From Air to Brain: Environmental Nanoparticles as Modifiable Risk Factors for Neurodevelopmental, Neurodegenerative,...

Area of Science:

• Environmental Health
• Neuroscience
• Toxicology

Background:

• Ultrafine particles (UFPs, ≤100 nm) and environmental nanoparticles are emerging biologically active pollutants.
• These particles can cross critical biological barriers like the blood-brain barrier and placenta.
• Growing evidence links UFPs to various neuropsychiatric conditions, but this is poorly integrated into public health frameworks.

Purpose of the Study:

• To systematically review and synthesize human and experimental findings on the neuropsychiatric and neurodevelopmental effects of environmental nanopollutants.
• To distinguish between different types of nanoparticles (UFPs, environmental nanoparticles, engineered nanomaterials) based on properties and exposure.
• To highlight the need for regulatory action and integration into clinical practice.

Main Methods:

• A narrative systematic review was conducted.
• Searches were performed in PubMed, Web of Science, Scopus, and Google Scholar up to November 2025.
• Inclusion criteria focused on peer-reviewed human and animal studies assessing mental health or neurological outcomes of nanopollutant exposure.

Main Results:

• Epidemiological studies link traffic-related air pollution and combustion-derived UFPs to increased risks of cognitive impairment, autism spectrum disorder, depression, schizophrenia, and neurodegenerative diseases (Alzheimer's, Parkinson's, ALS).
• Prenatal and early life exposures are associated with cortical thinning, altered neurodevelopment, and early proteinopathies.
• Key underlying mechanisms include neuroinflammation, oxidative stress, and protein aggregation.

Conclusions:

• Environmental nanopollutants are an under-recognized, modifiable risk factor for neuropsychiatric and neurodegenerative diseases.
• A paradigm shift is needed to incorporate environmental exposure history into mental health research, risk assessment, and prevention.
• Urgent regulatory action targeting nanopollutant emissions and exposure, especially in vulnerable populations, is critical for mitigating long-term neurological consequences.