New studies of King County, Washington find that sprawl is linked to dirtier air and bigger bellies. Walkable neighborhoods (those places with higher residential density, more street connections, and nearby to shops, schools, and parks) appear to be healthier for residents and less damaging to air quality—even when taking into account age, income, education and ethnicity.

A few key findings (liberally excerpted from the full coverage in the Seattle Times):

  • On average the Body Mass Index—a measure of height and weight—of residents of the more walkable neighborhoods was lower, and they were more likely to get 30 minutes of daily exercise.
  • People who lived and worked in more walkable neighborhoods produced fewer pollutants associated with smog.
  • A 5 percent increase in a neighborhood’s walkability index was associated with a 0.23-point drop in Body Mass Index. Bigger changes in a neighborhood’s walkability would be expected to produce greater differences in weight.