This map shows modeled outdoor noise across St. Marks 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 36 St. Marks residents, or 14.4%, live above that level. By land area, 8.2% of St. Marks is above 55 dBA.
See how noise in St. Marks compares to similar-sized cities.
Noise by Part of St. Marks
Average noise levels for St. Marks residents, grouped by direction from the center of St. Marks. Central St. Marks carries the highest population-weighted average; Eastern St. Marks carries the lowest. Just 0% of residents in Eastern St. Marks live in blocks above the EPA's 55 dBA threshold, a fifth of the share in Central St. Marks.
Central St. Marks
16% of people above 55 dBA
Eastern St. Marks
0% of people above 55 dBA
Northern St. Marks
12% of people above 55 dBA
Southern St. Marks
31% of people above 55 dBA
Western St. Marks
10% of people above 55 dBA
Central St. Marks sounds about 38% louder than Eastern St. Marks to the human ear, 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 US-19 /us-27a/us-98 do you need to be?
US-19 /us-27a/us-98 produces an estimated 64 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 30% of St. Marks sits under tree canopy (about average for cities) and roughly 8% 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.