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Study links increased exposure to air pollution to increased risk of eczema
Last reviewed: 02.07.2025
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A recent study published in PLoS One found that exposure to fine particulate matter (PM2.5) found in air pollution is associated with an increased risk of developing eczema. PM2.5 concentrations can nearly double the likelihood of developing this inflammatory skin condition.
Eczema, which affects 5.5–10% of American adults and 10.7% of children, has become increasingly common since the industrial era, suggesting that environmental factors, including air pollution, play a significant role in the condition.
PM2.5 — particles smaller than 2.5 micrometers — can penetrate deep into the respiratory system, enter the blood and lymph, and then spread to various organs, including the skin. These particles contain components such as polycyclic aromatic hydrocarbons (PAHs), which can disrupt the skin barrier, cause oxidative damage, and inflammation.
The study used data from the All of Us Research Program, which includes representatives of marginalized populations. The sample included 12,695 people with eczema and 274,127 people without the condition. PM2.5 levels were determined based on 2015 data from the Center for Air, Climate and Energy Studies (CACES). PM2.5 exposure levels were correlated with demographic factors, lifestyle, and co-occurring atopic conditions such as food allergies and asthma.
Key Results
- In areas with higher PM2.5 levels, the risk of eczema was significantly higher.
- People living in areas with high PM2.5 concentrations had a 166% increased risk of eczema, even after accounting for demographics, smoking, and atopic diseases.
- These findings are consistent with other studies from Germany, Taiwan and Australia, which also found a two-fold increase in the risk of eczema with every 10 µg/m³ increase in PM2.5.
Possible mechanisms
PM2.5 contains PAHs that activate the aryl hydrocarbon receptor (AhR) pathway, which is associated with eczema-like reactions in mice. Increased levels of chemicals that stimulate this pathway, such as artemin and reactive oxygen species, can trigger inflammatory processes.
Conclusions
The study findings highlight the link between air pollution and inflammatory skin conditions such as eczema, highlighting the need to:
- Improved air quality;
- Carrying out preventive measures, such as using filters, reducing time spent outdoors during periods of high pollution;
- Development of pharmacological agents capable of modulating the AhR pathway and reducing its activity.
These findings highlight the importance of integrating measures to reduce air pollution exposure into public health strategies.