If you hike through the Appalachian Mountains, you’ll spot stands of dead and weakened trees. If you live in a city, you might notice worn stone buildings, streaks on your car roof or corroded metal railings and statues. You can see the effects of acid rain nearly everywhere you go, but with media and public attention turned to the more ominous prospect of global warming, acid rain has fallen by the wayside. The scourge from the sky almost seems like a 20th-century problem — an issue dealt with in the 1980s and 1990s by legislation.
