Mother Nature Network: Tiffany Mellers jogs behind her two daughters as they pedal their bikes along a ribbon of packed sand along Long Island Sound. They are good girls, Mellers said. They deserve a healthy life. Behind them, a 500-foot tall candy-stripe smokestack, a fixture of Bridgeports waterfront for nearly five decades, rises in the distance. A third generation of residents is now growing up in its shadow. But today this old giant is merely a vestige of this regions coal-fired past. New England is virtually...