Contents

• Introduction
• EPA's 2013 Changes to the PM NAAQS
• Designation of Geographical Nonattainment Areas
• NAAQS Designation Process
• Designations for the 2013 PM_2.5 Annual NAAQS
• EPA April 2015 Amended Final Designations
• EPA January 2015 Final Designations
• State Recommendations and EPA August 2014 EPA Proposed Designations in Response
• Comparing EPA's Final Nonattainment Designations for the 2013 PM NAAQS with the 2006 and 1997 PM_2.5 NAAQS Final Designations
• Demonstrating Attainment with the 2013 PM_2.5 NAAQS
• State Implementation Plans (SIPs)
• EPA NAAQS Implementation Rules/Guidance
• National Regulations
• New Source Review
• Transportation Conformity
• Conclusion

Summary

On April 7, 2015, the Environmental Protection Agency (EPA) published amendments to the January 15, 2015, final rule designating areas for compliance with the 2013 primary annual National Ambient Air Quality Standard (NAAQS) for fine particulate matter (PM_2.5). Revising a NAAQS established under the Clean Air Act (CAA) sets in motion a process under which the states and EPA identify areas that exceed the standard ("nonattainment areas") using multi-year air quality monitoring data and other criteria, requiring states to take steps to reduce pollutant concentrations in order to meet the standard.

The 2013 revisions to the PM NAAQS were the subject of considerable congressional oversight. EPA's designation of nonattainment areas may be an issue of interest and debate among Members of Congress, states, and other stakeholders. The PM NAAQS revisions, published January 2013 changed the annual health-based ("primary") standard for "fine" particulate matter 2.5 micrometers or less in diameter (or PM_2.5) to a limit of 12 micrograms per cubic meter (µg/m³) from the 15 µg/m³ limit. Revisions to the PM NAAQS retained the existing 24-hour primary standard for PM_2.5 of 35 µg/m³ (as promulgated in 2006) and the existing standard for larger, but still inhalable, "coarse" particles 10 micrometers or less in diameter, or PM₁₀.

During EPA's consideration of alternative approaches for revising the PM NAAQS, many stakeholders and some in Congress expressed concern about the potential impacts associated with an increased number of areas that may be deemed nonattainment under a more stringent standard. The number of areas ultimately determined nonattainment for the revised PM NAAQS were considerably fewer than some had anticipated.

Based on its review of recently submitted 2014 air quality data, EPA's April 2015 modifications to the final area designations for the 2013 PM NAAQS resulted in nine areas consisting of 20 counties in four states designated as nonattainment. All but two of the 20 counties have been previously designated as nonattainment for the 2006 and/or the 1997 PM_2.5 NAAQS. In accordance with a decision by the U.S. Court of Appeals for the District of Columbia Circuit on January 4, 2013, EPA classified all areas determined to be in nonattainment as "moderate" nonattainment areas under the authority of Section 188 of the CAA.

In comparison to the nonattainment area designations as amended by EPA in April 2015, EPA's final designations published in January 2015 were composed of 14 areas comprising 38 counties in 6 states. The EPA April 2015 amended designations changed the nonattainment designation of two areas in Pennsylvania (four counties) and one each in Ohio (three counties) and Ohio (four counties)/Kentucky (three counties) to "unclassifiable/attainment" and one area in Kentucky (two counties)/Indiana (two counties) to "unclassifiable." EPA also designated five areas in Georgia (including two counties in Alabama and South Carolina) as unclassifiable.

States have 18 months from the April 15, 2015, effective date of EPA's final designations to submit State Implementation Plans, which identify specific regulations and emission control requirements intended to bring an area into compliance or maintain compliance. Section 188 of the CAA requires that moderate nonattainment areas achieve attainment as expeditiously as practicable but no later than the end of the sixth calendar year after designation as nonattainment.

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2013 National Ambient Air Quality Standard (NAAQS) for Fine Particulate Matter (PM2.5): Designating Nonattainment Areas

Introduction

Under Sections 108-109 of the Clean Air Act (CAA), Congress mandated that the Environmental Protection Agency (EPA) set national ambient (outdoor) air quality standards (or NAAQS) for pollutants whose emissions (1) "may reasonably be anticipated to endanger public health or welfare" and (2) "results from numerous or diverse mobile or stationary sources." The statute further requires that EPA review the latest scientific studies and either reaffirm or modify previously established NAAQS every five years. EPA has identified and promulgated NAAQS for six principal pollutants commonly referred to as "criteria pollutants":

• 1. Particulate matter (PM),
• 2. Ozone (O₃—a key measure of smog),
• 3. Nitrogen dioxide (NO₂, or NOx—inclusively, nitrogen oxides),¹
• 4. Sulfur oxides (SOx or specifically SO₂),
• 5. Carbon monoxide (CO), and
• 6. Lead (Pb).

For particulate matter (PM), EPA established short-term (24-hour) and long-term (annual) standards. Additionally, EPA established separate standards for two categories of PM based on size: "fine" particulate matter 2.5 micrometers or less in diameter (referred to as PM_2.5) and slightly larger, but still inhalable, particles less than or equal to 10 micrometers (referred to as PM₁₀). EPA last reviewed and revised the PM NAAQS in 2006. (See PM NAAQS chronology presented in Table A-1.)

On January 15, 2013, EPA published its revisions to the NAAQS for PM² to provide protection against potential health effects associated with short- and long-term exposure to particulates (including chronic respiratory disease and premature mortality).³ Because the agency finalized its decision on December 14, 2012, EPA frequently refers to these changes as the "2012 PM NAAQS."⁴ In this report, CRS will refer to the changes as the 2013 PM NAAQS based on the January 15, 2013, publication date of the final rule.

EPA's 2013 PM NAAQS revisions primarily tightened the pre-existing (2006 and 1997) standards for "fine" particulate matter PM_2.5 and affected only the stringency of the annual PM_2.5 standard.⁵ The 24-hour PM_2.5 standard as revised in 2006 was not similarly strengthened in the 2013 NAAQS revisions. The standards for slightly larger, but still inhalable, particles less than or equal to 10 micrometers (PM₁₀) established in 1987⁶ were also not changed to a more stringent level in the 2013 PM NAAQS revisions.⁷

Establishing NAAQS does not directly limit emissions or directly compel specific emissions controls; rather, it represents the EPA administrator's formal judgment regarding the level of ambient pollution that will protect public health with an adequate margin of safety. Promulgation of NAAQS sets in motion a process under which the states and EPA first identify geographic nonattainment areas (i.e., those areas failing to meet the NAAQS) based on monitoring and analysis of relevant air quality data. States then submit State Implementation Plans (SIPs), which identify specific regulations and emission control requirements that are to bring areas into compliance as well as actions for maintaining compliance.

On April 7, 2015,⁸ EPA published amendments to the final designations for the 2013 PM_2.5 NAAQS that were published on January 15, 2015.⁹ The changes to area designations were the result of air quality data for 2014 recently submitted by affected states. The effective date of April 15, 2015 (90 days from the date of publication) for the final designation rule remained unchanged.

The final area designations as amended and published in the April 7, 2015, Federal Register encompass 20 counties or portions of counties (nine areas) in four states as nonattainment only for the 2013 revised annual PM_2.5 standard. EPA also designated five areas in Georgia (including two adjacent counties in Alabama and South Carolina) as unclassifiable. In the final designation rule as published on January 15, 2015,¹⁰ EPA had designated 38 counties or portions of counties (14 areas) in six states. At that time EPA announced that it was also deferring initial designation for 10 areas in three states by up to one year as a result of insufficient data. Included were all of Florida, all of Tennessee except for three counties, and eight areas in Georgia (including two adjacent counties in Alabama and South Carolina). The EPA also designated three areas (including all of Illinois) as "unclassifiable" due to insufficiencies in the available ambient air quality monitoring data for these areas for the three-year period (2011-2013).

The April 2015 modifications did not impact EPA's designation determinations for areas in Indian country as published in January 2015. Twelve areas in Indian country adjacent to counties designated nonattainment in two areas in California were designated nonattainment for the 2013 annual PM_2.5 standard. EPA designated all remaining state areas and areas in Indian country as "unclassifiable/attainment" for the 2013 annual PM_2.5 standard, indicating that "the areas either have attaining [sic] air quality monitoring data or that air quality information is not available because the areas are not monitored, and the EPA has not determined that the areas contribute to a violation in a nearby area."¹¹

As EPA had specified in its April 2013 area designation guidance to states and tribes,¹² the initial area designations for all 2013 PM_2.5 NAAQS nonattainment areas are classified as "moderate" as provided under Section 188(a) of Subpart 4 of Part D of Title I of the CAA.¹³ EPA had previously implemented the PM_2.5 NAAQS—including nonattainment determinations for the 1997 and 2006 revisions—only under the general implementation provisions in Subpart 1 (§171-§176) of Part D in Title I of the CAA ("Subpart 1"). However, in a January 4, 2013, decision,¹⁴ the U.S. Court of Appeals for the District of Columbia Circuit determined that EPA had erred in implementing the PM_2.5 NAAQS under Subpart 1 and required the agency to implement the PM_2.5 NAAQS under Subpart 4 of Part D in Title I of the CAA ("Subpart 4").¹⁵

This CRS report focuses primarily on the NAAQS implementation process for designating geographical nonattainment areas with respect to the tightening of the PM_2.5 annual standard under the 2013 particulates NAAQS, including comparisons with the final designations under the 2006 and 1997 PM_2.5 NAAQS revisions. EPA is not requiring new nonattainment designations for the PM_2.5 24-hour standard or the PM₁₀ standard, as the levels for these standards were unchanged in the 2013 revisions.

Also included in this CRS report is a brief overview of states' subsequent obligations for developing and submitting SIPs for attaining or maintaining compliance with the NAAQS. Appendix A presents a chronology of PM NAAQS regulations, and Appendix B includes a comparative table of the implementation timeline for the 1997, 2006, and 2013 PM NAAQS. The table in Appendix C provides a state and county breakdown of EPA's final designated nonattainment areas published in January and April 2015, areas proposed by EPA in August 2014, and recommendations by the states for the 2013 annual PM_2.5 NAAQS compared to the final EPA designations for the 2006 (24-hour) and 1997 (annual) PM_2.5 NAAQS for those states and counties. Table D-1 in Appendix D identifies areas in Indian country designated nonattainment for the 2013 PM NAAQS.

EPA's 2013 Changes to the PM NAAQS

The CAA provides for two types of NAAQS: (1) primary standards, "the attainment and maintenance of which in the judgment of the [EPA] Administrator ... are requisite to protect the public health" with "an adequate margin of safety";¹⁶ and (2) secondary standards,¹⁷ which are necessary to protect public welfare¹⁸—a broad term that includes visibility impairment as well as damage to crops, vegetation, and effects on soil and nutrient cycling, water, wildlife, property, building materials, etc.

EPA's 1997 revisions to the PM NAAQS¹⁹ revised the standards that focused on particles smaller than 10 microns (PM₁₀ or coarse particles) established in 1987²⁰ and introduced standards for "fine" particles smaller than 2.5 microns (PM_2.5) for the first time. The primary NAAQS as revised included a daily (24-hour) limit for both PM_2.5 and PM₁₀ and an annual limit for PM_2.5. (EPA revoked the previous annual limit for PM₁₀ in 2006.)

Achieving attainment of the annual standard requires that the three-year average of the weighted annual arithmetic mean PM concentration at each monitor within an area must not exceed the maximum limit set by the agency. The 24-hour standards are a concentration-based percentile form, indicating the percentage of the time that a monitoring station can exceed the standard. For example, a 98^th percentile 24-hour standard indicates that a monitoring station can exceed the standard 2% of the days during the year. For PM_2.5 and PM₁₀, EPA set the secondary (welfare) NAAQS the same as the primary standards.

As modified and published in the January 15, 2013, Federal Register,²¹ the PM_2.5 and PM₁₀ primary (public health) standards as set in the final rule are as follows:

• PM_2.5: EPA revised the annual standard of 15 micrograms per cubic meter (µg/m³) by setting a new limit to 12 µg/m³. (EPA's proposed rule included an optional limit of 13 µg/m³ and solicited comment for 11 µg/m³.) Compliance with the "annual" standard is determined by whether the three-year average of its annual average PM_2.5 concentration (at each monitoring site in the area) is less than or equal to 12 µg/m³; as proposed, EPA retained the daily (24-hour) standard at 35 µg/m³ based on the current three-year average of the 98^th percentile of 24-hour PM_2.5 concentrations as established in 2006.
• PM₁₀: EPA retained the current daily PM₁₀ standard of no more than one exceedance of concentrations of 150 µg/m³ per year on average over three years; there is no current annual standard for PM₁₀. (EPA eliminated²² the previous annual maximum concentration standard of 50 µg/m³ in 2006.)

EPA retained the secondary annual PM_2.5 standard at 15 µg/m³.

Designation of Geographical Nonattainment Areas

Designating geographical areas as not achieving the established NAAQS based on monitoring and analysis of relevant air quality data is a critical step in NAAQS implementation. Section 107(d) of the CAA (42 U.S.C. 7407) establishes the process for designating "attainment" (or alternatively "unclassifiable") and "nonattainment" areas and setting their boundaries, but it allows the EPA administrator some discretion in determining what the final boundaries of the areas will be. Areas are identified as nonattainment when they violate or contribute to the violation of NAAQS.

Under Section 107(d)(1) of the CAA, the governor of each state must submit a list identifying designations for a NAAQS "by such a date as the [EPA] Administrator may reasonably require, but not later than 1 year after promulgation" of the new or revised NAAQS. EPA must promulgate final designations "as expeditiously as possible" but no later than two years from the date of promulgation of the new or revised NAAQS. Section 107(d) of the CAA provides for an extension of up to one year if the EPA administrator "has insufficient information to promulgate designations." The process leading up to final designation determinations has in the past extended beyond the established deadlines as states have continuously reviewed and analyzed data and modelling results with EPA.

For the 2013 NAAQS, state submissions were to be submitted by December 13, 2013, and EPA was to promulgate final designations by December 12, 2014.²³

NAAQS Designation Process

The NAAQS designation process is intended as a cooperative federal-state-tribal process in which states and tribes provide initial designation recommendations to EPA for consideration. Section 107(d)(1)(A) (42 U.S.C. 7407) of the CAA requires the governor of each state to submit a list to EPA of all areas in the state "designating as ... nonattainment, any area that does not meet (or that contributes to ambient air quality in a nearby area that does not meet) an air quality standard" (emphasis added). Areas are identified as "attainment/unclassifiable"²⁴ when they meet the standard or when the data are insufficient for determining compliance with the NAAQS.

Tribes have been encouraged to submit NAAQS designation recommendations. The area designation requirements under the CAA (Section 107(d)) are specific with respect to states but do not explicitly reference Indian tribes or Indian country. EPA follows the same designation process for tribes per Sections 110(o) and 301(d) of the CAA and pursuant to the 1988 Tribal Authority Rule, which specifies that tribes shall be treated as states in selected cases (40 C.F.R. Part 49).²⁵

Following state and tribal designation submissions, the EPA Administrator has discretion to make modifications, including to the area boundaries. As required by the CAA (Section 107(d)1(B)(ii)), the agency must notify the states and tribes regarding any modifications, allowing them sufficient opportunity to demonstrate why a proposed modification is inappropriate, but the final determination rests with EPA.

Measuring and analyzing air quality to determine where NAAQS are not being met is a key step in determining an area's designation. Attainment or nonattainment designations are made primarily on the basis of three years of federally referenced monitoring data.²⁶ EPA began developing methods for monitoring fine particles at the time the PM_2.5 NAAQS were being finalized in 1997, and operation of the network of monitors for PM_2.5 was phased in from 1999 through 2000. EPA's final designations for the 2013 particulates NAAQS were based on 2011-2013 monitoring data.

The network of monitors and their locations has been modified over time. In conjunction with the October 2006 publication of the revised particulates NAAQS, for example, EPA amended its national air quality monitoring requirements, including those for monitoring particle pollution.²⁷ The amended monitoring requirements were intended to help federal, state, and local air quality agencies by adopting improvements in monitoring technology. Additional modifications to the PM NAAQS monitoring network were included in the final January 2013 rule.²⁸

EPA also considers a number of other relevant factors when designating nonattainment areas²⁹ and recommends that states apply these factors in their determinations in conjunction with other technical guidance. Examples of these factors include:

• population density and degree of urbanization (including commercial development);
• location of sources in relation to population;
• existing emission controls;
• traffic and commuting patterns and growth rates;
• weather and transport patterns (meteorology);
• geography/topography; and
• jurisdictional boundaries such as counties (or portions of counties), tribal reservations, metropolitan planning areas, and air districts.

States and tribes may submit additional information on factors they believe are relevant for EPA to consider.

Entire metropolitan areas may be designated nonattainment in some cases based on monitoring data in a single location taking into account other factors. States' or tribes' boundary recommendations for an area are to also show that violations are not occurring in those portions of the recommended area that have been excluded and that they do not contain emission sources that contribute to the observed violations.

The CAA does not specifically require combining neighboring counties within the same nonattainment area, but it does require the use of metropolitan statistical area boundaries in the more severely polluted areas (§107(d)(4)(A)(iv)). However, unlike the 1997 PM_2.5 standards, Metropolitan Statistical Areas or Consolidated Metropolitan Statistical Areas³⁰ did not generally serve as the "presumptive boundary" for nonattainment areas under the 2013 PM_2.5 standards. EPA made this change when determining nonattainment for the 2006 PM_2.5 standards. Rather than establish a presumption for the minimum size of an area, in its June 2007 guidance³¹ EPA instructed states and tribes to evaluate each area on a case-by-case basis. EPA expected that nonattainment areas for the 2006 24-hour PM_2.5 would include counties with monitors violating the 24-hour standard and nearby counties that contribute to that violation.

EPA also recommended that states and tribes consider using common boundaries for areas to be designated as nonattainment for both the annual and 24-hour PM_2.5 standards. In April 2013, EPA provided similar guidance to states and tribes with regard to the 2013 revisions of the annual PM_2.5 standards.³² States used this information, in conjunction with air emission and air quality data—as well other relevant factors listed above as recommended in EPA's guidance in determining the boundaries for the designated areas.

Designations for the 2013 PM_2.5 Annual NAAQS³³

Section 107(d)(1) of the CAA requires states to submit area designation recommendations no later than one year following the promulgation of a NAAQS standard.³⁴ During November 2013, four states—California, Idaho, Ohio, and Pennsylvania—provided EPA with recommended nonattainment boundaries for the 2013 revised primary annual PM_2.5 standard. Remaining states, the District of Columbia, Puerto Rico, and Guam recommended all areas as attainment or unclassifiable/attainment.³⁵ EPA also received six tribal recommendations of attainment or unclassifiable/attainment.³⁶ EPA has indicated that seven tribes are eligible to submit recommendations under Section 107(d), but all tribes were invited to submit recommendations or to comment on state and EPA recommendations.³⁷

EPA responded to these recommendations in August 2014, and promulgated the final area designations as published January 15, 2015.³⁸ These final designations for the 2013 PM_2.5 NAAQS reflected some modifications to EPA's August 2014 proposed designations.³⁹ EPA subsequently amended the final designations based on complete, quality assured, and certified air quality data for 2014 recently submitted by several states. These modifications, and a technical correction,⁴⁰ were published April 7, 2015.⁴¹

EPA April 2015 Amended Final Designations

The final area designations as amended and published in the April 2015 Federal Register encompass 20 counties or portions of counties (nine areas) in four states—California, Idaho, Ohio, and Pennsylvania—as nonattainment only for the 2013 revised annual PM_2.5 standard. The remaining nearly 3,000 counties in the United States were classified as unclassified or unclassified/nonattainment for the 2013 revised annual standard. Comparatively, EPA's final designations for nonattainment of the 2006 and 1997 PM_2.5 NAAQS (those areas with or contributing to air quality levels exceeding the annual and 24-hour PM_2.5 standards or both) included all or part of 242 counties in 28 states and the District of Columbia.⁴²

As EPA indicated in its April 2013 area designation guidance to states and tribes, the initial area designations for all 2013 PM_2.5 NAAQS nonattainment areas were classified as "Moderate" as provided under Subpart 4 of Part D of Title I of the CAA (Section 188(a)).⁴³ EPA may reclassify as "serious" those nonattainment areas that EPA determines cannot practicably attain the PM_2.5 NAAQS by the applicable attainment date or has not in fact attained the PM_2.5 NAAQS after each area's applicable attainment date has passed. Such a determination would trigger additional implementation requirements on the state that were not previously included in SIPs under Subpart 1 of the CAA.

As a result of its review of 2014 air quality data most recently submitted by affected states, EPA's re-designations resulted in 5 fewer areas, 18 fewer counties, and 4 states instead of six previously designated as nonattainment in January 2015 (see Table C-1). The re-designations include all 5 counties in two areas previously designated nonattainment in Kentucky, the only 2 counties in one area in Indiana, 7 counties in two areas in Ohio, and 4 counties in two areas in Pennsylvania. The area in Indiana (2 counties) and one of the two areas in Kentucky (2 of the 5 counties) were re-designated unclassifiable. All of the remaining areas were re-designated unclassifiable/nonattainment.

The 12 areas in Indian country adjacent to counties in two areas designated nonattainment in California (Los Angeles–South Coast Air Basin and San Joaquin Valley) in the January 2015 final designations were not affected by EPA's April 2015 amendments (see Table D-1).

EPA also designated five areas in Georgia (including two counties in Alabama and South Carolina) as unclassifiable. EPA had deferred its determination for these areas in the January 2015 final designation rule. As indicated earlier, EPA also made a technical correction regarding Allegheny County in Pennsylvania, affirming that the entire county was designated nonattainment. All other designation determinations, including 12 areas in Indian country adjacent to counties in areas designated nonattainment in California, remain as published January 2015.

Counties included in EPA's amended final nonattainment area designations for the 2013 PM_2.5 NAAQS are indicated in the map in Figure 1. Although EPA's final designations for the 2013 PM NAAQS do not identify areas violating the 24-hour PM_2.5 standard, as the level is unchanged from the 2006 PM NAAQS, the map distinguishes those counties not previously designated as nonattainment for the annual or the 24-hour PM_2.5 standards.

Figure 1. EPA's April 2015 Amended Final Designations of Geographical Areas as Nonattainment for the 2013 Annual PM2.5 NAAQS (violating the 2013 PM2.5 primary annual standard (12 μg/m3) only)

Source: Prepared by the Congressional Research Service based on EPA's final designations for the 2013 PM2.5 revised annual NAAQS, with data compiled from EPA's website for prior PM NAAQS final designations, http://www.epa.gov/pmdesignations/. Notes: Partial counties are shown on the map as whole counties. EPA's final designations did not include any counties or partial counties in Alaska or Hawaii.

While the nonattainment areas for the 2013 NAAQS may seem small compared with the approximately 3,000 counties in the United States, PM NAAQS nonattainment counties tend to have larger populations than those in attainment. Roughly 28 million people⁴⁴ reside in the 39 counties EPA designated as nonattainment for the 2013 annual PM_2.5 NAAQS. Comparably, at the time of EPA's final designation for the 2006 PM NAAQS, more than 70 million people (over 20% of the U.S. population)⁴⁵ lived in the 120 counties designated as nonattainment for the 2006 24-hour PM_2.5 NAAQS. For the areas designated for 1997 PM NAAQS, nearly 90 million people (about 30% of the U.S. population)⁴⁶ lived in the 205 counties designated as nonattainment.

EPA January 2015 Final Designations

In a final rule published in January 2015, EPA had designated 14 areas in six states—California, Idaho, Indiana, Kentucky, Ohio, and Pennsylvania—as nonattainment only for the 2013 revised annual PM_2.5 standard, the same as the agency proposed in August 2014 (see Table C-1 for state-by-state county/area nonattainment designations). The 14 nonattainment areas included 38 counties or portions of counties, one less than EPA proposed (Lake County, OH). (See the map depicting EPA January 2015 final nonattainment area designations in Appendix E.) EPA also designated 12 areas in Indian country adjacent to counties in two areas designated nonattainment in California: Los Angeles–South Coast Air Basin and San Joaquin Valley (see Table D-1).

In the January 15, 2015, Federal Register, EPA announced that it was also deferring initial designation for 10 areas in three states by up to one year as a result of data validity issues. Included are all of Florida, all of Tennessee except for three counties, and eight areas in Georgia (including two counties in Alabama and South Carolina). EPA had previously proposed to designate the areas in Tennessee and three of the eight areas in Georgia as unclassifiable. Florida was added as EPA indicated that it had only recently identified data quality issues in that state.⁴⁷

The EPA also designated three areas as unclassifiable: Puerto Rico, the U.S. Virgin Islands, and all of Illinois (including two adjacent counties in Indiana as part of the Chicago area and four counties and one city in Missouri included in the St. Louis area) as "unclassifiable." All remaining state areas and areas in Indian country were designated as "unclassifiable/attainment" for the annual PM_2.5 standard.

State Recommendations and EPA August 2014 EPA Proposed Designations in Response

Four states—California, Idaho, Ohio, and Pennsylvania—identified 12 areas comprising 25 counties, including six partial counties (see Table C-1 for state-by-state county/area nonattainment designations).⁴⁸ The recommended designations were primarily based on 2010-2012 monitoring data, criteria and technical guidance from EPA and assistance from its regional offices, and states' own relevant information and criteria. States providing revised determinations based their area designation recommendations on 2011-2013 monitoring data.

As required by statute, EPA responded to the states with its recommended modifications to the states' proposed area designations for the 2013 PM_2.5 NAAQS for the annual standard in letters on or about August 19, 2014.⁴⁹ As EPA did in implementing the 2006 and 1997 PM_2.5 NAAQS, and as it has done with NAAQS for other criteria pollutants, the agency used its discretion to identify areas as nonattainment in states that had recommended all areas as attainment or unclassifiable/attainment, expand the size of nonattainment areas (i.e., added more counties or portions of counties), or combine areas that states listed as separate areas into a single larger unit. EPA also combined nonattainment counties across state lines into the same nonattainment areas if the counties are part of the same metropolitan area.

In its August 2014 response to states, EPA proposed 14 areas comprised of 39 counties—25 whole and 14 partial counties—in six states as nonattainment only for the revised 2013 primary annual PM_2.5 standard. (See table in Appendix C for state-by-state county/area nonattainment designations.) In addition to the four states that had previously identified counties as nonattainment for the 2013 PM_2.5 NAAQS, EPA added seven counties in Kentucky and Indiana, four of which are included in the nonattainment area designated as Louisville-KY/IN. The three additional counties in Kentucky are adjacent to counties in an area previously recommended for nonattainment designation by Ohio; EPA refers to the area as Cincinnati/Hamilton-OH/KY. EPA also designated as nonattainment additional counties in Pennsylvania and Ohio that had not been previously recommended as nonattainment by those states for the 2013 PM_2.5 NAAQS. Several of the 14 nonattainment areas included counties from multiple states.

In the August 29, 2014, Federal Register notice⁵⁰ announcing the posting of the response letters, EPA also indicated that due to data validity issues it was extending the designation period by up to one year, to December 2015, for 10 counties in Alabama, Georgia, and South Carolina.⁵¹ EPA determined that the information currently available for these areas was insufficient for making designations.⁵² In addition, due to data quality assurance issues at several monitoring sites, EPA indicated that it intended to designate as "unclassifiable" two territories, one area in Indian country, three areas in Georgia, all counties in Illinois, two counties in Indiana, four counties and a city in Missouri, and all counties except three (Chattanooga area) in Tennessee.⁵³ EPA indicated that it intended to designate all remaining areas throughout the United States, including areas in Indian country and territories, as unclassifiable/attainment.

Per the CAA, states and tribes were provided the opportunity to submit additional relevant information to demonstrate why EPA's modifications to the states' recommendations were inappropriate prior to the agency's final designations. Although the CAA provides for up to 120 days, the EPA August 2014 response letters for all states with areas intended to be designated nonattainment urged states to submit "additional information for the EPA to consider" by October 29, 2014. Several states, including all those with areas EPA intended to designate nonattainment, submitted their responses to the EPA's August 2014 proposed designations by the October 2014 deadline.⁵⁴ As with past designations by EPA, a number of states challenged the agency and maintained support for their original recommendations.

Comparing EPA's Final Nonattainment Designations for the 2013 PM NAAQS with the 2006 and 1997 PM_2.5 NAAQS Final Designations

EPA's final designations for nonattainment of the 2006 and 1997 PM_2.5 NAAQS (those areas with or contributing to air quality levels exceeding the annual and 24-hour PM_2.5 standards or both) included all or part of 242 counties in 28 states and the District of Columbia.⁵⁵ More than 2,900 counties in 30 states were designated as attainment/unclassifiable for the 2006 24-hour and 1997 annual PM_2.5 NAAQS. See the map in Figure 2.

Based on EPA's April 2015 amended final designations for the 2013 PM_2.5 annual standard, two counties (or portions) of the 20 counties are designated nonattainment for PM_2.5 for the first time, but the majority of the counties overlap with EPA's final nonattainment designations for the 2006 and 1997 PM_2.5 annual and/or 24-hour standards. Of the remaining 18 counties designated as nonattainment for the 2013 revised annual PM_2.5 standard, two have not been previously designated for the annual standard but were designated as nonattainment for the 24-hour standard, and the remaining 16 counties have been previously designated as nonattainment only for the annual standard or for the annual and the 24-hour PM_2.5 standards (see Table in Appendix C). The map in Figure 3 presents the overlap of the April 2015 amended nonattainment designations for the 2013 PM_2.5 annual standard with those areas designated nonattainment for the 2006 and 1997 PM_2.5 standards.

EPA final designations published on November 13, 2009, for the 2006 PM NAAQS included 31 areas in 18 states comprising 120 counties (89 counties and portions of 31 additional counties) for nonattainment of only the revised 2006 24-hour PM_2.5 standard.⁵⁶ EPA's November 2009 final designations did not include new counties violating the annual standard, as the level was unchanged from the 1997 PM_2.5 NAAQS. EPA's designations for the 1997 PM_2.5 NAAQS included all or part of 204 counties in 20 states and the District of Columbia. Most of the counties were exceeding only the annual standard, only 12 counties were exceeding both the 24-hour and the annual standards, and no counties were exceeding only the 24-hour standard. (For a historical presentation of the 1997 NAAQS designations, see Figure F-1 in Appendix F.)⁵⁷

Figure 2. Counties in Nonattainment for the 2006 24-Hour (65 μg/m3) Standards and/or 1997 PM2.5 NAAQS Annual (15 μg/m3): U.S. EPA Final Designations

Source: Prepared by the Congressional Research Service based on EPA final designations for the 2006 and 1997 PM2.5 NAAQS. Nonattainment counties for the annual standard are based on the October 2006 final area designations for the 1997 PM2.5 NAAQS; nonattainment counties for the 24-hour standard are based on EPA's November 2009 final designations for the 2006 PM2.5 NAAQS.

Figure 3. EPA Final Area Designation as Amended April 2015 Nonattainment Areas for the 2013 PM2.5 NAAQS Compared to EPA's Nonattainment Designations for the 2006 and 1997 PM2.5 NAAQS (violating the 2013 annual [12 μg/m3], compared to 1997 annual standard [15 μg/m3] and/or the 2006 24-hour [35 μg/m3] standard)

Source: Prepared by the Congressional Research Service with data compiled from EPA's website for PM designations, http://www.epa.gov/pmdesignations/. Nonattainment counties for the 2013 annual standard are based on EPA April 2015 amended final designations; previously designated nonattainment counties for the annual standard are based on the October 2006 final area designations for the 1997 PM2.5 NAAQS; previously designated nonattainment counties for the 24-hour standard are based on EPA's November 2009 final designations for the 2006 PM2.5 NAAQS. Note: Partial counties are shown on the map as whole counties. EPA's designations for the 2013 PM NAAQS did not include any counties or partial counties in Alaska or Hawaii.

Table 1 below illustrates the comparative geographic distribution of counties in areas that EPA designated as nonattainment as amended and published April 7, 2015, for the 2013 PM_2.5 NAAQS and those counties in EPA's final area designations for the 2006 and 1997 PM_2.5 NAAQS.

It is difficult to anticipate what effect the EPA final area designations for the 2013 PM_2.5 NAAQS may have on current control measures in these areas. In some of these areas, current measures focused on achieving attainment for the 1997 annual standard and 2006 24-hour PM_2.5 standard may require supplemental or significant modifications to ensure compliance with the stricter annual standard. The impacts could vary substantially from area to area within a state and from state to state depending on many factors, including the type and locations of primary emission sources, current control measures, the extent to which the area is exceeding the standard, topography, weather, etc. For the most part, these measures will be established by the states in their SIPs.

Once final designations take effect, they become an important component of state, local, and tribal governments' efforts to reduce fine particle pollution. The designations govern what subsequent regulatory actions states, tribes, and EPA must take in order to improve or preserve air quality in each area.

Demonstrating Attainment with the 2013 PM_2.5 NAAQS

Under the CAA, EPA sets the nationwide standard for criteria pollutants, and EPA and states are responsible for placing limits on emissions that contribute to criteria pollution and for regulating entities that emit criteria pollutants. Areas designated as attainment/unclassifiable will not have to take steps to improve air quality, but under the statute they must take steps to prevent air quality from deteriorating to unhealthy levels. For those areas designated as nonattainment, state, local, and tribal governments must outline detailed control requirements in plans demonstrating how they will meet and/or maintain compliance with the 2013 PM_2.5 annual standard. These plans are defined as state implementation plans and referred to as SIPs (TIPs for tribal implementation plans).

As discussed previously in this report, in response to a January 2013 D.C. Circuit Court decision⁵⁸ EPA has classified all initial nonattainment area designations for the 2013 PM_2.5 annual standard as moderate. EPA had previously implemented the PM_2.5 NAAQS, only under the general implementation provisions in Subpart 1 of the act. Subpart 4 requires EPA to classify areas based on the severity of their fine particle pollution problem. Subpart 1 does not include classification requirements for nonattainment areas but does authorize EPA to establish classifications if the agency deems it appropriate.

The Subpart 4 requirements for areas classified as moderate are generally comparable to those of Subpart 1. However, under Subpart 4,⁵⁹ states have 18 months from the date of EPA's final designations to submit SIPs, which identify specific regulations and emission control requirements that will bring an area into compliance. Implementing the PM_2.5 NAAQS under Subpart 1 required submission of SIPs three years from the date of EPA's final designations.

Under Subpart 4, EPA may reclassify as "serious" any nonattainment area that the agency determines cannot practicably attain the PM_2.5 NAAQS by the applicable attainment date or those areas classified as moderate that do not attain the PM_2.5 NAAQS after their applicable attainment date has passed. Subpart 4 introduces additional statutory SIP planning requirements for areas classified as serious.⁶⁰ These additional requirements must be reflected in the states' initial SIP submissions.

States must achieve attainment for moderate areas as expeditiously as practicable but no later than six years after designation and serious areas must achieve attainment no later than 10 years from designation as nonattainment under Subpart 4. Under the general provisions in Subpart 1, which has no classifications, attainment must be achieved no later than five years from the effective designation date. Both Subpart 4⁶¹ and Subpart 1⁶² include provisions for extensions.

Even though EPA has concluded that although in many cases attainment will be reached as the result of several promulgated federal regulations, states will very likely require some local controls because of the requirements of the CAA. All areas no matter their classification of attainment or nonattainment will be required under the CAA⁶³ to conduct emission inventories which will provide states the basis for states to analyze and estimate the extent to which various sources are contributing to nonattainment.

To achieve the most expeditious attainment date for an area, EPA has recommended that states first identify emission reduction programs that have already been adopted and are being implemented at the federal, state, and local levels. The agency also recommends that states evaluate additional control measures and control technologies—reasonably available control measures (RACM) and reasonably available control technology (RACT)—for an area. States are required under the CAA⁶⁴ to impose RACM and RACT that can be implemented on sources located in nonattainment areas and to adopt enforceable regulations to ensure these areas will attain as expeditiously as practicable.

Some have expressed concern that a nonattainment designation may negatively impact an area's economic development, as potential additional requirements associated with achieving compliance may deter investment. EPA and others contend that the benefits associated with the CAA exceed the costs and that, while short-term impacts may vary, historical evidence suggests that impacts on overall economic growth concurrent with environmental (including CAA) regulations are generally less significant than often anticipated.⁶⁵

As indicated earlier in this report, based on EPA's January 2015 final designations for the 2013 PM_2.5 annual standard, three counties (or portions) of the 38 counties identified in the rule would be designated nonattainment for PM_2.5 for the first time. Nevertheless, exceeding the 2013 PM_2.5 annual standard may have implications with respect to existing SIPs, the extent of which could vary significantly from area to area based on many factors. In some cases SIPs may require substantial modifications, while in other cases the current SIP may be sufficient to achieve compliance with both standards.

State Implementation Plans (SIPs)

Section 110(a)(1) of the CAA requires states to submit new or revised SIPs that provide for implementation, maintenance, and enforcement of the new or revised NAAQS. All states are required to submit SIPs that include the basic program requirements for managing air quality required in Section 110(a)(2) of the CAA showing that they have the capacity to attain, maintain, and enforce the revisions associated with the PM_2.5 NAAQS. These "infrastructure SIP" submissions must address a number of basic elements, including:

• Ambient air quality monitoring and data systems,
• Programs for enforcement of control measures,
• Adequate authority and resources to implement the plan, and
• Prohibition of interstate pollution transport.

Section 110(a)(2)(D)(i) of the act contains four elements that revised SIPs must address. The first two elements of this section require each state in its SIP to demonstrate adequate provisions for the ability to prohibit air emissions within the state that (1) contribute significantly to another state's nonattainment of the NAAQS, or (2) interfere with another state's maintenance of the NAAQS.

The specific provisions for requirements for all nonattainment areas designated as moderate under Subpart 4 of Part D of the CAA include:

• Nonattainment new source review (§172(c)(5)) permit program providing that permits meet the requirements of Section 173 of the act (§189(a)(1)(A));
• Attainment demonstration or demonstration that attainment by the applicable attainment date is impracticable (§189(a)(1)(B));
• Assurance of implementation of RACM and RACT (§189(a)(1)(C));
• Quantitative milestones and demonstration of reasonable further progress (§189(c)); and
• Control requirements applicable to major stationary sources precursors⁶⁶ (§189(e)).

EPA NAAQS Implementation Rules/Guidance

The EPA typically publishes an "implementation rule" that describes the requirements that states and tribes must meet in their implementation plans to achieve and maintain attainment. The rule also provides guidance and procedures for establishing controls to achieve and maintain attainment. In addition, the implementation rule generally includes guidance for submitting a SIP when reaching attainment within the five-year requirement is impractical. The implementation rule takes into account existing (oftentimes pending) federal regulations that contribute to controlling criteria pollutants and their precursors.

EPA published a proposed implementation rule for the PM_2.5 NAAQS on March 23, 2015.⁶⁷ The public comment period was extended to May 29, 2015. The EPA proposal would apply to the 2013 annual PM_2.5 NAAQS, the 2006 24-hour PM_2.5 NAAQS, and "any future revisions to the PM_2.5 NAAQS." EPA also proposed revocation of the 1997 primary annual PM_2.5 standard because it was revised in the 2013 PM NAAQS. The proposal details (1) how air agencies are to meet statutory SIP requirements under Subpart 4 for areas designated nonattainment PM_2.5 NAAQS, (2) "specific attainment planning requirements" as they would pertain to areas based on their classification as moderate or serious, and (3) the process for reclassifying moderate areas to serious. The proposed PM_2.5 NAAQS implementation rule would replace EPA's "2007 PM_2.5 Implementation Rule''⁶⁸ and portions of the ''2008 PM_2.5 New Source Review (NSR) Rule."⁶⁹ These rules were remanded to EPA by the U.S. Court of Appeals for the D.C. Circuit Court in its January 2013 decision.⁷⁰

In June 2014, EPA published a final rule reclassifying 1997 and 2006 nonattainment as "moderate" and set a deadline for December 31, 2014, for states to submit outstanding SIP requirements.⁷¹ The basic framework of the implementation rule for the 1997 PM_2.5 NAAQS published in April 2007 included a description of the requirements that states and tribes must meet in their implementation plans to achieve and maintain attainment of the 2006 standards. The 2007 rule was based on statutory requirements under Subpart 1 of the CAA. In addition to the 2007 implementation rule for the 1997 PM_2.5 NAAQS, EPA outlined implementation guidance regarding the development of SIPs to demonstrate attainment with the 2006 PM_2.5 NAAQS in a March 12, 2012, memorandum to EPA regional air directors.⁷² The memorandum was withdrawn on June 6, 2013, following the January 2013 D.C. Circuit Court decision.

National Regulations

EPA expects that in many cases emission reductions from implementing existing national regulations and strategies will provide a framework for helping states achieve attainment with the PM_2.5 NAAQS. These national actions include:

• Cross-State Air Pollution Rule;⁷³
• Mercury and Air Toxics Standards;⁷⁴
• Light-Duty Vehicle Tier 2 Rule;⁷⁵
• Motor Vehicle Emission and Fuel Standards Tier 3 Rule;⁷⁶
• Heavy Duty Diesel Rule;⁷⁷
• Clean Air Nonroad Diesel Rule;⁷⁸
• Regional Haze Regulations and Guidelines for Best Available Retrofit Technology Determinations;⁷⁹
• NOx Emission Standard for New Commercial Aircraft Engines;⁸⁰
• Emissions Standards for Locomotives and Marine Compression-Ignition Engines;⁸¹
• Emission Standards for Ignition Engines, Control of Emissions for Nonroad Spark Ignition Engines and Equipment;⁸²
• Category 3 Oceangoing Vessels;⁸³
• Reciprocating Internal Combustion Engines National Emissions Standards for Hazardous Air Pollutants;⁸⁴ and
• New Source Performance Standards and Emissions Guidelines for Hospital/Medical/Infectious Waste Incinerators Final Rule Amendments.⁸⁵

New Source Review⁸⁶

Areas designated nonattainment, as well as those designated unclassifiable or unclassifiable/attainment for the NAAQS, are also subject to new source review (NSR) requirements. Enacted as part of the 1977 CAA amendments and modified in the 1990 CAA amendments, NSR is designed to ensure that newly constructed facilities or substantially modified existing facilities do not result in violation of applicable air quality standards. NSR provisions outline permitting requirements both for construction of new major pollution sources and for modifications to existing major pollution sources. The specific NSR requirements for affected sources depend on whether the sources are subject to "Prevention of Significant Deterioration" (PSD) or nonattainment provisions.⁸⁷

Over time, EPA has promulgated rules⁸⁸ that contain certain NSR program requirements for sources that emit PM_2.5 and its precursors, including SIP modifications to state NSR programs to account for emissions of PM_2.5. For example, the January 2013 final PM NAAQS includes revisions to the PSD permitting program (rules) with respect to the revised PM NAAQS so as not to "unreasonably delay" pending permits and establish a "grandfather" provision for permit applications if (1) the permitting agency deemed an application complete by December 14, 2012; or (2) a draft permit or preliminary determination has been issued for public comment by the date the revised 2013 PM NAAQS went into effect (60 days after January 15, 2013, publication in the Federal Register).⁸⁹

Transportation Conformity⁹⁰

If new or revised SIPs for attainment establish or revise a transportation-related emissions budget or add or delete transportation control measures, they will trigger "conformity" determinations. Transportation conformity is required by the CAA, Section 176(c),⁹¹ to prohibit federal funding and approval for highway and transit projects unless they are consistent with ("conform to") the air quality goals established by a SIP and will not cause new air quality violations, worsen existing violations, or delay timely attainment of the national ambient air quality standards.

On March 24, 2010, EPA published a final rule amending the transportation conformity regulation primarily to incorporate the October 17, 2006, strengthening of the 24-hour PM_2.5 air quality standard and revocation of the annual PM₁₀ standard.⁹² The final rule, which affects implementation of conformity in PM_2.5 and PM₁₀ nonattainment and maintenance areas, also addresses a court remand concerning hot-spot⁹³ analyses as they apply to PM_2.5 and PM₁₀, as well as to carbon monoxide and nonattainment and maintenance areas.

On March 14, 2012, EPA published a final rule⁹⁴ restructuring sections of the conformity rule (40 C.F.R. 93.109 and 93.119) so that existing requirements apply to new or revised NAAQS. EPA also released associated implementation guidance in July 2012. The rule is intended to remove the need to amend the transportation conformity rule merely to reference specific new NAAQS.

Conclusion

States will have 18 months from April 15, 2015, the effective date of EPA's final designations for the 2013 PM_2.5 NAAQS, to submit SIPs, which identify specific regulations and emission control requirements that are to bring an area into compliance. Following EPA approval of SIPs, implementation through imposition of control measures, where necessary, is to occur for several years. Under CAA, Section 188 of Subpart 4, states must achieve attainment as expeditiously as practicable but no later than the end of the sixth calendar year after designation as nonattainment:⁹⁵ December 2021 for the 2013 PM_2.5 standard. (See timeline presented in Appendix B).

Because of health and cost implications, NAAQS decisions have historically been the source of significant concern to some Members of Congress. The evolution and development of the PM NAAQS, in particular, has been the subject of extensive oversight. (Appendix A presents a chronology of PM NAAQS regulations.) EPA's failure to complete timely review and revision of the NAAQS as required under the CAA has also been an area of concern to some in Congress and others.

Some Members expressed concerns in hearings, letters to the EPA administrator, and proposed legislation in anticipation of potential changes to the PM NAAQS leading up to the January 2013 final published revisions. Some Members⁹⁶ and industry stakeholders had urged EPA to delay the final rule, while others, including some states⁹⁷ and various environmental and public health advocacy groups, urged timely completion of a tighter standard.

Changes to the NAAQS have historically triggered litigation alleging that the standards are too stringent or not stringent enough and often result in delays in implementation. The agency's final designations of nonattainment areas and the implementation of the 2013 PM_2.5 NAAQS are expected to generate further interest and oversight.

Chronology of EPA's National Ambient Air Quality Standards (NAAQS) Regulations for Total Suspended Particulates (TSP) and Particulate Matter (PM) 1971-2013

EPA first promulgated annual and 24-hour NAAQS for PM_2.5 in July 1997. EPA had previously addressed particulate matter by regulating "total suspended particles" (TSP) in 1971, followed by the agency's regulation of PM₁₀ in 1987.

Comparative Timeline for Implementing the 1997, 2006, and 2013 PM_2.5 NAAQS

The timeline presented in Table B-1 reflects the most recent key milestone dates for implementing the 1997 and 2006 NAAQS and estimates for the 2013 PM_2.5 NAAQS, including actual completions. These milestones are driven primarily by statutory requirements. The table mimics an EPA milestone schedule outlined in an April 1, 2003, memorandum to EPA regional administrators that also provided the nonbinding guidance for implementation of the 1997 PM_2.5 area designations⁹⁸ and the agency's projected timeline for the 2006 PM_2.5 NAAQS.⁹⁹

Comparison of EPA Nonattainment Areas for the 2013 PM_2.5 Annual Standard and Previous PM_2.5 Standards

EPA Nonattainment Areas for the 2013 PM_2.5 Annual Standard in Indian Country

As noted earlier in this report, the area designation requirements under the CAA (Section 107(d)) are specific with respect to states but do not explicitly reference Indian tribes or Indian country. EPA follows the same designation process for tribes per Sections 110(o) and 301(d) of the CAA and pursuant to the 1988 Tribal Authority Rule, which specifies that tribes shall be treated as states in selected cases.¹⁰⁰ EPA encouraged tribes to submit NAAQS designation recommendations or to comment on state and EPA recommendations.¹⁰¹

EPA indicated that 32 tribes participated in the area designation process for the 2013 annual PM_2.5 standard.¹⁰² Six of the 32 tribes submitted letters with designation recommendations. With the exception of areas in the Indian country of the Pechanga Band of Luiseno Indians,¹⁰³ all of tribal lands were designated as part of adjacent state areas. Of the 32 participating tribes, EPA designated 12 tribal land areas adjacent to two areas in California as nonattainment. The remaining 20 participating tribes, including the lands of the Pechanga Band of the Luiseno Mission Indians, and all other areas of the country were designated unclassified/nonattainment.

Table D-1 below identifies those areas in Indiana country designated by EPA to be nonattainment based on their proximity to state counties in areas designated as nonattainment. For those tribal lands areas designated by EPA other than nonattainment, including those tribes submitting recommendations, see EPA's website "Area Designations for the 2012 Annual Final Particle (PM_2.5) Standard: Tribal Recommendations and EPA Responses for Area Designations (http://www.epa.gov/pmdesignations/2012standards/tribalrec.htm).

Counties in Nonattainment for the 2013 PM_2.5 NAAQS Annual (12 μg/m³): U.S. EPA January 15, 2015, Final Designations and Comparison with the 2006 and 1997 PM_2.5 NAAQS Final Designations

The following maps present EPA's final nonattainment area designations as published in the Federal Register on January 15, 2015, which EPA subsequently amended April 7, 2015, based on more current air quality data (2012-2014). The maps include comparisons to 2006 and 1997 PM_2.5 NAAQS final designations.

Based on EPA's April 2015 amended final designations for the 2013 PM_2.5 annual standard, three counties (or portions) of the 38 counties are designated nonattainment for PM_2.5 for the first time, but the majority of the counties overlap with EPA's final nonattainment designations for the 2006 and 1997 PM_2.5 annual and/or 24-hour standards. Of the remaining 35 counties designated as nonattainment for the 2013 revised annual PM_2.5 standard, five have not been previously designated for the annual standard but were designated as nonattainment for the 24-hour standard, and the remaining 30 counties have been previously designated as nonattainment only for the annual standard or for the annual and the 24-hour PM_2.5 standards. (See Table in Appendix C.)

Counties included in EPA's January 2015 final nonattainment area designations for the 2013 PM_2.5 NAAQS are indicated in the map in Figure E-1. Although EPA's final designations for the 2013 PM NAAQS do not identify areas violating the 24-hour PM_2.5 standard, as the level is unchanged from the 2006 PM NAAQS, the map distinguishes those proposed counties not previously designated as nonattainment for the annual or the 24-hour PM_2.5 standards. The map in Figure E-2 presents the overlap of the January 2015 nonattainment designations for the 2013 PM_2.5 annual standard with those areas designated nonattainment for the 2006 and 1997 PM_2.5 standards.

Figure E-1. EPA's January 2015 Final Designations of Geographical Areas as Nonattainment for the 2013 Annual PM2.5 NAAQS (violating the 2013 PM2.5 primary annual standard (12 μg/m3) only)

Source: Prepared by the Congressional Research Service based on EPA's final designations for the 2013 PM2.5 revised annual NAAQS, with data compiled from EPA's website for prior PM NAAQS final designations, http://www.epa.gov/pmdesignations/. Notes: Partial counties are shown on the map as whole counties. EPA's final designations did not include any counties or partial counties in Alaska or Hawaii.

Figure E-2. EPA Final Area Designation as of January 15, 2015: Nonattainment Areas for the 2013 PM2.5 NAAQS Compared to EPA's Nonattainment Designations for the 2006 and 1997 PM2.5 NAAQS (violating the 2013 annual [12 μg/m3], compared to 1997 annual standard [15 μg/m3] and/or the 2006 24-hour [35 μg/m3] standard)

Source: Prepared by the Congressional Research Service with data compiled from EPA's website for PM designations, http://www.epa.gov/pmdesignations/. Nonattainment counties for the 2013 annual standard are based on EPA January 2015 final designations; previously designated nonattainment counties for the annual standard are based on the October 2006 final area designations for the 1997 PM2.5 NAAQS; previously designated nonattainment counties for the 24-hour standard are based on EPA's November 2009 final designations for the 2006 PM2.5 NAAQS. Notes: Partial counties are shown on the map as whole counties. EPA's final designations did not include any counties or partial counties in Alaska or Hawaii.

Counties in Nonattainment for the 1997 PM_2.5 NAAQS Annual (15 μg/m³) and/or 24-Hour (65 μg/m³) Standards: U.S. EPA Final Designations

The figure below provides a historical presentation of counties designated as nonattainment for the 1997 PM_2.5 NAAQS. All counties were designated nonattainment for the PM_2.5 annual standard or both the annual and 24-hour PM_2.5 standards. No counties were designated nonattainment only for the 24-hour PM_2.5 standard.

Figure F-1. Counties in Nonattainment for the 1997 PM2.5 NAAQS Annual and/or 24-Hour Standards: U.S. EPA Final Designations annual (15 μg/m3) and/or 24-hour (65 μg/m3)

Source: Prepared by the Congressional Research Service based on EPA's final designations for the 1997 PM2.5 NAAQS with data obtained from EPA. There were no PM2.5 nonattainment areas in Hawaii or Alaska.

Author Contact Information

Footnotes

1.	The NAAQS is for NO2; nitrogen gases that are ozone precursors are referred to as nitrogen oxides or NOx.
2.	For background of the process used to establish the 2013 particulates NAAQS and analysis of associated issues, see CRS Report R42934, Air Quality: EPA's 2013 Changes to the Particulate Matter (PM) Standard, by [author name scrubbed].
3.	U.S. Environmental Protection Agency, "National Ambient Air Quality Standards for Particulate Matter; Final Rule," 78 Federal Register 3085-3287, January 15, 2013, http://www.gpo.gov/fdsys/pkg/FR-2013-01-15/pdf/2012-30946.pdf. See also EPA's PM Regulatory Actions website at http://epa.gov/pm/actions.html.
4.	The EPA administrator signed the final PM NAAQS rule on December 14, 2012, as per a June 6, 2012, order issued by the U.S. Court of Appeals for the District of Columbia Circuit in response to petitions filed by advocacy groups and 11 states (American Lung Association v. EPA, D.D.C., No. 1:12-cv-243, order issued June 6, 2012) and as agreed to in a September 4, 2012, consent decree (American Lung Association v. EPA, D.D.C., No. 1:12-cv-243, order signed September 4, 2012). See also EPA, "Proposed Consent Decree," 77 Federal Register 38060, June 26, 2012, http://www.gpo.gov/fdsys/search/pagedetails.action?granuleId=2012-15603&packageId=FR-2012-06-26&acCode=FR, and American Lung Association v. EPA, D.D.C., No. 1:12-cv-243, joint motion filed June 5, 2012.
5.	For the 2006 PM NAAQS see EPA, "National Ambient Air Quality Standards for Particulate Matter," 71 Federal Register 61144-61233, October 17, 2006, http://www.gpo.gov/fdsys/pkg/FR-2006-10-17/pdf/06-8477.pdf; for the 1997 PM NAAQS, see EPA, "National Ambient Air Quality Standards for Particulate Matter," Federal Register 38652-38854, July 18, 1997, http://www.gpo.gov/fdsys/pkg/FR-1997-07-18/pdf/97-18577.pdf, and http://www.gpo.gov/fdsys/pkg/FR-1997-07-18/pdf/97-18578.pdf. See also EPA's PM Regulatory Actions website at http://epa.gov/pm/actions.html, and CRS Report RL33254, Air Quality: EPA's 2006 Changes to the Particulate Matter (PM) Standards, by [author name scrubbed] and [author name scrubbed], Air Quality: EPA's 2006 Changes to the Particulate Matter (PM) Standards, by [author name scrubbed] and [author name scrubbed] and CRS Report RL32431, Particulate Matter (PM2.5): Implementation of the 1997 National Ambient Air Quality Standards (NAAQS), by [author name scrubbed].
6.	Federal Register 24634-24715, July 1, 1987.
7.	EPA announced that it has initiated the next round of review of the PM NAAQS by issuing a call for research information. U.S. Environmental Protection Agency (EPA), "Notice of Workshop and Call for Information on Integrated Science Assessment for Particulate Matter," 79 Federal Register 71764, December 3, 2014, http://www.gpo.gov/fdsys/pkg/FR-2014-12-03/pdf/2014-28278.pdf.
8.	U.S. Environmental Protection Agency, "Additional Air Quality Designations and Technical Amendment to Correct Inadvertent Error in Air Quality Designations for the 2012 [2013] Primary Annual Fine Particle (PM2.5) National Ambient Air Quality Standards (NAAQS)," 80 Federal Register 18535-18551, April 7, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-04-07/pdf/2015-07948.pdf. See EPA "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard: Regulatory Actions" at http://www.epa.gov/pmdesignations/2012standards/regs.htm.
9.	U.S. Environmental Protection Agency, "Air Quality Designations for the 2012 Primary Annual Fine Particle (PM2.5) National Ambient Air Quality Standards (NAAQS)," 80 Federal Register 2206-2284, January 15, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-01-15/pdf/2015-00021.pdf. As per statutory scheduling requirements, the EPA Administrator signed on December 18, 2014. The effective date of the designations is 90 days after the publication in the Federal Register.
10.	Partly in response to comments received from states, the final designations published on January 15, 2015, reflected some changes to proposed designations identified by the agency in an August 29, 2014, Federal Register notice. EPA, "EPA Responses to State and Tribal 2012 Primary Annual Fine Particle Designation Recommendations," 79 Federal Register 51517-51520, August 29, 2014, http://www.gpo.gov/fdsys/pkg/FR-2014-08-29/pdf/2014-20641.pdf. See also EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard: Regulatory Actions," http://www.epa.gov/pmdesignations/2012standards/regs.htm.
11.	See footnote 9, p. 2208.
12.	See EPA, "April 2013 Guidance for Area Designations for the 2012 Annual PM2.5 NAAQS," p. 6, http://www.epa.gov/pmdesignations/2012standards/docs/april2013guidance.pdf.
13.	Subpart 4 §188(a) [42 U.S.C. §7513] includes a two-tier classification ("moderate" and "serious") requirement for areas designated nonattainment for PM NAAQS. Sections 188-189 of Subpart 4 contain requirements that EPA had not previously required states to address, including, in particular, in the event that EPA reclassifies a moderate nonattainment area to a serious nonattainment area. States must therefore submit plans that reflect the additional requirements.
14.	Natural Resources Defense Council and Sierra Club v. EPA, 706 F.3d 428 (D.C. Cir. 2013). See also EPA "Particulate Matter Regulatory Actions: Summary of January 4, 2013 Court Decision," http://epa.gov/pm/2013/20130104dcdecision.pdf.
15.	EPA published a final rule reclassifying nonattainment areas as "moderate" for the 1997 and 2006 PM NAAQS and set a deadline for December 31, 2014, for states to submit outstanding State Implementation Plans (SIPs) requirements. EPA, "Identification of Nonattainment Classification and Deadlines for Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine Particle (PM2.5) National Ambient Air Quality Standard (NAAQS) and 2006 PM2.5 NAAQS; Final Rule," 79 Federal Register 31566, June 2, 2014, http://www.gpo.gov/fdsys/pkg/FR-2014-06-02/pdf/2014-10395.pdf. See also EPA's "Fact Sheet" and information regarding the November 15, 2013, proposed rule and the January 4, 2013, D.C. Circuit Court decision on the agency's website "Particulate Matter Regulatory Actions" at http://epa.gov/pm/actions.html.
16.	42 U.S.C. 7409(b)(1).
17.	42 U.S.C. 7409(b)(2).
18.	42 U.S.C. 7602(h).The use of public welfare in the CAA "includes, but is not limited to, effects on soils, water, crops, vegetation, manmade materials, animals, wildlife, weather, visibility, and climate, damage to and deterioration of property, and hazards to transportation, as well as effects on economic values and on personal comfort and well-being, whether caused by transformation, conversion, or combination with other air pollutants."
19.	See 62 Federal Register 38652-38896, July 18, 1997.
20.	PM10 NAAQS were promulgated in 1987. See 52 Federal Register 24640, July 1, 1987.
21.	See footnote 3.
22.	This decision was based on the findings in the EPA PM criteria document and staff paper, and the CASAC's concurrence, that the studies reviewed did not provide sufficient evidence regarding long-term exposure to warrant continuation of an annual standard. See EPA, "National Ambient Air Quality Standards," Section III, 71 Federal Register 2653, January 17, 2006.
23.	See EPA, "National Ambient Air Quality Standards; Final Rule," Section IX, 78 Federal Register 3249-3251, January 15, 2013, http://www.gpo.gov/fdsys/pkg/FR-2013-01-15/pdf/2012-30946.pdf.
24.	Section 107(d)(1)(A)(iii) of the CAA provides that any area that EPA cannot designate on the basis of available information as meeting or not meeting the standards should be designated as unclassifiable.
25.	For information regarding tribes that have participated in the PM2.5 designation recommendation process, see EPA, "Fine Particle (PM2.5) Designations," http://www.epa.gov/pmdesignations.
26.	A federally referenced monitor is one that has been accepted for use by EPA for comparison of the NAAQS by meeting the design specifications and certain precision and bias (performance) specifications (40 C.F.R. Part 58).
27.	EPA, "Revisions to Ambient Air Monitoring Regulations; Final Rule," 71 Federal Register 61235-61328, October 17, 2006, http://www.gpo.gov/fdsys/pkg/FR-2006-10-17/pdf/06-8478.pdf.
28.	EPA, "National Ambient Air Quality Standards for Particulate Matter," Section VIII, 79 Federal Register 3233-3248, January 15, 2013, http://www.gpo.gov/fdsys/pkg/FR-2013-01-15/pdf/2012-30946.pdf.
29.	See EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard: Designation Guidance and Data," http://www.epa.gov/airquality/particlepollution/designations/2012standards/techinfo.htm.
30.	As defined by the Office of Management Budget. For more information on metropolitan areas, see U.S. Census Bureau, "Metropolitan and Micropolitan Statistical Areas Main," http://www.census.gov/population/www/estimates/aboutmetro.html.
31.	See EPA's June 2007 guidance for area designations for the 2006 24-hour PM2.5 NAAQS at http://www.epa.gov/airquality/particlepollution/designations/2006standards/techinfo/june_2007_guidance_for_area_designations_for_2006_24-hour_pm2.5.pdf.
32.	See EPA's April 2013 guidance for area designations for the 2012 annual PM2.5 NAAQS at http://www.epa.gov/pmdesignations/2012standards/docs/april2013guidance.pdf.
33.	For detailed PM2.5 state/county geographical designation recommendations by EPA and those from individual states and tribes for the 1997, 2006, and 2012 PM2.5 NAAQS, see EPA, "Fine Particle (PM2.5) Designations," http://www.epa.gov/pmdesignations.
34.	For the 2013 PM NAAQS, state recommendations were due by December 13, 2013.
35.	See EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard: State Recommendations and EPA Responses for Area Designations," http://www.epa.gov/pmdesignations/2012standards/state.htm.
36.	See EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard: Initial Designations for Tribes," http://www.epa.gov/pmdesignations/2012standards/tribal.htm.
37.	See footnote 9, specifically p. 2209 of 80 Federal Register 2206-2284, January 15, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-01-15/pdf/2015-00021.pdf.
38.	See footnote 9.
39.	See EPA, "Final Area Designations for the 2012 National Air Quality Standard for Fine Particles: Responses to Significant Comments on the State and Tribal Designation Recommendations for the 2012 Annual PM2.5 National Ambient Air Quality Standard (NAAQS)," December 17, 2014, Docket Number EPA-HQ-OAR-2012-0918, http://www.epa.gov/pmdesignations/2012standards/final/20141217rtc.pdf.
40.	EPA corrected an inadvertent error in the initial designation for Allegheny County in Pennsylvania. EPA amended the designation table for Pennsylvania to reflect that the county in its entirety is designated nonattainment and that no portion of the county is designated unclassifiable/attainment for the 2012 PM NAAQS. See footnote 8, specifically p. 18538 of 80 Federal Register, 18535-18551, April 7, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-04-07/pdf/2015-07948.pdf.
41.	See footnote 8.
42.	See EPA's PM2.5 designations websites at http://www.epa.gov/pmdesignations and http://www.epa.gov/oar/oaqps/greenbk/qnca.html. See also CRS Report R40096, 2006 National Ambient Air Quality Standards (NAAQS) for Fine Particulate Matter (PM2.5): Designating Nonattainment Areas, by [author name scrubbed].
43.	See EPA, "April 2013 Guidance for Area Designations for the 2012 Annual PM2.5 NAAQS," p. 6, http://www.epa.gov/pmdesignations/2012standards/docs/april2013guidance.pdf.
44.	Based on extrapolation of the county population (2010 Census), which EPA identified in its "Book Nonattainment Areas for Criteria Pollutants" (see http://www.epa.gov/oar/oaqps/greenbk/anayo_pa.html). Estimated total population is 316 million for 2013 based on U.S. Census Bureau, "USA Quick Facts," http://quickfacts.census.gov/qfd/states/00000.html.
45.	Based on estimated total population of 314 million for 2012 from the U.S. Census Bureau, 2000 Census data, http://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=PEP_2012_PEPAGESEX&prodType=table.
46.	See footnote 44.
47.	See EPA, "Final Area Designations for the 2012 National Air Quality Standard for Fine Particles: Fact Sheet," http://www.epa.gov/pmdesignations/2012standards/final/20141218fs.pdf.
48.	See footnote 35.
49.	For information regarding EPA's August 19, 2014, intended designations, see EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard," http://www.epa.gov/airquality/particlepollution/designations/2012standards/index.htm.
50.	EPA, "EPA Responses to Significant Comments on the State and Tribal Designation Recommendations for the 2012 Annual PM2.5 National Ambient Air Quality Standard (NAAQS)," http://www.epa.gov/pmdesignations/2012standards/final/20141217rtc.pdf. See additional information at EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard: Regulatory Actions," http://www.epa.gov/pmdesignations/2012standards/regs.htm.
51.	EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard Regulatory Actions: Fact Sheet," http://www.epa.gov/pmdesignations/2012standards/docs/20140819factsheet.pdf.
52.	For a list of the deferred areas, see EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard Regulatory Actions: Deferred Areas," http://www.epa.gov/pmdesignations/2012standards/docs/20140819deferredlist.pdf.
53.	For a list of the areas EPA proposed to designate as unclassified, see EPA, "Area Designations for the 2012 Annual PM2.5 Standards," http://www.epa.gov/pmdesignations/2012standards/docs/20140819unclassifiablelist.pdf. See also EPA, "Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard Regulatory Actions: Fact Sheet," http://www.epa.gov/pmdesignations/2012standards/docs/20140819factsheet.pdf.
54.	See communications between states and EPA at EPA, "Recommended Area Designations for the 2012 National Air Quality Standards for Fine Particles: State Recommendations and EPA Responses for Area Designations," http://www.epa.gov/pmdesignations/2012standards/staterec.htm; for tribes see "Recommended Area Designations for the 2012 National Air Quality Standards for Fine Particles: Tribal Recommendations and EPA Responses for Area Designations," http://www.epa.gov/pmdesignations/2012standards/tribalrec.htm.
55.	See EPA's PM2.5 designations websites at http://www.epa.gov/pmdesignations and http://www.epa.gov/oar/oaqps/greenbk/qnca.html. See also CRS Report R40096, 2006 National Ambient Air Quality Standards (NAAQS) for Fine Particulate Matter (PM2.5): Designating Nonattainment Areas, by [author name scrubbed].
56.	74 Federal Register 58688-58781, November 13, 2009; see also EPA, "Area Designations for 2006 24-Hour Fine Particulate (PM2.5) Standards—Regulatory Actions," http://www.epa.gov/pmdesignations/2006standards/regs.htm#4.
57.	For a detailed side-by-side presentation of EPA final designations for the 2006 and 1997 PM2.5 see Table B-1 in Appendix B of CRS Report R40096, 2006 National Ambient Air Quality Standards (NAAQS) for Fine Particulate Matter (PM2.5): Designating Nonattainment Areas, by [author name scrubbed].
58.	See footnote 14.
59.	Part D of Title I §189(a)(2)(B).
60.	EPA references the "General Preamble" of the CAA and "Addendum" as guidance for the specific Subpart 4 statutory requirements: "State Implementation Plans; General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990," 57 Federal Register 13498, April 16, 1992, and "State Implementation Plans for Serious PM10 Nonattainment Areas, and Attainment Date Waivers for PM10 Nonattainment Areas Generally; Addendum to the General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990," 59 Federal Register 41998, August 16, 1994.
61.	EPA may grant no more than two one-year extensions of the initial attainment date for moderate designated areas under Section 188(d) of the CAA and no more than five years for areas designated as serious under Section 188(e).
62.	Under Section 172(a)(2)(A) of the CAA, EPA may grant an area an extension of the initial attainment date for one to five years (in no case later than 10 years after the designation date for the area).
63.	Under 40 C.F.R Part 51, Subpart A, states are required to provide annual statewide inventory data for selected source categories no matter the area designations determinations.
64.	Section 172(c)(1).
65.	See EPA, "The Clean Air Act and the Economy," http://www.epa.gov/air/sect812/economy.html.
66.	The term precursor refers to a directly emitted pollutant that, when released to the atmosphere, forms or contributes to the formation of a secondary pollutant for which an ambient air quality standard has been adopted.
67.	EPA, "Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements; Proposed Rule," 73 Federal Register 15340- 15474, March 23, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-03-23/pdf/2015-06138.pdf. See also EPA's PM Regulatory Actions website at http://epa.gov/pm/actions.html for a fact sheet and prepublication version of the proposed rule as signed by the EPA administrator on March 10, 2015.
68.	EPA, "Final Clean Air Fine Particle Implementation Rule," 72 Federal Register 20286-20667, April 25, 2007, http://www.gpo.gov/fdsys/pkg/FR-2007-04-25/pdf/E[phone number scrubbed].pdf. The rule addresses attainment demonstration and modeling, local emission reduction measures (including RACT, RACM, and reasonable further progress), regional emission reduction strategies, innovative program guidance, emission inventory requirements, transportation conformity, and stationary source test methods.
69.	EPA, "Implementation of the New Source Review (NSR) Program for Particulate Matter Less Than 2.5 Micrometers (PM2.5); Final Rule," 73 Federal Register 28321-28350, May 26, 2008, http://www.gpo.gov/fdsys/pkg/FR-2008-05-16/pdf/E8-10768.pdf.
70.	See footnote 14.
71.	EPA, "Identification of Nonattainment Classification and Deadlines for Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine Particle (PM2.5) National Ambient Air Quality Standard (NAAQS) and 2006 PM2.5 NAAQS; Final Rule," 79 Federal Register 31566, June 2, 2014. See also EPA's "Fact Sheet" and information regarding the November 15, 2013, proposed rule and the January 2013 D.C. Circuit Court decision on the agency's website at http://epa.gov/pm/actions.html.
72.	Memorandum from Stephen D. Page, Director, Office of Air Quality Planning and Standards, to EPA Regional Air Directors (Regions I-X), "Implementation Guidance for the 2006 24-Hour Fine Particle (PM2.5) National Ambient Air Quality Standards (NAAQS)," http://www.epa.gov/ttn/naaqs/pm/pdfs/20120302_implement_guidance_24-hr_pm2.5_naaqs.pdf.
73.	See EPA's website "Interstate Air Pollution Transport" at http://www.epa.gov/airtransport/.
74.	See EPA's website "Mercury and Air Toxics Standards" at http://www.epa.gov/mats/.
75.	EPA, "Control of Air Pollution from New Motor Vehicles: Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control Requirements," 65 Federal Register 6698-6870, February 10, 2000, http://www.gpo.gov/fdsys/pkg/FR-2000-02-10/pdf/00-19.pdf.
76.	Tier 3 vehicle standards set new limits starting September 2017 for tailpipe and evaporative emissions from passenger cars, light-duty trucks, medium-duty passenger vehicles, and some heavy-duty vehicles. EPA, "Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards," 70 Federal Register 23413-23886, April 28, 2014, http://www.gpo.gov/fdsys/pkg/FR-2014-04-28/pdf/2014-06954.pdf. EPA released amendments and clarifications to the rule in January of 2015; see EPA's website "Tier 3 Vehicle Emission and Fuel Standards Program" at http://www.epa.gov/otaq/tier3.htm.
77.	EPA, "Control of Emissions of Air Pollution from 2004 and Later Model Year Heavy-Duty Highway Engines and Vehicles; Revision of Light-Duty On-Board Diagnostics Requirements," 65 Federal Register 59896-59978, October 6, 2000, http://www.gpo.gov/fdsys/pkg/FR-2000-10-06/pdf/00-20144.pdf.
78.	EPA, "Control of Emissions of Air Pollution from Nonroad Diesel Engines and Fuel," 69 Federal Register 38958-39273, June 29, 2004, http://www.gpo.gov/fdsys/pkg/FR-2004-06-29/pdf/04-11293.pdf.
79.	EPA, "Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) Determinations," 70 Federal Register 39104-39172, July 6, 2005, http://www.gpo.gov/fdsys/pkg/FR-2005-07-06/pdf/05-12526.pdf.
80.	EPA, "Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures," 70 Federal Register 69644-69687, November 17, 2005, http://www.gpo.gov/fdsys/pkg/FR-2005-11-17/pdf/05-22704.pdf.
81.	EPA, "Control of Emissions of Air Pollution from Locomotive Engines and Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder; Republication," 73 Federal Register 37095-37350, republished June 30, 2008, http://www.gpo.gov/fdsys/pkg/FR-2008-06-30/pdf/R8-7999.pdf.
82.	EPA, "Control of Emissions from Nonroad Spark-Ignition Engines and Equipment," 73 Federal Register 59034-59380, October 8, 2008, http://www.gpo.gov/fdsys/pkg/FR-2008-10-08/pdf/E8-21093.pdf.
83.	EPA, "Control of Emissions from New Marine Compression-Ignition Engines at or Above 30 Liters per Cylinder," 75 Federal Register 22895-23065, April 30, 2010, http://www.gpo.gov/fdsys/pkg/FR-2010-04-30/pdf/2010-2534.pdf.
84.	EPA, "National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines," 75 Federal Register 51569-51608, August 20, 2010, http://www.gpo.gov/fdsys/pkg/FR-2010-08-20/pdf/2010-20298.pdf; EPA, "National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines; Final Rule," Final Amendments, 78 Federal Register 6674-6724, January 30, 2013, http://www.gpo.gov/fdsys/pkg/FR-2013-01-30/pdf/2013-01288.pdf; see also EPA's Air Toxics website "Stationary Internal Combustion Engines" at http://www.epa.gov/ttn/atw/icengines/index.html.
85.	EPA, "Standards of Performance for New Stationary Sources and Emissions Guidelines for Existing Sources: Hospital/Medical/Infectious Waste Incinerators," 74 Federal Register 51368-51415, October 6, 2009, http://www.gpo.gov/fdsys/pkg/FR-2009-10-06/pdf/E9-22928.pdf.
86.	For an overview, including statutory authority and regulations, see EPA, "New Source Review (NSR)," http://www.epa.gov/air/nsr/.
87.	See CAA, §§171-178, codified at 40 C.F.R. 52.24(f)(10). Section 166 of the CAA authorizes EPA to establish regulations for PSD of any pollutant for which EPA has issued a national standard.
88.	For more information regarding these NSR rules and standards, see EPA, "New Source Review: Regulations and Standards," http://www.epa.gov/air/nsr/actions.html.
89.	See EPA, EPA's Revised Air Quality Standards for Particle Pollution: Monitoring, Designations and Permitting Requirements, fact sheet, http://www.epa.gov/pm/2012/decfsimp.pdf. See also EPA, EPA's Proposal to Update the Air Quality Standards for Particle Pollution: Monitoring, Designations and Permitting Requirements, fact sheet, http://www.epa.gov/airquality/particlepollution/2012/fsimp.pdf.
90.	See EPA's "Transportation Conformity" at http://www.epa.gov/otaq/stateresources/transconf/index.htm.
91.	42 U.S.C. 7506(c).
92.	EPA, "Guidance for Transportation Conformity Implementation in Multi-Jurisdictional Nonattainment and Maintenance Areas," http://www.epa.gov/otaq/stateresources/transconf/regs/420b12046.pdf. See also EPA Transportation Conformity Rule PM2.5 and PM10 Amendments, 75 Federal Register 14259, March 24, 2010, http://www.gpo.gov/fdsys/pkg/FR-2010-03-24/pdf/2010-5703.pdf. Prior to the final rule EPA provided interim guidance for meeting conformity requirements: Interim Transportation Conformity Guidance for 2006 PM2.5 NAAQS Nonattainment Areas (EPA-420-B-09-036, November 2009). See also EPA's "Transportation Conformity: Regulations" at http://www.epa.gov/otaq/stateresources/transconf/conf-regs.htm.
93.	Transportation projects that must be analyzed for local air quality impacts.
94.	EPA, "Transportation Conformity Rule Restructuring Amendments," 77 Federal Register 14979, March 14, 2012, http://www.gpo.gov/fdsys/pkg/FR-2012-03-14/pdf/2012-6207.pdf.
95.	Implementing PM NAAQS under Section 176 of Subpart 1 in the CAA requires submission of SIPs three years from the date of EPA's final designations and compliance with the new standard no later than five years from the effective designation date.
96.	See letter from Representative Bob Latta et al. to EPA administrator Lisa Jackson, November 21, 2012, http://latta.house.gov/uploadedfiles/2012_11_29_final_pm2_5_letter_signed_w_attchmt.pdf. See also press release, "Latta Sends Letter to EPA Expressing Concerns for Proposed Legislation," Representative Bob Latta, http://latta.house.gov/news/documentsingle.aspx?DocumentID=314585.
97.	See December 6, 2012, letter from nine state attorneys general to the acting administrator of the Office of Information and Regulatory Affairs, White House Office of Management and Budget, http://www.eenews.net/assets/2012/12/10/document_gw_02.pdf.
98.	EPA memorandum from the Office of Air and Radiation Assistant administrator Jeffrey R. Holmstead to EPA Regional Administrators, "Designations for the Fine Particle National Ambient Air Quality Standards," April 1, 2003, p. 3, http://www.epa.gov/ttn/oarpg/t1/memoranda/naqsfp_gda.pdf.
99.	See EPA overview for the 2006 review of the PM NAAQS, http://www.epa.gov/airquality/particlepollution/pdfs/20061013_presentation.pdf, slide #9.
100.	(40 C.F.R. Part 49). For information regarding tribes that have participated in the PM2.5 designation recommendation process, see EPA, "Fine Particle (PM2.5) Designations," http://www.epa.gov/pmdesignations.
101.	See footnote 9, specifically p. 2209 of 80 Federal Register 2206-2284, January 15, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-01-15/pdf/2015-00021.pdf.
102.	EPA, "Area Designations for the 2012 Annual Final Particle (PM2.5) Standard: Initial Designations for Tribes," http://www.epa.gov/pmdesignations/2012standards/tribal.htm.
103.	As per its December 20, 2011, "Policy for Establishing Separate Air Quality Designations for Areas of Indian Country" (see memorandum at http://www.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20111220_page_policy_aq_designations_areas_indian_country.pdf), EPA designated the lands of the Pechanga Band of the Luiseno Mission Indians separate from adjacent/surrounding state areas. See footnote 9, specifically p. 2207 of 80 Federal Register 2206-2284, January 15, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-01-15/pdf/2015-00021.pdf.