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Air Pollution Found to Decrease Some Cognitive Functions

  • Writer: FibonacciMD
    FibonacciMD
  • 5 days ago
  • 3 min read

New Research Links Poor Air Quality to Reduced Focus and Emotion Recognition


In a study published February 2025, researchers looked at the effect of air quality on cognitive function.  There were 26 subjects, mean age of 27.7 years, who performed cognitive tests and were then exposed either to air with high particulate matter concentrations or fresh air for one hour.  Four hours after exposure, the cognitive tests were repeated.  Lit candles were used to increase particulate matter in the air which was consistent with particulate matter in an urban area.  Participants in both the clear and polluted air groups did one session with nose clips just oral breathing and one session breathing both through the nose and the mouth. 


It was reported that there were significant reductions in selective attention (the ability to focus on one thing while ignoring distractions) and emotion expression discrimination (the ability to recognize differences between emotions as they are expressed through facial expressions, body language, vocalizations, and other cues) after particulate matter exposure when compared to subjects in the clean air breathing group.  Air quality did not significantly impact psychomotor vigilance (a person's ability to focus and respond to visual or auditory stimuli in a timely manner) or working memory performance (the ability to actively hold and manipulate a small amount of information for a brief period, allowing completion of complex cognitive tasks like reasoning, problem-solving, and decision-making). 


As there was no difference in cognitive testing between oral versus oral with nasal breathing, the authors postulated that the negative effects on cognition might be from inhalation of substances in the lung rather than through the nose and olfactory bulb (the part of the brain that processes smells). 


This study was a very small one with few subjects and as such results need to be confirmed with larger studies.


Comments:

According to the World Health Organization (WHO), air pollution both outside and inside the home is responsible for an estimated seven million premature deaths world-wide.  99% of the world’s population are thought to reside in areas where air particulates exceed the WHO guideline limits and contain high levels of pollutants.  It is thought that pollutant particulate matter of less than 2.5 micrometers (also called microns) in diameter is responsible for most of the negative effects on human health.  (Copy paper is typically 50 to 100 micrometers thick.)


In this interesting study, reducing air quality by burning candles appeared to adversely affect some cognitive functions.  Caution is advised given there were very few subjects, but there is other scientific literature that supports this concept.  Air pollution in other research has been shown to potentially increase the incidence of cognitive decline and dementia.  Animal studies have demonstrated that air pollution can increase inflammation, oxidative stress, and affect neurotransmitters in the brains of rodents.  


This current study adds to other previously published studies that suggest that air pollution is harmful in many ways, including potentially having a negative effect on cognitive abilities. 


 

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