Study Links Traffic Pollution to Brain Inflammation and Alzheimer's Disease

Dorian Martin Health Guide
  • From 1996 to 2000, my parents lived in a home in Austin, Texas that was next to one of the busiest highways in the United States – Interstate 35. That corridor is an important conduit for commerce between the U.S. and Mexico, and needless to say, big trucks and other vehicles are constantly navigating that road at all times of the day and night. And early morning and afternoon rush hours continued to increase, especially as people moved into more affordable housing in the towns outside of Austin.

    I noticed that while they lived at that residence, Mom increasingly had difficulty breathing due to her Chronic Obstructive Pulmonary Disease (COPD) caused by too many years of smoking. Research previously has linked air pollution and respiratory distress. But it turns out that may not have been the only thing that was worsening due to the air pollution created by the vehicles on that highway. Mom’s descent into dementia may have been hastened due to living close to that congested freeway.

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    Researchers from the University of Southern California recently announced that they found that mice which were subject to traffic pollution showed signs of inflammation that was similar to Alzheimer’s disease. The study was published in the journal of Environmental Health Perspectives. According to Tim Beissmann of Car, the researchers exposed the mice to traffic pollution for five hours a day, three times a week for 10 weeks.  Researchers believe the combination of tiny particles produced by burning fossil fuels as well as eroding car parts and road surfaces were the cause of brain damage. “You can’t see them, but they are inhaled and have an effect on brain neurons that raises the possibility of long-term brain health consequences of freeway air,” said university professor and senior author Caleb Finch, an expert in the effects of inflammation and holder of the ARCO/William F. Kieschnick Chair in the Neurobiology of Aging at USC. Beissmann explained further, stating, “The neurons involved in learning and memory loss also showed significant damage, and the brain neurons of developing mice did not grow as well as those not subjected to the particles.”

    You would think that the recent improvement in a car’s technology would limit the level of pollution, but that’s not the case. Bryan Walsh of reported, “The particulates in the experiment are tiny — perhaps one-thousandth the width of a human hair, and far too small to be trapped by car filtration systems.”  The researchers are not sure how to protect people who live in urban areas from this type of toxicity. “Commuters might be able to switch their modes of transportation, or even work from home — but those unfortunate enough to live near freeways have little defense against air pollution,” Walsh wrote.


    • The authors hope to conduct follow-up studies on issues, including:
    • The memory functions in animals exposed to freeway particulates;
    • The life span of exposed animals;
    • The interaction of particulates with other components of smog, such as heat and ozone;
    • The potential for recovery between periods of exposure;
    • The comparison of effects from artificially and naturally occurring nanoparticles;
    • The chemical interactions between freeway particulates and brain cells.

    This study supports the findings from another study of autopsies performed on adults in Mexico. That study found greater signs of brain inflammation and premature aging in subjects from Mexico City compared to ones from the less polluted city of Veracruz.

Published On: May 09, 2011