James E. McCarthy
Specialist in Environmental Policy
The Environmental Protection Agency (EPA) is nearing the end of a statutorily required review of the National Ambient Air Quality Standards (NAAQS) for ozone. EPA is likely to propose a revised standard in 2014, with promulgation perhaps a year later.
NAAQS are standards for outdoor (ambient) air that are intended to protect public health and welfare from harmful concentrations of pollution. If the EPA Administrator changes the standard to a lower level, she would be concluding that protecting public health and welfare requires lower concentrations of ozone pollution than were previously judged to be safe. In high enough concentrations, ozone has been found to aggravate heart and lung diseases and may contribute to premature death. It also can have negative effects on forests and crop yields, which the secondary NAAQS are intended to protect.
As of July 2013, 123 million people (40% of the U.S. population) lived in areas classified nonattainment for the primary (health-based) ozone NAAQS. If the standards are further strengthened, more areas might be affected, and sources that contribute to that nonattainment might have to impose more stringent emission controls. This could be costly: in 2011, EPA concluded that strengthening the primary NAAQS from 75 parts per billion to 70 ppb would cost at least $19 billion annually by 2020.
EPA last revised the ozone standard in March 2008, but the standards chosen at that time remain subject to controversy. A 23-member panel of EPA science advisers, chosen from outside the agency, unanimously recommended a more stringent range of standards than the Administrator chose. In 2009, the agency agreed to reconsider the 2008 standard, but the process was shortcircuited by a presidential decision to await conclusion of the next regular review—the review now nearing completion.
The agency begins a NAAQS review by compiling an Integrated Science Assessment, which summarizes the science surrounding the standards. The current assessment, released in February 2013, finds that the evidence associating ozone exposure with morbidity and mortality has strengthened since the 2008 review was completed. This would appear to support more stringent standards.
Proposed standards might raise a number of issues, including whether their expected benefits justify their costs. This is a perennial issue raised by stakeholders when EPA considers revising the NAAQS. As the Clean Air Act is currently written, however, the agency is prohibited from weighing costs against benefits in setting these standards. The statute simply states that the Administrator is to set the primary standard at a level requisite to protect the public health, allowing an adequate margin of safety. A unanimous Supreme Court has found that the absence of language mentioning cost means that costs are not to be considered in setting these standards. Many in Congress would like to change this to require a cost or cost-benefit consideration: in the 112th Congress, House-passed legislation would have done so.
A related question is how nonattainment areas would lower emissions sufficiently to comply with a more stringent standard. Current federal standards for cars, trucks, nonroad vehicles and engines, power plants, and other stationary pollution sources are not strong enough to bring many areas into attainment, thus requiring local pollution control measures in those cases. To attain more stringent standards, there might be increased pressure to strengthen federal controls on the sources that contribute to ozone pollution; Congress might also revisit the perennial issue of how to control sources that contribute to pollution downwind, in other states.
There are also monitoring issues: at present, only 675 of the nation’s 3,000 counties have ozone monitors in place.
This report discusses the standard-setting process, the specifics of the current and most recent reviews, and issues that may be raised as EPA brings the current review to completion.
Date of Report: November 7, 2013
Number of Pages: 20
Order Number: R43092
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