Snakeater
All states have on there books, noise pollution standards. The standards are broken down into day time (0600-2200 can vary from state to state) night time standards.
When written the standard were meant for Industry, night time standards are generally in the 48-50 db range, while day time noise is generally in the 65-70 db range. Some counties and cities have more restrictive standards. A call to the local/state EPA-DEP should confirm the standards for your particular area. Trick is to get an inspector out while the noise is occurring. I can almost guarantee that leaf blowers will exceed the day time standard, distance is critical. You can also buy a decimal ( db) meter from Radio Shack or Fisher Scientific.
In the mid 90's I worked on a Nat Gas fired Power Plant outside of Quetta Pakistan ( one of the true armpits of the earth). The projected noise emissions at the fence line were in the 50-51 db range. No neighbors with-in a 2 mile radius. World Bank participated in the project and had established a night time standard of 49 db. We planted trees around the fence line to create a sound barrier. The difficult/expensive part was getting water in a desert for the trees.
Well the plant started up and inspectors came out an took readings around the perimeter, and the reading were in the 45-46db range. There were a lot of happy faces in the meeting that day. A couple of months later a Chicken farm about 3 miles away began complaining about noise from the plant disturbing the chickens. Out come the inspectors who find nothing changed perimeter reading still low. They go visit the farmer and take readings in the evening in the 55 db range. Turns out the farm is
3 miles straight line from the plant gates. Noise is being funneled out the gate and directed at the farm. The are no natural barriers between the plant and the farm.
We ended up putting acoustical strips in the gates chain link fence.