|Projected non-attainment by county in 2020 under the range of the proposed new limits. Source: EPA. Click to enlarge.|
The US Environmental Protection Agency (EPA) proposed updates to its national ambient air quality standards (NAAQS) for harmful fine particle pollution (PM2.5). These microscopic particles can penetrate deep into the lungs and have been linked to a wide range of serious health effects, including premature death, heart attacks, and strokes, as well as acute bronchitis and aggravated asthma among children.
EPA’s proposal would strengthen the annual health standard for PM2.5 to a level within a range of 13 µg/m3 to 12 µg/m3. The current annual standard is 15 µg/m3, which has been in place since 1997. By proposing a range, EPA said it will collect input from the public as well as a number of stakeholders, including industry and public health groups, to help determine the most appropriate final standard to protect public health. Other aspects of the proposed rulemaking include:
Retaining the existing 24‐hour fine particle standard of 35 µg/m3, which was set in 2006.
Setting a separate fine particle standard to improve visibility, primarily in urban areas. EPA is proposing two options for this 24‐hour standard, at 30 deciviews or 28 deciviews. (A deciview is a yardstick for measuring visibility.)
Retaining existing secondary standards for PM2.5 and PM10 identical to primary standards to provide protection against other effects, such as ecological effects, effects on materials, and climate impacts.
For coarse particles (PM10), the proposal would retain the existing 24‐hour standard of 150 µg/m3, which has been in place since 1987.
EPA is proposing to grandfather pre-construction permitting applications that have made substantial progress through the review process at the time the final standards are issued. The agency is also proposing updates and improvements to the PM2.5 monitoring network that include relocating a small number of monitors to measure fine particles near heavily traveled roads. EPA’s proposal does not require additional monitors. In addition, the proposal would update the Air Quality Index (AQI) for particle pollution.
A federal court ruling in 2009 required EPA to update the standard based on best available science by October 2011. After EPA did not meet that deadline, a court order issued earlier this month required the agency to issue its new proposal to update the standards by today.
The proposed changes, which are consistent with the advice from the agency’s independent science advisors, are based on an extensive body of scientific evidence that includes thousands of studies—including many large studies which show negative health impacts at lower levels than previously understood.
EPA projects that 99% of US counties will meet the proposed standards without undertaking any further actions to reduce emissions.
Because reductions in fine particle pollution have direct health benefits including decreased mortality rates, fewer incidents of heart attacks, strokes, and childhood asthma, these standards have major economic benefits with comparatively low costs, EPA suggests.
Depending on the final level of the standard, estimated benefits will range from $88 million a year, with estimated costs of implementation as low as $2.9 million, to $5.9 billion in annual benefits with a cost of $69 million—a return ranging from $30 to $86 for every dollar invested in pollution control. While EPA cannot consider costs in selecting a standard under the Clean Air Act, those costs are estimated as part of the analysis undertaken for all significant regulations, as required by Executive Order 13563 issued by President Obama in January 2011.
EPA will accept public comment for 63 days after the proposed standards are published in the Federal Register. The agency will hold two public hearings; one in Sacramento, CA. and one in Philadelphia, PA. Details on the hearings will be announced shortly. EPA will issue the final standards by 14 December 2012.