Besides inciting the occasional bout of road rage, traffic jams may have other harmful effects on the brain, say scientists.
A growing body of research on traffic pollution and the brain has shown there's more to it than we think. One Wall Street Journal article on the topic points out that scientists are taking a two-pronged approach by looking at public health studies as well as experiments in the lab.
Association studies are finding links between higher exposure to pollution and certain cognitive problems. Researchers such as Columbia University's Frederica Perera are discovering that pollution's imprint can begin before birth, as newborns with higher exposure show permanent genetic differences from other babies. Coupled with findings that kids exposed to higher rates of pollution perform worse in intelligence and emotional tests raises questions about how pregnant women and children can reduce their exposure.
In one experiment, Perera asked pregnant women in Poland to carry around air monitors in order to collect data about the quality of air the future mothers were breathing. She tracked the children after birth and found those with higher exposures lagged behind developmentally.
Other measurements show that older women exposed to higher levels of particulate matter had a higher chance of developing neurodegenerative problems such as Alzheimer's disease. In the United States, where industry emits more particulate matter than vehicles at times, it's hard to tease out other sources of emissions. For the most part, though, there's a relationship between local traffic and exposure, which has become apparent by studying mice, too.
Scientists suspect that this particulate matter — a mixture of droplets, acids, dust and even metals — may be a large component of the problem. At present, the U.S. Environmental Protection Agency states that particles smaller than 10 micrometers in diameter are especially dangerous, since they can move beyond the nose and throat into the lungs (and, one can assume, the brain).
It's been established that being exposed to particulate matter influences a person's chance of developing respiratory and heart problems, but pinning down trends for the brain has been difficult, mostly because researchers have to measure effects indirectly. Even then, it's hard to exclude other factors that might be at play.
The idea that pollution has negative health effects might seem obvious to some, but the research community is only beginning to explore the range of potential effects on development and cognition in the long term.
So far, changes that ease traffic — whether it be better timed lights during rush hour or placing E-ZPass systems near tollways — have been effective in curbing pollution levels, according to the WSJ article.
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