This map shows modeled outdoor noise across 20657 at 100-meter resolution, combining road, aviation, and rail sources. Green areas measure below 45 dBA. Orange and red exceed the EPA's 55 dBA outdoor threshold linked to long-term health effects. Use the layer toggles to view each source on its own or all together.
What the numbers sound like
- 30 dBAWhisper
- 40 dBASoft rainfall
- 45 dBAQuiet suburban street at night
- 50 dBAQuiet office
- 55 dBAEPA outdoor threshold: light traffic 100 ft away
- 60 dBANormal conversation an arm's length away
- 65 dBABusy restaurant
- 70 dBAHighway traffic 50 ft away
- 80 dBACity bus interior
Population Above the EPA Outdoor Threshold
The EPA's 55 dBA outdoor reference level is a common benchmark for residential noise exposure, especially for activity interference, annoyance, and long-term community noise concerns. About 3,407 20657 residents, or 18.3%, live above that level. By land area, 22.3% of 20657 is above 55 dBA.
See how noise in 20657 compares to similar-sized zip codes.
Noise by Part of 20657
Average noise levels for 20657 residents, grouped by direction from the center of 20657. The highest population-weighted average is in central 20657; the lowest is in northwestern 20657, where just 6% of residents live in blocks above the EPA's 55 dBA threshold, a third of the share in the loudest section.
Central 20657
19% of people above 55 dBA
Northern 20657
15% of people above 55 dBA
Northeastern 20657
13% of people above 55 dBA
Southwestern 20657
7% of people above 55 dBA
Northwestern 20657
6% of people above 55 dBA
To the human ear, noise in central 20657 sounds about 38% louder than in northwestern 20657, a 4.6 dBA gap. Every 10 dBA roughly doubles perceived loudness. Within any of these directions, two homes a quarter mile apart can still differ by 10 or more dBA depending on how close they sit to a major highway.
How far back from do you need to be?
produces an estimated 70 dBA at its loudest centerline points. Noise drops logarithmically with distance, with the exact rate depending on what's between you and the road. Tree cover, walls, terrain, and pavement type all matter. At roughly a quarter mile back, traffic fades into the noise level of a soft rainfall.
Calculated from the model's calibrated attenuation formula. About 75% of 20657 sits under tree canopy (much heavier than most zip codes) and roughly 5% is impervious surface like pavement and rooftops. Both are folded into the per-place decay rate above. Heavier canopy pulls noise down faster with distance; impervious surfaces slow the drop.