4 The record articles

2015 Ozone NAAQS Implementation Update and Possible NOx Reductions for Portland Cement Kilns

Posted: October 8th, 2017

Authors: Lindsey K. 

October 1, 2017 marked the date by which U.S. EPA was anticipated to promulgate final area designations (i.e., attainment or nonattainment) for the 2015 ozone National Ambient Air Quality Standard (NAAQS).  U.S. EPA reduced the ozone NAAQS from 75 parts per billion (ppb) to 70 ppb on October 1, 2015, initiating a two-year timeline for states and tribes to provide designation recommendations to U.S. EPA and for U.S. EPA to promulgate final designations.  Final designations will result in a multi-year timeline for states and tribes to promulgate rules intended to bring nonattainment areas into attainment.

Let’s dive a little further into what’s happened and what to expect for the 2015 ozone NAAQS, particularly for Portland cement kilns in the Ozone Transport Region (OTR).


Ozone (O3), more specifically ground-level ozone, is not directly emitted by stationary or mobile sources; rather, it is created by a chemical reaction caused by solar radiation interacting primarily with oxides of nitrogen (NOX) and volatile organic compounds (VOC).  Therefore, NOX and VOC are referred to as ozone precursors.  Ground-level ozone is commonly referred to as “haze” or “smog” and can be seen by the naked eye, particularly near city skylines or mountain ranges.  According to U.S. EPA, “[b]reathing ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and airway inflammation. It also can reduce lung function and harm lung tissue.”  The intent of the ozone NAAQS, as with NAAQS for other pollutants, is to establish acceptable levels of ambient ozone and to require reductions in ozone concentrations in areas that are not attaining those levels by reducing emissions of the ozone precursors NOX and VOC.  Ambient ozone concentrations in a given locale can also be influenced by the transport of precursor pollutants from other geographic areas (i.e., upwind states), but that is a subject for a future discussion.  The NAAQS establishes a primary standard to protect public health, and a secondary standard to protect public welfare, which can include environmental impacts such as to vegetation.

On October 1, 2015, U.S. EPA signed the Final Rule for the 2015 Ozone NAAQS; it was published in the Federal Register on October 26, 2015 following the proposed rule signed on November 25, 2014 and published on December 17, 2014.  As described above, the primary and secondary NAAQS were both reduced from 75 ppb to 70 ppb.  The averaging time and form of the standards remained the same (i.e., 8-hour and annual fourth-highest daily maximum, respectively).  October 1, 2015 was a deadline established by court order for U.S. EPA to sign the final NAAQS.  Similarly, the final 2015 secondary standard addressed a court remand of the 2008 secondary standard.


The timeline for implementing a new NAAQS is several years, and begins with initial area designations, which involves “identifying areas of the country that are not meeting the new or revised NAAQS along with the nearby areas that contain emissions sources that contribute to the areas not meeting the NAAQS.”  This step is a combined effort between U.S. EPA, states, tribes, and local agencies, and was scheduled to take place as presented in the following table reproduced from U.S. EPA’s Guidance on Area Designations for the 2015 Ozone NAAQS:




The EPA promulgates 2015 Ozone NAAQS rule

October 1, 2015

States and tribes submit recommendations for ozone designations to the EPA

No later than October 1, 2016

The EPA notifies states and tribes concerning any intended modifications to their recommendations (120-day letters)

No later than June 2, 2017 (120 days prior to final ozone area designations)

The EPA publishes public notice of state and tribal recommendations and the EPA’s intended modifications, if any, and initiates 30-day public comment period

On or about June 9, 2017

End of 30-day public comment period

On or about July 10, 2017

States and tribes submit additional information, if any, to respond to the EPA’s modification of a recommended designation

No later than August 7, 2017

The EPA promulgates final ozone area designations

No later than October 1, 2017


Following final ozone area designations, states with nonattainment areas are to develop State Implementation Plans (SIPs) to attain the NAAQS.  In this step, “states first take into account projected emission reductions from federal and state rules that have been already adopted at the time of plan submittal. […] States will then evaluate the level of additional emission reductions needed for each nonattainment area to attain the O3 standards ‘as expeditiously as practicable,’ and adopt new state regulations as appropriate.”  U.S. EPA anticipates that many existing or new rules will result in preliminary emissions reductions (e.g., Cross-State Air Pollution Rule (CSAPR), NOX SIP Call, National Emission Standards for Hazardous Air Pollutants (NESHAPs), etc.).


State and tribe designation recommendations have been submitted to U.S. EPA.  Some submittals commended U.S. EPA on the revised NAAQS, while others referenced petitions for vacating the rule.  On November 17, 2016, U.S. EPA published its Proposed Implementation of the 2015 National Ambient Air Quality Standards for Ozone: Nonattainment Area Classifications and State Implementation Plan Requirements, in which it is proposing to retain most of the 2008 ozone NAAQS implementation provisions.  “States with areas designated nonattainment have 2 years from the effective date of nonattainment designation to submit SIP revisions addressing emission inventories (required by [Clean Air Act (CAA)] section 182(a)(1)), [Reasonably Available Control Technology (RACT)] (CAA section 182(b)(2)) and emissions statement regulations […] (CAA section 182(a)(3)(B)) […]”  Further, “states in the OTR are required to submit SIP revisions addressing the RACT requirements of CAA section 184 no later than 2 years after the effective date of designations for the revised ozone NAAQS.”  That means upon final promulgation of area designations, the clock starts ticking for states, tribes, and local agencies to develop SIPs.

On June 6, 2017, U.S. EPA issued a one-year extension to the October 1, 2017 area designation deadline (i.e., to October 1, 2018).  However, the extension was withdrawn on August 2, 2017, followed by the release of six “regulatory relief” options for states to use for implementing the 2015 ozone NAAQS.  Be sure to read Ashley Howard’s article for more information on these options.


“The Ozone Transport Commission (OTC) is a multi-state organization created under the Clean Air Act […] responsible for advising [U.S.] EPA on transport issues and for developing and implementing regional solutions to the ground-level ozone problem in the Northeast and Mid-Atlantic regions.”

The OTC advises U.S. EPA regarding the states in the OTR (i.e., Connecticut, Delaware, the District of Columbia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont), as well as Virginia.  “States in [the OTR] are required to submit a SIP and install a certain level of controls for the pollutants that form ozone, even if they meet the ozone standards.”  As presented above, SIP revisions for OTR states addressing the RACT requirements of CAA sections 182 and 184 will be due no later than two years after final area designations, which, according to U.S. EPA’s anticipated timeline, would be October 1, 2019 (i.e., two years after October 1, 2017 final area designations).

During its September 7, 2017 Stationary Area Source, Modeling, Mobile Source and Technical Support Committee meeting, the OTC released a “Draft White Paper on Control Measures for NOX Emissions from Two Source Categories.”  One of the two source categories is natural gas pipeline compressor prime movers (i.e., compressor engines and turbines), for which OTC has proposed an updated Model Rule for control of NOX emissions, as well as other recommendations for reducing emission of VOC.  The second of the two source categories is cement manufacturing, particularly Portland cement kilns, which represent the second largest source of non-EGU emissions from stationary sources in the OTR, second only to waste treatment and disposal.  Because individual Portland cement kilns represent a concentrated source of NOX emissions (like an EGU), they represent a cost-effective approach towards reducing NOX emissions in the eyes of regulators.  Consequently, the OTC has taken notice with the draft white paper recommending the following NOX control methods:

  • Install low NOX burners on all kilns
  • Modify each kiln to implement mid-kiln firing
  • Install post-combustion SNCR
  • Convert and retrofit a wet process cement kiln to the more efficient dry cement manufacturing process

The draft white paper goes on to state that “modifying or replacing all wet kilns to modern technology should be considered feasible.”  The recommendations to install controls and especially modify/convert/retrofit kilns to reduce emissions of NOX is significant and, where technically feasible, would require substantial capital investments by cement manufacturers to implement those changes, particularly this soon after facilities recently complied with the applicable RACT rules intended to implement the 2008 ozone NAAQS.  For example, Pennsylvania’s Additional RACT Requirements for Major Sources of NOX and VOCs codified at 25 Pa. Code 129.96-.100 (commonly referred to as RACT 2) was finalized on April 23, 2016 and established a compliance date of January 1, 2017.  Presumptive emissions limits between 2.36 and 3.88 pounds of NOX per ton of clinker produced, consistent with OTC 2006 recommendations, were established for cement kilns under Pennsylvania’s RACT 2 rule.

Comments on the draft white paper and other draft documents shared during the September 7, 2017 OTC meeting were due by September 29, 2017.  The next OTC meeting is scheduled for November 15, 2017.


I asked one of my colleagues with extensive cement experience for his thoughts on the proposed OTC recommendations for Portland cement kilns, and he noted that “having to [apply these changes] could have serious impacts on some [cement] plants’ ability to remain profitable.”  He also noted that many of the recommended controls have recently and historically been determined to be technically or economically infeasible based on evaluations to implement other rules such as Pennsylvania Best Available Technology (BAT), Pennsylvania RACT 2, and Best Available Retrofit Technology (BART).

Pennsylvania “RACT 3” may only be two years away, but it is already on our radar.  Pennsylvania RACT is of particular interest because, as noted in OTC’s draft white paper (specifically, the Appendix A table entitled “Cement Kilns in CSAPR U and OTR States”), 11 of the 17 Portland cement kilns in OTC states are in Pennsylvania, so OTC’s recommendations could have significant impacts on Pennsylvania Portland cement kiln operations.  It is important to note, however, that OTC’s recommendations are based on emissions data from 2014; if emissions continue to decline due to RACT and other rules, the effectiveness of these recommendations may be impacted by the time RACT 3 arrives.

ALL4 is paying close attention to the final 2015 ozone NAAQS area designations and these OTC recommendations for Portland cement kilns.  Should you have any questions or want to learn more about the information presented here, don’t hesitate to reach out to me at 610.933.5246 x122 or Roy Rakiewicz at 610.933.5246 x127.


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