Latest Developments (see below)

There are three forms of visibility impairment - a reduction in one's ability to see clearly or far: urban haze, "plume blight", and regional haze. Urban haze, often referred to as "brown cloud", comes from the scattering of light due to various types of pollution from a wide range of sources found in large cities.

• Phoenix Visibility
• Tucson Visibility

"Plume blight" or Reasonably Attributable Visibility Impairment (RAVI)

Can be a plume of pollution rising from a specific source, but it commonly refers to pollution coming from the stack or chimney of a stationary source (e.g., electrical generating station or copper smelting operation).

Good Visibility

Poor Visibility

Regional Haze

Regional Haze is defined as visibility impairment caused by the emission of air pollutants from numerous sources located over a wide geographic area.

The Regional Haze Rule (RHR)

The RHR outlines the requirements for states to follow in order to address haze impairing pollutants (71 FR 60631 , Oct. 13, 2006). The purpose of the rule is to improve visibility at the 158 national parks and wilderness areas throughout the U.S. (formally known as mandatory Federal Class I areas). States are required to demonstrate reasonable progress towards the national visibility goal established in 1977 by the Clean Air Act (Section 169A and 169B): "The prevention of any future, and the remedying of any existing impairment of visibility in mandatory class I Federal areas which impairment results from man-made air pollution." Arizona has 12 Class I areas. States, with the assistance of regional planning organizations (RPOs), are required to submit a State Implementation Plan to the U.S. EPA every five years outlining how the State is progressing on attainment of the national goal. The RPO assisting the western states is the Western Regional Air Partnership, or WRAP .

Best Available Retrofit Technology (BART)

The RHR requires Best Available Retrofit Technology (BART) to be considered as a control measure on specific categories of major stationary sources of haze-producing pollutants in existence prior to the 1977 Clean Air Act Amendments. Most of these sources are refineries, smelters and coal-fired electrical generating units (EGUs) that emit 250 tons per year (TPY) of sulfur dioxide (SO2), oxides of nitrogen (NOX), and particulate matter (PM). Should a source be found BART-eligible, a determination of the source's contribution to visibility impairment and the resulting emission reductions from the application of BART is conducted. General information on BART is available from WRAP . The WRAP site also has a list of sources throughout the Western region that have been determined to be "Subject to BART" and exempted as not "Subject to BART" .

Arizona has completed the BART determinations for applicable sources within the state. Summaries on the BART analyses can be found in the final Regional Haze SIP. The full BART determinations can be found in Appendix D.

Catalyst Paper (Snowflake) Inc. (formerly Abitibi Consolidated)

• Letter from Catalyst (formerly Abitibi) Regarding BART Eligibility (September 17, 2007)
• Catalyst (formerly Abitibi) BART Submittal (January 17, 2008)
• Response from Catalyst Regarding ADEQ Request for Additional Information (June 15, 2009)

Arizona Public Service (APS) Cholla

• BART Analysis for Cholla Unit 2 (January 2008)
• BART Analysis for Cholla Unit 3 (January 2008)
• BART Analysis for Cholla Unit 4 (January 2008)
• APS Cholla Response to ADEQ Request for Additional BART Information (June 18, 2009)
• Draft APS Cholla Regional HAZE SIP revision (2015)

Arizona Electric Power Cooperative (AEPCO), Inc.

• BART Analysis for Apache Generating Station - Steam Unit 1 (December 2007)
• BART Analysis for Apache Generating Station - Steam Unit 2 (December 2007)
• BART Analysis for Apache Generating Station - Steam Unit 3 (December 2007)
• AEPCO Response to ADEQ Request for Additional BART Information (July 08, 2009)

Salt River Project (SRP) Coronado

• SRP Coronado BART Report (February 08, 2008)
• SRP Response to ADEQ Request for Additional BART Information (June 25, 2009)

APS (West Phoenix facility) and Chemical Lime Company (Nelson facility) were found to be BART eligible. ADEQ received the following analyses and determined that these facilities were not subject to BART.

• APS West Phoenix Potentially Subject to BART Determination Response (October 04, 2007)
• CLC Nelson BART Applicability Modeling Analysis (September 21, 2007)

Arizona Regional Haze State Implementation Plan (SIP)

The RHR requires states to submit a plan under Section 308 or Section 309. States submitting Regional Haze Plans under Section 309 of the RHR are required to submit plans to address visibility impairment at Class I areas not covered by Section 309 plans. States submitting under Section 309(g) must follow the provisions of Section 308(d)(1) through (4) of the RHR.

In 2010, Arizona opted out of Section 309 and will submit a plan under Section 308. The plan will address all of Arizona’s Class I areas. A Regional Haze stakeholder meeting was held on October 19, 2010, at ADEQ. The following materials were distributed at the meeting:

• Agenda
• Arizona Regional Haze Summary
• Arizona Regional Haze BART Summary

The public comment period for the proposed plan began October 28, 2010 and ended December 2, 2010. A public hearing was held at ADEQ on December 2, 2010. The final SIP was submitted to U.S. EPA on March 2, 2011.

• Arizona Regional Haze State Implementation Plan Under Section 308 of Federal Regional Haze Rule
• Arizona Regional Haze 308 SIP (SIP only)
  • Appendix A
  • Appendix B
  • Appendix C
  • Appendix D
  • Appendix E

See Also:

• Learn more about Regional Haze
• View an interactive demonstration of haze
• Learn what areas in the western US are affected
• U.S. EPA: Visibility

Archived Documents

• Regional Haze State Implementation Plan Revision 2004

For more information, please contact us.