This map shows modeled outdoor noise across Northborough 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 3,415 Northborough residents, or 22.6%, live above that level. By land area, 29.7% of Northborough is above 55 dBA.
See how noise in Northborough compares to similar-sized cities.
Noise by Part of Northborough
Average noise levels for Northborough residents, grouped by direction from the center of Northborough. Northern Northborough carries the highest population-weighted average; Eastern Northborough carries the lowest. Just 22% of residents in Eastern Northborough live in blocks above the EPA's 55 dBA threshold, three-quarters of the share in Northern Northborough.
Central Northborough
21% of people above 55 dBA
Eastern Northborough
22% of people above 55 dBA
Northern Northborough
29% of people above 55 dBA
Southern Northborough
17% of people above 55 dBA
Western Northborough
24% of people above 55 dBA
Northern Northborough sounds about 22% louder than Eastern Northborough to the human ear, a 2.9 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 I-290 do you need to be?
I-290 produces an estimated 77 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 60% of Northborough sits under tree canopy (heavier than most cities) and roughly 13% 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.