Harry is 72 and goes to bed early, at about 7 p.m. He wakes up at 5 a.m. and takes a two-hour nap at 3 p.m. every day. But he still feels tired. His wife, Helen, on the other hand, goes to bed at 11:30 p.m. and also gets up at 5 a.m. She is frequently awakened during the night by Harry’s loud snoring, is sleeping less as she gets older, and doesn’t have her usual energy.

Inhale . . . exhale . . . inhale . . . exhale. Do you know what you’re breathing? In 2006 24% of people age 65 and over lived in counties with unhealthy ozone levels, and 21% lived in counties where fine particle matter exceeded national standards.