While helping out someone that was looking for fatal accident data, I ran across a cool map service hosted by the US DOT Bureau of Transportation Statistics.  Looking at the REST endpoint for their map services, I found the National Transportation Noise Map.  The service description reads:

The National Transportation Noise Map is developed using a 24-hr equivalent sound level (LEQ, denoted by LAeq) noise metric. The results are A-weighted noise levels that represent the approximate average noise energy due to transportation noise sources over the 24 hour period at the defined receptors. This map includes simplified noise modeling and is intended for the tracking of trends, it should not be used to evaluate noise levels in individual locations and/or at specific times. https://maps.bts.dot.gov/noise/

If you click on the link in the description, it will take you to a document that outlines how the noise levels were collected and processed.  A few points about the data:

• It is a simplified noise model to track trends
• Flight operations are averaged into a single average annual day
• Military operations were not included unless they were at a joint-use or commercial airport
• Helicopter operations were not included
• Flight track info was available for some airports for the modeling, and for the ones that did not have any flight track info, a straight-in and out procedure was modeled
• For the road noise model, average annual daily traffic values were used in conjunction with vehicle types and speed, distributed evenly across 24 hours
• The noise level cutoff of 35 db(A) was used

Adding the image service to ArcMap displayed this in the LA basin area:

I then changed the color ramp so high noise levels were red and low noise levels were blue.

Pretty cool … unless you live near LAX!