AQ-2013-005 EXECUTIVE SUMMARY.PDF

Executive Summary
of the Report to the Board of Supervisors
Prepared by the Maricopa County Air Quality Department
Board Hearing Date: December 9, 2015
Case #/Title: AQ-2013-005-New Source Review
Agenda Item: C-85-16-003-M-00
Supervisor Districts: All Districts
The Maricopa County Air Quality Department (department) complied with all statutory and county policies
throughout this rulemaking process. Per the Enhanced Regulatory Outreach Program (EROP) Policy: “In addition
to the required staff report, an executive summary of the report including an overview of stakeholder input and
staff responses will be provided to the Board of Supervisors at least one week prior to any Board of Supervisors’
public hearing.”
Overview Of The Report To The Board Of Supervisors: The department is requesting the Board of
Supervisors to approve amendments to Maricopa County Air Pollution Control Regulations regarding New
Source Review (NSR) and approve submitting the amended rules as a revision to the (Arizona) State
Implementation Plan (SIP).
The purpose of this rulemaking is to update the department’s NSR rules in order to secure their approval as part of
the SIP under the federal Clean Air Act. The update will be consistent with revisions the Arizona Department of
Environmental Quality (ADEQ) and the U.S. Environmental Protection Agency (EPA) made to the NSR Program
required by the federal Clean Air Act.
NSR is a long-standing Clean Air Act permitting program that requires businesses to get an air pollution control
permit before they start construction or make major modifications to their business. NSR must ensure that air
quality is not significantly degraded from the addition of new or modified businesses, while also providing
flexibility to businesses to improve or modernize their operations. Air quality permits must include an air quality
analysis to demonstrate that new emissions emitted from the business will not cause or contribute to a violation of
a National Ambient Air Quality Standard. Permit fees are not changing due to this rulemaking.
Overview Of Stakeholder Input And Staff Responses: The department received written comments from the
Salt River Project Agricultural Improvement and Power District (SRP) via the Enhanced Regulatory Outreach
Program (EROP) website; they stated their opinion as “other”. The comments and the department’s responses are
provided below.
Comment #1: Proposed “Permitting Threshold”
The new MCAQD Rule 100, Section 200.86 related to “Permitting Threshold” defines the new trigger levels as
follows: 0.3 tpy for lead (Pb); 0.5 tpy for particulate matter nominally less than 2.5 microns (PM2.5), particulate
matter nominally less than 10 microns (PM10), volatile organic compounds (VOC), and any single hazardous air
pollutant (HAP) (other than Pb); and 1.0 tpy for sulfur dioxide (SO2), nitrogen oxide (NOx), carbon monoxide
(CO), total HAPs, and any other “regulated air pollutant.” The proposed thresholds are inconsistent with the
current MCAQD thresholds in Rule 100, Section 200.58, which states the following: “Insignificant Activity: For
the purpose of this rule, an insignificant activity shall be any activity, process, or emissions unit that is not subject
to a source-specific applicable requirement, that emits no more than 0.5 ton per year of hazardous air pollutants
(HAPs) and no more than two tons per year of a regulated air pollutant, and this is either included in Appendix D-
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List of Insignificant Activities of these rules or is approved as an insignificant activity under Rule 200-Permit
Requirements of these rules. Source-specific applicable requirements include requirements for which emissions
unit-specific information is needed to determine applicability.” The 0.5 and 2 tpy thresholds noted above are also
defined as the Insignificant Emissions Rate (IER) in the MCAQD December 29, 2006 “Interim Guidance
Document For Title V Permit Revisions,” which has been applied to Title V permit revisions in the county since
2007. The proposed thresholds are also inconsistent with “Permitting Exemption Thresholds” proposed by the
ADEQ NSR rules, which are as follows: 0.3 tpy for lead (Pb); 50 tpy for CO; 20 tpy for VOC, NOx, and SO2; 7.5
tpy for PM10; and 5 tpy for PM2.5 (primary emissions only). MCAQD retained the historic 0.5 tpy threshold for
HAPs and utilized ADEQ’s proposed 0.3 tpy threshold for Pb. At a minimum, MCAQD should revise the
threshold for all pollutants, other than lead, to be consistent with its definition of Insignificant Emissions Rate
(IER) in the December 29, 2006 “Interim Guidance Document For Title V Permit Revisions.”
Response #1: Proposed “Permitting Threshold”
In response to SRP’s comment regarding permitting thresholds, the department is proposing to de-couple the
permitting thresholds from the definition of “insignificant activity”. The department is proposing to maintain the
current permitting thresholds but to convert the thresholds from pounds per day to tons per year. The department
is proposing to retain the original definition of “insignificant activity” as written in Rule 100, Section 200.58 (new
Section 200.63) with the deletion of “and that is either included in Appendix D-List of Insignificant Activities of
these rules”. Appendix D is proposed to be repealed in this rulemaking. In addition, in Rule 200, Section 305.4
(Exemptions), the department is proposing to delete the text “Insignificant activities, provided any single or
combination of insignificant activities have total uncontrolled emissions less than the permitting thresholds as
defined in Rule 100 of these rules” and to add activities, processes, or emissions units that were proposed to be
listed in the proposed new definition of “insignificant activity” in Rule 100 and that are proposed to be deleted in
Rule 200, Section 303.3(c).
Comment #2: Proposed “Minor NSR Modification Threshold”
The new MCAQD Rule 100, Section 200.70(f) related to “Minor NSR Modification Threshold” defines the new
trigger levels as follows: 0.3 tpy for lead (Pb); and 5 tpy for PM2.5 (primary emissions only), PM10, SO2, NOx,
VOC, and CO. The proposed thresholds are also inconsistent with the corollary “Minor NSR Modification”
proposed by the ADEQ NSR rules, which are the same as the “Permitting Exemption Thresholds” listed above.
The MCAQD proposal is similar to ADEQ’s for Pb and PM2.5 but with much lower thresholds for all other
pollutants (CO, VOC, NOx, SO2, and PM10). SRP understands that Maricopa County is a nonattainment area for
ozone and PM10, which may justify a lower threshold for VOC, NOx, and PM10. However, the thresholds proposed
by MCAQD seem more appropriate for severe and extreme nonattainment areas and such low thresholds leave no
room for future downward adjustment in the case of a severe nonattainment designation of Maricopa County.
Therefore, consistent with ADEQ’s program, MCAQD should change the minor NSR permitting thresholds to
match ADEQ’s thresholds for all pollutants other than the nonattainment pollutants. SRP proposes that for PM10,
VOC, and NOx MCAQD adopt a conservative threshold of 40% of the “Significant” emission rates in MCAQD
Rule 100, Section 200.99 as follows: 0.3 tpy for lead (Pb); 50 tpy for CO; 20 tpy for SO2; 16 tpy for VOC, NOx,
and 6 tpy for PM10; and 5 tpy for PM2.5 (primary emissions only).
Response #2: Proposed “Minor NSR Modification Threshold”
Given the permitting thresholds and the applicability criteria in the numerous source-specific emission control
rules in place to address county nonattainment areas, the department is proposing to define permitting thresholds
that would trigger minor NSR modifications at different levels than ADEQ proposed. The permitting thresholds
that would trigger minor NSR modification are proposed as follows: 5.0 tons per year-PM2.5, PM10, SO2, NOx,
VOC, and CO; 0.3 tpy for lead. In ADEQ’s Notice of Final Rulemaking (18 A.A.R. 1542, July 6, 2012), ADEQ
states “ADEQ confirms that the amendments to the State’s NSR program are designed to meet federal Clean Air
Act requirements solely for the areas subject to ADEQ’s jurisdiction and may not be sufficient to meet those
requirements for nonattainment areas subject to MCAQD’s jurisdiction.”
Comment #3: Development Of A “Registration” Program
In a May 22, 1996 letter addressing the adequacy of ADEQ’s permitting program, EPA Region 9 stated that
“ADEQ could develop a source registration program for smaller facilities that would achieve that same
environmental benefit as a traditional permitting program.” (Per Arizona Department of Environmental Quality
(ADEQ), State Implementation Plan Revision, New Source Review, Final Version, October 2012, Page 1547) As
a result, the proposed ADEQ NSR rules contain a new “Registration” program to minimize the burden imposed
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on currently unpermitted or smaller emission sources. The MCAQD rules do not propose the development of a
similar registration program. The changes being proposed to the MCAQD permitting and Minor NSR thresholds
are expected to bring numerous currently unpermitted and smaller emission sources into the MCAQD permitting
program. Under the current proposed MCAQD rules, such sources will likely need to obtain an MCAQD Non-
Title V permit, which can require a complicated application for the applicants and consume MCAQD permit
engineering resources with no measurable improvement to county air quality. Due to the impact on MCAQD
permit engineering resources, other larger industrial sources with pending Title V and Non-Title V permit actions
may experience permit processing delays that could be detrimental to the county’s business and economic
advantage.
Response #3: Development Of A “Registration” Program
The commenter has mischaracterized the department’s existing permitting thresholds. The proposed permitting
thresholds simply convert the existing pounds per day thresholds in Rule 200, Section 303.3(c)(7)(j) to the less
burdensome tons per year format. This change may actually reduce not increase the number of permits issued by
the department. Based on experience in administering the existing permit program, the department’s Permit
Engineering Division estimates that it will process approximately 100 applications for permits or permit revisions
subject to minor NSR per year. The Permit Engineering Division also estimates that on average the additional
time for processing the minor NSR components (applicability and air quality impact analyses) of a permit or
permit revision application will be 2 hours per application for SCREEN modeling for ambient air quality
assessment and 5 hours per application for reviewing refined modeling performed by the source. The Permit
Engineering Division further estimates that the department will perform SCREEN modeling for the air quality
impact assessment on approximately 95% of the permit applications and will review the refined modeling
performed by the source on approximately 5% of the permit applications. In addition, the department’s existing
general permit program which falls under its minor NSR program is a less costly alternative currently available to
many small businesses (e.g. dry cleaners, gas stations, surface coating operations, auto body shops, etc.). The
general permits are designed specifically with small businesses in mind. General permitted sources will not incur
the cost of an ambient air quality assessment as this would be done up front when the general permit is established
rather than when an authorization to operate is issued. Many small businesses currently required to obtain permits
are eligible for a general permit and are not required to get a Non-Title V permit. Thus, for some small businesses,
the general permit program is an existing and less costly alternative to the Non-Title V permit.
Comment #4: Minor NSR Reasonably Available Control Technology (RACT) Determinations
The MCAQD NSR rules propose a new Rule 241, Section 307 that the agency shall determine RACT for minor
NSR purposes, as follows: (1) For sources subject to source-specific rule under Regulation III (Control of Air
Contaminants), RACT is the emissions limitation in the applicable rule and (2) For all other sources, RACT shall
be determined by one of the following: technology that may previously have been applied to a similar, but not
necessarily identical, source category; a control technique guideline (CTG) issued by the EPA under Clean Air
Act (CAA) section 108(f)(1); or an emissions standard established or revised in a New Source Performance
Standard (NSPS) or National Emission Standard for Hazardous Air Pollutants (NESHAP) after November 15,
1990. However, the ADEQ NSR rules proposed at R18-2-334(D) that the agency shall accept a requirement
proposed as RACT if it complies with the most recently adopted guidelines or standards from the list below. The
differences with respect to the MCAQD proposal are in bold text. “a. A control technique guideline (CTG) issued
by the EPA under CAA section 108(f)(1); b. An emissions standard established or revised in an NSPS or
NESHAP after November 15, 1990; c. An applicable requirement in ADEQ or county rules that has been
spefically identified as constituting RACT; d. A RACT standard imposed on the same type of source by a
General Permit; and e. A RACT standard imposed on the same type of source within the past 10 years.”
(The rules also not that to facilitate identification of previously imposed RACT standards, the ADEQ will
establish an online database of historic RACT determinations). A comparison of the proposals above indicates
that ADEQ allows applicants to use standards contained in General Permits. Additionally, ADEQ will develop an
online tool to summarize historic RACT determinations. The addition of the two remaining ADEQ RACT
determination sources would provide more flexibility in meeting the RACT obligations of the proposed MCAQD
NSR rules. Therefore, MCAQD should add these remaining two remaining ADEQ RACT demonstration sources
in the proposed revisions.
Response #4: Minor NSR Reasonably Available Control Technology (RACT) Determinations
With historical nonattainment areas, the department has implemented RACT as required by the Federal CAA
Sections 172(c)(1), 182, and 189. Each nonattainment area plan contains a RACT SIP and the associated RACT
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rules. As a result, using general permits to establish RACT is not an option in Maricopa County. For the unique
process not subject to RACT, an applicant may propose RACT consistent with the definition of “RACT” in Rule
100 that allows for RACT technology that may previously have been applied to a similar, but not necessarily
identical source category. The department processes 1 -2 such applications per year and almost all utilize the
provision in Rule 100. Consistent with the Maricopa County obligation under A.R.S. § 49-480(B), the department
is proposing to adopt NSR amendments that are substantially identical to the ADEQ and EPA NSR programs for
major sources and amendments that generally impose no greater procedural burden than ADEQ’s procedures for
minor sources. However, due to long-standing nonattainment area federal requirements, Maricopa County’s
permitting thresholds are lower than ADEQ’s permitting thresholds. Under A.R.S. § 49-479(C), a county may not
adopt a rule or ordinance that is more stringent than the rules adopted by ADEQ for similar sources unless it
demonstrates compliance with the applicable requirements of A.R.S. §49-112. Under § 49-112(A), the county
may adopt a rule that is more stringent than or in addition to a provision of A.R.S. Title 49 or an ADEQ rule
under specific conditions including peculiar local conditions, necessary to prevent a significant threat to public
health or environment, or required under a federal statute or regulation. The proposed rule amendments relating to
minor NSR included in this rulemaking are designed to address a lack of explicit procedures designed “to assure
that national ambient air quality standards are achieved,” as required by CAA § 110(a)(2)(C). Maricopa County’s
current minor source permitting rules require the inclusion of “[e]nforceable emission limitations and standards,
including operational requirements and limitations that ensure compliance with all applicable requirements.” Rule
220, Section 302.2. They therefore satisfy the requirement in EPA’s minor NSR rules to assure that minor sources
do not violate “applicable portions of the control strategy.” Maricopa County's permit rules for minor NSR
impose no greater procedural burden than procedures for the review, issuance, revision and administration of
permits issued by the State. However, Maricopa County's rules and procedures contain requirements specific to
nonattainment area status, increment consumption analysis and impacts on nearby nonattainment areas. These
requirements result in permit conditions that address the source's proximity to the PM10 and ozone nonattainment
areas, specific atmospheric and geographical conditions found at the source's location, control technology
provisions required by the CAA for nonattainment areas, and other control measures adopted into various
nonattainment SIPs for Maricopa County. Specifically, various SIPs for Maricopa County have required the
adoption of reasonably available control technology (RACT), best available control technology (BACT), and
most stringent measures (MSM) as required by CAA §§ 172, 182, 188, and 189.
Comment #5: Application Of RACT To Proposed Modifications
The ADEQ NSR rules propose at R18-2-334(C)(1) that RACT shall be implemented for each emissions unit that
will experience an increase in the potential to emit of a regulated minor NSR pollutant in an amount greater than
or equal to 20% of the permitting exemption threshold (i.e., not all emission sources at a new source must address
RACT). This provision allows the application of controls to the emissions unit that contribute to the bulk of the
site’s emissions and reduces the burden of either (1) applying control to emissions units or (2) developing
technical and economic infeasibility demonstrations for small emissions units and spending permit engineering
and processing resources on such demonstrations. The proposed MCAQD NSR rules do not include such an
allowance. As a result, all emissions units associated with a modification may need to be considered for RACT
demonstration. As discussed above, this could lead to significant consumption of MCAQD permit engineering
resources on smaller emission units with no measurable improvement to county air quality. Due to the impact on
MCAQD permit engineering resources, other larger industrial sources with pending Title V and Non-Title V
permit actions may experience permit processing delays that could be detrimental to the county’s business and
economic advantage. Therefore, MCAQD should add a 20% threshold for the implementation of RACT on
sources experiencing emission increases greater than the proposed “Permitting Thresholds.”
Response #5: Application Of RACT To Proposed Modifications
Since Maricopa County’s numerous federally approved RACT rules contain applicability criteria that determine
when RACT must be applied, setting a general RACT threshold is not an option in Maricopa County. Based on
experience in administering the existing permit program, the department’s Permit Engineering Division estimates
that it will process approximately 100 applications for permits or permit revisions subject to minor NSR per year.
The Permit Engineering Division also estimates that on average the additional time for processing the minor NSR
components (applicability and air quality impact analyses) of a permit or permit revision application will be 2
hours per application for SCREEN modeling for ambient air quality assessment and 5 hours per application for
reviewing refined modeling performed by the source. The Permit Engineering Division further estimates that the
department will perform SCREEN modeling for the air quality impact assessment on approximately 95% of the
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permit applications and will review the refined modeling performed by the source on approximately 5% of the
permit applications.
Comment #6: “NAAQS Compliance Assessment”
The new MCAQD NSR proposed rule at Rule 241, Section 308 “NAAQS Compliance Assessment” notes that an
ambient air quality assessment must demonstrate that new emissions would not interfere with attainment or
maintenance of the NAAQS. Such demonstration would require an evaluation of the impact from the source or
modification, as well as the addition of a representative background. For PM10 (which is also a nonattainment
pollutant), most of the monitors around Maricopa County register ambient concentrations that exceed the
NAAQS. As a result, MCAQD should define an alternate procedure in the rule that can be executed when
developing the ‘NAAQS Compliance Assessment” for nonattainment pollutants. Furthermore, MCAQD does not
currently have air dispersion modeling guidelines, although a request for proposals (RFP #15076) for “Air Quality
Dispersion Modeling Guideline Development” was issued in July 2015. MCAQD must continue with the process
of developing guidelines, allowing public participation in the development of such guidelines, and allow the use
of modeling guidelines from other Arizona agencies, such as the ADEQ, in the interim.
Response #6: “NAAQS Compliance Assessment”
Thank you for the comment. The department is currently using ADEQ guidelines for major source permitting.
Recognizing that a Maricopa County-specific guideline would be necessary, the department issued a request for
proposal (RFP) for a small business user-friendly guideline as a supplement to the ADEQ guideline providing
Maricopa County-specific data and resources. The RFP also reflects the department’s intent to hold public
workshops on the draft document.
Comment #7: Timing Of Public Notice On Proposed Rules
The MCAQD “Report To The Board Of Health” indicates that “…the Department is reviewing its NSR rules to
make sure that whatever the EPA has disapproved in ADEQ’s NSR rules will be written in such a way that it is
approvable by the EPA in the department’s NSR rules.” (Per Report To The Board Of Health To Initiate
Regulatory Change, Prepared By The Maricopa County Air Quality Department, Case #/Title: AQ-2013-005-
New Source Review (NSR), Meeting Date: July 27, 2015) This implies that further revisions could be made to the
proposed MCAQD NSR rules as the ADEQ received the final “limited approval and limited disapproval” on their
NSR program on June 29, 2015, and further refinements to the ADEQ NSR rules are in process. For example,
ADEQ had proposed under R18-2-334 that an application may be processed as a minor permit revision if the
results of the SCREEN model show expected concentrations, including background concentrations, are less than
75% of the applicable standard. MCAQD has a similar proposal in their proposed NSR rules. The June 29, 2015
final EPA “limited approval and limited disapproval” rejected ADEQ’s initial proposal. This is just one example
of an issue that is expected to affect the current draft of the MCAQD NSR rules. As a result, MCAQD should
delay public notice of its rule package until MCAQD can assess and incorporate all of the changes that ADEQ is
implementing in their rules to address the basis for EPA’s “limited disapproval”.
Response #7: Timing Of Public Notice On Proposed Rules
According to Arizona Revised Statutes § 49-471.07(C), “The Board of Supervisors shall not adopt a rule or
ordinance that is substantially different from the proposed rule or ordinance contained in the Notice of Proposed
Rulemaking…” Since the Notice of Proposed Rulemaking was published on July 31, 2015 (21 A.A.R. 1302), the
department is proposing additional amendments to its NSR rules. The scope of the amendments incorporate
changes that ADEQ is implementing in their rules to address the basis for EPA’s “limited disapproval” and to
comport with federal regulations, e.g., clarify definitions so they more closely match federal definitions, delete
minor NSR rule provisions that allow certain permit revisions to be processed as minor permit revisions and
delete the 5 tpy lead threshold as it’s not required under federal regulations. In addition to such amendments being
described in Item #12 in this Draft Notice of Final Rulemaking, such amendments are described in a Notice of
Supplemental Proposed Rulemaking which will be published in the Arizona Administrative Register on October
9, 2015; this will allow Stakeholders 30-days to submit comments regarding such additional amendments. The 30-
day comment period will close on November 9, 2015.
Comment #8: Version Date For Dispersion Models
Pursuant to MCAQD proposed Rule 100, Section 200.111: “Screen Model: The AERSCREEN air dispersion
model published by the Administrator in April 2011 and available on the Support Center for Regulatory
Atmospheric Modeling website: http://www.epa.gov/ttn/scram.” It is to be noted that the current applicable
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version of the AERSCREEN model is 15181, which was released by EPA in 2015. The April 2011 version is no
longer applicable. Since EPA releases updates to dispersion models on a frequent basis, MCAQD’s rules should
not identify the date of the model version to be used. MCAQD should adopt ADEQ’s proposed definition of
“Screening Model” meaning “air dispersion modeling performed with screening techniques in accordance with 40
CFR 51 Appendix W.”
Response #8: Version Date For Dispersion Models
In Rule 100, Section 200.113 (Definition of “Screening Model”), the department is proposing to change the
definition of “screen model” to the definition of “screening model” so it is consistent with ADEQ’s NSR rules
R18-2-301(21) and to change the term as used in Rule 241, Section 308.1.
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