AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing to determine that the West Pinal County, Arizona nonattainment area did not attain the 1987 24-hour national ambient air quality standards (NAAQS or “standard”) for particulate matter with a diameter of ten micrometers or smaller (PM₁₀) by December 31, 2018, the statutory attainment date for the nonattainment area. This proposal is based on the EPA's calculation of the PM₁₀ design value for the nonattainment area over the 2016-2018 period, using complete, quality-assured, and certified PM₁₀ monitoring data. If the EPA makes a final determination that West Pinal County has failed to attain the PM₁₀ NAAQS by its attainment date, then Clean Air Act (CAA) section 188(b)(2) requires that the nonattainment area be reclassified to Serious by operation of law. Within 18 months from the effective date of a reclassification to Serious, the State must submit State Implementation Plan (SIP) revisions that comply with the statutory and regulatory requirements for Serious PM₁₀ nonattainment areas.

DATES:

Written comments must be received on or before May 7, 2020.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-R09-OAR-2020-0151 at https://www.regulations.gov. For comments submitted at Regulations.gov, follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the FOR FURTHER INFORMATION CONTACT section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/​dockets/​commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT:

Jerry Wamsley, EPA Region IX, (415) 947-4111, wamsley.jerry@epa.gov.

SUPPLEMENTARY INFORMATION:

Throughout this document, “we,” “us” and “our” refer to the EPA.

Table of Contents

I. Background and Regulatory Context

II. Criteria for Determining That an Area Has Attained the 1987 24-Hour PM₁₀ NAAQS

III. The EPA's Proposed Action and Associated Rationale

A. Data Completeness, Network Review, and Certification of Data

B. Finding of Failure to Attain the PM₁₀ NAAQS

IV. Summary of Our Proposed Action

V. Statutory and Executive Order Reviews

I. Background and Regulatory Context

The EPA sets the NAAQS for certain ambient air pollutants at levels required to protect public health and welfare. Particulate matter with an aerodynamic diameter less than or equal to a nominal ten micrometers (microns), or PM₁₀, is one of the ambient air pollutants for which the EPA has established health-based standards, and we have promulgated and revised the PM₁₀ NAAQS several times.

The EPA revised the NAAQS for particulate matter on July 1, 1987, replacing standards for total suspended particulates (TSP, particulate less than 30 microns in diameter) with new standards applying only to particulate matter up to 10 microns in diameter.^[1] In 1987, the EPA established two PM₁₀ NAAQS, an annual standard and a 24-hour standard. An area attains the 24-hour PM₁₀ standard of 150 micrograms per cubic meter (μg/m^[3] ) when the expected number of days per calendar year with a 24-hour concentration exceeding the standard (referred to as an “exceedance”) over a three-year period, is equal to or less than one.^[2] The annual PM₁₀ standard was revoked on October 17, 2006.^[3]

On May 31, 2012, the EPA designated a portion of state lands in Pinal County, Arizona (“West Pinal County”) as nonattainment for the 1987 p.m.₁₀ NAAQS based on 2006-2008 data.^[4] As a result of the nonattainment designation, West Pinal County was classified as a “Moderate” PM₁₀ nonattainment area.

For a PM₁₀ nonattainment area classified as Moderate under the CAA, section 188(c) of the CAA states that the Moderate area attainment date is “as expeditiously as practicable, but no later than the end of the sixth calendar year after the area's designation as nonattainment.” Consequently, the applicable attainment date for West Pinal County, designated nonattainment in 2012, was December 31, 2018. CAA section 188(b)(2) requires the EPA to determine whether any PM₁₀ nonattainment area classified as Moderate attained the 24-hour PM₁₀ NAAQS by the area's attainment date and requires the EPA to make such a determination within six months after that date. If the EPA determines that a Moderate area has not attained the NAAQS by the relevant attainment date, then the area shall be reclassified as a Serious area by operation of law. As discussed previously, the 1987 24-hour PM₁₀ NAAQS is met when the expected number of exceedances averaged over a three-year period is equal to or less than one at each monitoring site within the nonattainment area.

II. Criteria for Determining That an Area Has Attained the 1987 24-Hour PM10 NAAQS

Generally, the EPA's determination of whether an area's air quality meets the 1987 24-hour PM₁₀ NAAQS is based on three years of complete, quality-assured data that has been gathered at established state and local air monitoring stations (SLAMS) in a nonattainment area and entered into the EPA's Air Quality System (AQS) database.^[5] Data from ambient air monitors operated by state or local agencies in compliance with the EPA monitoring requirements must be submitted to AQS. Monitoring agencies certify annually that these data are accurate to the best of their knowledge. Accordingly, the EPA relies primarily on data in AQS when determining the attainment status of nonattainment areas.

Ambient air quality data must generally meet data completeness requirements for each year under consideration. The completeness requirements are met when at least 75 percent of the scheduled sampling days for each quarter have valid data.^[6] The data requirements for showing that a monitor has failed an attainment test, and thus recorded a violation of the PM₁₀ standard, are less stringent and the 75 percent data capture requirement does not apply provided there is sufficient data to unambiguously establish nonattainment of the standard.^[7]

III. The EPA's Proposed Action and Associated Rationale

This proposed action is pursuant to the EPA's statutory obligation, under CAA section 188(b)(2), to determine whether the West Pinal County nonattainment area has attained the 1987 24-hour PM₁₀ NAAQS by its December 31, 2018 attainment date. As discussed in Section II, a nonattainment area's ambient data must meet several criteria if the EPA is to determine that the nonattainment area has met the 24-hour PM₁₀ NAAQS. These criteria include complete, quality-assured and certified data collected from a valid ambient air quality monitoring network and a design value calculated from the ambient data to be less than the applicable NAAQS.

A. Data Completeness, Network Review, and Certification of Data

In accordance with 40 CFR part 50, Appendices J and K, a finding of attainment of the 1987 24-hour PM₁₀ NAAQS must generally be based upon complete, quality-assured data gathered at monitoring sites in the nonattainment area and entered in the AQS. For the 24-hour PM₁₀ standard, Appendix K provides that all data produced by SLAMS and other sites submitted to the EPA in accordance with the part 58 requirements be used for evaluating attainment.^[8]

The PM₁₀ ambient air quality monitoring data collected within the West Pinal County nonattainment area for the 2016-2018 three-year period must meet data completeness criteria, or otherwise unambiguously establish nonattainment according to 40 CFR part 50, Appendix K, section 2.3. The ambient air quality monitoring data completeness requirements are met when quarterly data capture rates for all four quarters in a calendar year over a three-year period are at least 75 percent. For the purposes of this proposal, we reviewed the data for the 2016-2018 period for completeness and determined that the PM₁₀ data met the completeness criterion for all 12 quarters at PM₁₀ monitoring sites in the West Pinal County nonattainment area.^[9]

The EPA's determination as to whether an area has attained the PM₁₀ NAAQS pursuant to CAA section 188(b)(2) is based on monitored ambient air quality data. The validity of this determination of attainment depends in part on whether the monitoring network adequately measures ambient PM₁₀ levels in the nonattainment area. The Pinal County Air Quality Control District (“Pinal County”) is the governmental agency with the authority and responsibilities under the State's laws for collecting ambient air quality data for the West Pinal County nonattainment area. Pinal County submits annual monitoring network plans to the EPA. These plans discuss the status of the ambient air monitoring network, as required under 40 CFR part 58. The EPA reviews these annual network plans for compliance with the applicable reporting requirements in 40 CFR 58.10. With respect to PM₁₀, the EPA has found that the annual network plans submitted by Pinal County meet the applicable requirements under 40 CFR part 58.^[10] Furthermore, we concluded from our 2019 Technical Systems Audit of Pinal County's ambient air quality monitoring program that the ambient air monitoring network currently meets or exceeds the requirements for the minimum number of monitoring sites designated as SLAMS for PM₁₀ in the West Pinal County nonattainment area.^[11] Pinal County certifies annually that the data it submits to AQS are quality-assured and has done so for each year relevant to our determination of attainment, 2016-2018.^[12]

B. Finding of Failure To Attain the PM ₁₀ NAAQS

As discussed previously, the EPA's evaluation of whether the West Pinal County nonattainment area has met the 1987 24-hour PM₁₀ NAAQS is based on our review of the monitoring data, the adequacy of the PM₁₀ monitoring network in the nonattainment area, and the reliability of the data collected by the network. The PM₁₀ standard is attained when the expected number of exceedances, averaged over a three-year period, is less than or equal to one. The expected number of exceedances averaged over a three-year period at any given monitor is known as the PM₁₀ design value for that site. The PM₁₀ design value for the nonattainment area is the highest design value from a monitor within that area. Three consecutive years of air quality data are required to show attainment of the PM₁₀ standard.

Table 1 provides the 2018 PM₁₀ design values for all regulatory monitoring sites measuring PM₁₀ within the West Pinal County nonattainment area, expressed as a single value representing the average expected exceedances over the three-year period, 2016-2018.^[13] The PM₁₀ data show that the design values at multiple monitoring sites are greater than 1.0 estimated annual average exceedances of the 1987 24-hour PM₁₀ NAAQS. Consequently, the EPA proposes to determine, based upon three years of complete, quality-assured and certified data from 2016-2018, that the West Pinal County nonattainment area did not attain the 1987 24-hour PM₁₀ NAAQS by the applicable attainment date of December 31, 2018.

If the EPA determines that a Moderate nonattainment area has failed to attain the PM₁₀ NAAQS by its applicable attainment date, then CAA section 188(b)(2) provides that the area shall be reclassified as a Serious area by operation of law. Accordingly, if the EPA takes final action on our proposed determination that the West Pinal County Moderate area failed to attain the 1987 24-hour PM₁₀ NAAQS by December 31, 2018, the area will be reclassified to Serious. The EPA is taking comment on this proposed finding of failure to attain and reclassification of the West Pinal County PM₁₀ nonattainment area from Moderate to Serious.

IV. Summary of Our Proposed Action

In accordance with section 188(b)(2) of the CAA, the EPA is proposing to determine that the West Pinal County Moderate nonattainment area did not attain the 1987 24-hour PM₁₀ NAAQS by its applicable attainment date of December 31, 2018. Our proposed determination that West Pinal County failed to attain the PM₁₀ NAAQS is based on complete, quality-assured, and certified PM₁₀ monitoring data for the appropriate three-year period, 2016-2018. We are soliciting comment on this proposed finding that the West Pinal County Moderate nonattainment area failed to attain the 24-hour PM₁₀ NAAQS.

If we finalize our action as proposed, West Pinal County will be reclassified as a Serious PM₁₀ nonattainment area by operation of law and will be subject to all applicable Serious area attainment planning and nonattainment New Source Review requirements. This includes the requirement to submit a Serious area air quality plan within 18 months of the effective date of our final rule, per section 189(b)(2) of the CAA. This Serious area air quality plan must demonstrate attainment of the 24-hour PM₁₀ NAAQS by December 31, 2022, ten years after the area's designation to nonattainment, per section 188(c)(2) of the CAA.

We will accept comments from the public on these proposals for the next 30 days. The deadline and instructions for submission of comments are provided in the DATES and ADDRESSES sections at the beginning of this preamble.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review, and Executive Order 13563: Improving Regulation and Regulatory Review

This action is not a significant regulatory action under the terms of Executive Order 12866 (58 FR 51735, October 4, 1993) and Executive Order 13563 (76 FR 3821, January 21, 2011), and therefore was not submitted to the Office of Management and Budget (OMB) for review.

B. Executive Order 13771: Reducing Regulations and Controlling Regulatory Costs

This action is not an Executive Order 13771 regulatory action because it is not a significant regulatory action under Executive Order 12866.

C. Paperwork Reduction Act

This action does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501-3521) because it does not contain any information collection activities.

D. Regulatory Flexibility Act

I certify that this action will not have a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (RFA), 5 U.S.C. 601-612. This action will not impose any requirements on small entities. This proposed action, if finalized, would require the state to adopt and submit SIP revisions to satisfy the statutory requirements that apply to Serious areas and would not itself directly regulate any small entities. We continue to be interested in the potential impacts of the proposed rule on small entities and welcome comments on issues related to such impacts.

E. Unfunded Mandates Reform Act

This action does not contain any unfunded mandate of $100 million or more and does not significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act (UMRA) (2 U.S.C. 1531- 1538). This action itself imposes no enforceable duty on any state, local, or tribal governments, or the private sector. This action proposes to determine that the West Pinal County nonattainment area failed to attain the 1987 24-hour PM₁₀ NAAQS by its applicable attainment date, which would trigger reclassification as a Serious nonattainment area and existing statutory timeframes for the state to submit SIP revisions. Such a reclassification in and of itself does not impose any federal intergovernmental mandate.

F. Executive Order 13132: Federalism

This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132 (64 FR 43255, August 10, 1999). The requirement to submit SIP revisions to meet the 1987 24-hour PM₁₀ NAAQS is imposed by the CAA. This proposed rule does not alter the distribution of power and responsibilities established in the CAA. Thus, Executive Order 13132 does not apply to this action. In the spirit of Executive Order 13132 and consistent with EPA policy to promote communications between the EPA and state and local governments, the EPA specifically solicits comments on this proposed action from state and local officials.

G. Executive Order 13175, Consultation and Coordination With Indian Tribal Governments

This action does not have tribal implications as specified in Executive Order 13175. No areas of Indian country are located within the West Pinal County PM₁₀ nonattainment area. Therefore, no tribal areas are implicated in the area that the EPA is proposing to find failed to attain the 1987 24-hour PM₁₀ NAAQS by the applicable attainment date. The CAA and the Tribal Authority Rule establish the relationship of the federal government and tribes in developing plans to attain the NAAQS, and this rule does nothing to modify that relationship. Thus, Executive Order 13175 does not apply to this action.

H. Executive Order 13045, Protection of Children From Environmental Health Risks and Safety Risks

The EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997) as applying only to those regulatory actions that concern environmental health or safety risks that the EPA has reason to believe may disproportionately affect children, per the definition of “covered regulatory action” in section 2-202 of the Executive Order. This proposed action is not subject to Executive Order 13045 because the effect of this proposed action, if finalized, would be to reclassify the West Pinal County nonattainment area as Serious nonattainment for the 1987 24-hour PM₁₀ NAAQS, which would trigger additional Serious area planning requirements under the CAA. This proposed action does not establish an environmental standard intended to mitigate health or safety risks.

I. Executive Order 13211, Actions That Significantly Affect Energy Supply, Distribution, or Use

This proposed rule is not subject to Executive Order 13211, “Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355, May 22, 2001) because it is not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act

This action is not subject to the requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because it does not involve technical standards.

K. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Population

Executive Order 12898 (59 FR 7629, Feb. 16, 1994) establishes federal executive policy on environmental justice. Its main provision directs federal agencies, to the greatest extent practicable and permitted by law, to make environmental justice part of their mission by identifying and addressing, as appropriate, disproportionately high and adverse human health or environmental effects of their programs, policies, and activities on minority populations and low-income populations in the United States. The EPA has determined that this action will not have disproportionately high and adverse human health or environmental effects on minority or low-income populations because it does not affect the level of protection provided to human health or the environment. The effect of this proposed action, if finalized, would be to reclassify the West Pinal County nonattainment area as Serious nonattainment for the 1987 24-hour PM₁₀ NAAQS, which would trigger additional Serious area planning requirements under the CAA.

List of Subjects in 40 CFR Part 52

• Environmental protection
• Air pollution control
• Particulate matter
• Incorporation by reference
• Intergovernmental relations
• Reporting and recordkeeping requirements

Authority: 42 U.S.C. 7401 et seq.

Footnotes