Aerosol science, the study of airborne particles from the nanometre to the millimetre scale, has been increasingly in the public consciousness in recent years, particularly due to the role played by aerosols in the transmission of COVID-19. Vaccines and medications for treating lung and systemic diseases can be delivered by aerosol inhalation, and aerosols are widely used in agricultural and consumer products. Aerosols are a key mediator of poor air quality and respiratory and cardiac health outcomes. Improving human health depends on insights from aerosol science on emission sources and transport, supported by standardised metrology. Similar challenges exist for understanding climate, with aerosol radiative forcing remaining uncertain. Furthermore, aerosol routes to the engineering and manufacture of new materials can provide greener, more sustainable alternatives to conventional approaches and offer routes to new high-performance materials that can sequester carbon dioxide. The physical science underpinning the diverse areas in which aerosols play a role is rarely taught at undergraduate level and the training of postgraduate research students (PGRs) has been fragmentary. This is a consequence of the challenges of fostering the intellectual agility demanded of a multidisciplinary subject in the context of any single academic discipline. To begin to address these challenges, we established the EPSRC Centre for Doctoral Training in Aerosol Science in 2019 (CDT2019). CDT2019 has trained 92 PGRs with 40% undertaking industry co-funded research projects, leveraged £7.9M from partners and universities based on an EPSRC investment of £6.9M, and broadened access to our unique training environment to over 400 partner employees and aligned students. CDT2019 revealed strong industrial and governmental demand for researchers in aerosol science. Our vision for CDT2024 is to deliver a CDT that 'meets user needs' and expands the reach and impact of our training and research in the cross-cutting EPSRC theme of Physical and Mathematical Sciences, specifically in areas where aerosol science is key. The Centre brings together an academic team from the Universities of Bristol (the hub), Bath, Birmingham, Cambridge, Hertfordshire, Manchester, Surrey and Imperial College London spanning science, engineering, medical, and health faculties. We will assemble a multidisciplinary team of supervisors with expertise in chemistry, physics, chemical and mechanical engineering, life and medical sciences, and environmental sciences, providing the broad perspective necessary to equip PGRs to address the challenges in aerosol science that fall at the boundaries between these disciplines. To meet user needs, we will devise and adopt an innovative Open CDT model. We will build on our collaboration of institutions and 80 industrial, public and third sector partners, working with affiliated academics and learned societies to widen global access to our training and catalyse transformative research, establishing the CDT as the leading global centre for excellence in aerosol science. Broadly, we will: (1) Train over 90 PGRs in the physical science of aerosols equipping 5 cohorts of graduates with the professional agility to tackle the technical challenges our partners are addressing; (2) Provide opportunities for Continuing Professional Development for partner employees, including a PhD by work-based, part-time study; (3) Deliver research for end-users through partner-funded PhDs with collaborating academics, accelerating knowledge exchange through PGR placements in partner workplaces; (4) Support the growth of an international network of partners working in aerosol science through focus meetings, conferences and training. Partners and academics will work together to deliver training to our cohorts, including in the areas of responsible innovation, entrepreneurship, policy, regulation, environmental sustainability and equality, diversity and inclusion.

Along the well-to-wake value chain from upstream processes associated with fuels production and supply, components manufacture, and ships construction to the operation of ports and vessels, the UK domestic and international shipping produced 5.9 Mt CO2eq and 13.8 Mt CO2eq, respectively in 2017, totalling 3.4% of the UK's overall greenhouse gas emissions. The sector contributes significantly to air pollution challenges with emissions of nitrogen oxide, sulphur dioxide and particulate matters, harming human health and the environment particularly in coastal areas. The annual global market for maritime emission reduction technologies could reach $15 billion by 2050. This provides substantial economic opportunities for the UK. The Department for Transport's Clean Maritime Plan provides a route map for action on infrastructure, economics, regulation, and innovation that covers high technology readiness level (TRL 3-7). There is a genuine opportunity to explore fundamental research and go beyond conventional marine engineering and naval architecture and exploit the UK's world-leading cross-sectoral fundamental research expertise on hydrodynamics, fuels, combustion, electric machines and power electronics, batteries and fuel cells, energy systems, digitization, management, finance, logistics, safety engineering, etc. The proposed UK-MaRes Hub is a multidisciplinary research consortium and will conduct interdisciplinary research focussed on delivering disruptive solutions which have tangible potential to transform existing practice and reach a zero-carbon future by 2050. The challenges faced by UK maritime activity and their solutions are generally common but when deployed locally, they are bespoke due to the specifics of the port, the vessels they support, and the dependencies on their supply chains. Implementation will be heavily dependent on the local community, existing infrastructure, as well as opportunities and constraints related to the supply, distribution, storage and bunkering of alternative fuels, in decarbonising port handling facilities and cold-ironing, with the integration of renewable energy, reducing air pollution, to land-use and increased capacity and capability, and the local development of skills. The types of vessels and the cargoes handled through UK ports varies and are related to several factors, such as geographical location, regional industrial and business activity and wider transport links. Therefore, UK-MaRes Hub aims to feed into a clean maritime strategy that can adapt to place-based challenges and provide targeted technical and socio-economic interventions through a novel Co-innovation Methodology. This will bring together Research Exploration themes/work packages and Responsive Research Fund project activity into focus on port-centric scenarios and assess possibilities to innovate and reduce greenhouse gas emissions by 2030, 2040 and 2050 timeframes, sharing best practice across the whole maritime ecosystem. A diverse, and inclusive Clean Maritime Network+ will ensure wider dissemination and knowledge take-up to achieve greater impact across UK ports and other maritime activity. The Network+ will have coordinated regional activity in South-West, Southern, London, Yorkshire & Lincolnshire, Midlands, North-West, North-East, Scotland, Wales, and Northern Ireland. An already established Clean Maritime Research Partnership has vibrant academic, industrial, and civic stakeholder members from across the UK. UK-MaRes Hub will establish a Clean Maritime Policy Unit to provide expert advice and quantitative evidence to enable rapid decarbonisation of the maritime sector. It will ensure that the UK-MaRes Hub is engaging with policymakers at all stages of the hub activities.