States and local governments, mostly in California and areas east of the Mississippi, may be required to take a variety of steps to control ozone, such as stricter controls on factory emissions, cutbacks in automobile use or gasoline vapor recovery controls.
The previous one-hour ozone standard affected only 110 million people in fewer than half as many counties. The new, stricter standard of 0.08 parts per million averaged over eight hours, results from dozens of studies that showed longer exposure to low levels of ozone damages the respiratory and immune systems. The eight-hour rule was issued in 1997, but had been held up by a lengthy legal battle that went all the way to the Supreme Court.
Odorless and invisible, ground-level ozone is a major component of the smog that forms on hot summer days. Ozone can irritate a person's airways, reduce lung function, aggravate asthma and damage the cells lining the lungs. It also may aggravate chronic lung diseases like emphysema and bronchitis, reduce the immune system's ability to fight off bacterial infections in the respiratory system. Long-term, repeated exposure may cause permanent lung damage.
EPA Administrator Mike Leavitt emphasized that the new rules don't result from dirtier air the air is actually growing cleaner. The stricter standards are needed, he explained, because of "our new understanding about health threats."
EPA has announced a suite of inter-related actions known as the Clean Air Rules of 2004, designed to help states and localities to meet a stricter national standard for ground-level ozone. The Clean Air Interstate Rule addresses power plant emissions of sulfur dioxide (SO2) and nitrogen oxide (NOx), both of which blow across state lines and foul the air in downwind cities.
EPA's Clean Air Non-road Diesel Rule will regulate emissions from construction and other non-road equipment powered by diesel engines. The rule also cuts sulfur levels in diesel fuel by more than 99 percent over current levels. Both actions will significantly help localities achieve cleaner air and cut ozone pollution.
"These ozone standards are strong medicine," Leavitt wrote the governors in the 31 nonattainment states. But EPA under the Bush administration is attempting to balance environmental protection with policies that foster economic growth.
"As a former governor of Utah, I recognize that having parts of your state designated as being in nonattainment will require more actions on your part to achieve cleaner, healthier air," Leavitt added. "We need to work together to make certain your state can, as others have in the past, clean the air while sustaining economic growth."
