Revised On: Feb. 26th, 2025 - 01:32 pm
County Affected:
Parts of Santa Cruz County | View on a Map >
Nonattainment Area Designation Date:
Nov. 13, 2009
Learn more about the designation in the Federal Register (FR) (55 FR 58688, Page 16) | View >
Classification Level:
Moderate
Pollutant of Concern:
PM2.5 (particulate matter 2.5 microns or less in diameter; 2006 standard)
Summary:
The Nogales PM2.5 planning area was designated under the 2006 PM2.5 National Ambient Air Quality Standards (NAAQS) and changes have occurred to several regulatory programs and controls that enabled the area to attain the standard. Permanent improvements to the truck/commercial vehicle port of entry and administrative programs have contributed to reductions in concentrations of PM2.5. Improved fuel standards have also added to reductions. In addition, changes to the ambient monitor have resulted in more accurate recording of ambient air quality. The analyses and data provided in this plan coupled with the prior submission in 2013 demonstrate that all nonattainment area and redesignation requirements have been met. The clean air quality record, enforceable control measures, and projections of future emissions all show that the area will continue to maintain the 2006 PM2.5 air quality standards through 2032.
Regulatory Background:
The U.S. Environmental Protection Agency (EPA) strengthened the primary and secondary 24-hour PM2.5 NAAQS in December 2006. Under Clean Air Act (CAA) section 107(d), each state must make recommendations for areas that meet, cannot be classified, or do not meet new or revised NAAQS within one year following the promulgation of such standards. In December 2007, ADEQ submitted its initial designation recommendations to EPA, recommending that all portions of the state be designated attainment except for the Nogales area in Santa Cruz County.
In November 2009, EPA designated the Nogales area as a moderate PM2.5 nonattainment area for the 2006 PM2.5 NAAQS. The nonattainment designation was for the 24-hour PM2.5 standard and unclassifiable/attainment for the annual standard.
On Jan. 7, 2013, EPA made a final determination that the Nogales area met the 24-hour PM2.5 NAAQS based on monitoring data from 2009 – 2011. This clean data determination suspended some CAA State Implementation Plan (SIP) requirements for as long as the area continues to attain the standard. These SIP elements included reasonable further progress (RFP), attainment demonstration, reasonably available control measures (RACM), and contingency measures.
To satisfy the CAA requirements for nonattainment areas that were not suspended by the clean data determination, ADEQ developed and submitted a SIP revision to EPA in September 2013. The submittal provided annual 2008 and 2010 emission estimates for PM2.5 and PM2.5 precursors (nitrogen oxides, volatile organic compounds, sulfur dioxide, and ammonia). The EPA approved the submittal on Feb. 9, 2015, effective March 11, 2015.
On May 10, 2017, EPA finalized the determination that the Nogales PM2.5 Nonattainment Area had attained the NAAQS by the statutory attainment date. Specifically, EPA determined that seven areas (including Nogales) attained the 2006 24-hour PM2.5 NAAQS by Dec. 31, 2015, which was based on monitoring data from 2013 to 2015.
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