Lower summer ozone levels give Eastern lungs a break

Summer air quality has improved in 19 Eastern states, thanks to a federally mandated cap-and-trade system for nitrogen oxides*. According to a report released yesterday by the U.S. EPA, nitrogen-oxide emissions from power plants and other sources in the region were about 50 percent lower in 2004 than in 2000, leading to a drop in ozone concentrations of about 10 percent. The federal plan, implemented under the Clean Air Act, sets overall state caps for emissions, but allows dirtier plants to meet their targets by buying credits from cleaner ones. Some eco-advocates have criticized this approach, saying it allows plant owners to evade upgrades to the best available pollution-reduction technology, while others laud the combo of mandatory limits with market mechanisms. The feds argue that cap-and-trade gives operators an incentive to control emissions from the biggest sources first. But all sectors hailed Thursday’s lung-friendly news as a sign of much-needed progress.

*[Correction, 22 Aug 2005: This summary originally stated the cap-and-trade system and power-plant emissions were of nitrous oxides. Instead, the pollutants in question are nitrogen oxides.]

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