< Back to all evidence

Health

Last updated

July 26, 2025

Cognitive health

Air pollution and cognitive health research reveals that virtually the entire global population faces risks to brain function from environmental pollutants. The World Health Organisation estimates that 99% of the world's population is exposed to pollution levels above recommended thresholds, creating a worldwide cognitive health crisis. Studies demonstrate measurable impacts on memory, attention, and other brain functions from both short-term and long-term pollution exposure. Explore the growing body of evidence showing how air quality affects mental performance and cognitive ageing, and what this means for protecting brain health across the lifespan.

WHO estimates that 99% of the world’s population is exposed to pollution above recommended levels (Drew, 2025)
Children living in the highly polluted city had lesions in the white-matter tracts that connect brain regions more than did children in less-polluted areas. They also performed comparatively poorly on cognitive task (Drew, 2025)
Observational studies have also linked air pollution to structural changes in the brain, such as reduced hippocampal volume, that are consistent with heightened dementia risk in older adults (Drew, 2025)
- An increase in exposure to air pollution seems to alter communication between brain regions (Drew, 2025)
Reduced ability to focus (Lee, 2025)
- Short-term exposure to air pollution, specifically particulate matter (PM), can impair cognitive function.
- Researchers tested 26 participants before and after exposure to either high PM levels (from candle smoke) or clean air for an hour. They found that pollution exposure reduced selective attention and emotional recognition, making individuals more prone to distractions and potentially affecting social behavior. However, working memory remained unaffected.
- Air pollution could impact daily activities like shopping, work productivity, and social interactions.
- Researchers emphasize that certain groups may be more vulnerable to these effects, highlighting the need for better air quality management
Candle flames and cooking particles can impair brain function (Vaughan, 2025)
- Short term exposure to candle burning, including candle burning, impairs the brains ability to focus and interpret other’s emotions
- Inhaling PM2.5 negatively affects cognitive function
- Cause of dementia to affecting the intellectual development of children
- 26 people - took cognitive test before and 4 hours after spending an hour in an unventilated room with a candle burning or in a room with normal ambient air - working memory and reaction time were unaffected, but those in room with candle did worse on more complex tests such as selective attention and emotion regulation
French CONSTANCES Cohort (Sakhvidi et al., 2022)
- Increased exposure to black carbon and NO2 was linked to poorer cognitive performance, especially in executive functions and semantic fluency.
- PM2.5 exposure significantly affected the semantic fluency test.
- A 1 interquartile range (IQR) increase in exposure led to 1%–5% decline in cognitive performance.
A one standard deviation increase in PM2.5 decreases overall test scores by 8.2% of a standard deviation, math scores by 10.7%, reading scores by 6.4%, and English scores by 3.5%. (Villalobos & Blackman, 2025)
The study suggests that the negative effect of air pollution on academic performance is stronger in middle-income countries compared to high-income countries (Villalobos & Blackman, 2025)‍
PM pollution has a detrimental effect on selective attention, with participants performing worse on cognitive tests after exposure to pollutants compared to before exposure (Faherty et al., 20215)

< Back to all evidence

Cognitive health

ON THIS PAGE

Stay Connected with Air Aware Labs

Send us mail on