Required by the Clean Air Act a State Implementation Plan (SIP) is a federally approved and enforceable plan developed by a state or local authority which identifies how it will meet and/or maintain the National Ambient Air Quality Standards (NAAQS). There are various types of SIPs developed by a state or local authority which contain certain rules showing the ability to: attain, maintain, and enforce the NAAQS. Different types of SIPs include: Attainment, Non-Attainment, Maintenance, and Infrastructure SIPs. Attainment of the NAAQS within Pima County is covered under the Pima County portion of the Arizona State Implementation Plan(s).
U.S. Environmental Protection Agency Status of Pima County State Implementation Plan (SIP)
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Draft, Proposed, and Final State Implementation Plan (SIP) Actions
TEP-Irvington Regional Haze source-specific revision to the PDEQ SIP
Summary: PDEQ is proposing this submittal to the Pima County Portion of the Arizona State Implementation Plan (SIP) to add Section VI of the proposed Tucson Electric Power (TEP) Irvington a.k.a. H.Wilson Sundt Generating Station (IGS) Air Quality Permit. PDEQ proposes to submit this revision to U.S. Environmental Protection Agency (U.S. EPA) for approval as a source-specific revision to the PDEQ SIP. In the near future the PDEQ SIP revision will be included in the Arizona Department of Environmental Quality’s (ADEQ’s) comprehensive regional haze SIP revision and will support the enforceability of ADEQ’s long-term strategy pursuant to 40 CFR 51.308(f)(2) of the federal regional haze program. The federal regional haze program requires States to submit a long-term strategy for addressing regional haze visibility impairment in mandatory federal class I areas. These federal class I areas are granted special air quality protections under Clean Air Act section 162(a). The proposed permit revision amends the Class I PSD permit for TEP-IGS and pertaining only to Unit 3. Unit 3 is currently not equipped with any pollution control device for Nitrogen Oxide (NOx) emissions. More stringent and enforceable operational restrictions on Unit 3, to reduce NOx emissions, are identified in Section VI of the proposed permit and if approved shall become effective one year after the U.S. EPA approves ADEQ’s Regional Haze NOx Reasonable Progress determination for TEP-IGS Unit 3 and adopting Section VI of this permit as part of the Arizona comprehensive regional haze SIP.
Inactive mineral tailings impoundment and slag storage area within the Ajo PM10 Planning Area
Summary: PDEQ is proposing revisions to the Pima County portion of the Arizona State Implementation Plan. The proposed revision to the Arizona State Implementation Plan (SIP) includes the following rules from Pima County Code (PCC) Title 17: PCC 17.16.125. PCC Section 17.16.125 is a new section that was adopted at the January 22, 2019, Pima County Board of Supervisors Hearing which is noticed separately. Pursuant to Section 107(d)(4)(B) of the Clean Air Act (CAA), the U.S. Environmental Protection Agency (EPA) designated an area in northwest Pima County as a “moderate” nonattainment area for the 1987 24‐hour Particulate Matter National Ambient Air Quality Standards (NAAQS), specifically particulate matter with a diameter of 10 micrometers or less (PM10). EPA based its designation on recorded violations of the standard at an ambient monitoring site within the County. The purpose of this SIP revision is to add a specific rule for the Ajo Planning Area to meet CAA requirements for an approved maintenance plan and have the area redesignated to attainment for the 24-hour PM10 NAAQS.
Infrastructure SIP Revision
Summary: PDEQ is proposing revisions to the Pima County portion of the Arizona SIP in response to two Federal Register notices of Final Rule pertaining to rules within Pima County Code that are not yet included in the SIP. In response to the EPA actions published in the FR, PDEQ is proposing to submit PCC 17.04.190, PCC 17.12.040, and PCC 17.24.040 for incorporation into the Arizona SIP.
Startup, Shutdown, Malfunction - Comment to EPA
Summary: In the Proposed Rule published on February 22, 2013 (Applying to Excess Emissions During Periods of Startup, Shutdown, and Malfunction) the EPA solicited comment from PDEQ on SIP Rule 706(D). PDEQ submitted a comment letter to the EPA in response to the Proposed Rule.