Parents know about certain drawbacks to urban living, but to a degree, we've been living in ignorant bliss. Scientists haven't pushed the issue of how life in polluted areas can make children sick. We need more information if we want healthy kids.

A study published in the American Journal of Epidemiology in 2007 shows a link between traffic pollution and lower intelligence in children. Granted, more studies need to be done to show why this link exists, and how it can be helped, but in the meantime we can all do our part to cut our emissions.

The problem

Scientists claim that traffic pollution contributes more to global warming than anything else. Much of this comes from diesel fuel used in the shipping industry, but a good chunk also comes from average, everyday commuters driving to and from work. In theory, these emissions rise up into the atmosphere, creating insulation and raising temperatures all over the Earth. The result is catastrophic weather changes, displaced species and the eventual collapse of ecosystems.

Because the Earth has gone through natural periods of heating and cooling, some scientists don't support the theory. Last year a Senate GOP subcommittee released a report titled "U.S. Senate Report: Over 400 Prominent Scientists Disputed Man-Made Global Warming Claims in 2007." Many people read this and jumped to the conclusion that emissions aren't a health risk. Virtually no credible scientists argue that case, regardless of their stances on global warming. Pollution's effects on the atmosphere can't be confused with its effect on the human body.

We already know, for instance, that black carbon particles inhaled through the nose can make their way into the brain and cause swelling and dysfunction. We know that lead poisoning and fluoride overdose can lead to mental retardation. Dr. Shakir Franco Suglia and her research team from the Harvard School of Public Health set out to see how traffic pollution affects cognitive skills.

The study

To prove a link between car emissions and IQ scores, the study first had to measure other known factors. Prenatal smoking and exposure to second-hand smoke, lead levels and low birth weight all have been proven to affect IQ. The study also took into account other factors that might affect results, including the education level of the parents involved, and the language primarily spoken at home.

Researchers took samples at 80 sites around Boston over a period of 2,127 days. Between the ages of 8 and 11, the participants took two intelligence tests, the Kaufman Brief Intelligence Test and the Wide Range Assessment of Memory and Learning. These measured different kinds of cognitive ability, including verbal and nonverbal skills and memory retention.

The team compared estimated exposure to traffic emissions to the test results of 202 healthy kids. Even when grouped by other risk factors, kids living in areas with more pollution tested an average of 3.7 points lower on IQ tests. Urban living has its benefits, but now we know it may pose health risks to the brain.

On its own, the study only alerts us about a potential problem. The scientists involved emphasize this shows a need for further study. We need to know why these kids test lower, and how the catalyst occurs so we can work against it. For now, there is no solution, except perhaps moving to an area with cleaner air. Where will we go once we run out of places to move?

The solution

Whether or not you believe in global warming, getting tough on traffic works to improve your health. You don't really need a hybrid (or a bus pass) to do that, either. Steps taken from the comfort of home can effectively fight pollution in our communities, and all over the world.

Demand higher standards for air quality. Encourage funding for public transportation. Donate to environmental charities that support sustainable living, such as the Coalition for Clean Air, or Trees, Water & People. Most importantly, support more research. This study didn't solve the problem. It let us know one potentially exists, and we can't waste that information.

Dr. Suglia's research team showed us there might be a connection between car emissions and lowered intelligence. We must work to make sure that's not the case. To do that we'll need more answers, but we can help our kids by taking baby steps of our own.