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Phoenix Area Ozone Actions

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May 2005: Final Redesignation for the 1-hour ozone standard
March 2005: Proposed Redesignation for the 1-hour ozone standard
May 2001: Final Finding of Attainment of 1-hour standard for ground-level ozone
May 2000: Proposed Finding of Attainment of 1-hour standard for ground-level ozone
March 1999: Proposed updates to the rate of progress plan
May 1998: Phoenix meets 15 percent rate of progress emission reduction plan
November 1997: Phoenix fails to attain the 1-hour standard for ground-level ozone

May 2005: Final Redesignation for the 1-hour ozone standard

On May 20, 2005, EPA finalized the redesignation of the Phoenix metropolitan area to attainment of the 1-hour national air quality standard for ground-level ozone, the primary component of smog, and approved the plan showing maintenance of the standard to 2015. Phoenix has not exceeded the 1-hour ozone standard in the last eight years, despite its growth into one of the country's major metropolitan areas. The State Implementation Plan (SIP) revisions that EPA is approving include substitution of the clean fuel fleet program requirement with the cleaner burning gasoline program, adoption of the serious area 1-hour ozone plan, and adoption of the 1-hour ozone maintenance plan for the Phoenix metropolitan 1-hour ozone nonattainment area. We are approving Arizona’s request to redesignate the Phoenix metropolitan 1-hour ozone nonattainment area from nonattainment to attainment. The documents that support this rulemaking are listed below.

Reducing ground-level ozone benefits the health and welfare of all the people who live in the Phoenix area and who are exposed to this pollutant. This milestone was achieved due to the cooperative efforts of the entire community, as well as the State's support for key air quality improvements, including:

The area continues to exceed the newer, more protective 8-hour national standard (.08 ppm). In order to meet the 8-hour standard, the community will need to make additional progress to control ground-level ozone.

Contact Information

Wienke Tax (tax.wienke@epa.gov)
Office of Air Planning
EPA Region 9
(520) 622-1622

March 2005: Proposed Redesignation for the 1-hour ozone standard

The above actions were proposed on March 14, 2005

Contact Information

Wienke Tax (tax.wienke@epa.gov)
Office of Air Planning
EPA Region 9
(520) 622-1622

May 2001: Final Finding of Attainment for ground-level ozone

On May 16, 2001, EPA finalized its finding of attainment for the Phoenix area for the 1-hour national air quality standard for ground-level ozone, the primary component of smog. Phoenix has not exceeded the 1-hour ozone standard during any days in the last four years, despite its growth into one of the country's major metropolitan areas. The documents that support this finding are listed below.

Reducing ground-level ozone benefits the health and welfare of all the people who live in the Phoenix area and who are exposed to this pollutant. This milestone was achieved due to the cooperative efforts of the entire community, as well as the State's support for key air quality improvements, including:

Arizona's record of clean air makes several of the previous air quality planning requirements unnecessary. However, EPA has not yet redesignated the area to attainment with the 1-hour ozone standard. Arizona must first submit an air quality maintenance plan showing how the Phoenix area will maintain the 1-hour ozone standard for 10 years.

In addition, the area continues to exceed the newer, more protective 8-hour national standard (.08 ppm). In order to meet the 8-hour standard, the community will need to make additional progress to control ground-level ozone.


May 2000: Proposed Finding of Attainment for ground-level ozone

On May 19, 2000, EPA proposed to find that the Phoenix metropolitan serious ozone nonattainment area had attained the 1-hour ozone standard by its Clean Air Act deadline of November 15, 1999.

March 1999: Proposed updates to the rate of progress plan

Changes occurred to several control measures used to meet the 15 percent emission reduction. To account for these changes, EPA proposed to slightly revise the 1998 demonstration.

The proposed changes delete or add to the control strategy measures that have already been adopted in the Phoenix area. EPA proposed no new emission control regulations. This proposal did not alter EPA's basic conclusion that the Phoenix metropolitan area would meet the 15 percent Rate of Progress requirement as soon as practicable.

May 1998: Phoenix meets 15 percent rate of progress emission reduction plan

In May of 1998, EPA found that the Phoenix metropolitan area has in place sufficient ozone control measures to meet the 15 percent rate of progress emission reduction requirement in the Clean Air Act.

The Clean Air Act requires areas designated as ozone nonattainment areas to reduce emissions of volatile organic compounds by fifteen percent from 1990 levels by 1996. Volatile organic compounds (VOCs) react in the atmosphere with nitrogen oxides to form ground-level ozone; therefore, reductions in VOCs contribute to a reduction in ambient air levels of ozone. Sources of VOCs include automobiles, lawnmowers and other small engines, gasoline, paints, consumer products such as hair spray, and industrial operations that apply coatings to surfaces such as printing, semiconductor manufacturing, and furniture manufacturing.

November 1997: Phoenix Fails to Attain the 1-hour Standard for Ground-Level Ozone

On November 6, 1997, EPA announced its finding that the Phoenix metropolitan area failed to meet the health-based 1-hour air quality standard for ground-level ozone (smog) by its Clean Air Act deadline of November 15, 1996. As a result of this finding, the EPA reclassified the area's ozone air quality from "moderate" to "serious." This classification triggered new planning and control requirements to continue progress toward attaining the ozone standard by the end of 1999.

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