Robert M. Reed, an associate professor of medicine and a pulmonary and critical care specialist at the University of Maryland, uses a spirometer to measure the rates that people can empty their lungs as well as the total amounts of air that they can blow out. He found while studying an Amish community in Lancaster, Pa., that even a small amount of secondhand smoke exposure can have negative health effects. (Photo by Algerina Perna/Baltimore Sun/TNS) *** Please Use Credit from Credit Field ***