Older Diesel Engines Linked to Brain Cell Damage, Raising Concerns About Neurodegenerative Disease Risk
Recent research indicates that emissions from older diesel engines may pose a threat to brain health, specifically impacting crucial immune cells called microglia. While modern diesel vehicles equipped with Euro 6 standards and particle filters produce substantially “cleaner” emissions, older models lacking these technologies release particles that demonstrably disrupt microglial function, potentially increasing the risk of chronic neuroinflammation and neurodegenerative diseases.
Microglia act as the brain’s primary immune defense, constantly working to clear cellular waste and maintain balance. A study led by Dr. Sohvi Ohtonen at Karolinska Institutet exposed microglia to particles from both older (“A20, A0”) and newer (“E6”) diesel engines. The results were stark: exposure to particles from older engines triggered marked changes in gene expression, reduced activity in lysosomes and phagocytosis (cellular waste removal processes), and activated cellular stress pathways like ferroptosis and pyroptosis. These disruptions hinder the brain’s ability to clear waste, fostering an surroundings conducive to chronic neuroinflammation.
In contrast, E6 particles from modern, Euro 6 compliant engines had “almost no impact” on the microglia under the study’s conditions.However, researchers caution that even prolonged exposure to diesel pollution from newer vehicles could still contribute to an increased risk of brain diseases, suggesting further refinement of fuel composition - specifically reducing aromatic compounds and black carbon – could mitigate toxicity across all vehicle types.
The key difference lies in the particle composition. Older diesel engines, “often lacking modern filtration systems“, generate particles rich in black carbon and polycyclic aromatic hydrocarbons (PAHs). Modern Euro 6 vehicles, equipped with particle filters, primarily emit E6 particles with significantly lower concentrations of these toxic components.
Determining which category your vehicle falls into is straightforward: check section V.9 of your vehicle’s registration document (gray card). The presence of “EURO 6”, “EURO 6b”, or “EURO 6d-TEMP” indicates compliance with the newer, cleaner standards.
This research aligns with broader studies linking air pollution – particularly fine particulate matter (PM2.5), nitrogen dioxide, and soot - to an increased risk of dementia. The findings underscore that air pollution’s impact extends beyond the lungs, directly affecting brain health and potentially contributing to the progress of neurodegenerative diseases. Further research is needed to fully understand the long-term effects of different engine and fuel technologies on brain function.
