Human health in an increasingly urbanized and warming world

Both natural and man-made environments present serious hazards to human health. Exposure to risk factors such as air pollution, hot and cold weather and extreme events can cause reductions in general health and wellbeing, illness, hospitalization and even death. In the UK, an estimated 29,000 deaths are associated with particulate matter (PM) air pollution each year. In August 2003, a severe heatwave across Europe led to over 2,000 deaths in England, and 15,000 in France. It is estimated that this heatwave was responsible for up to 70,000 deaths over Europe as a whole.

Urban populations are especially vulnerable to the risks from environmental hazards. For example, air pollution tends to be higher in cities, and the extra warming due to the urban heat island effect (which describes the increased temperature experienced in towns and cities compared with rural areas) leads to heat-related health impacts, including mortality. The Urban Heat Island (UHI) interacts with air pollution and can make it worse in cities, especially during heatwaves. Urban surfaces can even interact with weather systems and alter rainfall levels, leading to urban flooding from surface water runoff.

Risks to health from environmental hazards in urban areas are increasing, due to the effects of climate change, increasing urbanization and ageing (more vulnerable) populations in most parts of the world. In 2010, more people across the world were classed as living in urban areas than rural areas for the first time. The UK is particularly urbanized; according to the 2011 census, 85% of people are classed as living in urban areas. The 2017 UK Government's Climate Change Risk Assessment highlights the need for more research into the health impacts of climate change, particulary for heat, and acknowledged the increased risks to health for urban populations. Climate change will exacerbate the effects of heat on health, through increases in mean temperature and more frequent and intense heatwaves. It is also likely to modify rainfall patterns, and alter concentrations of air pollutants such as ozone and PM, all of which will affect health.

Policies relating to climate change mitigation or adaptation require robust scientific evidence of the potential range of health impacts from multiple factors before implementation. Planned 'environmental change' in the form of interventions such as urban greening and building adaptation measures are designed to reduce future climate change as well as to adapt to the consequences of it. However, urban or building level interventions may also result in unintended negative health impacts such as increased air pollution, and these should be fully understood before measures are widely adopted.

Relating environmental factors to population exposure requires a multi-disciplinary approach using a combination of epidemiological analysis, exposure assessment and chemistry or climate modelling. This process can be challenging, and a number of limitations may affect each stage of the Health Impact Assessment (HIA) process, including a lack of observational data, or insufficient representation of urban areas in modelling studies to assess temperature or air pollution exposure. The work proposed here will improve the representation of urban areas within regional meteorological and chemistry-climate models; investigate health impacts relating to the UHI and the impacts of the UHI on indoor temperature (where people spend the majority of their time) and the potential costs and benefits to health from a range of urban planning interventions.

Quantifying existing health impacts in urban environments as well as the additional risks relating to climate change and planned environmental change will strengthen the evidence base for health impacts in the urban environment, help to inform public health, air pollution and urban planning policies, and will ultimately lead to an increase in the health of the population.

The multi-disciplinary and applied nature of the proposed research, which is at the academic - policy interface, ensures there are likely to be applications for the public health, environmental and urban planning sectors, policymakers, national and local Government, and the general public. The research also has the potential to address questions which are often not broached in individual disciplines. I believe I am in a unique position, with experience working across meteorology, climate change and public health, which will enable me to advance the understanding of the potential impacts of climate change on health, in urban environments. In particular, I intend to produce research outputs which can feed into and influence policy measures about adaptation to, and mitigation of climate change, reducing the impacts of air pollution and building resilience to risks from overheating in urban areas.

Benefits of the proposed research include strengthening the evidence base and quantification of the potential risks from environmental change, which will aid policymakers. Urban planners will benefit from guidance based on scientific evidence as to the effects of environmental change on indoor temperatures when tailoring housing designs to be 'climate-ready' in future. My research to date has been cited as evidence in the Climate Change Risk Assessment, the National Adaptation Programme and the IPCC Special Report on Extreme Events. Policy documents such as the PHE Heatwave Plan for England are based on the latest research available, and my research on the UHI and air pollution can make an advance here.

Air pollution is currently a high priority in the environmental public health strategy for Public Health England, and represents a high priority for Government. Improvements to air quality modelling techniques used to calculate health impacts are therefore vital to the air pollution and public health communities. There will be benefits for policymakers who are interested in reducing health impacts from climate change and air pollution, for example, local authorities such as Greater London Authority and Birmingham City Council, as well as the chemistry-climate modelling community.

Finally, since climate change and environmental hazards affect every one of us, the research proposed is likely to have positive impacts on the health of the general population, and may help vulnerable groups to avoid exposure, and reduce risks to health. I will therefore continue my collaboration with public health professionals, Governmental and non-Governmental bodies, and through Public Health England to ensure that I respond to the needs of policymakers and that my research addresses areas of broad societal importance as much as possible.