"Tall smokestacks are one reason that emissions from coal-fired power plants are blown across state lines, making it more difficult for downwind states to clean up their air, a new Government Accountability Office study found.
Nationwide, there are now 284 smokestacks in operation that are more than 500 feet tall, the report says. About 35 percent of those are in five states along the Ohio River Valley -- Ohio, Kentucky, Indiana, Illinois and Pennsylvania.
Power companies build tall stacks to avoid causing air quality problems in the area around coal plants. But the states along the I-95 corridor in the Northeast blame tall smokestacks for their struggles to meet federal air quality goals, claiming that the stacks feed into fast air currents that carry soot- and smog-forming emissions for hundreds of miles.
GAO found that many older coal plants have tall smokestacks and no modern pollution controls. Fifty-six percent of the boilers attached to tall stacks lack scrubbers to control sulfur dioxide (SO2), and 63 percent do not have controls to trap emissions of nitrogen oxides (NOx)."