When Michael Howard arrives for a checkup with his lung specialist, he's worried about how his body will cope with the heat and humidity of a Boston summer. "I lived in Florida for 14 years and I moved back because the humidity was just too much," Howard tells pulmonologist Mary Rice, as he settles into an exam room chair at a Beth Israel Deaconess HealthCare clinic. Howard, who is 57, has COPD, a progressive lung disease that can be exacerbated by heat and humidity. Even inside a comfortable, climate-controlled room, his oxygen levels worry Rice. Howard reluctantly agrees to try...