The long-known negative effects of air pollution on the lungs and cardiovascular system are just the tip of the iceberg. More and more scientific studies are pointing out that substances and particles in polluted air can also significantly damage the human brain and contribute to the development of serious neurological diseases, including Alzheimer's disease and dementia.

Research from around the world has long suggested that up to 90% of the world's population breathes air that exceeds the safe limits set by the World Health Organization (WHO). The main causes are increasing urbanization, climate change, worsening urban traffic and the increase in forest fires. In addition to outdoor sources, household air pollution is a particular problem, which threatens the world's most vulnerable and poorest communities the most. It is estimated that around three billion people cook over open fires or on stoves burning wood, coal, kerosene or biomass.

Scientists are uncovering increasingly concrete evidence of a direct link between air pollution and neurological disorders. For example, studies in Mexico City have shown the occurrence of pathological changes typical of Alzheimer's disease in children. These alarming findings are complemented by research from the United States, according to which the risk of developing dementia is almost twice as high in older women who live in areas severely affected by air with increased concentrations of health-threatening particles.

One of the most dangerous factors is small PM (particulate matter) particles, especially PM2.5 with a diameter of less than 2.5 micrometers, which come from car exhaust, smoke and burning materials. Even smaller ultrafine particles (less than 0.1 micrometers) may be even more dangerous, according to scientists, but their regulation is still insufficient and inconsistent. These particles can bypass the protective barriers of the human body and penetrate the brain through the olfactory nerve or bloodstream. They bring with them harmful contaminants such as dioxins, chemical compounds and heavy metals, which directly damage nerve cells and cause dangerous inflammatory processes.

Furthermore, animal experiments have shown that exposure to air pollution during pregnancy and early development of offspring causes permanent neurological changes, including reduced learning abilities, loss of nerve connections (synapses) and earlier formation of amyloid plaques typical of Alzheimer's disease. In other studies on rodents, social behavior disorders, autism-like changes and memory impairment have been observed.

Human studies also confirm these risks. Scientists in the Canadian province of Ontario have shown that living away from major roads and busy traffic routes reduces the risk of dementia. A similar study in Barcelona, Spain, showed that children who attend schools exposed to heavy traffic have slower cognitive abilities. A large American study found that women living in areas with high concentrations of PM particles are up to twice as likely to develop dementia.

These results clearly confirm that reducing air pollution is not only a health but also an economic priority. Experts point out that any reduction in emissions would significantly reduce the number of cases of neurological diseases, especially Alzheimer's disease and dementia, thereby saving significant financial resources in health and social systems.

Although many questions remain unanswered, scientists unanimously call for urgent action to limit emissions from transport, households and industry. Stricter standards for diesel cars, support for clean mobility, the use of better fuels and the reduction of other sources of pollution are essential.

The world is facing a serious challenge. Our air is becoming a risk not only to the environment and our lungs, but also to the most vulnerable and sensitive part of our body: our brain. It is high time to act - our mental health, quality of life and the future of future generations are at stake. Spring

The entire study was published in the journal  Proceedings of the National Academy of Sciences .