Generally, the synoptic-scale transport of pollution by winds in the middle latitudes goes from west to east. Building the smokestacks in the Tennessee River Valley power plants nearly 1000 ft. tall has resulted in the immediate area not getting the coal smoke, but regions far downwind get the stuff when it finally reaches the ground.

The NE region of the U.S. is downwind of the power generating plants in the Ohio and Tennessee River Valleys.

There is a small area of acidity in Southern California (that does not show up on this map). This is due to the deposition of NOx as nitric acid (HNO₃) in fog and rain drops. This is a local scale problem, rather than a regional scale one like the general sulfuric acid deposition in the Northeast, since the NOx tends to stay in the L.A. air basin. In areas downwind of large electric power plants, the low pH of the rain is partially due to the NOx emissions from the coal furnaces.