EPA established the limits by determining the amount of NOx emissions that would remain in each state after reasonable, cost-effective control measures were applied. States are required to have controls in place on larger industrial sources by May 2003. Along with these controls and other necessary measures including mobile source controls, states must meet their overall NOx budgets by September 2007. The rule does not prescribe how states should reduce emissions to meet their NOx budget. Instead it allows states the flexibility to develop customized plans that will most effectively and cost-efficiently help them meet their reduction goals.
Electric utilities are likely to be one of the major sources targeted for reductions.
OTAG identified utilities as a major source for achieving significant NOx reductions, and EPA's analysis agrees with OTAG's recommendations. Emission reductions from utilities and other large boilers would be more cost effective in terms of dollars spent per ton of NOx reduced, particularly when compared to sources that have already reduced emissions substantially. This is a proven, cost-effective technique for achieving overall emissions reductions while providing flexibility to affected sources. This type of program already is being successfully implemented for sulfur dioxide emissions in EPA's Acid Rain Program. In 1997, EPA issued a new standard based on 8-hour concentrations of ozone.