A cacophony of sounds on a summer's day

摘要

An ambitious National Park Service project exploits computer algorithms to predict the loudness of a typical summer day from coast to coast. The project's newest map (above, with yellow representing the loudest noise) includes natural sounds, but it's the human-made features that jump out. The eastern half of the United States is louder than the West, according to the map, set to be released February 16 at the annual meeting of the American Association for the Advancement of Science in San Jose, Calif. The map shows an average volume, the sound level that's exceeded about half the time at particular spots. (Typical conversation registers at roughly 50 to 60 decibels.) Airplanes arcing high over the continent don't show up well, but cities and loud highways are clearly visible.