How air pollution may be undermining your brain—one breath at a time

A decade-long study shows that specific pollutants, especially from industry and residential fuels, are linked to falls in memory, executive function and language skills in older adults.

Study: Cognitive performance and long-term exposure to outside air pollution: findings of the harmonized cognitive assessment protocol Substudy of the English longitudinal study of aging (Elsa-Hcap). Image Credit: Neil Bowman/Shutterstock.com

Although the relationship between air pollution and cognitive decline has been properly established, we still know surprisingly little about how specific types of air pollution influence different areas of cognitive functions – or how different emission sources play a role in this process.

A recent study published in The magazines of Gerontology shed new light on these questions, focus on older adults and investigates three important domains of cognitive performance for about a decade of exposure to air pollution.

Introduction

Cognitive decline is a common aspect of aging, so that both the quality of life and life expectancy is often reduced. Air pollution is estimated to contribute to 2.6% of the cases of dementia more than some better known risk factors such as high blood pressure or a sitting lifestyle.

Under various pollutants, nitrogen dioxide (NO₂) and fine particles smaller than 2.5 microns in diameter (PM2.5) have emerged as the most connected to cognitive disorders. These pollutants can harm the brain and cardiovascular system due to both direct exposure and systemic effects.

PM2.5 and NO₂ in particular come from multiple sources, and the physical and chemical composition of these emissions can vary. For example, traffic -related pollution is often rich in black carbon and nitrates, while agricultural emissions usually contain more ammonium.

These differences can influence the health results. In the US, for example, new cases of dementia are the strongest associated with PM2.5 from agriculture and forest fires.

This new study wanted to investigate how long -term exposure to various sources for air pollution relates to cognitive performance over time.

About the study

Researchers used data from the Harmonized Cognitive Assessment Protocol (HCAP) 2018, part of the English longitudinal study of aging (Elsa). They estimate average outdoor concentrations of NO₂, total PM2.5 and PM2.5 from specific sources in the course of the years 2008 to 2017.

They then assessed how these exposures are related to three cognitive domains – memory, executive function and language – as well as the overall cognitive function.

The analysis is adapted for potential confounders, including age, gender, socio -economic status, national versus urban location and educational background. Existing health problems were not charged.

Study findings

The average age of participants was 65. About 77% lived in urban areas. A quarter was in the highest socio -economic bracket, while 14% fell into the most disadvantaged quintile.

Between 2008 and 2017, the average NO₂ exposure was approximately 23 μg/m³, and from 2010 to 2017 the average PM2.5 levels were approximately 12 μg/m³. Encouraging both pollutants fell over time – not from 28 μg/m³ in 2008 to 21 μg/m³ in 2017, and PM2.5 decreased from 13.5 μg/m³ to 10.3 μg/m³ for a comparable strainage width.

Higher pollution levels were associated with lower cognitive scores, although this relationship followed a reverse J-shape. The worst global cognitive scores were observed at the highest levels of NO₂ and total PM2.5, in particular in residential environments. Executive function and memory followed similar patterns with PM2.5 lighting.

Interesting is that although the general cognitive function was not clearly influenced by the source of emissions, were language skills. Exposure to PM2.5 of industrial activities and combustion of residential fuel – including biofuel, oil, natural gas and coal – was consistently linked to poorer language performance.

These results correspond to earlier findings, although some earlier studies have demonstrated inconsistent connections between pollution and domain -specific cognitive results. What distinguishes this research is the identification of certain emission sources as potential contributors to language -related decline, which points to possible damage to the temporary lobe of the brain, which controls language processing.

Conclusions

This study contributes to a growing number of evidence that suggests that air pollution affects cognitive function, especially in older adults.

Although general cognition, memory and executive function all showed some vulnerability, the most consistent and specific impact on language power – was mainly in relation to emissions from industrial and residential sources of incinerations.

An alarming collection meals: all Participants were exposed to pollution levels that are larger than the 2021 air quality guidelines of the World Health Organization. This emphasizes an urgent need for more effective strategies for public health and environmental policy that is aimed at reducing pollution, in particular in risky areas.

Wider efforts can also include investments in housing, city planning, access to health care and environmental monitoring.