To protect and improve the health of the UK population, it is important to fully understand what environmental risks we are exposed to. We can assess exposure by measuring levels of potential toxicants (i) within the blood and/or urine of a subset of people (human biomonitoring), (ii) within the environments that people spend their time (environmental monitoring), and (iii) developing modelling tools to predict exposures across wider populations. In this theme we will focus on improving the assessment of indoor and outdoor chemical, metal, gas, nanoparticle, bioaerosol and e-cigarette exposures, using a range of techniques such as analytical chemistry, DNA sequencing, computer modelling, systematic reviews and epidemiology. The data generated will inform further epidemiological, mechanistic and responsive research projects across Themes II, III and IV to advance our understanding of exposures to a range of known and emerging environmental toxicants, and support interventions to improve public health through risk assessment and management.

The impacts of ambient air pollution on the heart and lung are well established, but recent evidence has indicated wider health impacts across the life course, from adverse birth outcomes, to impacts on childhood and adolescent mental health, to dementia risk in the elderly. Theme II aims to expand research in these emerging areas to inform national government both on the scale of the problem and potential mitigation strategies, such as the implementation of Clean Air Zones. We also seek to increase the evidence base on exposures and health impacts within understudied transport micro-environments (within the road transport sector and on the London Underground), as well as within the broader indoor environment, expanding beyond a consideration of standard criterion pollutants. These activities will complement the work in Themes I and IV. Work within Theme II, as well as within Theme III will also address the relative hazard of pollutants that are often highly correlated in ambient air, particularly combustion derived particulate matter and nitrogen dioxide, to help refine public health policy.

This theme aims to understand the mechanistic pathways, linking ambient air pollution exposure to disease outcomes and to use experimental models to investigate complex pollutant mixture effects and interactions within the body. Technologies including metabolomics will be used to identify potential biomarkers of human exposure and outcome. There is also a particular focus on cellular and molecular effects of different types of inhaled particle (combustion and non-combustion) across projects, allowing prioritisation of hazardous components for future study. This theme is also tasked with investigation of the contribution of NO2 and e-cigarettes to human disease outcomes.

Theme IV has a diverse portfolio of projects under the umbrella of emerging hazards and preparedness and aims to address issues of public concern. Aims for the first two years have been set based on current emerging concerns. Across the theme projects there is an initial focus on information gathering and the writing of reviews to identify key knowledge gaps that will drive the latter stages of this theme. This theme also includes a 20% responsive research capacity which may be utilised to respond quickly to any novel emerging issues. This has already happened. We have replaced a planned body of work on fracking because of the withdrawal of Government support for fracking within the UK. A new project on the health impacts of perfluorinated compounds has been included as a response to concerns raised by the Department for Environment, Food and Rural Affairs (DEFRA) and the Environment Agency (EA). If another issue emerges which is relevant to the HPRU the aims and projects may be rearranged at any time to provide response capacity.