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Proposed Air Quality Regulations and Plans


Following are summaries of proposed new air quality regulations and proposed amendments to existing regulations and the New Mexico State Implementation Plan. For updates, please periodically check back at this webpage. For information on policies and procedures for air quality permitting, please go to the Permitting Home Page.



Proposed Repeal of 20.2.20 NMAC – Lime Manufacturing Plants.

The Improving Environmental Permitting Initial Report identified 20.2.20 NMAC – Lime Manufacturing Plants – Particulate Matter (Part 20) as one of several rules that should be reviewed for potential revision or repeal. Part 20 establishes particulate matter (PM) emissions limits for lime manufacturing plants and lime hydrators. This rule is part of the New Mexico State Implementation Plan (SIP) for air quality. Part 20 differs from federal rules that regulate lime manufacturing (40 CFR 60, Subpart HH, Standards of Performance for Lime Manufacturing Plants (NSPS Subpart HH) and 40 CFR 63, Subpart AAAAA, National Emissions Standards for Hazardous Air Pollutants for Lime Manufacturing Plants (NESHAP Subpart AAAAA)) as follows:

(1) the Part 20 PM emission limit for lime kilns that are subject to NSPS Subpart HH but not NESHAP Subpart AAAAA is one-half that of the revised New Source Performance Standards (NSPS);

(2) the Part 20 opacity limit is more stringent than that required by NSPS Subpart HH; and

(3) Part 20 regulates PM emissions from lime hydrators, about which federal rules are silent. Currently, there are no facilities in New Mexico subject to either NSPS Subpart HH or NESHAP Subpart AAAAA.

NMED intends to propose to the Environmental Improvement Board (EIB) that this rule be repealed. A repeal of Part 20 would eliminate the 0.15 pound per ton of lime feed PM emissions limit for lime hydrators. Affected facilities would only be required to comply with the applicable portions of NSPS Subpart HH and NESHAP Subpart AAAAA.

Because Part 20 is part of the NM SIP, NMED would be required to demonstrate to the Environmental Protection Agency (EPA) that the proposed repeal will not negatively affect the attainment or maintenance of any National Ambient Air Quality Standard (NAAQS), as required by Section 110(l) of the Clean Air Act (CAA). The 110(l) demonstration would provide that:

  1. There are no lime manufacturing sources in New Mexico subject to NSPS Subpart HH or NESHAP Subpart AAAAA that would be affected by the repeal of Part 20.
  2. The only source currently subject to Part 20 is Lhoist North America’s (a/k/a Chemical Lime Co.) lime hydrator, located in Belen, NM. The most recent dispersion modeling analysis conducted for this facility demonstrates that the facility will not cause a violation of the NAAQS, as permitted and constructed.
  3. This source’s potential to emit PM is based on a permit limit, which is federally enforceable via SIP-approved 20.2.72 NMAC, Construction Permits (Part 72). If Part 20 were repealed, an NSR permit would still be required for the Lhoist facility. Should Lhoist apply for a permit revision, Part 72 would still require the applicant to show compliance with the NAAQS. Therefore, the facility would not interfere with attainment or maintenance of the NAAQS.

The proposed repealed rule may be downloaded from the link below.

Please contact Neal Butt at (505) 476-4317 or if you have questions or comments concerning the proposed repeal.

Recently Approved Changes to Air Quality Regulations and Plans

Following are summaries of recently approved changes to New Mexico air quality regulations and the New Mexico State Implementation Plan. These changes were approved by either the Environmental Improvement Board or U.S. EPA within the last two years. For updates, please check back periodically at this webpage.

SO2 Data Requirements Rule – Implementation of the 2010 1-hour Sulfur Dioxide Primary National Ambient Air Quality Standard

The U.S. EPA requires each State to supply information regarding sources which emit greater than 2,000 tons per year of sulfur dioxide in order to determine compliance with the 2010 1-hour primary standard. The schedule of required information includes:



Although most areas of the country (including all of New Mexico) have already been designated for attainment/nonattainment of the standard, some areas of the country remain unclassifiable. By summer of 2020, EPA expects to have enough data to designate the remaining areas. States with areas not attaining the standard will then have two years to complete attainment plans. For more information on the 2010 SO2 NAAQS, visit EPA’s web page which includes various documents related to the third round of area designations.

For questions related to the Data Requirements Rule or the SO2 NAAQS, please contact Cindy Hollenberg at or at (505) 476-4356.

Municipal Solid Waste Landfills – New Source Performance Standards and Emission Guidelines

In August 2016, EPA issued revised standards for both new and existing municipal solid waste landfills (MSWLs). The New Source Performance Standards at 40 CFR 60 Subpart XXX apply to landfills constructed or modified after July 17, 2014. The Emission Guidelines at 40 CFR 60 Subpart Cf apply to landfills constructed or modified on or prior to this date. Both of these federal rules aim to reduce landfill gas emissions. The New Source Performance Standard were incorporated by reference into the New Mexico Administrative Code (NMAC) on April 28, 2017.

Subpart Cf, promulgated under Section 111(d) of the Clean Air Act, requires that states, tribes and local authorities with jurisdiction over existing landfills develop a plan to implement the emission guidelines. One aspect of that state plan, for New Mexico, is the amendment of 20.2.64 NMAC – Municipal Solid Waste Landfills (Part 64).

On April 28, 2017, the Environmental Improvement Board unanimously approved the adoption of the State Plan implementing the emission guidelines and the repeal and replacement of Part 64.

NMED submitted the approved State Plan implementing the Emission Guidelines in early May, 2017. On May 31, 2017, the EPA issued a 90-day stay on both the NSPS and EGs. This 90-day stay expired on August 29, 2017.  Therefore, the 2016 federal rules are currently in effect. However, EPA is reconsidering several issues in these final rules. EPA does “not plan to prioritize” the review of submitted state plans and issuance of a Federal Plan for states that failed to submit a state plan. For more information on these rules and rule history, visit EPA’s web page for landfills.

If you have further questions regarding the State Plan development, contact Cindy Hollenberg, or (505) 476-4356. For questions regarding implementation of the emission guidelines, contact EPA Region 6 (

Incorporation by Reference of federal NSPS, NESHAP and MACT rules

 At a public hearing held April 28, 2017, the Environmental Improvement Board approved amendments to the dates of incorporation by reference contained in 20.2.77 NMAC (New Source Performance Standards), 20.2.78 NMAC (Emission Standards for Hazardous Air Pollutants), and 20.2.82 NMAC (Maximum Achievable Control Technology Standards for Source Categories of Hazardous Air Pollutants). The previous update for Parts 77, 78 and 82 was September 15, 2015. Since the most recent date of incorporation, there have been 28 changes to various federal New Source Performance Standards, Emission Standards for Hazardous Air Pollutants, and Maximum Achievable Control Technology Standards. Adoption of the proposed incorporation by reference will change the “through date” in Parts 77, 78 and 82 to reference the changes made at the federal level through January 15, 2017.

Please contact Mark Jones at or at (505) 566-9746 for additional information.

Revisions to the New Mexico State Implementation Plan Regarding Startup, Shutdown and Malfunctions

A public hearing, held September 9, 2016, approved revisions to the State Implementation Plan (SIP) for New Mexico. The SIP revisions are in response to a final action issued by the U.S. Environmental Protection Agency (EPA). On June 12, 2015, the EPA published its final action to ensure states have plans in place that are fully consistent with the Clean Air Act and recent court decisions concerning startup, shutdown and malfunction (SSM) operations.

In response to this final action, the New Mexico Environment Department Air Quality Bureau proposed revisions to the State Implementation Plan (SIP). These SIP revisions entail removing applicable sections of 20.2.7 NMAC – Excess Emissions during Malfunction, Startup, Shutdown, or Scheduled Maintenance from the SIP. The proposal was unanimously approved by the Environmental Improvement Board on September 9, 2016.

For more information, please contact Robert Spillers at (505) 476-4324 or by email to

Repeal of 20.2.37 NMAC – Petroleum Processing Facilities.

At a public hearing held August 12, 2016, the Environmental Improvement Board unanimously approved the repeal of 20.2.37 NMAC. Part 37 was adopted in 1974
and specifies emissions limits and other operating requirements for existing (constructed prior to July 1, 1974) and new petroleum refineries and natural gas processing facilities. This rule regulates emissions from several processes associated with petroleum processing facilities and has not been substantially revised since 1984. The rule was identified in the November 2012 Improving Environmental Permitting Report for potential revision or repeal. The Air Quality Bureau has conducted a thorough analysis of the rule as well as other similar federal rules that apply to this industry, and has concluded that the rule can be repealed without a relaxation of emissions controls or an adverse effect on air quality

Please contact Mark Jones at or at (505) 566-9746 for additional information.

Repeal of 20.2.36 NMAC – Petroleum Refinery Sulfur

 At a public hearing held December 18, 2015, the Environmental Improvement Board unanimously approved the repeal of 20.2.36 NMAC. Part 36 was adopted in 1974, establishing sulfur limits (sulfur recovery standards) and other requirements for existing and new petroleum refineries.

Federal New Source Performance Standards (NSPS) regulations, 40 CFR Part 60, Subparts J and Ja (NSPS J and Ja) and other permit conditions require sulfur emission limits that are more directly related to air emissions of sulfur than Part 36. Part 36 is outdated; it was adopted at a time when Continuous Emissions Monitoring Systems (CEMS) were not widely in use. This leads to enforceability issues due to a lack of monitoring requirements. Also, the regulation is not part of the State Implementation Plan (SIP) under the federal Clean Air Act, and therefore is not federally enforceable by the EPA. In comparison, Subparts J and Ja require continuous monitoring, which provides for more effective enforcement of the emission limits.

Repeal of Part 36 benefits the State by removing outdated, redundant requirements. Since existing federal regulations establish sulfur limits for existing and future refineries, a repeal of Part 36 would not negatively affect air quality.

Please contact Mark Jones at or at (505) 566-9746 for additional information.

Recent EPA Approvals of Regulatory Changes or Plans

Following are links to recently approved regulatory changes or plans. To view all EPA approvals related to the State Implementation Plan, please visit the electronic code of federal regulations.

NM Regulations:


  • Infrastructure and Transport for 2008 lead (Pb) NAAQS (effective July 13, 2015) 80 FR 33191
  • Infrastructure for the 2008 ozone NAAQS (effective July 24, 2015) 80 FR 36246
  • Infrastructure for the 2010 NO2 NAAQS (effective July 24, 2015) 80 FR 36246
  • Infrastructure for 2010 SO2 NAAQS (effective November 13, 2015) 80 FR 61751
  • Infrastructure and transport for 2012 Fine Particulate Matter (PM2.5) NAAQS (Proposed – comments due January 25, 2018) 82 FR 60933

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