Effects of air and light pollution on brain and behavioral function: Potential synergy

The growing global prevalence of artificial light at night (ALAN) and air pollution has raised concerns regarding their effects on human health. Several epidemiological, preclinical, and clinical studies suggest that both ALAN and air pollution can independently contribute to adverse brain health outcomes, including cognitive decline, increased risk of neurodegenerative diseases, and behavioral disorders. Air pollutants can enter the bloodstream and reach the brain, leading to potential neuropathology. Exposure to ALAN disrupts circadian rhythms, suppresses melatonin production, and alters sleep patterns, causing detrimental health consequences. Recent research highlights a complex interaction between these two pollutants and emphasizes the need for future studies exploring their synergistic effects. The current review provides an overview of how air and light pollution influence brain health and lead to different physiological and behavioral issues. We explored the potential mechanisms that may underlie their combined effects, such as oxidative stress, inflammation, disruption of circadian rhythms, blood-brain barrier disruption, and genetic alterations. This review also calls for future research in order to investigate the biological pathways at play and identifies critical research gaps. Understanding the interaction between ALAN and air pollution is crucial for developing effective health care strategies to mitigate their harmful effects on the brain and central nervous system.