Noise Levels in Emerald Lake Hills, Redwood City, CA | Find Quiet Neighborhoods With Our Sound Map
52 dBA
Average noise across Emerald Lake Hills
Quiet office to normal conversation
1,305
Residents above the EPA 55 dBA threshold
23% of Emerald Lake Hills residents
83 dBA
Loudest residential point
Food blender at arm’s length
This map shows modeled outdoor noise across Emerald Lake Hills 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.
Overall
Road
Rail
Aviation
Click the map to explore
35 dBa55 dBa (EPA limit)90+ dBa
3545557090
Quietest (dBA)Loudest
Colorblind friendlyoff
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 1,305 Emerald Lake Hills residents, or 23.0%, live above that level. By land area, 30.7% of Emerald Lake Hills is above 55 dBA.
Average noise levels for Emerald Lake Hills residents, grouped by direction from the center of Emerald Lake Hills. Central Emerald Lake Hills carries the highest population-weighted average; Northern Emerald Lake Hills carries the lowest. Just 13% of residents in Northern Emerald Lake Hills live in blocks above the EPA's 55 dBA threshold, about half the share in Central Emerald Lake Hills.
Central Emerald Lake Hills
52.7 dBA · Moderate
Quiet office to normal conversation
26% of people above 55 dBA
QuietLoud
Eastern Emerald Lake Hills
52.4 dBA · Moderate
Quiet office to normal conversation
31% of people above 55 dBA
QuietLoud
Northern Emerald Lake Hills
49.1 dBA · Mostly quiet
Quiet office
13% of people above 55 dBA
QuietLoud
Southern Emerald Lake Hills
52.5 dBA · Moderate
Quiet office to normal conversation
24% of people above 55 dBA
QuietLoud
Western Emerald Lake Hills
51.6 dBA · Moderate
Quiet office to normal conversation
27% of people above 55 dBA
QuietLoud
Central Emerald Lake Hills sounds about 28% louder than Northern Emerald Lake Hills to the human ear, a 3.6 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 I-280 do you need to be?
I-280 produces an estimated 78 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.
At source
78 dBA
City bus interior
165 ft
64 dBA
Busy restaurant
330 ft
57 dBA
Normal conversation an arm’s length away
660 ft
49 dBA
Quiet office
¼ mile
41 dBA
Soft rainfall
½ mile
35 dBA
Soft rainfall
Calculated from the model's calibrated attenuation formula. About 23% of Emerald Lake Hills sits under tree canopy (heavier than most neighborhoods) and roughly 30% 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.
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Airport Noise
San Francisco International (SFO) sits northwest of Emerald Lake Hills. The U.S. Department of Transportation measures aviation noise around this airport directly, and the model uses those federal measurements rather than synthetic predictions.
Blocks under the approach and departure paths carry combined road-plus-aviation noise, with some exceeding 75 dBA on the map's Overall layer. Blocks on the opposite side of Emerald Lake Hills, particularly to the southeast, show no measurable aviation contribution. Use the Aviation toggle on the map above to isolate the airport's footprint.
How Noise Is Distributed Across Emerald Lake Hills
The bar chart below shows the share of Emerald Lake Hills residents in each noise band. About 86% of residents live below the EPA's 55 dBA threshold, and roughly 2% live in blocks above 60 dBA. Long-term exposure in that range is linked to elevated stress hormones and cardiovascular risk.
How Emerald Lake Hills Compares
Emerald Lake Hills sits at the quieter end of the spectrum. Below: how Emerald Lake Hills's average outdoor noise and share of residents above the EPA threshold compare with Centennial, Marina Lagoon, Stanford University, and Farm Hills.
Average noise level (dBA)
Emerald Lake Hills's 51.5 dBA pop-weighted average is at the quieter end of the spectrum. California as a whole averages 54.0 dBA and the U.S. averages 52.0 dBA. Both are lower than Emerald Lake Hills because most of either area is rural land away from major roads.
Share of residents above 55 dBA
About 23.0% of Emerald Lake Hills residents live in blocks where outdoor levels exceed the EPA's 55 dBA threshold. That's in the middle of its peer group. Measured by land area instead, 30.7% of Emerald Lake Hills's footprint sits above 55 dBA, against a California average of 36.0% and a national average of 28.1%.
What This Means if You're Moving to Emerald Lake Hills
Distance from highways matters more than the neighborhood name. Two homes in the same zip code can differ by 20 dBA if one sits 100 meters from I-280 and the other 500 meters away. The model captures this at 100-meter resolution, so noise exposure changes block by block.
Tree canopy can help reduce modeled noise exposure. Roughly 23% of Emerald Lake Hills is under tree cover (heavier than most neighborhoods), and the dominant land cover is low-intensity developed land. Both are measured from federal USDA Forest Service and USGS satellite imagery at 30-meter resolution. Streets with 60% or higher canopy show 3 to 5 dBA lower noise than comparable streets with bare ground or pavement, which is why the per-place decay rate above already accounts for it.
Airport noise is directional. San Francisco International's approach paths concentrate aviation noise to the northwest. Neighborhoods to the southeast of downtown show no measurable contribution from the airport.
Sources & Methodology
The BestNeighborhood noise model is calibrated against nearly one million federal ground-truth measurements across four states. Road noise is computed from segment-level federal traffic data and propagated outward using physics-based acoustic decay, with attenuation rates that depend on the surrounding land cover.
All inputs are published federal datasets. Block-level noise is computed by combining road, rail, and aviation sound sources in the energy domain, the same physics used in professional environmental noise assessments. Read the full methodology.
