One Hour of Air Pollution Exposure Impairs Brain and Lung Functions

A new study has found that breathing polluted air for only one hour can impact both brain and lung functions, including among healthy people.

Air pollution, particularly fine particulate matter (PM), is recognized as a major factor linked to serious health issues such as asthma and certain cancers, as well as an increasing association with potential cognitive impairments.

In this research, scientists exposed a group of adults over 50 years old, all with a family history of dementia but none diagnosed with it, to five different types of air for 60 minutes. The exposures included clean air, limonene gas (a citrus-scented compound used in cleaning products), diesel exhaust, wood smoke, and cooking emissions.

The average age of participants was 60, with the majority being men and white.

Following the exposure period, participants rested for four hours before undergoing tests measuring lung function, attention, working memory, emotion processing, motor response speed, and executive brain functions.

Results indicated that respiratory effects were strongest in those exposed to limonene gas, followed by wood smoke, diesel exhaust, and lastly cooking emissions, with slight decreases in lung function observed in some groups.

Regarding brain function, diesel exhaust had the most pronounced impact on executive functions, which govern planning, focus, and emotional control.

Researchers suggest these effects may stem from pollutants like nitrogen oxides affecting cerebral blood flow, thereby reducing brain efficiency.

Although exposure lasted only an hour, the study’s authors warned that repeated exposure to these pollutants over time could result in more serious health consequences, including potential cognitive problems.

Dr. Thomas Faherty, the study’s lead author and a postdoctoral researcher at the University of Birmingham, stated: "This study highlights the important link between lung and brain responses to air pollution."

He added: "Safely exposing participants to a realistic mix of pollutants allowed us to observe differences in the effects of each type, showing that the pollution source and chemical composition are key factors in determining its impact on the body."

Particulate matter originates from multiple sources such as vehicle exhaust, power plants, wildfires, and fuel combustion. Its small size enables it to penetrate deep into the lungs and enter the bloodstream.

Once inside the body, these particles can cause inflammation, affect blood vessels, raise blood pressure, increase arterial plaque buildup, and damage cells through oxidative stress.

Previous studies have linked fine particulate matter (PM2.5) to a higher risk of dementia; one study found that a slight increase in PM2.5 concentration could raise Alzheimer’s disease risk by approximately 9%.

The researchers emphasized the need for further studies on the long-term effects of various types of air pollution to better understand its relationship with public health and to develop more effective policies to protect vulnerable populations.