A researcher from The University of Manchester has contributed to a major World Health Organization (WHO) update revealing that global progress on reducing air pollution has slowed, with low- and middle-income countries continuing to face the greatest risks.
The new estimates, published by the WHO as part of its monitoring of the UN Sustainable Development Goals (SDGs), shows that while levels of fine particulate matter (PM2.5) declined globally up to 2020, they have since remained largely unchanged.
The new estimates will support global efforts to towards the WHO's new goal to cut deaths linked to anthropogenic (man-made) air pollution by 50% by 2040, providing a critical evidence base for international policy and action.
Dr Matthew Thomas, a Lecturer in Data Science & Analytics at The University of Manchester and Research Scientist at the National Centre for Atmospheric Science, developed the Data Integration Model for Air Quality (DIMAQ) in collaboration with the World Health Organization (WHO) during his PhD. Since 2016, DIMAQ has underpinned the WHO's global estimates of population exposure to ambient air pollution. This latest release, the first since 2021, incorporates new data and methodological advances to provide the most up-to-date assessment of global air pollution trends and inequalities.
Dr Thomas's work contributes directly to monitoring SDG indicator 11.6.2, which tracks annual levels of fine particulate matter (PM2.5) in cities, and SDG 3.9.1, which tracks the mortality rate attributable to ambient and household air pollution.
DIMAQ brings together satellite observations, atmospheric models, and ground-based monitoring data to provide a consistent picture of air pollution levels around the world, enabling meaningful comparisons between countries.
The updated figures highlight significant disparities between countries. In 2023, exposure to PM2.5 above the WHO Air Quality Guidelines was more than 13 times higher in low- and middle-income countries than in high-income countries, affecting around 6.5 billion people worldwide.
Exposure to both ambient and household air pollution remains a major driver of non-communicable diseases, including heart disease, stroke, chronic respiratory conditions and lung cancer, with the greatest burden falling on vulnerable populations.
Regional trends highlight mixed progress. While Asia bears the highest levels of air pollution, it also displays the greatest progress, while other regions, including Africa and Western Asia, have seen little change over the last decade.
Urban areas typically experience higher pollution levels than rural areas, but cities have also shown stronger improvements irrespective of their income level. In contrast, some rural areas, particularly in low-income countries, have seen pollution increase.
Bruce Gordon, Director a.i., Environment, Climate Change, One Health and Migration, WHO, said: "As the custodian of environmental health-related SDG indicators, WHO is committed to providing robust, evidence-based data, which is essential for bold decision-making. We cannot address the climate and air pollution crisis or protect public health without reliable information that highlights global inequalities and disparities. Placing science at the forefront to drive monitoring and foster multi-sectoral collaboration is crucial to ensuring universal access to clean air and energy, safeguarding both the health of people and planet-now and for future generations."
The ongoing use of Manchester-developed research highlights the University's contribution to tackling one of the world's most pressing environmental health challenges.
The work builds on Dr Thomas's wider research in modelling for global public health, spanning air pollution, environmental exposure assessment and environmental epidemiology. Previous iterations of DIMAQ highlighted that half of global population were experiencing increasing concentrations of PM2.5 in the early 2010s. Other works include personal exposure modelling to provide a more realistic assessment of exposure to air pollutions as we interact with the environment. His research aims to help provide the evidence needed to support public health policy and decision-making worldwide.
