I hope pollution levels are low in Boston because making a physical effort while breathing polluted air (= in a city with a lot of cars at rush hours) is not the best for your health.
Heart disease kills many more Americans than pollution. Even after factoring in the additional pollution exposure and traffic accident risk, cycling is still a net win:
Interesting study. Just as a slight criticism of your wording, although I don't think this applies to the study- a lot of deaths from heart disease are actually caused by air pollution. Inhalation of particulate matter is implicated in tens of thousands of deaths a year.
Even though exercise outweighs inhalation of fumes, air pollution is a serious issue, and many lives could be saved by its reduction. Hopefully that will be an extra benefit of electric and hybrid cars in cities.
As a bike commuter on a major city recently hit by a peak of air pollution (Paris), I've looked around for infos, and it's seems cyclists are less exposed to air pollution than motorists or even pedestrians.
I have thought about this a lot - I biked to every day this winter, and only took the train wearing a surgical mask a few dozen times when I couldn't bike. I didn't get sick this winter like I usually do.
I probably need to bike for the next 9 winters though before I can really attribute not getting sick to not taking the T and exercising.
