County Affected:

Parts of Santa Cruz County | View eMap >

Pollutant of Concern:

PM₁₀ (particulate matter 10 microns or less in diameter; 1987 standards)

Nonattainment Area Designation Date:

Oct. 31, 1990

Learn more about the designation in the Federal Register | View 55 Federal Register 45799 >

Classification Level:

Moderate

Summary: 

The concentration of PM₁₀ in the air in Nogales is occasionally above federal standards. ADEQ submitted a nonattainment State Implementation Plan (SIP) to the U.S. Environmental Protection Agency (EPA) in 2012. EPA approved the plan in 2012. The plan demonstrates that the Nogales area would be attaining the PM₁₀ standards, if not for international emissions | View 77 Federal Register 58962 >

Regulatory Background:

On July 1, 1987, EPA revised the particulate matter National Ambient Air Quality Standards (NAAQS). These primary and secondary standards apply to particulate matter 10 microns or less in diameter (PM₁₀) and superseded the previous total suspended particulate (TSP) standards. ADEQ began monitoring PM₁₀ in the Nogales Nonattainment Area in 1985 | View 52 Federal Register 24634 >

With the Clean Air Act (CAA) Amendments of 1990, areas where previous violations of the PM₁₀ standard had been recorded prior to Jan. 1, 1989, were designated nonattainment for PM₁₀ by operation of law and classified as moderate. These areas included all former Group II PM₁₀ planning areas like the Nogales PM₁₀ Nonattainment Area | View 55 Federal Register 45799 >

On March 15, 1991, EPA published a list of the areas designated nonattainment for PM₁₀ upon enactment of the 1990 amendments, including the Nogales Nonattainment Area | View 56 Federal Register 11101; March 15, 1991 > 

On Nov. 6, 1991, EPA codified the PM₁₀ nonattainment designations and moderate area classifications | View 56 Federal Register 56694 >

As stipulated in the 1990 CAA amendments, Arizona was required to submit a SIP for the Nogales PM₁₀ Nonattainment Area by Nov. 15, 1991, that demonstrated attainment of the PM₁₀ NAAQS by Dec. 31, 1994. Because Arizona did not submit a SIP for the Nogales Nonattainment Area by the Nov. 15, 1991, deadline, EPA made a finding of failure to submit a PM₁₀ SIP on Dec. 16, 1991 | View 57 Federal Register 19907 >

In response, on June 14, 1993, Arizona submitted the Final State Implementation Plan for the Nogales PM₁₀ Nonattainment Area (1993 Nogales NAA SIP). EPA found the plan to be complete by letter dated Nov. 30, 1993, but did not act on the plan.

In January 2011, EPA determined that the Nogales planning area attained the 1987 PM₁₀ NAAQS by the applicable attainment date of Dec. 31, 1994. This determination was based on ambient air quality monitoring data from 1992 – 1994, retroactively affirming that the area had met the federal standard for the PM₁₀ NAAQS by the Dec. 31, 1994, deadline established by the 1990 amendments of the CAA | View 75 Federal Register 67220 >

In May 2012, ADEQ submitted to EPA the moderate area PM₁₀ SIP for the Nogales Nonattainment Area. After reviewing the submittal, EPA published a notice of proposed rulemaking (NPRM) for full approval of the SIP on June 27, 2012 | View 77 Federal Register 38400 >

On Sept. 12, 2012, EPA finalized approval of the following plan elements as meeting the CAA requirements:

1. The 2008 base year and 2011 emissions inventories as meeting the requirements of CAA section 172(c)(3); 
2. The demonstration of attainment but for international emissions as meeting the requirements of CAA section 179B(a)(1);
3. The implementation of paving projects and capital improvement projects at the Ports of Entry within the Nogales NA prior to the CAA’s 1994 attainment deadline as meeting the RACM/RACT requirements of CAA sections 172(c)(1), 179B(a)(2), and 189(c)(1)(C);
4. The implementation of paving projects and capital improvement projects at the Ports of Entry to meet the RFP demonstration requirement of CAA sections 172(c)(2) and 179B(a)(2);
5. The implementation of post-1994 paving projects as meeting the contingency measure requirements of CAA sections 172(c)(9) and 179B(a)(2); and,
6. The 2011 attainment year motor vehicle emissions budget because it is derived from the section 179B demonstration and meets the requirements of CAA section 176(c) and of 40 CFR 93, subpart A | View 77 Federal Register 58962 >

Submitted SIPs for the Nogales PM₁₀ Nonattainment Area:

• 2012 State Implementation Plan Nogales PM₁₀ Nonattainment Area*
• 1993 State Implementation Plan for the Nogales PM Nonattainment Area *

*Documents available at the ADEQ Records Center | Submit Records Request >

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