"Poor air quality is the largest environmental risk to Public Health in the UK" [DEFRA, 2017]. Air pollution in the West Midlands affects some 2.8 million people, reducing average life expectancy by up to 6 months, and is responsible for economic costs estimated at £860m per year. Air quality is therefore a key priority for local and regional government, and increasingly the general public, with further emphasis arising from the "Diesel-gate" emissions scandal, and ongoing High Court challenges to the Government's Air Quality strategy. Historically, local air quality policy has been the responsibility of the individual Local Authorities. However, air pollution does not respect political boundaries, and the 2016 formation of the West Midlands Combined Authority will lead to an integrated approach to air pollution, under the Second Devolution Deal for the West Midlands (2017). In parallel, the NHS Sustainability Transformation Trust is bringing an integrated approach to health and social care provision - with air quality a core priority. This gives rise to a unique and timely opportunity to translate environmental science research expertise into regional policy and interventions to reduce air pollution. The University of Birmingham group has critical mass, international research expertise and NERC track record in air pollution, and its health and economic impacts. We have a history of links with regional partners, ranging from commissioned work and joint research projects to informal collaborations. Accordingly, we have developed the West Midlands Air Quality Improvement Programme (WMAQIP), through a co-design process alongside regional stakeholders including the WMCA / Mayor of the West Midlands, Local Authorities, private companies, industry sector bodies and third sector organisations, to deliver: -Situational awareness (understanding of air pollution levels and sources), e.g. applied to refinement of the Birmingham Clean Air Zone and design of future interventions in Coventry, avoiding over £5m annual costs plus benefits to visitors / commuters working in the cities. -Predictive Capability to evaluate AQ policy options, in comparison with business as usual predictions, for pollution levels, health and economic impacts - identifying interventions to achieve Birmingham City Council's goal of halving AQ-related mortality by 2030 (750 deaths/yr and £170m annual costs avoided); avoiding additional healthcare costs of £600m required under business-as-usual scenarios, and informing allocation of recurrent and one-off intra-city transport investment of £250m. -Application of the resulting capability to specific policy scenarios - including infrastructure design around the 2022 Birmingham Commonwealth Games to deliver improved air quality, understanding the air quality consequences of future vehicle fleet evolution to electric vehicles, and optimising air quality co-benefits from green infrastructure for HS2 development. WMAQIP directly addresses the UK Industrial Strategy grand challenge of Clean Growth, which commits the Government to "create a future where our cities benefit from cleaner air", and the Infrastructure foundation of productivity, which identifies a determination to "tackle air pollution and support affected areas, given the significant negative impact it has on public health, the economy and the environment." WMAQIP combines NERC research expertise with direct inputs from a range of partner organisations. The programme will deliver policy impact from application of environmental science applied to specific policy priorities through a cohort of Impact Fellows, physically embedded within stakeholder organisations to provide knowledge transfer and training, and hence lasting impact. Programme legacy will be maximised by formalising capabilities as tools which may be applied elsewhere, and actions to promote their dissemination.