By linking the noise model to national U.S. population data, we made some interesting discoveries. First, in both rural and urban areas, affluent communities were quieter. Neighborhoods with median annual incomes below US$25,000 were nearly 2 decibels louder than neighborhoods with incomes above $100,000 per year. And nationwide, communities with 75 percent black residents had median nighttime noise levels of 46.3 decibels – 4 decibels louder than communities with no black residents. A 10-decibel increase represents a doubling in loudness of a sound, so these are big differences.
[Very interesting post on human geography of noise pollution and hypothesizing about its causes from Discard Studies. For more information about human geography as a concept, check out the “Human Geography” chapters of WorldView Software’s World Geography.]