You can call me Caity.

Dr. Jackson, who was then the head of the National Center for Environmental Health at the CDC, was rushing to a meeting where leading epidemiologists would discuss the major health threats of the 21st century. On the side of the road he saw an elderly woman walking, bent with a load of shopping bags. It was a blisteringly hot day, and there was little hope that she would find public transportation.

At that moment, Dr. Jackson says, “I realized that the major threat was how we had built America.”