Climate policy must consider cross-border pollution “exchanges” to address inequality and achieve health benefits, research finds

(Press-News.org) Ambitious climate action to improve global air quality could save up to 1.32 million lives per year by 2040, according to a new study.

The research, led by Cardiff University, shows how developing countries rely heavily on international cooperation to see these benefits, because much of their pollution originates outside their borders.

The first-of-its-kind study analysed these cross-border pollution “exchanges” for nearly every country – 168 in total.

Their findings, published in Nature Communications, reveal how a fragmented world, with little collaborative climate mitigation policymaking, would lead to greater health inequality for poorer nations who have less control over their own air quality.

Their work focuses on the impact of fine particulate matter (PM2.5), exposure to which is the leading environmental risk factor for premature deaths globally.

Lead author Dr Omar Nawaz from Cardiff University’s School of Earth and Environmental Sciences, said: “While we know climate action can benefit public health, most research has ignored how this affects the air pollution that travels across international borders and creates inequalities between countries.

“Our analysis shows how climate mitigation decisions made in wealthy nations directly affect the health of people in the Global South, particularly in Africa and Asia.”

The team, which includes researchers at the University of Colorado Boulder, used advanced atmospheric modelling and NASA satellite data to simulate different future emissions scenarios for the year 2040.

Together with a health burden estimation, these data enabled the researchers to understand who benefits—and assess different levels of dependency—when countries implement climate mitigation policies.

“We wanted to see how the health benefits of action on climate change could differ when there is greater or weaker global cooperation,” explains Dr Nawaz. 

“We were surprised to find that although Asia sees the most total benefits from climate action to its large share of the population, African countries are often the most reliant on external action, with the amount of health benefits they get from climate mitigation abroad increasing in fragmented future scenarios.”

The team’s projections also show the balance of pollution flowing across borders may shift, even when total global air pollution declines.

This is vital information for policymakers and global aid organisations as they seek to address climate change challenges amidst domestic and international priorities.

Co-author Professor Daven Henze of the Department of Mechanical Engineering at the University of Colorado Boulder added: “Some climate policies could inadvertently make air pollution inequalities worse, specifically for developing nations that might rely heavily on their neighbours for clean air. It’s thus not sufficient to focus only on domestic co-benefits. More inclusive climate strategies entail explicitly accounting for evolving transboundary inequalities.

“Holistic climate policy should therefore evaluate how dependent a nation is on others’ emissions reductions, how mitigation scenarios reshape air-pollution flows across borders, and whether global efforts are helping or harming equity.”

The team plans to develop their analysis further by exploring how climate change itself alters the weather patterns that transport this pollution, as well as looking at other pollutant types like ozone and organic aerosols.

Their paper, ‘National climate action can ameliorate, perpetuate, or exacerbate international air pollution inequalities’, is published in Nature Communications.

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Notes to editors

Paper

The paper will appear online via the journal website at 10am GMT/5am ET on Thursday 12 February 2026.

The digital object identifier (DOI) number for this paper will be 10.1038/s41467-026-68827-0

Interviews

Interviews with the research team are available on request.

For more information contact: 

Jonathan Rees 

Communications and Marketing  

Cardiff University 

ReesJ37@cardiff.ac.uk  

Cardiff University is recognised in independent government assessments as one of Britain’s leading teaching and research universities and is a member of the Russell Group of the UK’s most research-intensive universities. The 2021 Research Excellence Framework found 90% of the University’s research to be world-leading or internationally excellent. Among its academic staff are two Nobel Laureates, including the winner of the 2007 Nobel Prize for Medicine, Professor Sir Martin Evans. Founded by Royal Charter in 1883, today the University combines impressive modern facilities and a dynamic approach to teaching and research. The University’s breadth of expertise encompasses: the College of Arts, Humanities and Social Sciences; the College of Biomedical and Life Sciences; and the College of Physical Sciences and Engineering. Its University institutes bring together academics from a range of disciplines to tackle some of the challenges facing society, the economy, and the environment. More at www.cardiff.ac.uk

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