The National Parks Service (NPS) has published a map that shows the average sound levels across the lower 48 U.S. states on a typical summer’s day. While the map was produced as part of the NPS’s work monitoring and controlling noise pollution in park ecosystems, it also incorporates data gathered in urban areas. At a glance you can see that the eastern half of the country is much noisier than the west, but if you really want to get away from it all, the NPS website has hi-res maps available to download so you can zoom in and find some peace and quiet among all that ruckus. Read on for details.
Among many other things, the NPS is mandated with preserving the soundscape of U.S. national parks, hence their need to record noise levels. To make the map, acoustic data were collected at 479 unique locations in national parks and then combined with addition data collected from urban and suburban areas. The NPS says that around 1.5 million hours of acoustical data contributed to the project. The information collected was then used to predict current sound levels across the country. To allow for varying conditions, the NPS states: “A model was developed to understand relationships between measured sound levels and variables such as climate, topography, human activity, time of day, and day of year.” More information on the metrics and measuring used can be found on the NPS site.
Thanks to the model NPS scientists developed, they were also able to filter the data to effectively turn down the human-caused noise, leaving an estimate of what the country would sound like without us. This was then used to generate a second map: one that shows “only physiographical sources of sound like wind, flowing water, precipitation, animals, and geological events.” The NPS points out that because the scenario presented in the second map is so much quieter than the first, the numbers in the map legends don’t even match up!
While the data collection was made over long-term periods, all conditions presented in the maps are “predicted for a typical daytime hour during the summer with calm weather conditions.” The NPS notes that sound levels are often lower at night and during winter, while higher sound levels tend to be found in wetter areas with more vegetation. This is thanks to factors such as the wind blowing through vegetation, the babble or roar of running water, and because vocal animals such as birds and frogs tend to be found in those conditions. If you can picture yourself at a campsite by a babbling brook on a summer’s day with only the birds to keep you company, click over to the NPS website and download a hi-res version of the map to find the perfect spot.
Via Tree Hugger
Maps by the National Parks Service