An aerosol consists of solid particles or liquid droplets dispersed in a gas phase with sizes spanning from clusters of molecules (nanometres) to rain droplets (millimetres). Aerosol science is a term used to describe our understanding of the collective underlying physical science governing the properties and transformation of aerosols in a broad range of contexts, extending from drug delivery to the lungs to disease transmission, combustion and energy generation, materials processing, environmental science, and the delivery of agricultural and consumer products. Despite the commonality in the physical science core to all of these sectors, doctoral training in aerosol science has been focussed in specific contexts such as inhalation, the environment and materials. Representatives from these diverse sectors have reported that over 90% of their organisations experience difficulty in recruiting to research and technical roles requiring core expertise in aerosol science. Many of these will act as CDT partners and have co-created this bid. We will establish a CDT in Aerosol Science that, for the first time on a global stage, will provide foundational and comprehensive training for doctoral scientists in the core physical science. Not only will this bring coherence to training in aerosol science in the UK, but it will catalyse new collaborations between researchers in different disciplines. Inverting the existing training paradigm will ensure that practitioners of the future have the technical agility and confidence to move between different application contexts, leading to exciting and innovative approaches to address the technological, societal and health challenges in aerosol science. We will assemble a multidisciplinary team of supervisors from the Universities of Bristol, Bath, Cambridge, Hertfordshire, Imperial, Leeds and Manchester, with expertise spanning chemistry, physics, biological sciences, chemical and mechanical engineering, life and medical sciences, pharmacy and pharmacology, and earth and environmental sciences. Such breadth is crucial to provide the broad perspective on aerosol science central to developing researchers able to address the challenges that fall at the boundaries between these disciplines. We will engage with partners from across the industrial, governmental and public sectors, and with the Aerosol Society of the UK and Ireland, to deliver a legacy of training packages and an online training portal for future practitioners. With partners, we have defined the key research competencies in aerosol science necessary for their employees. Partners will provide support through skills-training placements, co-sponsored studentships, and contribution to taught elements. 5 cohorts of 16 doctoral students will follow a period of intensive training in the core concepts of aerosol science with training placements in complementary application areas and with partners. In subsequent years we will continue to build the activity of the cohort through summer schools, workshops and conferences hosted by the Aerosol Society, virtual training and enhanced training activities, and student-led initiatives. The students will acquire a perspective of aerosol science that stretches beyond the artificial boundaries of traditional disciplines, seeing the commonalities in core physical science. A cohort-based approach will provide a national focal point for training, acting as a catalyst to assemble a multi-disciplinary team with the breadth of research activity to provide opportunities for students to undertake research in complementary areas of aerosol science, and a mechanism for delivering the broad academic ingredients necessary for core training in aerosol science. A network of highly-skilled doctoral practitioners in aerosol science will result, capable of addressing the biggest problems and ethical dilemmas of our age, such as healthy ageing, sustainable and safe consumer products, and climate geoengineering.