In a study conducted in Ontario, Canada that examined the medical records of more than 6.5 million people over the course of eleven years, researchers found that individuals living less than 50 meters (55 yards) from major roadways had a seven-percent higher risk of being diagnosed with dementia than those who lived at least 150 meters (164 yards) away. That's a significant increase.
According to the chief of environmental and occupational health at Public Health Ontario, and one of the paper's authors, Dr. Ray Copes, "This study suggests air pollutants that can get into the brain via the blood stream can lead to neurological problems."
If that is, indeed, the mechanism at play here, then we imagine the projected increase in low-and-no emission vehicles could diminish this particular impact over time. The study, which was published in the Lancet, does have a silver lining – there was no apparent increase in the occurrence of Parkinson's disease or multiple sclerosis in those living closest to heavy traffic.