US built taller smokestacks to cut local pollution; acid rain spread farther

An effort by American power companies to reduce local air pollution in the 1970s ended up creating a much wider environmental crisis, turning a local health problem into a continent-wide acid rain emergency. By building huge smokestacks to send coal emissions away from nearby towns, power companies pushed sulfur dioxide and nitrogen oxides into high-altitude winds. Instead of removing the pollution, the strategy carried these harmful chemicals hundreds of miles downwind, bringing acidic rain to forests, lakes and communities far from the power plants. Data collected in a major government investigation by the United States Government Accountability Office (GAO), titled Air Quality: Information on Tall Smokestacks and Their Contribution to Interstate Transport of Air Pollution (GAO-11-473), shows how the rapid spread of these giant structures changed air chemistry across North America.The rise of the giant chimneysIn 1970, the United States had only two industrial smokestacks taller than 500 feet.