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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Air Actions, Arizona

Particulate Matter Actions in Phoenix, Arizona

Actions Taken

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  • January 14, 2014: Particulate Matter in Maricopa County, Arizona
  • January 31, 2011: Finding of Failure to Submit Required PM-10 Plan
  • October 7, 2010: Extension of Comment Period for Proposed Action on the Phoenix PM-10 Plan
  • September 3, 2010: Proposed rule to partially disapprove Maricopa County‚Äôs air quality plan
  • May 21, 2010: EPA Decision on Phoenix Exceptional Event Claims
  • August 4, 2008: Final rule regarding BACM and MSM demonstrations. See below for docket number correction.
  • May 31, 2007: Proposed rule regarding BACM and MSM demonstrations.
  • May 25, 2007: Final Rule PM-10 Nonattainment Finding
  • March 15, 2007: Proposed PM-10 Nonattainment Finding
  • July 14, 2006: Final Rule for June 22, 2005 proposal
  • June 30, 2006: Proposed Approval of Rules and Commitments in a Particulate Matter (PM-10) Plan for the Salt River Area
  • June 22, 2005: Proposal to again approve the best available control measures (BACM) and most stringent measures (MSM) demonstrations in the Phoenix area's PM-10 plan in response to a 9th Circuit Court of Appeals remand to re-evaluate the feasibility of implementing California Air Resources Board (CARB) diesel fuel as a BACM.
  • January 14, 2002: Approval of Arizona's Plan to Meet the Particulate Matter Air Quality Standards in the Phoenix Area
  • September 17, 2001: Proposed Approval of State Plan to meet the 24-hour Particulate Matter Air Quality Standard in Phoenix
  • September 10, 2001: Approval of Revision to State Plan (a general permit rule to reduce fugitive dust from agricultural sources in the Phoenix area)
  • July 2001: Proposed Approval of State Measure to Reduce Dust from the Agricultural Sector
  • April 2000: Proposed Approval of Phoenix PM-10 Plan Action
  • December 1999: Approval of Revision to Federal Implementation Plan Fugitive Dust Rule
  • June 1999: Approval and Promulgation of Implementation Plans; Arizona -- Maricopa Nonattainment Area; PM-10
  • January 1999: Dust Rule Proposal
  • December 1998: Proposed Approval of State Commitment to Reduce Dust from the Agricultural Sector
  • October 1998: Federal Plan for Particulate Matter in Phoenix
  • April 1998: Proposed Federal Plan for Particulate Matter in Phoenix
  • February 1998: Serious Nonattainment

Proposed Approval of 2012 Five Percent Plan for PM-10 for the
Maricopa County Nonattainment Area

On January 14, 2014, Deputy Regional Administrator Alexis Strauss signed a Federal Register notice proposing to approve the 2012 Five Percent Plan for PM-10 for the Maricopa County Nonattainment Area. This proposal will be published in the Federal Register approximately two to three weeks after signature. EPA will accept comment on the proposal for 30 days after publication.

Contact Information:
Greg Nudd (nudd.greg@epa.gov) or 415-947-4107


January 31, 2011: Finding of Failure to Submit Required PM-10 Plan

On January 25, 2011, the State of Arizona withdrew the PM-10 plan for the Maricopa County nonattainment area. This plan is required under the Clean Air Act. The Federal Register notice below finds that the State has failed to submit a required plan and begins a sanctions clock. EPA also withdrew our previous finding that the motor vehicle emissions budget in the PM-10 plan was adequate. The area must now use a previously approved budget in their transportation planning activities.


October 7, 2010: Extension of Comment Period for Proposed Action on the Phoenix PM-10 Plan

EPA has decided to extend the comment period on our proposed action on the Phoenix area PM-10 plan. The close of the comment period has been extended from Oct. 12, 2010 to Oct. 20, 2010


September 3, 2010: Proposed Rule Regarding State SIP Plan

EPA is proposing to partially disapprove Maricopa County’s air quality plan because it does not adequately control emissions of coarse particulate matter (also known as PM-10).


May 21, 2010: EPA Decision on Phoenix Exceptional Event Claims

The EPA has decided to disapprove the Arizona Department of Environmental Quality's request to treat nearly all of the exceedances of the PM-10 standard in 2008 as due to Exceptional Events. This decision applies to four exceedances at one monitor in Phoenix. As a result, it will have implications for the PM-10 5% plan currently under review by EPA. A copy of the signed letter and technical support document may be found below.

Contact Information

Colleen McKaughan (mckaughan.colleen@epa.gov)
Associate Director, Air Division, EPA Region 9
(520) 498-0118


August 4, 2008: Final rule regarding BACM and MSM demonstrations.

Final rule to again approve the best available control measures (BACM) and most stringent measures (MSM) demonstrations in the Phoenix Area's PM-10 plan in response to a 9th Circuit Court of Appeals remand to re-evaluate the feasibility of implementing California Air Resources Board (CARB) diesel fuel as a BACM. NOTE: The "Addresses" section of the final rule gives an incorrect number for the docket for this rulemaking action. The correct docket number (as stated at the top of the document) is EPA-R09-OAR-2006-0571.

Contact Information

Carol Weisner (weisner.carol@epa.gov)
Office of Air Planning, EPA Region 9
(415) 947-4107


May 31, 2007: Proposed rule regarding BACM and MSM demonstrations.

Proposal to again approve the best available control measures (BACM) and most stringent measures (MSM) demonstrations in the Phoenix Area's PM-10 plan in response to a 9th Circuit Court of Appeals remand to re-evaluate the feasibility of implementing California Air Resources Board (CARB) diesel fuel as a BACM.

Contact Information

Carol Weisner (weisner.carol@epa.gov)
Office of Air Planning, EPA Region 9
(415) 947-4107


May 25, 2007: Final Rule PM-10 Nonattainment Finding

EPA has finalized its March 15, 2007 proposal to find that the Phoenix area has failed to attain the PM-10 standard. For more information on EPA's proposed action, please see the documents below or contact Colleen McKaughan (mckaughan.colleen@epa.gov) at (520) 498-0118.

Contact Information

Colleen McKaughan (mckaughan.colleen@epa.gov)
Associate Director, Air Division, EPA Region 9
(520) 498-0118

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March 15, 2007: Proposed PM-10 Nonattainment Finding

Phoenix is classified as a serious PM-10 nonattainment area and had an attainment deadline of December 31, 2006. EPA is proposing to find that Phoenix has failed to attain the 24-hour PM-10 standard by the attainment deadline. For more information on EPA's proposed action, please see the documents below or contact Colleen McKaughan (mckaughan.colleen@epa.gov) at (520) 498-0118.

Contact Information

Colleen McKaughan (mckaughan.colleen@epa.gov)
Associate Director, Air Division, EPA Region 9
(520) 498-0118


July 14, 2006: Final Rule for June 22, 2005 proposal

Approval of the best available control measures (BACM) and most stringent measures (MSM) demonstrations in the Phoenix area's PM-10 plan in response to a 9th Circuit Court of Appeals remand to re-evaluate the feasibility of implementing California Air Resources Board (CARB) diesel fuel as a BACM.

Related Documents

Contact Information

Carol Weisner (weisner.carol@epa.gov)
Office of Air Planning, EPA Region 9
(415) 947-4107


June 30, 2006: Proposed Approval of Rules and Commitments in a Particulate Matter (PM-10) Plan for the Salt River Area

EPA is proposing to approve rules and commitments for fugitive dust sources contained in an Arizona plan titled "Revised PM-10 State Implementation Plan for the Salt River Area", September 2005. The Salt River area is a 32-square-mile area in metropolitan Phoenix. The Phoenix area violates EPA's PM-10 air quality standards, which include a short-term (24-hour) standard and a long-term (annual) standard. The rules and commitments EPA is proposing to approve apply throughout the Phoenix area and will help the area make progress towards attaining the 24-hour PM-10 standard.

For more information on EPA's proposed approval, please see the documents below or contact colleen McKaughan of the Air Division, U.S. EPA Region 9, at (520) 498-0118 or email her at mckaughan.colleen@epa.gov.

Related Documents

Contact Information

Colleen McKaughan (mckaughan.colleen@epa.gov)
Associate Director, Air Division, EPA Region 9
(520) 498-0118


June 22, 2005: Proposal to again approve the best available control measures (BACM) and most stringent measures (MSM) demonstrations in the Phoenix area's PM-10 plan in response to a 9th Circuit Court of Appeals remand to re-evaluate the feasibility of implementing California Air Resources Board (CARB) diesel fuel as a BACM.

On January 14, 2002, EPA approved Arizona's plan to meet the particulate matter air quality standards in the Phoenix area (67 FR 48718, published July 25, 2002). Among other things, EPA approved the BACM and MSM demonstrations in the plan and granted the State's request for an attainment date extension for the area.

EPA's approval was challenged in the U.S. Court of Appeals for the Ninth Circuit. In response to the Court's remand, EPA has reassessed the BACM demonstration for the significant source categories of on-road and nonroad engines and equipment exhaust, specifically regarding whether or not CARB diesel fuel is a BACM. EPA has also reassessed the MSM demonstration.

As a result of these reassessments, EPA is again proposing to approve the BACM and MSM demonstrations in the plan and to grant the State's request to extend the attainment deadline from 2001 to 2006.

Contact Information

Carol Weisner (weisner.carol@epa.gov)
Office of Air Planning, EPA Region 9
(415) 947-4107

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January 14, 2002: Approval of Arizona's Plan to Meet the Particulate Matter Air Quality Standards in the Phoenix Area.

EPA has approved Arizona's plan to meet both the long-term (annual) and short-term (24-hour) particulate matter (PM-10) air quality standards in the Phoenix area by 2006.

The Phoenix metropolitan area is not currently meeting either the annual or the 24-hour health- based standard. Under the plan, the Arizona Department of Environmental Quality, Maricopa County, and the local cities and towns will implement control measures for all the primary sources of airborne particulates. The primary sources of particulate pollution in the Phoenix area are windblown dust from construction sites, agricultural fields, unpaved parking lots and roads, disturbed vacant lots, and paved road dust.

For more information on EPA's approval, please see the documents below or contact colleen McKaughan of the Air Division, U.S. EPA Region 9 at (520) 498-0118, or email her at mckaughan.colleen@epa.gov.


September 17, 2001: Proposed Approval of State Plan to meet the 24-hour Particulate Matter Air Quality Standard in Phoenix

EPA is proposing to approve Arizona's plan to meet the 24-hour particulate matter (PM-10) air quality standard in the Phoenix area by 2006. There are two PM-10 air quality standard, a 24-hour one and an annual one. We proposed to approve Arizona's plan to meet the annual standard in April 2000.

The Phoenix metropolitan area is currently in non-attainment of both the 24-hour and annual health-based standard. Under the plan we are proposing to approve, the Arizona Department of Environmental Quality, Maricopa County, and the local cities and towns will implement control measures for all the primary sources of airborne particulates. The primary sources of particulate pollution in the Phoenix area are windblown dust from construction sites, agricultural fields, unpaved parking lots and roads, disturbed vacant lots, and paved road dust.

We are accepting public comment on our proposed approval for 30 days following its publication in the Federal Register. If you would like further information, contact colleen McKaughan of the Air Division, U.S. EPA Region 9 at (520) 498-0118, or email her at mckaughan.colleen@epa.gov.


September 10, 2001: Approval of Revision to State Plan

On September 10, EPA Region IX's Acting Regional Administrator approved as revision to the Arizona State Implementation Plan, a general permit rule to reduce fugitive dust from agricultural sources in the Phoenix area. This approval should appear in the Federal Register in late September.

The state's general permit rule requires that by December 31, 2001, farmers must implement best management practices (BMPs) to reduce fugitive dust. BMPs are techniques verified by scientific research, that on a case by case basis are practical, economically feasible and effective in reducing dust emissions from commercial farming practices. The Governor of Arizona established a BMP committee comprised of local farmers, State and local agencies, and universities to develop these BMPs, a program designed to educate the agricultural community on the requirements under the State plan that began back in June 10, 2000.

If you have any questions please contact colleen McKaughan of the Air Division, U.S. EPA Region 9 at (520) 498-0118, or email her at mckaughan.colleen@epa.gov.


July 2001: Proposed Approval of State Measure to Reduce Dust from the Agricultural Sector in Phoenix

On June 29, 2001, EPA proposed to approve as revision to the Arizona State Implementation Plan, a general permit rule to reduce fugitive dust from agricultural sources in the Phoenix area.

The state's general permit rule requires that by December 31, 2001, farmers must implement best management practices (BMPs) to reduce fugitive dust. BMPs are techniques verified by scientific research, that on a case by case basis are practical, economically feasible and effective in reducing dust emissions from commercial farming practices. The Governor of Arizona established a BMP committee comprised of local farmers, State and local agencies, and universities to develop these BMPs, a program designed to educate the agricultural community on the requirements under the State plan that began back in June 10, 2000.

If you have any questions please contact colleen McKaughan of the Air Division, U.S. EPA Region 9 at (520) 498-0118, or email her at mckaughan.colleen@epa.gov.


April 2000: Proposed Approval of Phoenix PM-10 Plan Action

EPA is proposing to approve Arizona's plan to meet the annual particulate matter (PM-10) air quality standard in the Phoenix area. The proposed approval comes after we reviewed a revised plan submitted by the State in January.

The Clean Air Act requires us to set national health air quality standards for pollutants that threaten public health and the environment. When an area violates a health-based standard, the Act requires that the area be designated as "nonattainment" for that pollutant. Arizona is required to develop a plan to reduce particulate matter in the Phoenix area to healthy levels.

The plan we are proposing to approve is the latest in a series of state plan aimed at improving PM-10 air quality in the Phoenix area. Sanctions were imposed in Phoenix on March 2, 2000, because the state failed to correct deficiencies in its earlier plans for controlling particulate matter. With the proposed approval of the revised particulate matter plan, we are issuing an interim final determination that stays the sanctions until we take final aciton on the plan.

In our August 1998 Federal Implementation Plan, we issued a fugitive dust rule for the Phoenix area. That rule--which applies to disturbed vacant land, unpaved parking lots, and unpaved roads--is still in effect and its requirements are unchanged by our proposed approval of Arizona's serious area plan PM-10.

If you would like further information, please contact colleen McKaughan, Associate Director, air Division, U.S. EPA Region 9 at (520) 498-0118, or email her at mckaughan.colleen@epa.gov.


December 1999: Approval of Revision to Federal Implementation Plan Fugitive Dust Rule

EPA is finalizing proposed amendments to the moderate area federal implementation plan (FIP) for the Phoenix PM-10 nonattainment area. These amendments modify the fugitive dust rule to add or replace certain test methods and allow alternative control measures (ACMs) to be implemented without prior EPA approval. For the convenience of readers, the entire FIP rule is reprinted in this publication.


June 1999: Approval and Promulgation of Implementation Plans; Arizona -- Maricopa Nonattainment Area; PM-10

On June 17, 1999, EPA Administrator Carol Browner approved an Arizona plan to reduce fugitive dust from agricultural sources in the Phoenix area. This approved plan replaces the exisiting Federal measure for controlling dust which was announced in August, 1998.

The State plan requires that by December 31, 2001, farmers must implement best management practices (BMPs) to reduce fugitive dust. BMPs are techniques verified by scientific research, that on a case by case basis are practical, economically feasible and effective in reducing dust emissions from commerical farming practices. The Governor of Arizona has established a BMP committee comprised of local farmers, State and local agencies, and universities to develop these BMPs and submit them for approval in the State legislature. A program designed to educate the agricultural community on the requirements under the State plan will begin by June 10, 2000.

If you have any questions, please contact contact colleen McKaughan of the Air Division, U.S. EPA Region 9 at (520) 498-0118, or email her at mckaughan.colleen@epa.gov.

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January 1999: Dust Rule Proposal

EPA is proposing and taking comment on amendments to the final fugitive dust rule for the Phoenix PM-10 nonattainment area. Comments on the proposed amendments will be accepted until March 8, 1999. The Phoenix Federal Implementation Plan (FIP) fugitive dust rule covers unpaved roads, unpaved parking lots and vacant lots. The rule was finalized on August 3, 1998 (63 FR 41350). The final fugitive dust rule contains test methods for ascertaining source compliance with the rule requirements. As a result of additional technical field work EPA conducted in Phoenix, EPA is proposing to add or replace certain test methods in the FIP rule. The newly proposed test methods include a silt content test method for unpaved roads and unpaved parking lots, a visible crust test method for vacant lots and a vegetative density procedure for vacant lots with certain types of vegetation.

EPA is also proposing to include FIP rule coverage of privately owned unpaved roads that are also privately maintained. (These do not include unpaved roads on construction sites that have approved permits under Maricopa County Rule 310). The final FIP rule already requires controls for privately owned roads that are maintained by public entities. Finally, EPA is proposing to allow alternative control measures to be implemented without prior EPA approval, given that any measures applied must meet the rule’s dust control standards according to specified test methods.


December 1998: Proposed Approval of State Commitment to Reduce Dust from the Agricultural Sector

EPA is proposing to approve a revision to the Arizona State Implementation Plan (SIP) reflecting Arizona State legislation that provides for the implementation of best management practices to reduce fugitive dust from agricultural sources in the Maricopa County (Phoenix) PM-10 nonattainment area. Because EPA is proposing to approve the State legislation as meeting the reasonably available control measure (RACM) requirements of the Act, EPA is also proposing to withdraw a federal implementation plan (FIP) commitment to adopt and implement RACM for agricultural fields and aprons in the Maricopa area.


October 1998: Federal Plan for Particulate Matter in Phoenix

In response to a court order, on July 17, 1998 EPA issued a Federal Implementation Plan (FIP) for reducing particulate matter (PM-10), or dust, in Maricopa County, Arizona. PM-10 is particulate matter with a diameter of 10 microns or less (a human hair has a diameter of 70 microns). It may affect the respiratory system and can cause severe damage to lung tissue and premature death. The elderly, children, and people with chronic lung disease, influenza, or asthma are especially sensitive to high levels of particulate matter.


April 1998: Proposed Federal Plan for Particulate Matter in Phoenix

EPA today proposes a federal implementation plan (FIP) to address the moderate area PM-10 requirements for the Phoenix PM-10 nonattainment area. Specifically, for both the annual and 24-hour PM-10 standards, EPA is proposing a demonstration that reasonably available control measures (RACM) will be implemented as soon as possible, a demonstration that it is impracticable for the area to attain the standards by the statutory attainment deadline and a demonstration that reasonable further progress (RFP) is being met. Pursuant to a court order, EPA's final FIP must be signed by the EPA Administrator no later than July 18, 1998.

As part of its proposed RACM demonstration, EPA is proposing a fugitive dust rule to control PM-10 emissions from vacant lots, unpaved parking lots and unpaved roads, and is also proposing an enforceable commitment to ensure that RACM for agricultural sources will be proposed by September 1999, finalized by April 2000 and implemented by June 2000.

In addition, in today's document, EPA is withdrawing a 1996 proposal to restore its approval of the RACM, RFP and impracticability demonstrations in Arizona's moderate area PM-10 plan for the annual PM-10 standard for Phoenix and is proposing to disapprove the impracticability and RACM demonstrations because those demonstrations do not adequately address the CAA's moderate area PM-10 requirements.

Contact Information

Colleen McKaughan (mckaughan.colleen@epa.gov)
Associate Director, Air Division, EPA Region 9
(520) 498-0118


February 1998: Serious Nonattainment for PM-10

The metropolitan Phoenix area is a serious nonattainment area for inhalable particulate matter (known as PM-10 for particulate matter with a diameter of 10 microns or less). There are two health-based PM-10 ambient air quality standards, a long-term annual standard and a short-term 24-hour standard. air quality in the Phoenix area currently exceeds both standards.

Particulate matter affects the respiratory system and can cause damage to lung tissue and premature death. The elderly, children, and people with chronic lung disease, influenza, or asthma are especially sensitive to high levels of particulate matter.

Under the Clean Air Act, the State of Arizona was required develop a plan to reduce particulate matter in the Phoenix area to healthy levels. This plan was due to EPA by December 10, 1997. Arizona has been and is continuing to work diligently on a comprehensive particulate matter plan and submitted part of the required plan to EPA in May 1997. However, because Arizona has not yet submitted a complete plan, EPA is required to make a formal finding that the State has failed to submit a required plan under the Clean Air Act.

Below is the final action as published in the Federal Register on February 25, 1998.

Contact Information

Colleen McKaughan (mckaughan.colleen@epa.gov)
Associate Director, Air Division, EPA Region 9
(520) 498-0118

Federal Register Notice (final action, published February 25, 1998)

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