Coal combustion in the U.S. generates around 130 million tons of coal ash each year, with power plants being the largest contributors. Bottom ash is collected from combustion chambers and fly ash is gathered from smokestacks and air pollution control devices.
Human activities are not direct sources of a lot of ozone, but ozone concentrations increase to markedly unhealthy levels in many areas during the summer. About 30 years ago, atmospheric chemists solved this mystery.
We ecologists take a lot of flack for always having depressing news to report. It's not often we get to say there is good news on the environmental front, but those of us concerned with air pollution have certainly had reasons to smile this summer.
Several members of Congress and presidential hopefuls have proposed rolling back the Environmental Protection Agency's authority to regulate with the Clean Air and Clean Water acts as a solution to our woes.
There was some good news on the environment last week. In the 20-state area that participates in a cap-and-trade program to reduce emissions of nitric oxide (NOx) from power plants, the emissions declined 32 percent from 1997 to 2005.