2027-B13 Health risks from individual and synergistic heat and air pollution under climate change

PROJECT HIGHLIGHTS

  • Tackle an urgent global health challenge: quantify how extreme heat and air pollution interact to increase mortality, and identify the populations and regions most at risk. 
  • Work with cutting-edge climate data: use emerging CMIP7 simulations to project future compound heat–air-pollution events and associated health impacts across the twenty-first century. 
  • Strong policy and research impact: collaborate with the Met Office Hadley Centre to evaluate mitigation strategies and generate evidence to support integrated climate, air-quality and public-health policy. 

Overview

Extreme heat and air pollution are among the leading environmental threats to human health. They frequently occur together, yet their health impacts are still commonly assessed independently. This is important because simultaneous exposure may produce health effects greater than expected from either hazard alone. As climate change intensifies heat extremes and alters patterns of PM2.5 and ozone, understanding these interacting risks is increasingly important for climate adaptation, air-quality management and public-health protection. 

Our recent analysis across England and Wales provides compelling evidence of this interaction. In London, when temperature and PM2.5 simultaneously exceeded their 97.5th percentiles, the relative risk of all-cause mortality reached 1.51, with a relative excess risk due to interaction of 0.33. Synergistic effects were particularly strong for respiratory mortality, while older adults and females showed greater susceptibility (Fig. 1). Importantly, applying London’s higher absolute PM2.5 thresholds to other regions revealed similar synergistic effects where sufficient co-exposure occurred, suggesting that interactions may become especially important once pollution exceeds critical concentrations. 

These findings raise an urgent wider question: how important are synergistic heat–air-pollution health risks globally, and how will they change as the climate warms? Existing studies have examined historical interactions or projected future compound events, but a globally consistent framework linking observed synergistic mortality effects with future climate and air-pollution change is currently missing. 

This studentship will address this gap through four linked objectives: 

  • Establish how heat, PM2.5 and ozone have individually and synergistically affected mortality across different regions and vulnerable populations. 
  • Determine how the frequency, intensity and geographical distribution of compound heat–air-pollution events will change under future climate and emission scenarios. 
  • Quantify future mortality attributable specifically to synergistic exposure and determine where conventional single-hazard assessments underestimate health risks. 
  • Evaluate the health benefits and economic implications of alternative climate and air-quality mitigation strategies. 

By connecting observed health responses with emerging CMIP7 projections, the project will provide a global assessment of compound heat–air-pollution risks from the past through the twenty-first century. It will identify emerging hotspots and vulnerable populations and establish where integrated climate and air-quality interventions can deliver the greatest public-health benefits. 

Figure 1. The Relative excess risk due to interaction (RERI) between extreme heat and PM2.5 (97.5th percentile) in London. Results are presented for lags of 0–2 days. Higher RERI estimates were observed for respiratory mortality, for females, and for older age groups, suggesting greater susceptibility in these subpopulations. 

Multi-panel forest plot showing relative risk estimates (RERI) for mortality associated with different causes of death and population groups. Panels compare total, circulatory, respiratory, and other-cause mortality, as well as results by sex and age group. Points with error bars represent estimates for 1990, 1991, and 1992, with a horizontal dashed line marking the null value (RERI = 0). Respiratory mortality and older age groups generally show the highest positive risk estimates.

Case Projects

This project does not offer a CASE studentship

Host

  • University of Birmingham

Theme

  • Climate and Environmental Sustainability

Supervisors

Project investigator

Co-investigators

How to apply

Each host has a slightly different application process.
Find out how to apply for this studentship.

All applications must include the CENTA application form.
Choose your application route

  1. Historical synergistic health effects. Global daily mortality, temperature, PM2.5 and ozone datasets will be assembled to quantify individual and compound health effects. Time-stratified case-crossover or comparable epidemiological models will estimate exposure–response relationships and interactions, with analyses stratified by age, sex, cause of death and region. 
  2. Future compound exposure. Daily temperature, PM2.5 and ozone fields from CMIP7 will be evaluated in different countries/cities. Compound heat–pollution events will then be characterised under contrasting climate and emission scenarios. 
  3. Future synergistic health impacts. Historical exposure–response relationships will be applied to future climate, pollution, population and mortality projections to estimate heat-, pollution- and interaction-attributable mortality through the century. 
  4. Mitigation strategies. Alternative greenhouse-gas and air-pollution mitigation pathways will be compared in terms of avoided compound events, avoided deaths and, where suitable data are available, their relative costs and health benefits. 

DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.  

  • Training on CMIP7 modelling meteorological and air pollution (PM2.5, ozone) outputs 
  • R programming skills and machine learning. 
  • Efficient use of high-performance computer for data processing. 
  • Specific training on literature reading, review and scientific writing, and proposal writing will be provided on a regular basis during weekly supervisory meetings.  

Dr Steven Turnock (Met Office Hadley Centre) brings expertise in climate–air-quality interactions, atmospheric composition modelling and the health impacts of air pollution. His recent work has quantified future PM2.5- and ozone-related health burdens under alternative mitigation pathways and examined historical drivers of ozone-related mortality. He is also a contributor to AerChemMIP2, the atmospheric chemistry component of CMIP7, which will provide key future air-quality and climate simulations for this project. Collaboration with the Met Office will provide expertise in CMIP7 interpretation, model evaluation and translation of climate–air-quality projections into policy-relevant health evidence. 

Year 1 – Historical synergistic health effects
Compile and harmonise global mortality, temperature, PM2.5 and ozone datasets. Develop and validate the epidemiological framework for estimating individual and synergistic mortality effects, including analyses by age, sex, cause of death and region. Extend the England and Wales analysis to multi-country datasets and identify geographical variation in susceptibility when available. Complete relevant statistical, epidemiological and climate-data training. Output: first paper on historical global heat–air-pollution interactions. 

Year 2 – Future compound heat and air pollution
Acquire and evaluate daily temperature, PM2.5 and ozone output from CMIP7. Bias-correct model simulations against observations and characterise historical model performance. Quantify changes in the frequency, intensity, duration and spatial distribution of compound heat–PM2.5 and heat–ozone events under contrasting climate and emission pathways. Output: second paper on future global compound exposure. 

Year 3 – Future synergistic mortality risks
Combine CMIP7 projections with epidemiological exposure–response relationships, population projections, demographic change and baseline mortality. Quantify future mortality attributable to heat, air pollution and their interaction, and determine how much risk is missed when hazards are assessed independently. Identify future hotspots and vulnerable populations. Output: third paper on future compound health burdens. 

Year 4 – Mitigation, synthesis and policy implications
Evaluate climate, air-quality and integrated mitigation pathways in terms of avoided compound exposure and premature mortality. Where suitable data are available, assess mitigation costs alongside monetised or quantified health benefits to identify cost-effective strategies. Integrate findings across historical and future analyses, undertake uncertainty and sensitivity analyses, engage with relevant stakeholders, and complete thesis writing and dissemination. Output: mitigation/policy paper and PhD thesis. 

  1. Tong, C., Dai, Y., Hall, J., Chung, C.Y., Liu, B., Chen, X., Smith, E.R., Neal, L.S., Agnew, P., Turnock, S. and Shi, Z. (2026) ‘Higher air pollution amplifies mortality risks from extreme heat in England and Wales’. Under review in Nature Communications (available on request)
  2. Stafoggia, M. et al. (2023) ‘Joint effect of heat and air pollution on mortality in 620 cities of 36 countries’, Environment International, 181, 108258. https://doi.org/10.1016/j.envint.2023.108258.
  3. Turnock, S.T. et al. (2020) ‘Historical and future changes in air pollutants from CMIP6 models’, Atmospheric Chemistry and Physics, 20, pp. 14547–14579. https://doi.org/10.5194/acp-20-14547-2020.
  4. Turnock, S.T., Reddington, C.L. and West, J.J. (2023) ‘The air pollution human health burden in different future scenarios that involve the mitigation of near-term climate forcers, climate and land-use’, GeoHealth, 7(8), e2023GH000812. https://doi.org/10.1029/2023GH000812.
  5. Clayton, C.J., Turnock, S.T., Marsh, D.R., Graham, A.M., Reddington, C.L., Vohra, K. and McQuaid, J.B. (2025) ‘Reducing inequities in the future air pollution health burden over Europe’, Earth’s Future, 13(5), e2024EF005404. https://doi.org/10.1029/2024EF005404. 
  6. Zhang, X. and Gao, M. (2026) ‘Unveiling future individual and compound heat and air pollution extremes in China: Insights for mitigation’, Bulletin of the American Meteorological Society, 107(8). https://doi.org/10.1175/BAMS-D-25-0333.1. 

Further details and How to Apply

For any enquiries related to this project please contact:

Zongbo Shi

School of Geography Earth and Environmental Sciences 

University of Birmingham 

Birmingham 

B15 2TT 

United Kingdom 

Email: [email protected] 

Telephone: 01214149128 

 To apply to this project:  

  • You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.  
  • Please submit your application and complete the host institution application process via: https://admissions.bham.ac.uk/course-finder-landing-page/?code=LES068 Please select the PhD in Geography (CENTA) 2027 entry year Apply Now button. The CENTA Studentship Application Form 2027 and CV can both be uploaded to the Personal Statement section of the online form.  In the funding section of the online form please select Research Council Funding and then choose Natural Environment Research Council (NERC).  Please quote CENTA 2027-B13 when completing the application form.  

 Applications must be submitted by 23:59 GMT on Wednesday 6th January 2027.   

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