A study recently published in The Lancet Healthy Longevity journal shows that air pollution "can slow mental processing, impair memory, and cause changes in brain structure in old age, accelerating cognitive decline," according to the Spanish news agency EFE.

On the other hand, a study by the Spanish Society of Cardiology (SEC) and the Spanish Heart Foundation (FEC) found that air pollution increases hospitalizations and mortality from acute myocardial infarction during hospitalization, which, on days with high levels, can increase by up to 14%, according to EFE.

The first study investigated British citizens born after 1946, focusing on middle-aged adults (45 to 64 years old), and assessed their exposure to nitrogen dioxide (NO₂), nitrogen oxides (NOₓ), and fine particulate matter (PM₁₀ and PM₂₅).

Suspended particulate matter includes mineral and/or organic substances that can be found in the atmosphere in liquid or solid form. The most harmful to human health are those with an aerodynamic diameter of less than 10 µm, known as PM₅, as they can enter the respiratory system, explains the Portuguese Environment Agency.

When the participants were between 69 and 71 years old, their cognitive performance and brain structure were analysed through memory tests, processing speed, and brain imaging using magnetic resonance imaging.

The results show that increased exposure to nitrogen dioxide and particulate matter during middle age is associated with slower mental processing and a decline in cognitive function.

According to EFE, the scientists also observed that high levels of nitrogen oxides were associated with a reduction in hippocampal volume, while exposure to nitrogen dioxide and particulate matter was linked to dilation of the cerebral ventricles, indicators typically associated with brain atrophy.

The fact that the research reveals new evidence that air pollution has lasting effects on the human brain, beyond its physical health consequences, reinforces, according to the authors, the need to advance emissions reduction policies as an essential public health strategy to protect brain function in the long term.

For the cardiology study, data from 122 hospitals in the Spanish National Health System with environmental measuring stations located within a 10-kilometer radius and information on 115,071 patients over 18 years of age diagnosed with acute myocardial infarction between 2016 and 2021 were analysed.

The results showed that PM 2.5 particle concentrations greater than 10 micrograms per cubic meter in the three days prior to hospitalization are associated with a significant increase in hospital admissions for acute myocardial infarction, with up to 22 additional heart attacks for every 1,000 admissions.

Furthermore, when pollution levels are very high and exceed 25 micrograms per cubic meter, the risk of mortality increases by 14%, meaning that for every 125 people admitted to hospitals, there is approximately one more death than on days with cleaner air, noted Raquel Campuzano, lead author of the study, as cited by EFE.

"These particles [PM 2.5 and PM 10] can cause inflammation in the body, alter blood vessel function, and increase the risk of clots," effects that "are directly related to the progression of atherosclerosis (hardening and narrowing of the arteries) and the rupture of plaques that form in them, which can trigger serious events, such as a heart attack," warned Jordi Bañeras, co-author of the study.