The Kiev one sounds mechanical in origin. Probably a train, a heavy construction crane, or a ship in harbor. The other three sound like atmospheric disturbances.
Well said, the other three I'm curious on the make up of the areas. What kind of similarities there could be in cell tower make up, power, or perhaps combination of elements with human factors? It could be something that we are doing we aren't realizing we are doing. There are many things that occur on account of our actions we don't think on or predict well to understand consequences.