Regulatory certainty is a benefit for industry, allowing orderly design, planning, and budgeting for capital expenditures. Many environmental regulations have been in place for many years and provide a certain level of continuity. However, the national ambient air quality standard for ozone has not proven itself to be a model of stability over the years.

The Clean Air Act requires that national ambient air quality standards be set at a level that protects human health and the environment with an adequate margin of safety. For years, the standard for ozone was set at 80 parts per billion (ppb). In 2008, EPA lowered the standard to 75 ppb. However, when the Obama Administration entered office in January, 2009, EPA reviewed actions taken by the previous Bush Administration. As to ozone, EPA initiated a rule-making in 2010 to reconsider the 2008 Standard, relying on, among other things, the fact that 75 ppb was above the range recommended by EPA’s scientific advisory board and so may not be protective of human health. The reconsideration rule proposed that the standard be set between 60 and 70 ppb. Continue reading “The Ozone Two-Step” →