A troubling piece in the Wall Street Journal, “The Hidden Toll of Traffic Jams,” explains the deleterious effects of sitting in traffic jams:

New public-health studies and laboratory experiments suggest that, at every stage of life, traffic fumes exact a measurable toll on mental capacity, intelligence and emotional stability.

and

Recent studies show that breathing street-level fumes for just 30 minutes can intensify electrical activity in brain regions responsible for behavior, personality and decision-making, changes that are suggestive of stress, scientists in the Netherlands recently discovered. Breathing normal city air with high levels of traffic exhaust for 90 days can change the way that genes turn on or off among the elderly; it can also leave a molecular mark on the genome of a newborn for life, separate research teams at Columbia University and Harvard University reported this year.

The evidence is still largely circumstantial, as the article notes, but it is worrisome. My daily commute is about twenty miles one way, and I sit in traffic for close to two hours daily. That’s one aspect of my life that I would like to change.