by Sara Rimer

About the author: Sara Rimer is a reporter for the New York Times newspaper.

Priscilla Purvis was outraged when she saw a small boy buy a single cigarette at a convenience store in her inner-city neighborhood not long ago.

“He said, ‘Can I get a “loosie”"’ ” recalled Priscilla, 16, who has never smoked a cigarette and vows she never will. “He paid 15 cents for it and left. He was about 9 years old. I just went totally off on the store owner. I said, ‘He’s a little boy—that’s illegal.’”

Priscilla, who says she hopes never to catch her 11-year-old brother with a cigarette, added, “Now I’m thinking I should’ve gone after...