From killing over 600,000 elderly from dementia to an almost equal number of infants under the age of one-year, air pollution’s impact on young and old is explained simply through hard-hitting numbers in the latest State of Global Air  (SOGA) report, by the Boston-based Health Effects Institute. The report identifies plenty of scope for immediate policy action with multiple benefits for reducing an estimated 7.9 million deaths annually from air pollution. 

Dementia attributable to air pollution resulted in 626,000 deaths in 2023, a new report finds. That is more than one death every minute. 

This is the first time that the State of Global Air, an annual assessment of air quality worldwide, includes information about the burden of dementia attributable to air pollution – including some 28% of total dementia deaths every year.  

The new data is based on the 2023 Global Burden of Disease study by the Institute for Health Metrics and Evaluation (IHME), reflecting the growing epidemiological evidence about the higher levels of dementia disease and deaths in cities and regions that are more polluted.  

“The scientific evidence linking air pollution to increased dementia risk is now strong enough to justify policy action, even as research continues to refine causal mechanisms,” Dr Burcin Ikiz, a neuroscientist at Stanford University, told Health Policy Watch, adding that now, “multiple (studies) have shown consistent associations between long-term exposure to fine particulate matter (PM₂․₅), nitrogen oxides, and other traffic-related pollutants and higher rates of cognitive decline, Alzheimer’s disease, and all-cause dementia.”

Effects on brain health at all stages of life 

On both sides of the lifecycle, however, the toll is high. Air pollution contributed to 7.9 million deaths in 2023, including more than five million deaths from a range of non-communicable diseases in older adults. 

But it also kills approximately 610,000 babies under the age of one year old, who are more susceptible to pneumonia and other serious infections as a result of exposures to both fine particulates (PM 2.5), as well as ozone, and other noxious pollutants. 

As the report notes, “babies born prematurely or with low birth weight are more susceptible to lower respiratory infections and other serious infections, diarrheal diseases, inflammation, blood disorders, jaundice, and impacts on brain development. 

“If affected babies survive infancy, they remain at a higher risk for lower respiratory tract infections, other infectious diseases, and major chronic diseases throughout life.”

“We can’t say we didn’t know,” said George Vradenburg, founding chairman of the Davos Alzheimer’s Collaborative. “The evidence linking air pollution and dementia is now undeniable – and the story starts long before old age. Brain health begins before birth, shaped by the air a mother breathes and the environment a child grows up in. Policymakers have a chance to act on that science – to protect brain health across the lifespan and improve lives from the very start.”

Most air pollution deaths in lower-income countries

Most of the 7.9 million deaths continue to occur in lower-income countries, and more men than women died due to air pollution, the latest data also shows.

Source: State of Global Air, 2025.

Exposure to PM 2.5 has actually increased in seven of the world’s most populous countries between 2013 and 2023, the highest being in Nigeria, followed by Indonesia, Pakistan, Bangladesh, India, Brazil and Iran. 

Conversely, the biggest decreases in PM 2.5 exposure were seen in France, China and Germany. 

Despite massive reductions in ambient air pollution levels over the past decade,  China continues to be the world’s leading air pollution epicentre in terms of overall mortality – due to its sheer size. Other mortality hotspots include India and neighboring countries in South-East Asia along with Egypt and Nigeria.

There is some good news. Thanks to household air pollution (HAP) declining with the shift to cleaner cooking fuels, related deaths among women and young children who spend the most time around cookstoves, have been reduced. 

The trend has been most marked in India, Ecuador and China, although in parts of Africa household air pollution levels are also going down. In some countries, however, those gains have been offset by rising deaths due to ambient PM 2.5 and ozone pollution. 

Noncommunicable diseases are the cause of most air pollution-related deaths

About 95% of air pollution-related deaths in adults over the age of 60 are due to noncommunicable diseases – accounting for 5.8 million deaths in all.

Air pollution, especially small particulate (PM 2.5) exposure, is a leading risk factor for NCDs including: ischaemic heart disease, hypertension, chronic lung disease (COPD) and other lung diseases, as well as lung cancer and Type 2 diabetes. NCDs are now responsible for 65% of healthy life years lost, and 75% of deaths every year, according to the Seattle-based IHME. 

Even short-term exposures when PM 2.5 and other pollutant levels spike over a couple of days can result in health complications, increasing heart attacks, strokes and related hospitalization, as well as reducing the effectiveness of some chronic disease treatments, such as for cancer. 

Impacting on all forms of dementia

Exposure to PM 2.5 is associated with Alzheimer’s disease as well as other forms of dementia (e.g., vascular dementia), and mild cognitive impairment in older adults. These disorders can cause problems with thinking, memory, and decision-making, and typically worsen over time.

About 10 million people develop dementia each year, with incidence rising as the global population ages. The economic impact of this disease is estimated at over a trillion dollars a year, since people with dementia are dependent on daily care. A high prevalence of this disease has rippling effects on economic productivity for families and caregivers. Women bear the largest burden, being both more likely to provide care for people with dementia and are more likely to develop dementia themselves.

The report explains how air pollution, in particular PM 2.5, causes brain damage. The fine pollutants penetrate the lungs, circulating through the blood stream, and thus flowing to the brain, causing inflammation and brain tissue damage. 

While dementia largely affects the elderly population, air pollution exposure may also impact brain development and functioning in younger people, including an increased risk for neurodevelopmental disorders such as autism and psychological disorders such as anxiety and depression.

Scientists contributing to the report have called for more research on questions such as pollutant-specific effects, critical exposure windows across the lifespan, and risks in under-studied populations, particularly in low- and middle-income countries, where multiple environmental and socioeconomic factors may be harming the brain simultaneously.

Because air pollution affects such a broad swathe of the population in heavily polluted areas, even a small increase in neurodegeneration can have major effects at the societal scale.

Ozone pollution rising

The global average exposure to ambient ozone pollution has steadily increased since 1990, with the average exposure in 2020 reaching 49.8 parts per billion (ppb). At the country level, Qatar (67.6 ppb) had the highest exposure to ozone pollution, with Nepal (67.5 ppb), India (67.2 ppb), Bangladesh (65.4 ppb), and Bahrain (64.3 ppb) making up the remaining top five countries with the highest exposure. 

In the last two decades, the disease burden of ozone has increased by more than 50%, from 261,000 deaths in 2000 to 470,000 deaths in 2023.

Ground-level, or tropospheric, ozone is a pollutant that harms human health, damages plants, and contributes to climate change. It’s seen as a super pollutant, warming agents that are far more potent than carbon dioxide per ton; they have significant, harmful effects on both human health and the environment.

Ozone is formed through chemical reactions between nitrogen oxides, produced by burning fossil fuels, so places with heavy traffic are vulnerable, and volatile organic compounds (VOCs), in the presence of sunlight. 

Multiple benefits from pollution reductions

The report advocates for the multiple benefits of reducing air pollution exposure, including slowing climate change, reducing pollution-related illnesses, improving economic productivity, and healthcare savings. 

This poses an existential question to decision-makers and leaders in their fifties today, but who may also be more personally vulnerable to air pollution tomorrow. How should they factor in SoGA’s findings in their areas of work, many of which no doubt will have a bearing on air pollution emissions?

For example, every dollar spent on reducing air pollution in the United States, which passed its landmark Clean Air Act in 1970, has resulted in approximately $30 in benefits. In Delhi, with a much shorter historical record, the economic value of air pollution abatement still exceeds costs by 2 to 3.6 times, the report stated, citing World Bank data. 

Indeed, the latest SoGA report should further bolster demand for and action towards better air quality, its authors say. 

“Many people in decision-making roles are often at ages where the impacts can be more pronounced. Clean air action is an important way of helping ensure good health and better quality of life for all,” Pallavi Pant, head of Global Initiatives at Health Effects Institute, Boston, told Health Policy Watch. 

“The data presented in the State of Global Air report highlight the significant impacts of poor air quality on the health and well-being of billions of people around the world, especially those living in Asia and Africa,” said Pant, who oversaw the report’s preparation. “We hope this report can further bolster the demand for, and action towards, better air quality where it’s needed most.”

Image Credits: Photo by Steven HWG on Unsplash, HEI/State of Global Air , HEI/State of Global Air, HEI/State pf Global Air , Pixabay, WHO.