Introduction

In December 2012, the U.S. Environmental Protection Agency (EPA) finalized a new national clean air standard for fine particulate matter (PM 2.5), commonly referred to as soot. These microscopic particles are often emitted from diesel engines and power plants. When inhaled, the particles lodge deep inside the lungs and can cause asthma, acute bronchitis, heart attack, stroke, and even premature death, especially in vulnerable populations such as children and the elderly. EPA moved forward to strengthen the standard after new data confirmed that the standard set in 1997 did not adequately protect the public.

The Clean Air Act and EPA's Review of the PM (Soot) Standard

Under the Clean Air Act, EPA is tasked with setting national ambient air quality standards (NAAQS) for air pollutants to a level that protects public health and includes an adequate margin of safety. Once EPA has set standards, the Clean Air Act requires the agency to review them every five years. EPA set standards for fine particulate matter (PM 2.5) in 1997 but failed to complete a review in 2002, and in 2006 failed to revise the standard to a level that would adequately protect public health.

In 2012, the American Lung Association and the National Parks Conservation Association successfully petitioned the D.C. Circuit Court of Appeals to compel EPA to complete another long overdue review of the air quality standards for particulate matter, which had been in progress since 2007. When the agency performed the review, EPA scientists found that the existing annual standard for fine particulate matter did not adequately protect people from the dangerous health effects of exposure, such as premature death.

EPA's new rule lowers the annual limit of PM 2.5 from 15 micrograms per cubed meter (μg/m³, a measurement of the concentration of a pollutant in the air) to 12 μg/m³ but does not revise the existing standards for coarse particulate matter. All counties have until 2020 to meet the new soot standard. On the day the new rule was issued, 66 counties failed to comply and will have to improve their air quality.

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Billions in Benefits Expected

EPA and state rules already in place are expected to bring 99 percent of counties into compliance with the new standard without requiring an additional investment in pollution control technology. EPA estimates that the benefits of the new rule will far outweigh its costs.

Although the Clean Air Act prohibits EPA from considering the costs of new air quality standards, the Office of Information and Regulatory Affairs (OIRA) at the White House Office of Management and Budget (OMB) requires the EPA to prepare a cost-benefit analysis for air quality rules under Executive Order 12866. EPA makes the analysis available to the public for informational purposes.

EPA estimates that the monetary value of public health benefits produced by this rule will range from $4 billion to $9.1 billion by 2020, and the costs of pollution reduction will range from $53 million to $350 million. Even if the rule produces the lowest estimated benefits and highest costs, benefits will exceed costs at a 12 to 1 ratio. Under the best-case scenario, every dollar spent on pollution reduction would have a corresponding gain of $171 in public health benefits. In real-life terms, here are some of the health benefits of the standard:

Source: EPA, http://www.epa.gov/pm/2012/finalria.pdf (Table ES-4, at pg. ES-17).

Several small business organizations commended EPA's work on the new standard in a joint statement, in which they explained that the rule "will result in decreased mortality rates and fewer incidents of heart attacks, strokes, and asthma, consequently avoiding lost work days and pollution-related health care costs for businesses across the economy." The American Lung Association has also praised the new rule, noting that the more protective standard "will prevent heart attacks and asthma attacks, and will keep children out of the emergency room and hospitals."

EPA's cost-benefit analysis also noted several important benefits from improved air quality that the agency could not quantify: improved visibility from clearer skies, reduced injury to wildlife, and fewer greenhouse gas emissions.

New State Implementation Rules for Soot Will Also Be Required

Before the new soot standards were released, the Natural Resources Defense Counsel, Sierra Club, American Lung Association, and Medical Advocates for Healthy Air filed suit against EPA asking the D.C. Circuit Court to compel the agency to re-examine two implementation rules. The groups charged that EPA issued these rules under the wrong (and weaker) provision of the Clean Air Act, which allowed states too much flexibility in implementing the old soot standards. On Jan. 4, the D.C. Circuit agreed with the environmental groups, so EPA will have to use the correct provision of the Clean Air Act as it decides how to implement the new standard.

The new standard for fine particulates is a big step forward. As EPA issues and revises other standards to better protect the public and the environment, it will also need to ensure that its rules for implementation do not provide too much leeway for states, especially in areas that are not currently in compliance with EPA's air quality standards.

Editor's note: This article has been updated since its original publication date.