Last month, the Maryland Department of the Environment petitioned EPA to try to get the federal agency to force coal-fired power plants in Pennsylvania, Indiana, Ohio, Kentucky and West Virginia to step releasing so much air pollution, which drifts downwind and contributes to smog in Baltimore and elsewhere in Maryland.
The action was not unprecedented, because about 70 percent of the air pollution in Maryland comes from out of state.
But here’s what was amazing: Many of these power plants invested hundreds of millions of dollars to install air pollution control systems to filter out the pollutant of concern, nitrogen oxides. And these plants, for years, successfully ran these filtration systems (which use a technology called Selective Catalytic Reduction). But then a few years ago, they stopped. The plants just turned off the filters and let the pollutant, also called NOx, flow out freely.