Environmental pollution consists of a complex mixture of coarse, fine, and ultrafine particles, mainly particulate matter (PM) of various sizes, along with numerous toxic substances. The particles in ambient air are moderately miscellaneous in their biological, chemical, and physical properties. The components of PM stay in the environment for an extended period and travel for unbelievably long distances from one continent to another. The climate changes and current global warming phenomena may also lead to a warmer climate. These changes thereby affect the patterns of production, transportation, and deposition of pollutants. The air pollutants travel from the environment to the brain through the respiratory, olfactory, and gastrointestinal systems and enter into the blood circulation. The ultrafine PMs are highly reactive, toxic elements that cause oxidative stress. These air pollutants damage endothelial cells, the blood-brain barrier, and cerebral vasculature and assault the nervous system through numerous molecular and cellular pathways to cause oxidative stress, neuroinflammation, neurodegeneration, and neuronal damage. Health officials must take preventive measures and implement strict actions to ensure that policies are effective at regional and international levels to minimize pollution worldwide.