort. This will be achieved by using natural ventilation in buildings to reduce demand for energy and ensuring air pollutants are diluted below levels that cause adverse health effects, coupled with increased albedo to reduce the heat island effect plus green (parks) and blue (water) spaces to provide both cooling and filtration of pollutants. We have brought together a trans-disciplinary research team to construct this facility. It will be comprised of three components: (i) a fully resolved air quality model that interacts with sensor data and provides detailed calculations of the air flow, pollutant and temperature distributions in complex city geometries and is fully coupled to naturally ventilated buildings, and green and blue spaces; (ii) reduced order models that allow rapid calculations for real time analysis and emergency response; and (iii) a cost-benefit model to assess the economic, social and environmental viability of options and decision. The scientific air quality component is a fully-resolved computational model that couples external and internal flows in naturally ventilated buildings at the building, block and borough scales. It will be supported and validated by field measurements at selected sites and by wind tunnel and salt-bath laboratory studies. The reduced order models will be developed from the computational model and from laboratory process studies, and will be capable of producing gross features such as mean pollutant concentrations and temperatures. They will be used to provide capabilities for scoping studies, and real-time and emergency response. The cost-benefit model will provide the link between the scientific and engineering models and implementation advice. It will include modules for the built environment, public spaces and transportation, and provide estimates of the life-cycle costs and benefits of the various scenarios at the individual building, city block and borough scales. Eventually, it is envisaged that this will also include social and health effects.