The Environmental Protection Agency has proposed a regulation that aims to cut sulfur dioxide and nitrogen oxides emissions that are carried downwind from powerplants in 31 eastern states and the District of Columbia, posing harm in other parts of the country. EPA says that the proposed rule, which EPA Administrator Lisa Jackson signed on July 6, would cut SO2 emissions by 2014 by 71% from 2005 levels and trim NOx emissions by 52%. McCarthy says the first phase of the reductions would take place in 2012, assuming that the rule becomes final in 2011. Gina McCarthy, EPA's assistant administrator for
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.