Air pollution was responsible for 8.1 million deaths worldwide in 2021, making it the second largest risk factor for death, including for children under five.

BOSTON/NEW YORK, 19 JUNE 2024 – Air pollution is having an increasing impact on human health and has become the second leading global risk factor for death, according to the fifth edition of the State of Global Air (SoGA) report.

The report, released today by the Health Effects Institute (HEI), an independent nonprofit research organization based in the United States, finds that air pollution was responsible for 8.1 million deaths worldwide in 2021. In addition, many millions more people live with debilitating chronic diseases that place a huge burden on health systems, the economy and society.

The report, produced for the first time in partnership with UNICEF, finds that children under five are particularly at risk. Health consequences include premature birth, low birth weight, asthma and lung disease. In 2021, exposure to air pollution was linked to more than 700,000 deaths of children under five, making it the second biggest risk factor for death for this age group globally after malnutrition. A staggering 500,000 of these child deaths were due to household air pollution caused by indoor cooking with polluting fuels, mostly in Africa and Asia.

A global health problem

The new SoGA report provides a detailed analysis of the recently released data from the 2021 Global Burden of Disease study, which shows the serious health impacts of pollutants such as outdoor particulate matter (PM_2.5), household air pollution, ozone (O₃) and nitrogen dioxide (NO₂) on human health worldwide. The report includes data for more than 200 countries and territories around the world and shows that almost everyone on Earth breathes harmful air pollution every day, with far-reaching health consequences.

More than 90 percent of these global deaths from air pollution – 7.8 million people – are due to PM._2.5 Air pollution, including particulate matter_2.5 and household air pollution. These tiny particles, less than 2.5 microns in diameter, are so small that they can stay in the lungs and enter the bloodstream, affecting many organ systems and increasing the risk of non-communicable diseases in adults such as heart disease, stroke, diabetes, lung cancer and chronic obstructive pulmonary disease (COPD). According to the report, PM_2.5 has been shown to be the most reliable and accurate indicator of poor health care worldwide.

“We hope our report on the state of global air quality will provide both information and inspiration for change,” said HEI President Dr. Elena Craft. “Air pollution has a huge impact on health. We know that improving air quality and global public health is practical and achievable.”

Air pollution and climate change

PM_2.5 Air pollution is caused by the burning of fossil fuels and biomass in areas such as transport, homes, coal-fired power plants, industry and wildfires. These emissions not only affect people’s health, but also contribute to the greenhouse gases that are warming the planet. The most vulnerable populations are disproportionately affected by both climate hazards and polluted air.

In 2021, long-term exposure to ozone contributed to an estimated 489,518 deaths worldwide, including 14,000 ozone-related COPD deaths in the United States, more than in other high-income countries. As the world continues to warm due to the effects of climate change, areas with high NO₂ Higher ozone levels are to be expected, which will have even more serious health consequences.

This year’s report contains for the first time the pollution levels and associated health effects of nitrogen dioxide (NO₂), including the effects of NO₂ Stress on the development of childhood asthma. Traffic emissions are a major source of NO₂which means that densely populated urban areas, especially in high-income countries, often have the highest NO levels.₂ Stress and effects on health.

“This new report is a stark reminder of the significant impact of air pollution on human health, with the burden borne far too heavily by young children, the elderly and low- and middle-income countries,” said Dr. Pallavi Pant, Head of Global Health at HEI, who oversaw the release of the SoGA report. “This is a clear sign that cities and countries should consider air quality and air pollution as risk factors when developing health policies and other programs to prevent and control non-communicable diseases.”

Children’s health

Some of the worst health effects of air pollution are seen in children. Children are particularly vulnerable to air pollution and the damage from air pollution can begin in the womb and have lifelong health consequences. For example, children breathe more air per kilogram of body weight than adults and absorb more pollutants while their lungs, bodies and brains are still developing.

Young children’s exposure to air pollution is linked to pneumonia, which accounts for one in five child deaths worldwide, and asthma, the most common chronic respiratory disease in older children. Inequalities related to the impact of air pollution on children’s health are striking. Death rates from air pollution among children under five in East, West, Central and Southern Africa are 100 times higher than those among children in high-income countries.

“Despite advances in maternal and child health, nearly 2,000 children under the age of five die every day from the effects of air pollution,” said Kitty van der Heijden, UNICEF Deputy Executive Director. “Our inaction has profound implications for the next generation, with lifelong impacts on health and well-being. The global urgency is undeniable. It is imperative that governments and businesses take these estimates and locally available data into account and use them to take meaningful, child-sensitive action to reduce air pollution and protect children’s health.”

Progress is being made

But the SoGA report also contains some good news. Since 2000, the mortality rate among children under five has fallen by 53 percent. This is largely due to efforts to improve access to clean energy for cooking, but also to improvements in health care and nutrition, and greater awareness of the dangers associated with exposure to air pollution in the home.

Many countries, especially those with the highest levels of air pollution, are finally tackling the problem head-on. Measures to improve air quality in regions such as Africa, Latin America and Asia, such as installing air pollution monitoring networks, implementing stricter air quality policies or offsetting traffic-related air pollution by switching to hybrid or electric vehicles, are having a measurable impact on pollution and improving public health.

While progress is being measured, more can be done to prevent air pollution from becoming one of the greatest threats to millions of lives, ahead of other health risks.

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Notes for editors:

Air pollution has become the second leading risk factor for death for both the global population and children under five. The top five risk factors for death in each category are:

This report on the state of global air quality was produced by the State of Global Air initiative, a collaboration between the Health Effects Institute and the Global Burden of Disease project of the Institute for Health Metrics and Evaluation in partnership with UNICEF.

The report is based on data from the Institute for Health Metrics and Evaluation’s Global Burden of Diseases, Injuries, and Risk Factors Study (GBD 2021). This collaboration of more than 10,000 researchers worldwide produces globally comparable estimates of the impact of 88 environmental, behavioral, and nutritional risk factors on health in 204 countries and global territories.

With each update, the GBD study incorporates the latest science and methods to refine estimates of the burden of disease – or the impact on population health – from air pollution and other risk factors. Note that the data presented here are global estimates based on a range of publicly available datasets and do not necessarily represent datasets submitted by national governments to UN agencies. All GBD estimates are subject to a rigorous peer review process and the data have been published in The Lancet.