Here is a new startup, Howloud, taking on the challenge of calculating and mapping residential noise levels. If you live in LA or Orange Counties, enter your address to see your Soundscore.
Also, here is a KCAL 9 news piece about Howloud, and a LA Curbed article.
I noticed that the areas of Santa Clarita, Lancaster and Palmdale have not been calculated yet. Donate to their Kickstarter to get them done! Their plans are to build a sound map for North America, including mapping noise around buildings in 3D.