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Environmental Protection Agency (EPA).
The Oregon Department of Environmental Quality (ODEQ) submitted a revision to the State Implementation Plan (SIP), dated December 14, 2012, to address Clean Air Act (CAA or the Act) requirements for the Klamath Falls, Oregon nonattainment area for the 2006 24-hour fine particulate matter (PM2.5) national ambient air quality standard (NAAQS). The EPA proposes to approve the emissions inventory contained in the ODEQ's submittal as meeting the requirement to submit a comprehensive, accurate, and current inventory of direct PM2.5 and PM2.5 precursor emissions in Klamath Falls, Oregon. The EPA also proposes to approve PM2.5 control measures contained in the December 2012 submittal because incorporation of these measures will strengthen the Oregon SIP and reduce sources of PM2.5 emissions in the Klamath Falls, Oregon nonattainment area (Klamath Falls NAA) that contribute to violations of the 2006 PM2.5 NAAQS.
Comments must be received on or before January 29, 2015.
Submit your comments, identified by Docket ID No. EPA-R10-OAR-2013-0005, by any of the following methods:
- www.regulations.gov: Follow the on-line instructions for submitting comments.
- Email: R10-Public_Comments@epa.gov.
- Mail: Justin A. Spenillo, EPA Region 10, Office of Air, Waste and Toxics (AWT-150), 1200 Sixth Avenue, Suite 900, Seattle, WA 98101.
- Hand Delivery/Courier: EPA Region 10, 1200 Sixth Avenue, Suite 900, Seattle, WA 98101. Attention: Justin A. Spenillo, Office of Air, Waste and Toxics, AWT-150. Such deliveries are only accepted during normal hours of operation, and special arrangements should be made for deliveries of boxed information
Instructions: Direct your comments to Docket ID No. EPA-R10-OAR-2013-0005. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information the disclosure of which is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through www.regulations.gov or email. The www.regulations.gov Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through www.regulations.gov your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.
Docket: All documents in the docket are listed in the www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information, the disclosure of which is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy. Publicly available docket materials are available either electronically in www.regulations.gov or in hard copy during normal business hours at the Office of Air, Waste and Toxics, EPA Region 10, 1200 Sixth Avenue, Seattle WA, 98101.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Justin A. Spenillo at (206) 553-6125, email@example.com, or the above EPA, Region 10 address.End Further Info End Preamble Start Supplemental Information
Throughout this document whenever “we,” “us,” or “our” is used, we mean the EPA.
Table of Contents
A. PM2.5 National Ambient Air Quality Standards
B. Designation of PM2.5 Nonattainment Areas
C. Submittal Requirements for PM2.5 Nonattainment Areas
II. Analysis of the State's Submittal
A. Emissions Inventory
B. Description of the Klamath County PM2.5 Control Measures
III. Proposed Action
IV. Statutory and Executive Order Reviews
A. PM2.5 National Ambient Air Quality Standards
Under section 109 of the CAA, the EPA establishes NAAQS for certain pervasive air pollutants (referred to as “criteria pollutants”) and conducts periodic reviews of the NAAQS to determine whether they should be revised or whether new NAAQS should be established. After a new NAAQS is established or an existing NAAQS is revised, all areas across the country are evaluated to determine whether they meet the new or revised standard, and Start Printed Page 78373area designations are promulgated based on that evaluation.
On July 18, 1997, the EPA revised the NAAQS for particulate matter to add new standards for fine particles, using PM2.5 (particles less than or equal to 2.5 micrometers in aerodynamic diameter) as the indicator for the pollutant. The EPA established primary and secondary  annual and 24-hour standards for PM2.5 (62 FR 38652). The annual standard was set at 15.0 micrograms per cubic meter (μg/m3), based on a 3-year average of the annual mean PM2.5 concentrations, and the 24-hour standard was set at 65 μg/m3, based on the 3-year average of the 98th percentile of 24-hour PM2.5 concentrations. On October 17, 2006, the EPA revised the level of the 24-hour PM2.5 NAAQS to 35 μg/m3, based on a 3-year average of the 98th percentile of 24-hour concentrations (71 FR 61144). On December 14, 2012, the EPA revised the primary annual PM2.5 NAAQS to provide increased protection of public health and welfare from fine particle pollution (78 FR 3086, January 15, 2013). In that action, the EPA revised the primary annual PM2.5 standard, strengthening it from 15.0 micrograms per cubic meter (μg/m3) to 12.0 μg/m3, which is attained when the 3-year average of the annual arithmetic means does not exceed 12.0 μg/m3.
B. Designation of PM2.5 Nonattainment Areas
Effective December 14, 2009, the EPA established the initial air quality designations for most areas in the United States for the 2006 24-hour PM2.5 NAAQS (74 FR 58688, November 13, 2009). The Klamath Falls area was designated nonattainment for the 2006 24-hour PM2.5 NAAQS. The boundaries for this area are described in 40 CFR 81.338.
C. Submittal Requirements for PM2.5 Nonattainment Areas
In March 2012, the EPA issued guidance to states for implementation of the 2006 PM2.5 NAAQS (March 2012 Implementation Guidance). The guidance recommended that states make submissions for the 2006 PM2.5 NAAQS consistent with the substantive requirements developed for implementation of the 1997 PM2.5 NAAQS at 40 CFR part 51, subpart Z (Provisions for Implementation of PM2.5National Ambient Air Quality Standards, 40 CFR 51.1000, et seq.). In December 2012, based on the March 2012 Implementation Guidance, the ODEQ submitted a SIP revision intended to address the nonattainment planning requirements for the Klamath Falls NAA.
On January 4, 2013, the Court of Appeals for the District of Columbia remanded to the EPA the Clean Air Fine Particle Implementation Rule (72 FR 20586, Apr. 25, 2007) (hereafter referred to as the “PM2.5 implementation rule”) which formed the basis of the 40 CFR part 51, subpart Z nonattainment planning requirements. Natural Resources Defense Council v. EPA, 706 F.3d 428 (D.C. Cir. 2013). The Court concluded that the EPA had improperly based the PM2.5 implementation rule solely upon the requirements of part D, subpart 1 of the CAA, and had failed to address the requirements of part D, subpart 4. As a result of the Court's remand of the PM2.5 implementation rule, the EPA withdrew its March 2012 Implementation Guidance because it was based largely on the remanded rule promulgated to implement the 1997 PM2.5 NAAQS. The EPA is currently engaged in rulemaking to address the Court's remand of the PM2.5 implementation rule. In the interim, however, the EPA continues to take action on SIP submissions from states intended to address nonattainment planning requirements for the 2006 PM2.5 NAAQS, consistent with the CAA.
This action is limited to proposing approval of the emissions inventory of direct PM2.5 and PM2.5 precursors submitted by the ODEQ for the Klamath Falls NAA as required under section 172(c)(3) of the CAA, and the approval of specific control measures that are expected to strengthen the SIP. These control measures independently meet requirements for control measures in attainment plans and the emissions reductions they achieve will contribute to attainment of the 2006 PM2.5 NAAQS in the Klamath Falls NAA.
II. Analysis of the State's Submittal
A. Emissions Inventory
The EPA promulgated emissions inventory requirements for the 1997 PM2.5 NAAQS as part of the PM2.5 implementation rule at 40 CFR 51.1008. The decision in NRDC v. EPA remanded the PM2.5 implementation rule because it did not incorporate the specific particulate matter requirements of subpart 4, part D, title I. The emission inventory requirements set forth in the PM2.5 implementation rule were based on the CAA section 172(c)(3) requirements in subpart 1. Subpart 4 contains no specific provision governing emissions inventories for PM10 or PM2.5 nonattainment areas that supersedes the general emissions inventory requirement for all nonattainment areas in section 172(c)(3). See “State Implementation Plans; General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990,” (57 FR 13498, 13539, April 16, 1992) (hereinafter “General Preamble”). Accordingly, the EPA is evaluating the ODEQ's emissions inventory for the Klamath Falls NAA pursuant to the CAA requirements in section 172(c)(3).
Section 172(c)(3) of the CAA requires a state with an area designated as nonattainment to submit to the EPA for approval a comprehensive, accurate, and current inventory of actual emissions of the pollutant at issue, including emissions of any precursor of that pollutant, for the nonattainment area. These inventories provide a detailed accounting of all emissions and emissions sources by pollutant and precursor pollutant within the nonattainment area. In addition, inventories are used to model air quality to demonstrate attainment of the 2006 PM2.5 NAAQS as expeditiously as practicable. The EPA reviewed, in accordance with the August 2005 EPA guidance, “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter NAAQS and Regional Haze Regulations,” the procedures and methodologies used by the ODEQ to develop the emission inventory for the 2008 base year emissions inventory for the Klamath Falls NAA. In accordance with section 172(c)(3) and consistent with EPA guidance, Oregon's attainment plan as described below includes a comprehensive, accurate, and current inventory of emissions of all direct PM2.5 and PM2.5 precursors in the Klamath Falls NAA.
To develop an emissions inventory that matches the conditions under which the design value concentration are measured, the ODEQ emissions inventory addresses annual emissions, typical season day emissions, and worst case day emissions. Annual emissions, measured in tons per year (“tpy”), are the total amount of emissions over the course of a calendar year. The typical season day and worst-case day Start Printed Page 78374emissions are measured in pounds (lbs) per day and are calculated for the PM season, which is the four-month period between November and February when ambient PM concentrations from anthropogenic sources are generally the highest. Typical season day emissions are the average emissions over the four-month PM season, and worst case day emissions are the amount emitted on winter days with a diurnal temperature range representative of PM2.5 exceedances. Most source categories are modeled using the typical season day emissions. Worst-case day emissions are better suited for select sources, such as residential wood combustion and motor vehicles, with emissions highly dependent on temperature. At colder temperatures there is a behavioral increase in home heating using woodstoves, and vehicle emissions associated with start-up emissions are higher on colder days.
The year 2008 was selected by ODEQ as the base year for the emissions inventory because it was the most recent year that Oregon completed the NEI data submittal prior to the designation of the Klamath Falls NAA in 2009. The selection of 2008 as the baseline year for the emissions inventory is consistent with the emissions inventory requirement in section 172(c)(3) because it provides an inventory of emissions for one of the years relied upon for the nonattainment designation. The ODEQ's 2008 base year emissions inventory includes emissions of direct PM2.5 and PM2.5 precursors that cover the general source categories of stationary point sources, stationary nonpoint sources (area sources), non-road mobile sources, and on-road mobile sources. The main sources of emissions in the Klamath Falls NAA are residential wood combustion, mobile and non-road sources, and point sources. The pollutants that comprise the 2008 base year inventory include direct PM2.5 and the precursors to the formation of PM2.5 which are nitrogen oxide (NOX), volatile organic compounds (VOCs), ammonia (NH3), and sulfur dioxide (SO2).
The point source inventory provides facility-specific data for point source emissions from Klamath Falls' permitted stationary sources. Permitted point sources include industrial sources, non-industrial sources, gas stations, crematories, and portable sources. The emissions inventory includes actual point source emissions for both the annual and the seasonal inventory. For purposes of the worst-case day emission inventory, the emissions for permitted point sources are reported at 80% of the permitted operating capacity because such specific daily actual emissions are not available for permitted point sources in the same manner as annual and typical season emissions. The EPA agrees that 80% of permitted emissions is a conservative estimate for worst-case day actual emissions and, given that permitted point sources were not found to be significantly contributing to the monitored violations. This will be further discussed in a future notice when the EPA acts on the ODEQ's control strategy for the Klamath Falls NAA.
The complete inventory, located in the docket for this rulemaking, also includes a description of minor non-permitted point sources. Area sources for the Klamath Falls NAA are divided into six groups: Waste disposal, treatment and recovery; small stationary fossil fuel combustion; residential wood combustion; fugitive dust; evaporative/off-gassing emissions sources; and miscellaneous area sources. The on-road mobile source emissions inventory includes all sources of mobile exhaust, brake, and tire emissions generated by passenger vehicles, trucks, miscellaneous vehicles, and re-entrained road dust. Non-road mobile sources inventoried include aircraft, gasoline and diesel-powered vehicles and equipment, recreational marine vessels, and trains.
The ODEQ compiled the emissions inventory relying on information from a variety of sources. Permitted point source emissions data were taken from the ODEQ Tracking Reporting and Administration of Air Contaminant Sources (TRAACS) database which is submitted to the EPA National Emissions Inventory System. Many area source emissions were taken from the 2008 EPA National Emissions Inventory (NEI) v.1.5. The ODEQ Area Mobile Emissions Estimates (AMEE) database was also a source of emissions data for mobile emissions. Additional emissions information was taken from a 2007/2008 residential wood combustion survey and from use of the EPA Motor Vehicle Emission Simulator (MOVES). All remaining emissions were modeled or inventoried specifically for this attainment plan. The full emissions inventory submitted by the ODEQ and a detailed description of the methodology used to compile the inventory is presented in Attachment 3.3l of the SIP submittal included in the docket for this action.
Table 1 summarizes the annual emissions for Klamath Falls in 2008 and Table 2 summarizes the worst-case day emissions for Klamath Falls in 2008. Typical season day emissions information can be found in Attachment 3.3l of the SIP submittal included in the docket for this action.
|Start Printed Page 78375|
The EPA reviewed the results, procedures and methodologies for the 2008 base year emissions inventory in accordance with the EPA's current guidance, “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter NAAQS and Regional Haze Regulations” (August 2005). The ODEQ used standard procedures to develop the emissions inventory and appropriately used seasonal and worst-case day emissions inventories to represent episodic meteorological conditions when PM2.5 levels are of the greatest concern. For this reason, the EPA is proposing approval of Klamath Falls' 2008 base year emissions inventory as meeting the requirements of section 172(c)(3) of the CAA.
B. Description of the Klamath County PM 2.5 Control Measures
On December 12, 2012, the ODEQ submitted to the EPA for approval revisions to a number of rules related to the Klamath Falls NAA. These revisions consist of updates to identify the Klamath Falls NAA and to adopt local and state measures to ensure permanent and enforceable control strategies intended to bring the area back into attainment through control of PM2.5 and its precursors. Specifically, the ODEQ revised rules in Oregon Administrative Rules (OAR) Chapter 340, Divisions 200, 204, 225, 240, 262, and 264. These revisions, and the EPA's proposed actions on them, are described below.
Division 204: Designation of Air Quality Areas
The ODEQ revised OAR Chapter 340, Division 204 to include a description of the Klamath Falls PM2.5 NAA boundary. The EPA proposes to approve and incorporate by reference (IBR) this revision into the SIP because the area description is essential for delineating the nonattainment area, and we believe the area description is consistent with the EPA description in the designation for the area.
Division 225: Air Quality Analysis Requirements
The ODEQ revised OAR 340-225-0090, in conjunction with promulgating OAR 340-240-0550, as encouragement for direct PM10 and PM2.5 emissions reductions from residential wood-fired devices as a means to offset, in an equal or greater amount, emissions increases from new major sources or major modifications to major sources located in the Klamath Falls NAA, provided such sources do not cause or contribute to a violation of the NAAQS. The revisions to OAR 340-225-0090 exempt a source which proposes to use qualifying woodstove offsets from the need to conduct an air dispersion modeling analysis to demonstrate a net air quality benefit as would otherwise be required. Woodstove emissions are the primary source of PM2.5 emissions contributing to NAAQS violations in the NAA and reductions in woodstove emissions would presumptively result in a net air quality benefit when used to offset new emissions from a stationary source located within the NAA. A source proposing to use other sources of emission offsets, or woodstove offsets that don't meet the requirements of OAR 340-240-0550, would still need to conduct a dispersion modeling analysis to demonstrate a net air quality benefit. The revisions are designed to maintain and promote continued air quality improvement while allowing for economic growth that does not negatively affect the airshed.
In a letter dated September 15, 2014, Oregon withdrew the submitted SIP revision for OAR 340-225-0090(2)(a)(C). Accordingly, the EPA is not acting on the revisions to OAR 340-225-0090(2)(a)(C) which establish inter-pollutant offset ratios. Oregon may submit a revision in the future establishing inter-pollutant offset ratios supported by an appropriate demonstration, or alternatively revise these ratios in accordance with the July 21, 2011, EPA memorandum that addresses the Federal inter-pollutant offset policy (76 FR 80747). The EPA proposes to approve and IBR the revisions to OAR 340-225-0090, except for OAR 340-225-0090(2)(a)(C), and the revision to 340-225-0090(2)(a)(B) based on the PM2.5 inter-pollutant offset ratio, as it provides equivalent protection of the NAAQS and encourages improved air quality by reducing direct PM emissions from wood fired devices in the Klamath Falls NAA.
Division 240: Rules for Areas With Unique Air Quality Needs
Revisions to OAR 340-240-0110, 340-240-0030, 340-240-0500, 340-240-0510, 340-240-0520, 340-240-0530, 340-240-0540, 340-240-0550, 340-240-0560, describe and allow for the implementation of multiple control measures associated with emissions of PM2.5 in the Klamath Falls NAA. The ODEQ updated the rule definitions to include necessary cross-references to applicable rules and to add new definitions needed for implementation of the control measures. Control measures include opacity standards, fugitive emissions control, operation and maintenance plan requirements, industrial source compliance schedules, and residential wood fuel-fired device offset requirements for new sources, and PM2.5 and PM10 offsets.
The 20% opacity standard and fugitive emissions control rules limit emissions being emitted into the Klamath Falls NAA from stationary sources including industrial facilities. The operation and maintenance plan requirements and the industrial source compliance schedule (a schedule to develop and implement a plan for compliance with the opacity standards, fugitive emissions requirements, and operations and maintenance plans listed in OAR 340-240-0510 through -0540), support reduced particulate matter emissions through enhanced management of source operation. The offsets rules in OAR 340-240-0550, in coordination with the rule revisions in OAR Chapter 340, Division 225, allow for offsets to be obtained within the Klamath Falls NAA from residential wood combustion at a ratio of one ton of PM2.5 emissions to one ton of woodstove emissions reductions while ensuring that the increased emissions from new or modified sources will not cause or contribute to a violation of the NAAQS. The EPA proposes to approve these rules as they are permanent and enforceable SIP strengthening measures that contribute to progress toward attainment of the 2006 PM2.5 24-hr NAAQS in this area.Start Printed Page 78376
Division 264: Rules for Open Burning
The revisions to OAR Chapter 340, Division 264 enhance the open burning rule in Oregon and the Klamath Falls NAA. Specifically, the revised rule includes language aligning open burning with ideal dispersion conditions; provides a description and map of the Klamath Basin Open Burning Control Area; and provides rules specific to the Klamath Falls NAA prohibiting open burning from industrial, commercial, construction and demolition operations. The rule revisions will reduce emissions through the prohibition of open burning within the Klamath Falls NAA. The EPA proposes to approve and IBR these rule revisions because they are permanent and enforceable measures that support attainment and maintenance of the NAAQS by reducing the amount of particulate matter in the area.
Klamath County Clean Air Ordinances
In its December 12, 2012 submittal, the ODEQ included as control measures the 2007 and 2012 Klamath County Clean Air Ordinances. These two ordinances establish permanent and enforceable control measures on sources that account for the majority of PM2.5 emissions in the Klamath Falls NAA. The 2007 Klamath County Clean Air Ordinance is more specifically identified as Chapter 406, Ordinance No. 63.05, enacted August 7, 2007 (2007 Ordinance). The 2012 Klamath County Clean Air Ordinance is more specifically identified as Chapter 406, Ordinance No. 63.06, enacted December 31, 2012 (2012 Ordinance).
The 2007 and 2012 Ordinances were enacted to control emissions from home heating devices for the purpose of meeting the 2006 PM2.5 24-hr NAAQS. The 2007 ordinance provides for lower thresholds for yellow and red air quality advisory days which require the curtailment of wood burning and therefore reduce emissions of PM2.5 and PM2.5 precursors. With these lower thresholds, wood burning restrictions would be in place on days that most likely contribute to a 24-hour NAAQS violation. This provision, in conjunction with increased enforcement at the County level, is expected to be a core part of the area's attainment plan. The 2007 ordinance has provisions identical to the state wide Heat Smart Program that require removal of uncertified stoves upon sale of a home, and also provisions that reduce the number of available residential open burning days and prohibit the use of burn barrels. The 2012 ordinance required new and retrofit fireplaces to meet lower emissions standards.
The EPA proposes to approve and IBR the 2007 and 2012 Klamath Falls Clean Air Ordinances because they support attainment and maintenance of the NAAQS in the Klamath Falls NAA.
III. Proposed Action
The EPA proposes to approve the PM2.5 and PM2.5 precursor emissions inventory for the Klamath Falls NAA, submitted by ODEQ on December 12, 2012, as meeting the emissions inventory requirements of section 172(c)(3) of the CAA for 2006 PM2.5 24-hr NAAQS nonattainment area planning. The EPA also proposes to approve and incorporate into the SIP the specific control measures submitted by the ODEQ on December 12, 2012, to the extent set forth in this notice. These control measures are described in this action and are included in the docket for this proposed action. If approved, these specific control measures would become part of the Oregon SIP. The EPA is not taking action on certain aspects of the revisions submitted by the ODEQ. The EPA expects to take action on the remaining SIP revisions and any additional revisions that may be submitted by the ODEQ in the future.
IV. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely proposes to approve state law as meeting federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this proposed action:
- Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);
- Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
- Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
- Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
- Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
- Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
- Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
- Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and
- Does not provide the EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).
In addition, this SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the rule does not have tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), nor will it impose substantial direct costs on tribal governments or preempt tribal law.Start List of Subjects
List of Subjects in 40 CFR Part 52
- Environmental protection
- Air pollution control
- Nitrogen dioxide
- Incorporation by reference
- Particulate matter
- Reporting and recordkeeping requirements
- Sulfur oxides
- Volatile organic compounds
Dated: December 3, 2014.
Dennis J. McLerran,
Regional Administrator, Region 10.
1. For a given air pollutant, “primary” national ambient air quality standards are those determined by the EPA as requisite to protect the public health, and “secondary” standards are those determined by the EPA as requisite to protect the public welfare from any known or anticipated adverse effects associated with the presence of such air pollutant in the ambient air. See CAA section 109(b).Back to Citation
2. Memorandum from Stephen D. Page, Implementation Guidance for the 2006 24-Hour Fine Particulate (PM2.5) National Ambient Air Quality Standards (Mar. 2, 2012).Back to Citation
3. Memorandum from Stephen D. Page, Withdrawal of Implementation Guidance for the 2006 24-Hour Fine Particle (PM2.5) National Ambient Air Quality Standards (Jun. 6, 2013).Back to Citation
[FR Doc. 2014-30498 Filed 12-29-14; 8:45 am]
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