Just 60 minutes of exposure to polluted air can have an immediate impact on your brain. (Ahmet Misirligul/Shutterstock)
In a nutshell
- Just one hour of exposure to particulate matter air pollution can impair your ability to focus and read emotions, with effects lasting at least four hours after exposure – even at pollution levels commonly found in urban areas
- The cognitive effects occur whether breathing through the nose or mouth, suggesting air pollution likely affects brain function through lung-based mechanisms rather than direct neural pathways
- While pollution impairs selective attention and emotion recognition, basic mental functions like working memory and reaction time remain unaffected, indicating that higher-order cognitive processes are more vulnerable to air pollution’s effects
BIRMINGHAM, England — Next time you’re stuck in traffic breathing in exhaust fumes or walking past a construction site filled with dust, you might want to consider how those particles floating through the air could affect your brain function hours later. A new British study reveals that even brief exposure to particulate matter air pollution can impair your ability to focus on tasks, avoid distractions, and behave in socially acceptable ways.
During the study, published in Nature Communications, scientists discovered that breathing polluted air for just 60 minutes led to reduced performance in two key areas of brain function: selective attention (your ability to focus on relevant information while ignoring distractions) and emotion recognition (your capacity to accurately identify emotions in other people’s faces).
“Our study provides compelling evidence that even short-term exposure to particulate matter can have immediate negative effects on brain functions essential for daily activities, such as doing the weekly supermarket shop,” says co-author Dr. Thomas Faherty from the University of Birmingham, in a statement.
Particulate matter pollution consists of tiny particles suspended in the air. The most concerning are those known as PM2.5, particles smaller than 2.5 micrometers and about 30 times thinner than human hair. These microscopic particles can come from various sources: vehicle exhaust, construction dust, industrial emissions, and even household activities like cooking or burning candles. Their small size allows them to penetrate deep into the lungs and potentially enter the bloodstream.
How particulate matter impacts the brain
The study involved 26 adults ranging from 19 to 67 years old, with an average age of 27.7 years. Each participant took part in four different experimental sessions where they were exposed to either clean air or air containing elevated levels of PM pollution. The researchers created controlled pollution conditions by burning candles in a testing room, generating similar fine particles to those found in urban environments.
In some sessions, participants wore nose clips to restrict nasal breathing, while in others they breathed normally. This is the first study to experimentally manipulate inhalation routes of PM air pollution, and it found that cognitive impairment occurred regardless of whether participants breathed through their nose or mouth.
“Poor air quality undermines intellectual development and worker productivity, with significant societal and economic implications in a high-tech world reliant on cognitive excellence,” says co-author professor Francis Pope from the University of Birmingham.
Before and four hours after each exposure period, participants completed four different cognitive assessments. These evaluated working memory (holding and manipulating information temporarily), selective attention (focusing on relevant information while filtering out distractions), emotion expression discrimination (recognizing facial expressions), and psychomotor vigilance (sustained attention and reaction time).
Results showed significant declines in selective attention and emotion recognition abilities after breathing polluted air compared to clean air. The researchers suggest that inflammation caused by pollution may be responsible for these deficits, noting that while selective attention and emotion recognition were affected, working memory remained resilient to short-term pollution exposure.
Hours of damage from one hour of exposure
What sets this research apart is its demonstration of how quickly air pollution can affect brain function. Previous studies focused primarily on long-term exposure effects, such as the development of neurological conditions over years or decades. This new evidence shows that just one hour of breathing polluted air can impact cognitive performance several hours later.
The pollution levels used in the study reflect conditions many people encounter daily. During pollution exposure sessions, PM2.5 concentrations reached 28.54 micrograms per cubic meter. The World Health Organization recommends that 24-hour exposure should not exceed 15 micrograms per cubic meter, with annual limits below 5 micrograms per cubic meter. However, many cities worldwide regularly exceed these guidelines, particularly in rapidly developing regions or during periods of heavy traffic.
When selective attention is impaired, normally simple tasks become more challenging. Office workers might struggle to focus on important emails while filtering out office noise. Teachers might find it harder to maintain attention on individual students while managing a classroom. Even routine activities like driving require constant selective attention to focus on important signals while ignoring irrelevant information.
The impact on emotion recognition abilities raises additional concerns. This skill is crucial for social interactions, workplace collaboration, and customer service. Healthcare workers need to accurately read patient emotions. Teachers must recognize when students are confused or distressed. Business professionals rely on emotional intelligence during negotiations and team meetings.
“This study shows the importance of understanding the impacts of air pollution on cognitive function and the need to study the influences of different sources of pollution on brain health in vulnerable older members of society,” adds professor Gordon McFiggans from the University of Manchester.
Call for cleaner air — outdoors and indoors
The study’s findings add urgency to calls for stricter air quality regulations and public health measures. Cities worldwide are already implementing various strategies to reduce air pollution, from expanding public transportation and creating low-emission zones to promoting electric vehicles and improving building standards. However, more immediate actions are needed to prevent short-term exposure.
Air pollution currently stands as the leading environmental risk factor to human health. While its effects on the heart and lungs are well documented, scientists have increasingly found links to neurological conditions. Research has connected long-term exposure to increased risk of multiple sclerosis, Alzheimer’s disease, and Parkinson’s disease. In 2015 alone, approximately 4.2 million deaths were attributed to PM2.5 exposure.
In light of these findings, indoor air quality also deserves attention. Many people spend most of their time indoors, whether at home, work, or school. While buildings can provide some protection from outdoor pollution, indoor sources of particulate matter from cooking, cleaning products, or poor ventilation can also contribute to exposure. This raises questions about air quality standards for buildings and the potential need for better filtration systems.
The challenge now lies in translating this knowledge into effective policies and practical solutions to protect public health and cognitive function in an increasingly urbanized world.
Paper Summary
Methodology
The study utilized a sophisticated “within-subjects” design, meaning each participant experienced all four experimental conditions: clean air with normal breathing, clean air with restricted nasal breathing, polluted air with normal breathing, and polluted air with restricted nasal breathing. This design helps control for individual differences since each person serves as their own comparison. The researchers generated controlled pollution using candle smoke, which creates similar particulate matter to urban air pollution. Each exposure session lasted one hour, followed by a four-hour break before cognitive testing. Air quality was carefully monitored throughout the sessions, measuring PM2.5, PM10, carbon dioxide, and carbon monoxide levels.
Results
The study revealed two main findings: First, participants showed significant declines in selective attention after pollution exposure, demonstrating increased difficulty filtering out distractions. Second, their ability to accurately recognize emotions in facial expressions decreased notably after breathing polluted air compared to clean air. Importantly, these effects occurred regardless of breathing method, suggesting that pollution’s impact on cognition likely occurs through lung-based mechanisms rather than direct neural pathways. Basic cognitive functions like working memory and psychomotor vigilance remained unaffected, indicating that air pollution specifically impacts higher-order cognitive processes.
Limitations
Several factors limit the study’s broader applicability. The relatively small sample size of 26 participants, while statistically sufficient, may not represent all population groups. The participants were mostly young adults, so the findings might not fully apply to children or older adults who could be more vulnerable to pollution effects. Additionally, the study used candle-generated particulate matter, which might not perfectly replicate the complex mixture of pollutants found in urban air. The research also only examined effects four hours after exposure; longer-term impacts remain unknown.
Discussion and Takeaways
This research breaks new ground by demonstrating that even short-term exposure to air pollution can temporarily impair higher-order cognitive functions. The findings challenge previous assumptions about how quickly air pollution can affect brain function and suggest that its impacts might be more immediate than previously thought. The study also provides important insights into potential mechanisms, indicating that lung-based processes might be more important than direct neural pathways through the nose. These findings have significant implications for public health policy, urban planning, and workplace safety regulations.
Funding and Disclosures
The research was supported by the Natural Environment Research Council [grant number NE/W002213/1] and the University of Birmingham Institute for Global Innovation Clean Air Theme [grant number 5054]. The authors declared no competing interests.
Publication Information
The study, “Acute particulate matter exposure diminishes executive cognitive functioning after four hours regardless of inhalation pathway,” was published in Nature Communications on February 6, 2025 (Volume 16, Article number 1339). Thomas Faherty, Jane E. Raymond, Gordon McFiggans, and Francis D. Pope conducted the research at the Universities of Birmingham and Manchester.
