One Fine Mess

Revisions to air quality standards for particulate matter are being contested as both too harsh and overly lenient

• By Steven J. Christiansen, JD
• May 01, 2007

On Sept. 21, 2006, Stephen Johnson, administrator of the U.S. Environmental Protection Agency (EPA), signed the latest revisions to the National Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM), also known as PM-2.5. The last revisions to the PM-2.5 standards by EPA occurred in 1997. While these latest revisions represent a significant tightening of the existing PM-2.5 NAAQS, EPA’s revisions have left some insisting the new standards do not go far enough and others wondering how they will ever demonstrate attainment of these stricter standards.

The New Standards
In 1997, EPA issued the first PM-2.5 federal air quality standards and set the primary and secondary NAAQS at 15 micrograms per cubic meter (µg/m3) annual average and 65 µg/m3 24-hour (daily) average.1 At this time, EPA essentially let stand the PM-10 standards promulgated in 1987 with a daily standard of 150 µg/m3 and an annual standard of 50 µg/m3.2

A large number of parties addressing a broad range of issues challenged the 1997 PM-2.5 standards in court. In May 1999, a three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit), held (over one judge’s dissent) that EPA’s approach to establishing the standards effected “an unconstitutional delegation of legislative authority.”3 However, on appeal to the U.S. Supreme Court, EPA’s approach to setting air quality standards was upheld.4

Since 1997, EPA has undertaken a detailed review of the PM-2.5 standards culminating in the recent revisions. In the final rule, EPA retained the annual PM-2.5 NAAQS at 15 µg/m3. The agency, however, tightened the 24-hour PM-2.5 NAAQS by nearly 50 percent to 35 µg/m3. Furthermore, EPA retained the 24-hour PM-10 standard of 150 µg/m3, but revoked the annual PM-10 standard of 50 µg/m3.

On Oct. 6, 2006, EPA completed its regulatory impact analysis of the 2006 NAAQS for PM-2.5, concluding that the new federal air quality standards would yield $9 billion to $76 billion a year in health and visibility benefits by the year 2020.

Not Far Enough?
In issuing the new PM-2.5 NAAQS, EPA Administrator Stephen Johnson said, “today EPA is delivering the most health-protective national air standards in U.S. history to all 300 million Americans.” EPA further commented that the “final action significantly strengthens EPA’s previous daily fine particle standard….”

Not all interested parties agreed, however that EPA had gone far enough with these new, revised standards. On Sept. 29, 2006, the seven members of EPA’s Clean Air Scientific Advisory Committee (CASAC) sent a letter to the EPA administrator taking issue with EPA’s decision not to tighten the annual PM-2.5 standard in addition to the 24-hour standard.

In deliberations leading up to the final decision, CASAC had reviewed the scientific literature and recommended a revised 24-hour PM-2.5 standard between 30-35 µg/m3 and a revised annual standard between 13-14 µg/m3. In commenting on the administrator’s decision to leave the annual PM-2.5 standard unchanged at 15 µg/m3, CASAC said it was “concerned that EPA did not accept our finding that the annual PM-2.5 standard was not protective of human health and did not follow our recommendation for a change in that standard.”

On December 2006, a diverse number of groups filed petitions in the D.C. Circuit seeking review of the PM-2.5 NAAQS revisions. It is clear that the revisions will be challenged on a number of grounds including the decision not to revise the annual PM-2.5 standard, the overall stringency of the standards, and EPA’s decision not to exempt farm dust from regulation. Those challenging the PM-2.5 NAAQS revisions include the American Farm Bureau Federation, Environmental Defense, Utility Air Regulatory Group, and a coalition of states. Among other things, the decision not to revise the annual PM-2.5 standard will set up an interesting debate on the ability of CASAC to set the range of “acceptable” NAAQS revisions versus the inherent power of the EPA administrator to independently review the administrative record, exercise discretion and set standards protective of public health.

Stricter Rules for Farmers, Miners, and Nonattainment Areas
While CASAC and others have complained that EPA did not go far enough with the PM-2.5 revisions, others claim EPA’s recent action will create hardship for them. For example, when EPA proposed revisions to the PM NAAQS, it proposed a new PM indicator or coarse particles in terms of PM-10-2.5 (i.e., particles between 2.5 and 10 microns in diameter). EPA proposed to exclude from this coarse particle standard any mix of particles dominated by rural windblown dust and soils and PM generated by agricultural and mining sources. Specifically, EPA proposed that agricultural sources, mining sources and other similar sources of crustal material would not be subject to control in meeting the proposed coarse particle standard. The proposal also was to revoke all the PM-10 standards adopted in 1987 and issue a new coarse particle standard in the form of PM-10-2.5.

In the final rule, EPA retained the 24-hour PM-10 standard, but did not adopt either the proposed PM-10-2.5 indicator or the exemption for dust and PM from agricultural and mining sources. EPA’s decision not to adopt the agricultural/mining exemption has not been well received in particular by farming interests in the Midwest and South. These interests argue they are being unfairly targeted and the lack of an exemption could create economic hardship for them. These groups have initiated litigation to challenge the agency’s decision on this point.

The new 24-hour PM-2.5 standard will result in the creation of a number of areas that are not in compliance with the revised NAAQS (i.e. nonattainment areas). A good example of this is the western United States. Under the current 1997 PM-2.5 standards, the only western states with nonattainment areas are California and Montana. Under the revised standards, however, counties in Alaska, California, Idaho, New Mexico, Oregon, Utah and Washington will likely be designated nonattainment.

In Utah, the revised PM-2.5 NAAQS will likely require five metropolitan counties to be designated nonattainment. Four of these counties were previously designated nonattainment with the 24-hour PM-10 standard and were able to show compliance with that standard only after the adoption of the first PM-10 state implementation plan (SIP) in the country, which included capital expenditures in the tens of millions of dollars by a number of prominent industrial sources in these counties. So, a new nonattainment designation for PM-2.5 will likely be very challenging and expensive.

Facing Legal Challenges
EPA adopted a new, more stringent 24-hour PM-2.5 standard on Sept. 21, 2006. The new standard is nearly 50 percent more stringent than the existing PM-2.5 standard and will result in the creation of new nonattainment areas. Some of these new nonattainment areas may find demonstrating attainment of the new standard to be particularly challenging and expensive.

Agricultural and mining interests were not pleased to learn that an exemption for emissions of crustal, coarse particles from their operations would not be adopted by EPA and have challenged this decision in court. Similarly, scientists and environmental groups oppose the decision of EPA to leave the annual PM-2.5 NAAQS of 15 µg/m3 unchanged. These groups have also challenged this decision.

1 40 CFR § 50.7(a)(2006).

2 40 CFR § 50.6(a)(2006).

3 American Trucking Associations v. EPA, 175 F.3d 1027, 1034-1040 (D.C. Cir. 1999).

4 Whitman v. American Trucking Associations, 531 U.S. 457, 475-76 (2001).

This article originally appeared in the 05/01/2007 issue of Environmental Protection.