There is a mayor who has suggested broadcasting around town the sound of birds singing because it's supposed to make people happier. Who wouldn't enjoy the sound of repetitive chirping, warbling, and squawking? We could try broadcasting that throughout the streets of Normal. But why stop with sounds? Why not scents? The smell of hot tar used to fill potholes should make people happy. The smell of freshly cut grass without fertilizer or weed killer would be a nice change. And the smell of creosote (or whatever train smell you prefer) would reassure folks that we do need to invest in train travel. (I've lived next to railroad tracks and, trust me, there is a distinct aroma.)
The one problem with broadcasting sounds is that it is somewhat reminiscent of the Soviet Union's attempt to "cheer up" the area around Chernobyl (after the nuclear disaster) by playing music over loudspeakers. I'm always reminded of that when I visit the local outdoor shopping mall. Gives me the creeps (but doesn't stop me from spending money).