Page 1 of 27 Technical Support Document for Proposed Rule, Docket EPA

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Technical Support Document For the Review of “Arizona State Implementation Plan Revision for the Nogales PM 2.5

Nonattainment Area,” dated September 2013
And Its Appendix A: “Primary PM 2.5 and Secondary Precursor Emission Inventories for 2008 and 2010,” dated July 26, 2013,

As S ubmitted On September 6, 2013 By Arizona Department of Environmental Quality

Environmental Protection Agency

– Region 9

Air Division
A ugust 2014 Draft FinalPage 2 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 Summary This Technical Support Document (TSD) provides detailed review, discussion , and supporting rationale for EPA’s proposed action on the “Arizona State Implementation Plan Revision for the Nogales PM 2.5 Nonattainment Area” submitted on September 6, 2013 and addressing fine particle ( PM 2.5 ) and pr ecursor compounds emissions inventories for the Nogales nonattainment area. 1 The supporting documentation cited in this TSD and Arizona’s submitted documents can be found in the docket for today’s action
. 2 To summarize, we concur with the overall methodology, basis for allocating Santa Cruz County emissions to the Nogales nonattainment area, and allocation calculations used to produce the Nogales nonattainment area emissions inventories for PM 2.5 and its precursor pollutants. W e f ind that the Nogales nonattainment area calculated emissions inventories for P M 2.5 , ammonia ( N H 3 ) , oxides of nitrogen ( N O x ) , and sulfur dioxide ( S O 2 ) , four of five emissions inventories submitted, show little or no variance from our comparison data base, t he 2008 National Emissions Inventory

1 See correspondence from Eric C. Massey, Director, Air Quality Di vision of the Arizona Department of Environmental Quality to Jared Blumenfeld, Regional Administrator, U.S. Environmental Protection Agency, Region IX, dated September 6, 2013, and submittal titled “Arizona State Implementation Plan Revision for the Nogale s PM 2.5 Nonattainment Area”. 2 An electronic version of the docket can be viewed by visiting Regulations.gov and entering the docket number for today’s action, EPA

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- 0450 ( NEI ) version 3.0 emissions inventory. Even when considering its omitted source categories, t he submitted total volatile organic compound ( VOC ) emissions inventory shows a small overall
under estimate of 3 percent when compared to the corrected 2008 NEI version 3.0 Santa Cruz C ounty baseline VOC emissions inventory (see Table 6) , and a slightly larger variance of 10 percent when compared to the submitted Nogales nonattainment area VOC emissions invento ry (see Table 1 2 )
. This small overall underestimate of VOC emissions is not significant, and becomes less significant when considered against an adjusted increase provided by the submitted VOC on

- road mobile emissions inventory to the reference 2008 NEI o n - road mobile VOC emissions estimates (see Section 6). In this way, we consider the adjusted difference in the overall VOC emission inventory and our reference 2008 NEI version 3.0 emissions inventory to be closer to 3 percent rather than 10 percent , a sm all variance in the
context of the overall PM 2.5 emissions inventories
. Consequently, we are proposing to find that Arizona’s submitted P M 2.5 , N H 3 , N O x , S O 2 , and VOC emissions inventories meet the Clean Air Act s ection 172(c)(3) requirement to provide a comprehensive, accurate , and current inventory of actual emissions for the Nogales P M 2.5 nonattainment area
. 1.0 Background and Statutory Requirements Effective December 14, 2009, EPA established the initialPage 4 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 air quality designations for most areas in the United States regarding the 2006 24

- hour PM 2.5 N ational A mbient A ir Q uality
S tandard (NAAQS) ( 74 FR 58688 , November 13, 2009). Among these areas, EPA designated the Nogales area in Arizona as

n onattainment for the 2006 24

- hour PM 2.5 NAAQS. The boundaries
f or th e Nogales PM 2.5 nonattainment area are described in 40 CFR 81. 303
. 3 On January 7, 2013 , EPA finalized a determination that the Nogales nonattainment area had met the 2006 24

- hour PM 2.5 NAAQS ( 78 FR 887 )
. Th is determination of attainment was based on complete, quality

- assured, and certified ambient air quality data showing that the Nogales a rea had monitored attainment of the 2006 24

- hour PM 2.5 NAAQS over t hree consecutive years , from 200 9 to 20 11
. Given this determination , EPA applied its Clean
Da ta Policy and suspended the requirements for the Nogales area to submit an attainment demonstration, reasonably available control measures, a reasonable further progress (RFP) plan, and contingency measures for failure to meet RFP and att ainment deadlines for so long as the area continues to attain the 2006 24

- hour PM 2.5 NAAQS. The emission s inventory submittal requirement in CAA section 172(c)(3) , however, is not suspended

3 The Nogales PM 2 .5 nonat t ainment area is located in southern Santa Cruz County, Arizona, covering 76.1 square miles and is adjacent to the international border with Mexico. See Figure 1.1 of the submittal.Page 5 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 by way of th is determi nation of attainment and the application of EPA’s Clean Data Policy. 4 Section 172(c)(3) of the CAA requires a state with an area designated as nonattai nment for a NAAQS to submit a comprehensive, accurate , and current inventory of actual emissions for the nonattainment area for EPA’s review and approval
. EPA’s r equirements for an emission s inventory for the
PM 2.5 NAAQS are set forth in 40 CFR 51.1008
. 5 , 6 F or the P M 2.5 N A A Q S , the pollu t a nts that must be invento r ied a re directly emitted P M 2.5 , N H 3 , N O x , S O 2 , a nd V O C . 7 2.0 Arizona’s Submittal On September 6, 201 3, Arizona submitted “Arizona State

4 For EPA’s complete review of Nogales PM 2.5 air quality data and discussion of EPA’s application the Clean Data Policy, please see our proposed rule at 77 FR 65656, (October 30, 2012). 5 40 CFR 51.1008 (a)(2) and (b) do not apply for the Nogales area because the y relate to requirements for attainment demonstration s and reasonable further p rogress (RFP) ; these requirements were suspended for the Nogales PM 2.5 nonattainment area so long as the area continues to meet the PM 2.5 standard. For further discussion please see our final rule at 78 FR 887 (January 7, 2013 ) and proposed rule at 77 FR 65656 (October 30, 2012). 6 Although the U.S. Court of Appeals for the District of Columbia (DC Circuit) recently remanded this rule and directed EPA to re

- promulgate it pursuant to subpart 4 of part D, title I of the CAA ( see N atural Resources Defense Council v. EPA, 706 F.3d 428 (D
. C . Cir
. 2013)), the court’s ruling in this case does not affect EPA’s action on these emission s inventories. Subpart 4 of part D, title I of the Act contains no specific provision governing emission s inventories for PM 10 or PM 2.5 nonattainment areas that supersedes the general emission s inventory requirement for all nonattainment areas in CAA section 172(c)(3). See “State Implementation Plans; General Preamble for the Implementation of Title I of the Clean Air Act Amendmen ts of 1990,” 57 FR 13498, (April 16, 1992). 7 Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations, EPA

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- 001, August 2005 , updated November 2005. http://www.epa.gov/ttn/chief/eidocs/eiguid/eiguidfinal_nov2005.pdf
.Page 6 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 Implementation Plan Revision for the Nogales PM 2.5 Nonattainment Area”. Appendix A of this s ubmittal contains the “Primary PM 2.5 and Secondary Precursor Emission Inventories for 2008 and 2010, which is hereafter referre d to as “ Appendix A. ” Because much of the emissions inventory information and analyse s are located within Appendix A, this appendix is the primary focus of EPA’s review in this TSD . 3.0 Review of Emissions Inventory and Appendix A Methodology Most of Arizona’s submitted Nogales nonattainment area primary PM 2.5 and secondary precursor emission s inventories for 2008 and 2010 are derived from the data in EPA’s 2008 National Emission Inventory (NEI) versions 1.5 and 2.0 for Santa Cruz County, Arizo na . S ee Appendix A, section 3 , page 5
. Starting with 2008 NEI Santa Cruz County emissions estimates , ADEQ allocated the share of n on attainment area emissions from county

level emissions estimates by one of three characteristics and their relat ed percentages : (1) human

- induced activities/source categories were allocated by nonattainment area population share, 66.1 percent; (2) location

- based activities/source categories were allocated by nonattainment area share of land area, 6.15 percent; and , ( 3) location specific sources, such as point sources, were fully allocated to the nonattainment area, as applicable. In the case of on

- road mobile source emission estimates , Santa Cruz County emissions were estimate d using thePage 7 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 EPA approved Motor Vehicle Em issions Simulator ( MOVES ) 2010b model and then allocated by nonattainment area p opulation share.
See Appendix A, Table 3.1 , page 8, for population and land area allocation ratios ; and , see Appendix A, section 2 , page 4, for their derivation
. Next, ADEQ produced 2010 emissions inventor ies estimates for the Nogales nonattainment area from 2008 levels using a 2008 to 2010 population

- based growth rate of 1.1 percent for source categories that track with population growth
. For source categories tied to economic activity, no growth was assumed due to the continued economic recess i on during the 2008 to 2010 period. See Appendix A, section 3.4 , page 9 for ADEQ’s 2010 methodology discussion. The 2008 emissions inventories provide a calculation baseline for the 2010 emissions inventories. In turn, the 2010 emissions inventories provide an emissions estimate consistent with the time period (2009 to 2011) that EPA used to determine that the Nogales area was meeting the PM 2.5 NAAQS. Upon review of this metho dology, we find it acceptable and based on reliable estimates of population and land area. ADEQ’s population estimates are Arizona Department of Administration estimates that have been compared and reconciled with U.S.Page 8 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 Census figures. 8 We have verified t he land area allocation ratio using geographical information system applications. We concur in the location and magnitude of point source emissions , which

are discussed further in section 5.2 , below. 4.0 Review of Source Category and Pollutant Estimates for Santa Cruz County In our review, we compared ADEQ’s submitted Santa Cruz County estimates for PM 2.5 and the precursor pollutant s with the 2008 NEI version 3.0. We reasoned that we would find nominal differences between the versions (1.5 and 2.0) use d by ADEQ and the final version (3.0) of the NEI based on corrections and re

estimates . EPA’s 2006 PM 2.5 NAAQS implementation guidance required a December 2012 submittal of th ese Nogales area emissions inventor ies . Due to an intervening court decree vacating portions of this guidance related to state submittals, we advised ADEQ not to submit the Nogales PM 2.5 emissions inventory until we could provide guidance following the court’s decision (see footnote 6 for dis cussion and resolution)
. Consequently, the 2008 NEI version 3.0 was released in March 2013 prior to the submittal of the Nogales area PM 2.5 emissions inventory in September 2013. While we did not require ADEQ to

8 See page 29 (Appendix A) of Appendix A for 2008 and 2010 population estimates used by Arizona and derivation of 1.1 percent population growth rate from 2008 to 2010.Page 9 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 use NEI version 3.0 , given the ir emissions inventory was already drafted, we are review ing the submittal against NEI version 3.0 to ensure that any subsequent corrections or updates to the NEI reflect only nominal variances with Arizona’s submitted emissions inventor ies
. The 2011 NEI version 1.0 was released on September 30, 2013; consequently, it was not available to ADEQ for use in their submittal. This review is presented in a manner similar to the methodology used by ADEQ in their submittal. Because the 2008 Santa Cruz County emissions estimates provide the overall baseline for calculations, they will be reviewed first, followed by the 2008 and 2010 Nogales nonattainment area emissions estimates. A comparison of the submitted Santa Cruz County emissions inventories with the 2008 NEI version 3.0 emissions inventories shows slight differences among the totals, a percentage difference of 1 to 7 percent. See Table 1 below. Across source categories, t he non

- road mobile source category shows more variance relative to the other source categories. Across pollutants, the submitted VOC estimates show the largest variance from the 2008 NEI version 3.0 inventory, plus or minus 23 percent
for on

- road mobile s ources and non

- point sources. Consequently, we will review in more detail the non

- road mobile source category and the VOC emissions inventory to determine the cause of the differing emissions estimates. Before doing so, we will firstPage 10 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 Table 1, Comparison of 2008 Estimates of PM 2.5 and Precursor Pollutants for Santa Cruz County, Arizona: ADEQ Estimates (submitted) versus NEI version 3 estimates (uncorrected), Tons Per Year Pollutant by Source Category ADEQ Estimates (submitted) NEI version 3

Estimates (un corrected) Difference (NEI vs. ADEQ) Percentage

Difference PM 2.5 , Fine Particulates Non
- road Mobile Sources 19.9 21.9 2.0 10% Non
- Point Sources 656.1 656.4 0.3 0% On

- Road Mobile sources 38.0 41.8 3.8 10% Point Sources (see note)

--- --- --- --- Total 714.0 720.1 6.1 1% NH 3 , Ammonia Non
- road Mobile Sources 0.1 0.3 0.2 150% Non
- Point Sources 173.6 176.8 3.2 2% On

- Road Mobile sources 21.8 20.7

- 1.1

- 5%

Point Sources

--- --- --- ---

Total 195.6 197.8 2.2 1% NO x , Oxides of Nitrogen Non
- road Mobile Sources 216.3 269.3 53.0 24% Non
- Point Sources 91.0 91.4 0.5 0% On

- Road Mobile sources 1381.6 1398.5 16.9 1%

Point Sources

--- --- --- ---

Total 1688.8 1759.2 70.4 4% SO 2 , Sulfur Dioxide Non
- road Mobile Sources 4.2 4.9 0.7 16% Non
- Point Sources 47.5 48.1 0.6 1% On

- Road Mobile sources 11.3 11.8 0.5 4%

Point Sources

--- --- --- ---

Total 63.1 64.8 1.7 3% VOC, Volatile Organic Compounds Non
- road Mobile Sources 240.0 252.3 12.4 5% Non
- Point Sources 1420.3 1729.4 309.2 22% On

- Road Mobile sources 645.0 494.2

- 150.8

- 23%

Point Sources

--- --- --- ---

Total 2305.2 2475.9 170.7 7% Note: Point sources are not listed because they are specific to the Nogales nonattainment area ; see section 5.2 for our point source discussion. NEI VOC emission estimates shown here do not reflect the corrections described later in this document. Source: Appendix A, Section 4, Tables.
review the differences between the ADEQ emissions inventory andPage 11 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 the 2008 NEI that are described within their submittal, then we will review the submittal for undocumented variances from the NEI, particularly within the non

- road mobile emissions estimates and VOC emissions inventory. 4.1 ADEQ D ocumented Adjustments and Corrections In generating the pollutant specific emission s inventories for the individual source categories, ADEQ used the Santa Cruz County emissions estimates from the 2008 NEI versions 1.5 and 2.0. In some instances, however, ADEQ revised the 2008 NEI data, either based on more accurate local information, or to correct

errors they found in the data. See Appendix A, section 3.2.1 , page 7 and section 4.1 , page 10
. As described in section 3.2.1 of Appendix A , ADEQ did not generate reasonabl y accurate 2008 values for SO 2 and VOCs while estimating on

- road mobile emissions
. After consulting with EPA

Region 9 staff, ADEQ applied an agreed upon methodology to produce more reasonable results. See Appendix A’s appendi ces D and E for discussion an d calculations. In section 4.1, ADEQ documented two adjustments to the 2008
NEI data. While documented in Arizona’s submittal, these adjustments may not be reflected in the 2008 NEI version 3 database at this time. The first adjustment concerned NH 3 emissions from swine livestock operations. ADEQ adjusted the estimate for this source category from 209.9 tons per year toPage 12 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 0.14 tons per year, based on U.S. Department of Agriculture reported hog and pig populations for Santa Cruz County and updated emiss ion factor information. The second adjustment concerned a recurring error in the 2008 NEI data for Arizona where a 761.1 ton per year PM 10 estimate for mining activities was replicated across all Arizona counties. After a n investigation in the Nogales no nattainment area disclose d no mining sources, the PM 2.5 emissions related to mining activity
were removed from the submitted emissions inventory.
U pon review of the rationale and documentation presented for these adjustments to the 2008 NEI data, we concu r with ADEQ’s emissions estimates. These documented changes do not, however, explain the differences we observed within the non

- road mobile source category and the VOC emissions inventory , reviewed further below
. 4.2 Undocumented Adjustments to 2008 NEI Emissions Estimates
As discussed above , w hile most of the pollutant estimates differ slightly as to overall total compared to the 2008 NEI, version 3.0 , the non - road mobile source category shows the largest cross pollutant differences and the VOC emissions inventory show s the largest individual inter

- pollutant differences. Because it crosses all the pollutant inventories , the non

- road source category will be presented first followed by
the review of the VOC emissions inventory.Page 13 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 4.2.1 Non - Road Mobile Source Category Review
Our detailed review of the non

- road mobile source category showed that two source categories were not included in t he ADEQ emissions inventory: l ocomotive emissions were not included in
any pollutant inventories; a nd, pleasure craft , 2

- stroke and 4

- stroke gasoline engines were not included within the VOC emissions inventory. See Appendix A, Table 4.1, pages 12

- 13.
Table 2 below provides a comparison of the differences in
each source category once locomotive emissions are considered. A l arge proportion of the difference s in non

- road mobile source category emissions of PM 2.5 , NO x , and SO 2 are explained by the

o mission of locomotive emissions . The variances across pollutants whe n compared to total pollutant emissions, however, may be insignificant. For example, consider that NO x , the largest omitted locomotive pollutant , amounts to approximately 3 percent of total NO x emissions.
Table 2 , Comparison of 2008 Santa Cruz County Non - Road Mobile Emission Estimates : ADEQ Submitted versus Locomotive Emissions, (NEI version 3.0) All Pollutants (Tons) Difference (NEI vs. ADEQ) Mobile ,

Locomotive Emissions Percent

Difference Explained PM 2.5 , Fine Particulates 2 1.6 80%

NH 3 , Ammonia 0.2 0.02 10% NO x , Oxides of Nitrogen 53 49.5 93% SO 2 , Sulfur Dioxide 0.7 0.5 71% VOC, Volatile Organic Compounds 12.4 2.5 20% Note: “Difference” estimate taken from Table 1 , above
.

The remainder of the disparity between the submitted VOCPage 14 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 emissions inventory and the 2008 NEI version 3.0 VOC emissions estimate for non - road mobile VOC emissions is accounted for by missing emissions estimates from the pleasure craft 2

- and 4

- stroke gasoline engine source cat egory. These emissions equal 10.6 tons per year ( estimate includes exhaust, refueling, and evaporative emissions) , approximately equal to the 9.9 tons left unexplained by the locomotiv e emissions estimate. While it is possible there are no bodies of water in Santa Cruz County or the Nogales nonattainment area to support a pleasure craft emissions estimate , ADEQ did not explain this omission in it s submittal
. 4.2.2 VOC Emissions Inventory Review
Our review of ADEQ’s submitted Santa Cr uz County emissions inventory and the published County NEI version 3.0 emissions inventory disclosed disparities and errors with in each emissions inventory , ADEQ’s submittal and EPA’s NEI version 3.0 reference
document . We r eview here each County VOC emissions inventory to produce a corrected version of each for further comparison and reconciliation.
W hen comparing ADEQ ’s submitted VOC emissions inventory with the 2008 NEI version 3 .0 VOC emissions inventory, we found that the consumer, personal care products source category w as entered twice in the 2008 NEI inventory database under differentPage 15 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 source codes, once by ADEQ and again by EPA. 9 After review, we set aside the ADEQ submitted emissions estimate for consumer, personal care products of 20.6 tons from the non

- point source category estimate in both inventories, submitted and 2008 NEI version 3, (see Tables 3 and 4 below) in favor o f retaining the EPA emissions estimate (see Table 7 below). This leaves 1399.7 tons per year in the ADEQ VOC emission s inventory, s ee Table 3 below , which reflects the correction
. Table 3, Corrected ADEQ VOC Estimates for Santa Cruz County 2008 (Tons)

Source Category ADEQ Submitted Estimates Corrected ADEQ Estimates Non
- road Mobile Sources 240.0 240 .0 Non
- Point Sources 1420.3 1399.7 On

- Road Mobile sources 645.0 645 .0

Point Sources

--- ---

Total 2305.2 2284.7

Next, we did a similar exercise for the published 2008 NEI version 3.0 VOC emissions inventory for Santa Cruz County and our detailed review found double entries or errors in the sub

categories listed in table 4 below. Table 4, 2008 NEI version 3.0 VOC Non - Point Source Category Corrections by Sub - category, Emissions Estimates Removed (Tons) Consumer & Commercial , Household Products 38.6 Consumer & Commercial , FIFRA Related Products 38.2 Consumer , Pesticide Application 29.4 Consumer , Personal Care Products 20.6 Total 126.8

9 ADEQ’s submittal and line item entry to the 2008 NEI used standard source code (SCC) 2465100000, (20.6 tons), instead EPA used SCC 2460100000 (40.8 tons).Page 16 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 Consequently these entries were removed from our comparison NEI version 3.0 emissions inventory leaving the corrected non

- point and VOC emission s inventory below in Table 5. Table 5, Corrected 2008 NEI version 3.0 VOC Estimates for Santa Cruz County (Tons) Source Category NEI version 3 .0 Estimates Corrected NEI version 3 .0 Estimates Non
- road Mobile Sources 252.3 252.3 Non
- Point Sources 1729.4 1602.6 On

- Road Mobile sources 494.2 494.2

Point Sources

--- ---

Total 2475.9 2349.1

C omparing the corrected VOC emissions inventory data from the submittal and the 2008 NEI version 3.0 produces a difference of 64.4 tons, as shown in Table 6 below. Table 6, Comparison of 2008 Santa Cruz County VOC Emissions Estimates: Corrected ADEQ Versus Corrected 2008 NEI version 3.0 (Tons)

Source Category Corrected ADEQ Estimates Corrected

NEI V 3 .0 Estimates Difference Non
- road Mobile Sources 240 252.3

- 12.3 Non
- Point Sources 1399.7 1602.6

- 202.9 On

- Road Mobile sources 645 494.2 150.8

Point Sources

--- --- ---

Total 2284.7 2349.1

- 64.4

To review the VOC source category differences presented in Table 6, we have ex plained the differences in the n on - road mobile sources emissions inventory in Section 4.2.1 , above . The difference in the on

- road mobile sources is explained by the different estimation t echniques used by EPA in generating the 2008 NEI estimate compared to ADEQ’s use of the MOVES model
.Page 17 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 This difference is discussed next in section 4.2.2.1 of this TSD , followed by our further review of the non

- point source VOC emissions estimate , in Section 4.2.2.2
. 4.2.2.1 On - Road Mobile Source VOC Emissions Estimates In estimating on

- road mobile VOC emissions estimates for the 2008 NEI (all versions), EPA integrated the MOVES on - road mobile emissions factor model with the SMOKE19 emission s inventory model (hereafter referred to as “SMOKE

- MOVES”) to take advantage of the gridded hourly temperature informa tion available from meteorological data and to better account for the temperature sensitivity of on

- road emissions. 10 SMOKE

- MOVES requires emission rate “lookup” tables generated by MOVES that differentiate emissions by process (running, start

- up , vapor venting, etc.), vehicle type, temperature, speed, and hour of day, among other parameters . To generate the MOVES emission
rates that could b e applied across the U nited States (U.S.) , EPA used an automated process to run MOVES to produce emission factors by temperature and speed for 146 “representative counties” to which every other U.S. county could be mapped. In th e case of Arizona’s submitt ed emissions inventories , we believe that t he on - road mobile VOC emissions estimates provided

10 2008 Nat ional Emissions Inventory, version 3 Technical Support Document (Draft), U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, September 20 13 , pp. 112

- 123. See the following link: http://www.epa.gov/ttn/chief/net/2008neiv3 /2008_neiv3_tsd_draft.pdfPage 18 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 by ADEQ are a more accurate and representative estimate because they are specific to Santa Cruz County, rathe r than a representation of the C ounty , as used by EPA in the NEI to produce emission rates that could be used nationally. 4.2.2. 2 Non - point S ource VOC Emissions Estimates A comparison of the corrected ADEQ and NEI version 3.0 non

point source VOC emi ssion s inventories shows undocumented omissions of several source categories within the submitted VOC emissions inventory . See Table 7 below. These omi tted source categories a ccount for the 202.9 tons difference between the two

non - point source emissions estimates for ADEQ and the NEI version 3.0 , shown in T able 6. Table 7, 2008 NEI version 3.0 Santa Cruz County Non - point Source VOC Emissions Omitted from ADEQ 2008 Emissions Estimates (Tons) Source Category Dry Cleaning , All Processes 2.9 Consumer & Commercial , All Personal Care Products 40.8 Consumer & Commercial , All Auto Aftermarket Products 29.2 Consumer & Commercial , All Coatings & Related Products 20.4 Consumer & Commercial , All Adhesives & Sealants 12.2 Consumer & Commercial , Misc. Products (Not covered elsewhere) 1.5 Surface Coating s , Architectural Coatings 51.7 Surface Coatings , Traffic Markings 13 .0 Surface Coatings , Machinery & Equipment: SIC 35 0.1 Petroleum Product Storage , Residential & Commercial Portable Gas Cans* 26.7 Petroleum Product Storage , Airport/Aviation Gasoline: Stage 1 losses 3.3 Petroleum Product Storage , Airport/Aviation Gasoline: Stage 2 losses 0.2 Petroleum Product Storage , Storage & Transport, Trucks 0.7 Total 202.7 *Includes permeation, evaporation, diurnal losses, vapor displacement in filling, and spillage
.Page 19 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 4.2.3 Ammonia, Non - point Source Emission s Estimates Our review of the Santa Cruz County ammonia emissions inventory showed that n on - point so urce , residential fuel combustion natural g as emissions in the amount of 2.9 tons was omitted from the ADEQ submittal. While not significant in magnitude , this omission explains a large proportion of the difference in non - point source ammonia emission s between the ADEQ submittal and the 2008 NEI ver sion 3.0
. See Table 1, above. 5.0 Nogales Nonattainment Area Estimates As explained in our review of the ADEQ submitted emissions inventory methodology, most of the Santa Cruz County emissions estimates are allocated to the Nogales nonattainment area by two factors, population size and land area. Most source categor y emissions were allocated by population, with the following exceptions : a gricultur e and related ac tivities and prescribed forest burning emissions were allocated by land area; point

source emissions were allocated by location within the Nogales nonattainment area
. The tables in Section 4 of Appendix A show the individual allocations for each source c ategory. See Appendix A, Tables 4.1

- 4.4. We concur with the allocation assignments ADEQ has chosen. Section 5 of Appendix A describes the methods for estimating 2010 Nogales nonattainment area emissions inventoriesPage 20 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 from the 2008 emissions inventories. In general, population based human activity and resulting emissions were forecasted t o grow at the same rate as population growth from 2008 to 2010, 1.1 percent. See p ages 9 and 29 of Appendix A. For s ource categories that represented an economic enterprise / activity , those resulting emissions were assigned a no

- growth factor, given the e conomic recession of the time period. ADEQ developed 2010 on

- road mobile emission s estimates for Santa Cruz County via MOVES as described in section 3.2.1 of Appendix A and allocated by population. P oint source estimates for 2010 were held constant, again assuming no

- growth because of the economic recession of the time period. The tables within Section 5 of Appendix A show the individual growth assignment for each source category. We concur in the assignments ADEQ has chosen.
No table exceptions from the population and land use allocation rationale are locomotive emissions and point source emissions. We review each source category below in Sections 5.1 and 5.2
. 5.1 Locomotive Emissions Estimates
Santa Cruz County locomotive activity and resulting emission s may be allocated by estimat ing track mileage in the Nogales nonattainment area
. Using GIS mapping, w e e stimate that 11 of 29.8 county track miles are in the Nogales nonattainment

area ; therefore, the allocation ratio is 0.4. Consistent withPage 21 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 other economic activities and their expected growth, we assume that there was no growth in rail travel and transport of goods , given the economic recession of the time period. See Table 8 below for results. Table 8, 2008 and 2010 N on - Ro ad Mobile , Locomotive Emissions Allocated to Nogales Nonattainment Area , NEI version 3 .0 (Tons)

All Pollutants Santa Cruz County Nogales

Nonattainment Area PM 2.5 , Fine Particulates 1.6 0.64

NH 3, Ammonia 0.02 0.008 NO x , Oxides of Nitrogen 49.5 19.8 SO 2 , Sulfur Dioxide 0.5 0.2 VOC, Volatile Organic Compounds 2.5 1 .0

5.2 Point Source Emissions Estimates ADEQ determined that there are two point sources in the Nogales nonattainment area : the Nogales International Airport and the Valencia Power Plant. We concur with their findings and individual estimates for each source . The 2008 and 2010 individual emission s estimates for these two point sources are provided in Appendix A, Table 4.4 and Table 5.4, respectively, and assume no growth given the economic recession during this timeframe . See Table 9 below for an aggregated presentation of estimated point source emissions.Page 22 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 Table 9, 2008 and 2010 Nogales Nonattainment Area Point Source Emissions (Tons)
All Pollutants Nogales N onattainment A rea PM 2.5 , Fine Particulates 1. 4

NH 3 , Ammonia

--- NO x , Oxides of Nitrogen 11.1 SO 2 , Sulfur Dioxide 0.5 VOC, Volatile Organic Compounds 3.3

5.3 Estimated Omissions in Submitted Nogales Nonattainment Area Emissions Inventories In this section, we consolidate and present the emissions
not accounted for within the submitted Nogales PM 2.5 and precursor pollutant inventories.

 Within the PM 2.5 , NOx , and SO 2 emissions inventories, the

non - road locomotive emissions not accounted for are 0.64, 19.8, and 0.2 tons per year, respectively. See Table 8 above for the derivation of Nogales nonattainment area emission estimates from Santa Cruz County estimates.

 Within the NH 3 emission s inventory, the omitted emissions
from the non

- point source, residential fuel combustion, natural gas source category equal 1.9 tons per year when allocated from the Santa Cruz County emissions estimate to the Nogales nonattainment area by the population a llocation factor (0.661). See Section 4.2.3 above.

 We determined that the submitted VOC emissions inventory had the largest number of source categories and amount ofPage 23 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 emissions estimate s omitted from the reference 2008 NEI

ver s ion 3.0 VOC emission s inve ntory. With the exception of

non - road locomotive emissions, the Santa Cruz County emissions are estimated and allocated to the Nogales nonattainment area by the population allocation factor (0.661). See Table 10 below.
Table 10 , Estimated Nogales Nonatta inment Area VOC Emissions Omitted from ADEQ 2008 Emissions Estimates (Tons) Source Category Santa Cruz County Nogales

NA Dry Cleaning, All Processes 2.9 1.9 Consumer & Commercial, All Personal Care Products 40.8 27.0 Consumer & Commercial, All Auto Aftermarket Products 29.2 19.3 Consumer & Commercial, All Coatings & Related Products 20.4 13.5 Consumer & Commercial, All Adhesives & Sealants 12.2 8.1 Consumer & Commercial, Misc. Products (Not covered elsewhere) 1.5 1.0 Surface Coatings, Architectural Coatings 51.7 34.2 Surface Coatings, Traffic Markings 13 .0 8.6 Surface Coatings, Machinery & Equipment: SIC 35 0.1 0.07 Petroleum Product Storage, Residential & Commercial Portable Gas Cans* 26.7 17.6 Petroleum Product Storage , Airport/Aviation Gasoline: Stage 1 losses 3.3 2.2 Petroleum Product Storage , Airport/Aviation Gasoline: Stage 2 losses 0.2 0.1 Petroleum Product Storage , Storage & Transport, Trucks 0.7 0.5 Non
- road Mobile, Locomotive 2.5 1 Non
- road Mobile , 2

- and 4

- Stroke Gasoline Engines , Pleasure Craft 10.6 7.1 Total 202.7 142.2 *Includes permeation, evaporation, diurnal losses, vapor displacement in filling, and spillage

5. 4 Review and Analysis of Total Emissions Estimates and Omitted Emissions Estimates
The total emissions estimate s for each pollutant show a 0

- 15 percent reduction from 2008 to 2010. The emissions reductionsPage 24 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 are primarily due to federally mandated engine standards and cleaner burning diesel fuels causing reductions in on

- road mobile

sou rce emissions. See Table 1 1 below and Appendix A, Table 6.1 for detailed source category estimates.

T able 1 1 , Nogales Nonattainment Area Estimated Emissions (Tons)

Pollutant 2008 2010 Percent Change PM 2.5 , Fine Particulates 435.6 433.9 0%

NH 3 , Ammonia 37.4 36.1

- 3% NO x , Oxides of Nitrogen 1115.4 946.8

- 15% SO 2 , Sulfur Dioxide 39.1 36.2

- 7% VOC, Volatile Organic Compounds 1490.8 1445 .0

- 3% Source: Appendix A, Table 6.1 , page 28. These emissions estimates are not corrected , per the above discussion , because we will propose to approve the emission s inventories as submitted
. To assess the magnitude of the previously identified omitted emissions estimates for all pollutants, but primarily VOC
and NO x , the omitted emissions estimates were compared to th e submitted total estimates for each pollutant (s ee Table 1 2
below )
. The range of variability is 0

- 10 percent, with VOC emissions being under

- reported by 10 percent. The four remaining pollutant emissions inventories show an under

- estimate of 5 percent or less
.Page 25 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 Table 1 2 , Comparison of ADEQ’s 2008 and 2010 Nogales Nonattainment Area Estimated Emissions to Omitted Emissions by Pollutant.

Pollutant Estimated Omissions 2008 Percent of 2008 2010 Percent of 2010 PM 2.5 , Fine Particulates 0.6 435.6 0 % 433.9 0 %

NH 3 , Ammonia 1.9 37.4 5 % 36.1 5 % NO x , Oxides of Nitrogen 19.8 1115.4 2% 946.8 2% SO 2 , Sulfur Dioxide 0.2 39.1 1 % 36.2 1 % VOC, Volatile Organic

Compounds 1 4 2.2 1490.8 10 % 1445 .0 10 % Source: 2008 and 2010 emissions are taken from Appendix A, Table 6.1. Estimated omissions are taken from Tables 8 and 10 of this TSD , and ammonia non - point emissions estimates
. See Section 5.3 above for derivation of estimated omissions.

6.0 Summary and Conclusion
We concur with the overa ll methodology, basis for allocating county
- level emissions to the nonattainment area, and allocation calculations used to produce the Nogales nonattainment

area emissions inventories for PM 2.5 and its precursor pollutants. Considering the review of and c omparisons between the submitted baseline 2008 Santa Cruz County emissions and the subsequent NEI version 3.0, we found the r ange of variability to be 1

- 7 percent when considering the uncorrected totals within the emission s inventory database s ( see Table 1 of this TSD )
. After the emissions estimates were corrected, the variance of the total VOC emissions estimate , the source category with the highest total difference , is reduced to 3 percent ( see Table 6 )
. As presented in Table 1 2 , NEI version 3.0 emissions data omitted from the submitted Nogales nonattainment area emissions inventories range from 0

- 10 percent with four of five pollutant inventories showingPage 26 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 equal to or less than 5 percent total variance or under

report ing , and three of the pollu tant inventories show ing 2 percent or less variance or under

- report ing
. With regard to the completeness of the submitted emissions inventories and overall emissions estimates for the Nogales nonattainment area , ADEQ’s omission of the locomotive source category slightly affects the overall Nogales nonattainment area emissions estimates for PM 2.5, NO x , and SO 2 (see Table 12). T he NH 3 emissions inventory is affected similarly by the omission of residential gas heating emissions, but only by 5% of a relatively small total emissions inventory (see Table 12). Although the submitted VOC emissions inventory shows the largest number of unreported source categories and under

- estimat ed emissions, the amount of omitted emission estimates is mostly offset by the more
accurate o n - road mobile VOC emissions estimates, i.e., compare the 14 2.2 tons per year under

- report (see Table 10) to a 99.7 tons per year increase supported by ADEQ’s use of Santa Cruz County specific data within MOVES (see discussion in section 4.2.2.1)
. 11 To conclude, we find that P M 2.5 , N H 3 , N O x , and S O 2 , four of

11 See Table 1 for the 150.8 ton difference in the submitted Santa Cruz County on - road mobile VOC emissions es timate and the similar 2008 NEI version 3.0 emissions estimate . These additional 150.8 tons are allocated to the Nogales nonattainment area according to popula tion share (0.661) providing a source category emissions estimate adjustment of 99.7 tons per year. For reference, the VOC estimates in Table 12 incorporate this adjustment.Page 27 of 27 Technical Support Document for Proposed Rule, Docket EPA

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- 0450 five emissions inventories , show little or no variance as derived
from our reference emissions inventory, the 2008 NEI version 3.0 emissions inventory
. As described above, t he total VOC emissions inventory, considering i ts omitted source categories, shows a small overall difference of 3

- 10 percent when compared to either the 2008 NEI version 3.0 Santa Cruz C ounty baseline emissions inventory, or to the Nogales nonattainment area calculations
. We consider this variance to be small in the
context of the overall PM 2.5 emissions inventories
. Consequently,

we are proposing to find that Arizona’s submitted 2008 and 2010
P M 2.5 , N H 3 , N O x , S O 2 , and VOC emissions inventories meet the CAA

s ection 172(c)(3) requirement to provide a comprehensive,
accurate , and current inventory of actual emissions for the Nogales P M 2.5 nonattainment area
.