1



# Technical Support Document for EPA’s Proposed Action on the State of New Mexico ’s 2009 Infrastructure State Implementation Plan ( Transport Portion) for the 2006 24
- hour Fine Particulate ( PM2.5 ) National Ambient Air Quality Standard

**U.S. EPA Region 6**  **Feb ru**  **ary 2012** 2 For information on this technical support document, please contact: Erik Snyder Office of Air Quality

Assessment and Anal ys is U.S. Environmental Protection Agency

– Region 6

1445 Ross Ave. Suite 1200 Dallas, Texas 75202 ( 214 ) 665
- 7305 snyder.erik@epa.gov3



### Table of Contents I. Interstate Transport and New Mexico A. Clean Air Act Section 110(a)(2)(D)(i)(I) Requirements for the 2006 Fine Particulate Standards B. Summary

of Transport Assessment 1. Transport to Nonattainment Receptors in Western States 2. Transport to Maintenance Receptors in Western States 3
. Transport to Nonattainment and Maintenance Receptors in Eastern States C. Conclusion II. State of New Mexico ’s Assessment of Transport A. Summary

of State of New Mexico ’s Assessment of Transport B. EPA’s Evaluation of the State of New Mexico ’s Assessment of Transport III. Transport Assessment Methodology A. Discussion of Nonattainment and Maintenance Receptor Selection Methodology B
. Factors Considered in the Transport Anal ys is for Non attainment and Maintenan c e Receptors IV
. Transport Assessment for Non attainment Receptors A. Introduction B. Transport to Nearb y States 1. Utah C. Transport to Other Western States

– Nevada, California, Oregon, Washington, Id aho, and Montana 1. Nevada 2. California 3. Oregon 4
. Washington 5
. Id aho 6
. Montana D
. Transport to Eastern States V. Transport Assessment for Maintenance Receptors A. Introduction B
. Transport to Nearb y States 1
. Arizona 2. Utah 3. California C. Transport to Eastern States4



### Appendices Appendix A

– Non attainment and Maintenance Receptors List 1. List of Nonattainment and Maintenance Receptors Appendix B

– Non attainment Receptors 1. EPA Region 8 States

– Montana and Utah 2. EPA Region 9 States

– California and Nevada 3. EPA Region 10 States

– Id aho, Oregon, and Washington Appendix C

– Maintenance Receptors 1. EPA Region 8 States

– Utah 2. EPA Region 9 States

– California and Arizona Appendix D

– PM2.5 Data

– IM PROVE Data for Utah, Nevada , and California/Oregon Border Sites for the Years 2006

- 2010 1. Map of IMPROVE Monitoring Sites 2. Utah

– IMPROVE Data for the Years 2006

- 2010 3. Nevada

– IMPROVE Data for the Years 2006

- 2010 4. California/Oregon Border

– IMPROVE Data for the Years 2006

- 2010 Appendix E

– Additional Technical Data for Greater Salt Lake Area, Utah and Butte, Montana 1. Salt Lake City, Utah PM2.5 Data from 2006
- 2010 2. Butte, Montana PM2.5 Data from 2007

- 2010 3. Butte, Montana PM2.5 Speciation Data1

**I. Interstate Tr ansport and**  **New Mexico I.A. Clean Air Act**  **Section 110(a)(2)(D)(i)(I) Requirements**  **for the**  **2006 Fine Particulate Standard**  **s** Section 110(a)(2)(D)(i)(I) of the Clean Air Act (CAA) requires each state to prohibit emissions that contribute significantly to nonattainment, or interfere with maintenance , in any other state with respect to any primary or secondary nation al ambient air quality standard (NAAQS )

. The New Mexico Department of Environmental Quality (NMED ) submitted a letter , and supporting documentation on October 14, 2009 certifying that NMED has evaluated the New Mexico SIP , and found that the existing SIP does satisfy all the requirements of CAA section 110(a)(2)(D)(i)(I) for the 2006 PM2.5 NAAQS and n o further revisions are necessary

. The supporting documentation included a relevant technical anal ys is supporting New Mexico's conclusion as recommended by EPA's guidance memorandum that provides recommendations to states for making SIP submissions to meet the requirements of CAA section 11 O(a)(2)(D)(i) for the 2006 PM2.s NAAQS ("2006 PM2.s NAAQS Infrastructure Guidance" or "Guidance")

. 1 Based on our evaluation of NMED ’s submittal and other technical information , as discu ssed further below, we are proposing to approve the PM2.5 Transport Anal ys is and to conclude that additional control measures in New Mexico are not necessary under CAA section 110(a)(2)(D)(i)(I) for the 2006 24
- hour PM2.5 NAAQS because emissions from New M exico sources do not contribute significantl y to nonattainment or interfere with maintenance of these standards in any other state

.

1 See Memorandum from William T. Harnett entitled "Guidance on SIP Elements Required Under Sections 110(a)(l) and (2) for the 2006 24

- Hour Fine Particle (PM25) National Ambient Air Quality Standards (NAAQS)," September 25, 2009, available at http://www .epa .gov/ttn/caaa!t I /memoranda/20090925 harnett_pm25 sip 110a l2.pdf.; and See Memorandum from William T. Harnett entitled “Guidance for State Implementation Plan (SIP) Submission to Meet Current Outstanding Obligations Under Section 110(a)(2)(D)(i) for the 8
- hour ozone and PM2.5 National Ambient Air Quality Standards,” August 15, 2006, available at http://www.epa.gov/ttn/caaa/t1/memoranda/section110a2di_sip_guidance.pdf.2

**I.B. Summary of Transport Assessment I.B.1. Transport to Nonattainment Receptors**  **in Western States** EPA reviewed the s tate of New Mexico ’s PM2.5 Transport Anal ys is and additional technical information to evaluate the potential for New Mexico emissions to contribute significantly to nonattainment of the 2006 PM2.5 NAAQS at specified monitoring sites in the western United S tates
. EPA first identified as “nonattainment receptors” all monitoring sites in the western states that had recorded PM2.5 design values above 35 micrograms per cubic meter ( μg/m3), the level of the 2006 24

- hour PM2.5 NAAQS, during the ye ars 2008
- 2010. 2 See section III below (discussing EPA’s methodology for selection of nonattainment receptors, and providing a list and map of western receptors). As pollution is transported from the source area to a downwind receptor, dispersion of the pollutant both v ertically

and horizontally

occurs that results in ambient concentrations decreasing the further the distance away from the emission source on a general mathematical order of a 1/ (distance) x where initially the power x is approximately 2 and at longer distances the power x value is between 1 and 2

. Therefore, g eographic distance from a geographical area source of emissions to a downwind receptor area is an important relevant factor because the further away a receptor is from New Mexico’s emissions, the lower the potential ambient concentrations will be from New Mexico’s emissions if transport did occur. Therefore in the assessment of potential pollution transport, EPA first focused its review on information related to potential transport of PM2.5 pollution from New Mexico to the states bordering New Mexico : Arizona, Utah, Colorado, Oklahoma, and Texas. Of these bordering states, EPA identified only Utah as having a nonattainment rec eptor. As discussed further below, EPA believes that the following factors support a finding that emissions from New Mexico does not significantl y contribute to nonattainment of the 2006 PM2.5 NAAQS in Utah: (1) technical information indicating that elevated PM2.5 levels at nonattainment re ceptors are predominantly caused by

local emission sources, (2) air quality data indicating that regional background levels of PM2.5 are generall y low during the time periods of elevated PM2.5 at these receptors, (3) the distance to the receptor in the northwest quadrant of Utah, and (4) the presence of significant terrain, which creates a physical impediment to pollution transport. EPA also evaluated potential PM2.5 transport to potential nonattainment receptors in the more distant western states of Cali fornia, Nevada, Oregon, Washington, Idaho, Wyoming, and Montana. EPA believes that the following factors support a finding that emissions from New Mexico do not significantly contribute to nonattainment of the 2006 PM2.5 NAAQS in any of these states (excluding California): (1) the significant distance from the State of New Mexico to the nonattainment receptors in these states, (2) technical information indicating that elevated PM2.5 levels at nonattainment receptors in these states are predominantl y caused by local emission sources, (3) air quality data indicating that regional background levels of PM2.5 are generall y low during the time periods of elevated PM2.5 at these receptors, and (4) the presence of significant terrain, which creates a phys ical impediment to pollution transport. With respect to

2 Because CAIR did not cover states in the western United States, these data are not significantly impacted by the remanded CAIR . In contrast, recent air quality data in the eastern, midwestern and southern states are significantly im pacted by reductions associated with CAIR.3

California, technical information indicating that elevated PM2.5 levels at the nonattainment receptors are predominantly caused b y local emission sources and that the dominant air flows across California are from the west to the east support a finding that emissions from the state of New Mexico do not significantly contribute to nonattainment of the 2006 PM2.5 standards in California. We discuss these evaluations in more detail below. **I.B.2. Transport to Maint enance Receptors**  **in Western States** EPA reviewed the s tate of New Mexico ’s PM2.5 Transport Anal ys is and additional technical information to evaluate the potential for New Mexico emissions to interfere with maintenance of the 2006 24
- hour PM2.5 standards at specified monitoring sites in the western U.S. EPA first identified as “maintenance receptors” all monitoring sites in the western states that had recorded PM2.5 design values above the level of the 2006 24

- hour PM2.5 NAAQS ( 35 μg/m3) during the 2006
- 2008 and/or 2007
- 2009 periods but below this standard during the 2008

- 2010 period

. 3 See section III below (discussing EPA’s methodology for selection of maintenance receptors). A ll of these maintenance receptors in the western states are located in Arizona , Utah and California

. EPA thus evaluated the potential for transported New Mexico emissions to interfere with maintenance of the NAAQS at Arizona, Utah and California receptor locations

. 4 EPA believes that the following factors support a finding that emissions from sources in the State of New Mexico do not interfere with maintenance of the 2006 PM2.5 NAAQS in Arizona and Utah: (1) the significant distance from the State of New Mexico and the sources of New Mexico’s PM2.5 pollution to the maintenance receptors in these states, (2) technical information indicating that elevated PM2.5 levels at maintenance receptors in these states are predominantly caused b y local emission sources, (3) air quality data indicating that regional background levels of PM2.5 are generall y low during the time periods of elevated PM2.5 at these receptors, and (4) the presence of significant terrain, which creates a phys ical impediment to pollution transport. With respect to California, technical information indicating that eleva ted PM2.5 levels at the maintenance receptors are predominantly caused b y local emission sources and that the dominant air flows across California are from the west to the east support a finding that emissions from sources in th e state of New Mexico do not interfere with maintenance of the 2006 PM2.5 standards in California. We discuss these evaluations in more detail below. **I.B. 3**  **. Transport to Non**  **attainment and Maintenance Receptors in Eastern States**  EPA has also considered potential PM2.5 transport from New Mexico emission sources to the nearest potential nonattainment or maintenance receptors located in the eastern states within the domain of the modeling anal ys is for the Cross State Air Pollution Rule (CSAPR) (76 FR 48208 )

. The nearest nonattainment and/or maintenance receptor identified in the 2012 CSAPR modeling

3 As noted above, EPA can consider data from these years for state s in the western United States as such data is not im pacted by the remanded CAIR. 4 As this analysis is focused on interstate transport, EPA did not evaluate the impact of New Mexico emissions on maintenance receptors within New Mexico

.4

anal ys is is in Madison County , Illinois

. The CSAPR modeling did not analyze the contribution of New Mexico sources to Madison County , Illinois. Thus, EPA analyzed the magnitude of New Mexico ’s sulfur dioxide ( SO 2 ) and nitrogen oxides (NOx ) emissions relative to states found to have emissions that significantly contribute to nonattainment at that receptor. EPA also considered the distance of New Mexico from Madison County, Illinois relative to states found to significantl y contribute there. EPA believes that the following factors in comparison to other areas support a finding that emissions from New Mexico sources do not significantly contribute to nonattainment or interfere with maintenance of the 2006 24

- hour PM2.5 NAAQS at this location : (1) the relatively small magnitude of the emission inventory of PM2.5 precursors (SO 2 and NOx) in New Mexico combined with (2) the relatively long distance between the nearest portion of the s tate of New Mexico to the Madison County , Illinois receptor

. EPA believes that these factors also support a finding that emissions from New Mexico sources do not contribute significantl y to nonattainment or interfere with maintenance of the 2006 24
- hour PM2.5 NAA QS at any of the other CSAPR receptors, all of which are f arther from New Mexico than Madison County , Illinois and are less likely for New Mexico’s emissions to impact

. **I.C. Conclusion** EPA ’s review of available technical information and air quality data supports the conclusion in New Mexico ’s PM2.5 Transport Anal ys is that emissions of direct PM2.5 and PM2.5 precursors from the s tate of New Mexico do not significantly contribute to nonattainment in, or interfere with maintenance by , any other state with respect to the 2006 24
- hour PM2.5 standards

. Based on our evaluation of New Mexico ’s PM2.5 Transport Anal ys is and additional technical information, as discussed further below, EPA proposes to conclude that emissions of direct PM2.5 and PM2.5 precurso rs from the s tate of New Mexico do not significantly contribute to nonattainment or interfere with maintenance of the 2006 24
- hour PM2.5 standards in any other state and that CAA section 110(a)(2)(D)(i)(I) therefore does not require New Mexico to adopt additional controls to prohibit such impacts

. **II. State of New Mexico**  **’s Assessment of Transport II.A. Summary of State of**  **New Mexico ’s Assessment of Transport**  New Mexico ’s PM2.5 Transport Anal ys is contains the State’s assessment of the potential for emissions of PM2.5 and PM2.5 precursors from New Mexico sources to significantl y contribute to nonattainment or interfere with maintenance of the 24

- hour PM2.5 standards in any other state. 5 The state considered distance, topography and meteorology , stating that , “ The closest PM2.5 nonattainment area to New Mexico is approximately 600 miles away

in northwestern Utah. ” The state also considered the level of emissions in the s tate of New Mexico , and PM2.5 monitoring data. Based on these analyses, NMED conclude d that “ Due to the lack of PM2.5 nonattainment areas in or within close proximity to New Mexico, NMED has concluded that no revisions to the state’s 2007 SIP revision for 110(a)(2)(D)( i) are necessary at this time .” 6

5 See NM letter to EPA June 12, 2009. 6 Id.5

**II.B. EPA’s Evaluation of th e State of**  **New Mexico ’s Assessment of Transport** 

. EPA reviewed NMED’s analysis and a s explained in Section III below , EPA has supplement ed its evaluation of the PM2.5 Transport Anal ys is with additional technical information consistent with the methodologies and anal ys es developed in the Transport Rule (also called the “Cross

State Air Pollution Rule”) 7 and the 2005 “Clean Air Interstate Rule

. ” 8 Our proposed action takes into account both the State’s assessment in the PM2.5 Transport Anal ys is and our own supplemental assessment of relevant technical information , including the characteristics of the formation of elevated PM2.5 at nonattainment and maintenance receptors in neighboring states, and ambient PM2.5 levels at monito ring sites representative of regional background in nearb y states. This information is discussed further below. EPA’s supplemental anal ys is supports New Mexico’s conclusion that no further controls are necessary to prevent contribution to nonattainment o r interference with maintenance of the 2006PM2.5 NAAQS in areas outside New Mexico

. **III. Transport Assessment Methodology**  **III. A.**  **Discussion of Non attainment**  **and Maintenance Receptor Selection Methodology**  On September 25, 2009, EPA issued a guidance memo randum that provides recommendations to states for making submissions to meet the requirements of CAA section 110(a)(2)(D)(i) for the 2006 24
- hour PM2.5 standards. See Memorandum from William T. Harnett, Director, Air Quality Policy Division, to Regional Air Division Directors, Regions I

- X, “Guidance on SIP Elements Required Under Sections 110(a)(1) and (2) for the 2006 24

- Hour Fine Particle (PM2.5 ) National Ambient Air Quality Standards (NAAQS) , ” September 25, 2009 ( “2006 PM2.5 NAAQS Infrastructure Guidance” or “ Guidance ” ). 9 The Guidance recommends that each state explain in its section 110(a)(2)(D)(i)(I) SIP whether or not its emissions contribute significantl y to nonattainment or interfere with maintenance of the NAAQS in any other state, and to address any such impacts. See Guidance at 3, 4. The Guidance states as follows: The state's conclusion must be supported b y an adequate technical analysis. Information to support the state's determination with respect to significant contribution to nonattainment might include, but is not limited to, information concerning emissions in the state, meteorological conditions in the state and the potentially impacted states, monitored ambient concentrations in the state and the potentially impacted states, the distance to the nearest area that is not attaining the NAAQS in another state, and air quality modeling. The EPA believes that it would be appropriate for states to make this assessment by

considering the impact of current or future emissions on nearby nonattainment areas, and evaluating the air quality impact and potential mitigation strategies. 10

7 75 FR 45210 (August 2, 2010) (proposed Transport Rule) and 76 FR 48208 (August 8, 2011) (final Transport Rule). 8 70 FR 25172 (May 12, 2005). 9 Available at: http://www.epa.gov/ttn/caaa/t1/memoranda/20090925_harnett_pm25_sip_110a12.pdf 10 Guidance at 3.6

T o determine whether the CAA section 110(a)(2)(D)(i)(I) requirement is satisfied , EPA must determine whether a s tate’s emissions contribute significantl y to nonattainment or interfere with maintenance in downwind areas. If this factual finding is in the negative, then section 110(a)(2)(D)(i)(I) does not require any changes to a state’s SIP. I f, however, the evaluation reveals that emissions from sources within the state do contribute significantly to nonattainment or interfere with maintenance in other states, then the state must adopt substantive provisions to eliminate those emissions. The state could a chieve any required reductions through traditional command and control programs, or at its own election, through participation in a cap and trade program. Consistent with EPA's approach in the 1998 NOx SIP c all , the 2005 CAIR , and the 2011 Transport Rule, 11 EPA is evaluating these impacts with respect to specific monitors identified as having nonattainment and/or maintenance problems, which we refer to as “receptors.” 12 EPA notes that no single piece of information is by itself dispositive of the issue. Instead, the total weight of all the evidence taken together is used to evaluate significant contributions to nonattainment or interference with maintenance of the 2006 24

- hour PM2.5 NAAQS in another state. A receptor may

be a downwind location that is currently violatin g the PM2.5 NAAQS, has violated in the past, is projected to violate in the future, or may have trouble maint aining the NAAQS in the future. Nonattainment and maintenance receptors can be identified using future ye ar modeling, recent ambient data, or both. If appropriate future ye ar modeling is not available , 13 nonattainment and maintenance receptors can be identified using recent ambient air quality monitoring data. For this action, we evaluated the three most recent consecutive 3

- ye ar periods for which complete, quality

- assured and certified air quality

data were available (covering a 5

- year period) to calculate “design values” 14 for those periods

. Because EPA uses the most recent 3

- ye ar design value period for purposes of promulgating air quality

designations and redesignations, it is logical to use the most recent 3

- ye ar period to identify

“nonattainment” receptors. However, previous violations of the NAAQS are indicative of an air quality problem that may

return in the future. The year to year variability of emissions and/or meteorology may cause an area to have trouble maintaining the NAAQS in the future. Therefore, we have identified “maintenance” receptors by examining previous ye ars of data. This methodology is conceptuall y similar (although not identical) to the methodology that EPA used in the CSAPR to identify “nonattainment” and “maintenance” receptors. We applied the following m ethodology :

11 See NO x SIP Call, 63 FR 57371 (October 27, 1998); CAIR, 70 FR 25172 (May 12, 2005); and Transport Rule or Cross
- State Air Pollution Rule, 76 FR 48208 (August 8, 2011). 12 Air quality designations are not relevant to the methodology for identifying these “receptors .” 13 Available modeling data should be evaluated for the intended purpose. If modeling data is used to establish nonattainment and/or maintenance receptors, it should be for an appropriate future year (within the time frame of dow nwind attainment dates) and model performance should be shown to be acceptable for the upwind and dow nwind areas being considered. 14 “Design value” means the “calculated concentration according to the applicable appendix of [40 CFR part 50] for the highest site in an attainment o r nonattainment area.” 40 CFR 58.1 (definitions).7

Similar to the CSAPR analysis, we examined ambient data which spanned a 5

- year period. This allows examination of year to year variability. The three most recent consecutive three

- ye ar design value periods are 2006
- 2008, 2007
- 2009, and 2008
- 2010
. 15 1) N onattainment receptors are those sites that are violating the NAAQS in the most recent 3
- ye ar period

. 16 2) Maintenance receptors are those receptors that show attainment in the most recent 3
- year design value period (2008

- 2010) but violated the NAAQS in at least one of the previous two periods (2006

- 2008 and/or 2007

- 2009)

. Ambient data included the three most recent official design value periods availab le at the time of the anal ys is. The official design values are posted by EPA’s Office of Air Quality Planning and Standards ( OAQPS ) on the Air Trends website and are available at : http://www.epa.gov/airtrends/values.html

. A list of receptors selected for this int er stat e transport anal ys is is shown below in Figure III.A.1., and the corresponding map of receptors is shown below in Figure III.A. 2. Receptors with PM2.5 design values above the PM2.5 standard of 35μg/m 3 for the years 2008 through 2010 are listed as nonattainment receptors. Receptors with PM2.5 design values at or below the PM2.5 standard of 35μg/m 3 for 2008

- 2010 but above the standard for at least one of the previous 3

- ye ar periods (2006

- 2008 or 2007
- 200 9) are l isted as maintenance receptors. Based on this methodology , N ew Mexico, Colorado , and Wyoming do not contain any nonattainment or maintenance receptors

. To evaluate the potential for significant contribution to nonattainment in other states , EPA first evaluated potential transport to the nearest states with identified nonattainment receptors. The states bordering New Mexico with nonattainment receptors are Utah

. EPA then evaluated potential transport to other western states with nonattainment receptors located farther away , i.e., California, Nevada, Oregon, Wa shington, Idaho, and Montana. To evaluate the potential for interference with maintenance in other states , EPA evaluated potential transport to m aintenance receptors in Utah, Arizona and California , which are the onl y western states (outside of New Mexico ) with identified maintenance receptors.

15 As noted above, EPA can consider data from these years for states in the western United States as such data is not im pacted by the remanded CAIR. 16 When evaluating recent design values, it is not necessary to average the design values together to create a five

year weighted average. Weighted average data is only necessary when projecting modeling data to the future, since mo deled projections are generally based on only a single year (or less) of modeled meteorology.8 **Table III.A.1**  **. List of**  **Western Counties with**  **Daily PM2.5**  **Nonattainment or**  **Maintenance Receptors** 

**State County**  **AIRS ID**  **Design Value 20**  **06 -**  **08 Design Value** 

**20 07**  **- 09**  **Design Value**

**20 08**  **- 10**  **Receptor**

**Type** New Mexico Pinal 040213013 48 NA 40 NA 31 A Maintenance New Mexico Santa Cruz 040230004 40 NA 31 A 32 A Maintenance California Alameda 060010007 36 NA 34 A 30 A Maintenance California Butte 060070002 69 NA 59 NA 51 NA Nonattainment California Fresno 060190008 58 NA 60 NA 54 NA Nonattainment California Imperial 060250005 36 NA 34 inc

- a 32 inc

- a Maintenance California Inyo 060271003 34 inc

- a 38 NA 36 NA Nonattainment California Kern 060290016 70 NA 70 NA 65 NA Nonattainment California Kings 060310004 52 NA 53 NA 49 NA Nonattainment California Los Angeles 060370002 41 NA 42 NA 38 NA Nonattainment * California Merced 060472510 50 NA 51 NA 45 NA Nonattainment California Orange 060590007 38 NA 37 NA 30 A Maintenance California Riverside 060658005 53 NA 49 NA 41 NA Nonattainment * California Sacramento 060670006 54 NA 49 NA 40 NA Nonattainment * California San Bernardino 060712002 52 NA 48 NA 37 NA Nonattainment * California San Diego 060731011 9 inc

- a 9 inc

- a 43 NA Nonattainment California San Joaquin 060771002 51 NA 50 NA 44 NA Nonattainment California Santa Clara 060850005 36 NA 34 A 30 A Maintenance California Solano 060950004 36 NA 36 NA 31 A Maintenance California Stanislaus 060990006 67 inc

- na 60 inc

- na 55 NA Nonattainment California Sutter 061010003 47 NA 42 NA 36 NA Nonattainment California Tulare 061072002 57 NA 59 NA 51 NA Nonattainment Idaho Franklin 160410001 27 inc

- a 31 inc

- a 46 NA Nonattainment Idaho Shoshone 160790017 34 A 34 A 36 NA Nonattainment Montana Silver Bow 300930005 32 A 32 A 38 NA Nonattainment Nevada Washoe 320310016 35 A 39 NA 38 NA Nonattainment Oregon Klamath 410350004 46 NA 47 NA 45 NA Nonattainment Oregon Lake 410370001 41 inc

- na 41 NA 38 NA Nonattainment Oregon Lane 410392013 40 NA 41 NA 38 NA Nonattainment Utah Box Elder 490030003 35 A 37 NA 42 NA Nonattainment Utah Cache 490050004 36 NA 40 NA 43 NA Nonattainment Utah Davis 490110004 35 A 38 NA 38 NA Nonattainment Utah Salt Lake 490350003 45 NA 48 NA 45 NA Nonattainment * Utah Utah 490494001 44 NA 50 NA 41 NA Nonattainment * Utah Weber 490570002 36 NA 41 NA 38 NA Nonattainment * Washington Pierce 530530029 44 NA 46 NA 38 NA Nonattainment Washington Yakima 530770009 36 inc

- na 37 NA 37 NA Nonattainment NA = Not attaining; A = attaining; inc

- na = incomplete/not attaining; inc

- a = incomplete/attaining * = This county contains both nonattainment and maintenance receptors. See Appendix A of this TSD for more details.9

**Figure III.A. 2: Map of**  **Daily PM2.5**  **Nonattainment and Maintenance Receptors**

**III. B.**  **Factors Considered in Transport Analysis for**  **N on**  **attainment and M**  **aintenance R** **eceptors .**  Consistent with the recommendations in the Guidance, EPA reviewed emission inventory data , ambient monitoring data , and meteorological conditions within the state of New Mexico

. In addition, EPA reviewed PM2.5 monitoring data in areas representative of western regional background levels of PM2.5 in the nearb y states of Utah and Arizona as well as selected remote monitoring sites on the California

- Oregon border and in Oregon, Washington, Idaho, and Montana
. Finall y, EPA reviewed technical information related to each of the nonattainment and maintenance receptors in the potentially impacted states , including meteorological conditions and ambient PM2.5 monitoring data. S pecificall y, EPA reviewed the emission inventory data. B ased on 2005 and 2012 data in the USEPA Transport Rule Modeling , the PM2.5 Transport Analysis provides statewide emissions data as follows: 2005
- 3 43,139 tons of NOx and 50,755 tons of SO2 ; 2012

– 281,341 tons of NOx and 25,254 tons of SO2

. 17 The m onitored ambient PM2.5 concentrations for nonattainment

17 See Tables 7

- 1and 7

- 2 of the “Technical Support Document (TSD) for the final Transport Rule Docket ID No. EPA
- HQ
- OAR
- 2009
- 0491 Emissions Inventory Final Rule TSD,” June 28, 2011.10

and maintenance receptors in the state of New Mexico are shown above in Figure III.A.1 , “ List of Daily PM2.5 Nonattainment and Maintenance Receptors. ” All design values for the time period 2008

- 2010 within the state of New Mexico are below the PM2.5 24
- hour standard of 35μg/m 3

. Pinal County has design values above 35μg/m 3 for the earlier time periods of 2006

- 08 and 2007

- 09 , and Santa Cruz County has design values above 35μg/m 3 for 2006

- 08. EPA then reviewed PM2.5 monitoring data from relatively remote ambient air monitoring sites that EPA believes is representative of regional background PM2.5 levels in the western United States
. EPA reviewed five years of data collected at the IMPROVE 18 monitoring network at each of eight National Parks in Utah (Bryce Canyon, Zion, Capitol Reef, and Arches National Parks) and Nevada ( Jarbidge Wilderness Area and Great Basin National Park) , and at the California

Oregon border (Lava Beds National Monument and Crater Lake National Park). Ambient PM2.5 monitoring data, as well as chemical species data ( ammonium nitrate, ammonium sulfate, elemental carbon, organic carbon, sea salt, and soil) is available for each of these monitoring site s . We provide monitored PM2.5 data from each of the se monitoring sites during the 2006
- 2010 period , for each day when measurements occurred , as well as a map of the site locations in Appendix D of this TSD. This provides information about region al background level s of PM2.5 in the states surrounding New Mexico , as well as the chemical composition of the PM2.5 in these areas . Most of the e levated levels of PM2.5 in the western states are measured during the winter months. For example, of the 17 days with measured values above the standard in 2010 in Salt Lake City , eleven days were in January (with levels up to 76μg/m 3 ), and four days were in December (with levels up to 53μg/m 3 )

. The remaining two days above the standard were March 30 and April 27. The PM2.5 data for each of the eight IMPROVE monitoring sites indicate low background PM2.5 levels throughout the year, but especiall y during the winter months for each of th e ye ars from 2006 through 2010. For example, the PM2.5 values for January and December of 2010 at Bryc e Canyon N ational P ark , Utah are below 3μg/m 3

. In the winter, when the measured PM2.5 values i n Salt Lake City are as high as 76 μ g/m 3 , the PM2.5 values in remote areas are very low (below 3 μ g/m 3 ) , indicating that over 9 0 % of the PM in the urban area is locally generated. Because the PM2.5 at these location s is local in nature, it i s reasonable to conclude that emissions from New Mexico do not have a significant impact on nonattainment in Salt Lake City

. In contrast, an analysis of the CSAPR 2012 nonattainment and maintenance receptors shows that a large fraction of the daily PM2.5 concentrations in Eastern areas are from upwind states. For the 41 CSAPR daily PM2.5 nonattainment and maintenance receptors, the modeled upwind sulfate plus nitrate contribution to total PM2.5 ranged from a low

18 The Interagency Monitoring of Protected Visual Environments (IMPROVE) program is a cooperative measurement effort governed by a steering committee composed of representatives from Federal and regional

- state organizations. The IMPROVE monitoring program was established in 1985 to aid the creation of Federal and Stat e im plementation plans for the protection of visibility in Class I areas. The objectives of IMPROVE include establishing current aerosol conditions in mandatory class I areas; and identifying chemical species and emission sources responsible for existing man - made visibility impairment. http://vista.cira.colostate.edu/improve/Overview/IMPROVEProgram_files/frame.htm11

of 20% to a high of 53% with a median value of 37%. 19 Since CSAPR only tracked the contributions of sulfate and nitrate, these values represent the minimum percentage of upwind contribution to the receptors. Accounting for transport of additional primary PM2.5 species would only

increase the upwind percentage and therefore decrease the percentage of PM2.5 due to local sources. **Figure III .B.1. IMPROVE**  **PM2.5 Data for Bryce Canyon National Park for the Year 2010** 

In addition to reviewing background monitoring data which indicates that the elevated PM2.5 levels are not likely due to regional transport , EPA reviewed technical information , such as meteorologic al conditions and monitored ambient data, related to each of the areas with nonattainment and maintenance receptors in the potentially impacted states to determine whether local emissions cause or contribute to the elevated PM2.5 levels at these locations

. We discuss our evaluation for each of the areas with receptor s in the following sections. **I V**  **. Transport Assessme**  **nt for Nona ttainment Receptors**  **IV. A. Introduction**  Based on our methodology for selecting nonattainment receptors in Section III.A, above (Discussion of Nonattainment and Maintenance Receptor Selection Methodology ), EPA has identified nonattainment receptors in seven western states: Utah, Nevada, California, Oregon , Washington , Idaho , and Montana
. EPA has ev aluated technical information regarding transport for each of the areas with nonattainment receptors identified above, following the methodolo gy discussed in Section III. B. T ransport to the s tates which border New Mexico and have nonattainment receptors (Utah) is addressed first

. Transport to the more distant w estern s tates

19 See Memorandum to File, Brian Timin, EPA, Office of Air Quality Planning and Standards, “CSAPR Daily PM2.5 Upwind Contribution,” July 2012.12

with nonattainment receptors (Nevada, California, Oregon , Washington , Idaho , and Montana) are then addressed . Finally , transport to e astern s tates is addressed. **IV. B**  **. Transport to**  **Nea rby States**  **IV. B.1.**  **Utah 20**  Elevated levels of PM2.5 in the Utah nonattainment areas occur primarily in the winter months. 21 The levels of elevated PM2.5 in the S alt Lake City 2006 PM2.5 nonattainment area and the Provo 2006 PM2.5 nonattainment area are primarily due to local emissions, as noted in the discussion of Salt L ake City and Provo nonattainment areas below. Of the 17 days with measured values above the standard in 2010 in Salt L ake City , eleven days were in January (with levels up to 76μ g/m 3 ), and four days were in December (with levels up to 53μg/m 3 ). The remaining two days above the standard were March 30 and April 27. During the winter months, levels of PM2.5 at background monitoring sites located north of New Mexico and south of th e Utah nonattainment receptors 22 are very low, generally

below 3μg/m 3 , indicating that over 90% of the PM in the urban area is locall y generated. As discussed above, this supports our finding that PM2.5 levels are not likely to be cause d by

regional elevated PM2.5 levels. The local nature of the PM2.5 levels during the time period when the standard is exceeded and the low levels of background PM2.5 during these time periods support our finding that emissions from the state of New Mexico do not contribute significantly to nonattainment of the PM2.5 standard at these nonattainment receptors. Box Elder, Davis, Salt Lake, Tooele, and Weber Counties (Greater Salt Lake Area) All of Davis and Salt Lake c ounties, and portions of Box Elder, Too ele and Weber c ounties are designated as part of the Salt L ake City (SL C) 2006 PM2.5 nonattainment area (NAA)

. The SLC NAA is situat ed in a valley bordered on the w est by

the Stansbury Mountains, 23 Promontory Mountains and Great Salt L ake, and on the e ast b y the Wasatch Front. During inversions, the NAA becomes a closed airshed (save for potential transport between the Salt Lake City and Provo NAAs) featuring stagnant air masses and light winds which typically oscillate back and forth within the airshed . As the airshed is essentially capped during inversions, PM2.5 is formed in

- situ (and trapped) via fresh locall y derived emission sources and secondary chemistry

. 24 Speciation data from wintertime PM2.5 exceedance days from 2004

- 2006 showed the average c omposition of PM2.5 in Salt Lake City is 58% ammonium nitrate, 31% carbon and organic

20 For discussion of the Idaho/Utah

– Franklin County/Cache County area, see section IV.3.C Idaho of this TSD. 21 See Appendix E at E.1
. 22 IMPROVE monitoring network at each of six National Parks in Utah (Bryce Canyon, Zion, Capitol Reef, and Arches National Parks) and Nevada ( Jarbidge Wilderness Area and Great Basin National Park), 23 The Quqirrh Mountains lie between the Wasatch Front and the Stansbury Mountains. However, EPA determi ned that some areas located west of the Quqirrh Mountains should still be considered part of the SLC nonattainment area. 24 2006 24
- Hour PM2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document, December 2008, Index 583

- 669 at 40.13

compounds, 8% ammonium sulfate, and 2% crustal. Several factors, including significant mobile, point , and area sources contribute to primary and secondaril y formed PM2.5 that violate the standard during stable weather events associated with strong inversions. Utah County (Provo

- Orem) A large portion of Utah County is designated as the Provo 2006 PM2.5 nonattainment area. The Provo NAA is situated in the Utah Valley . Like the other low

- lying valleys just west of the Wasatch Front, the topography of the Utah Valley makes it prone to temperature inversions. During inversions, the Provo NAA features stagnant air masses and calm to light winds. As the airshed is essentiall y ca

pped, PM2.5 is formed in

- situ (and trapped) via fresh locally derived emission sources and secondary chemistry

. 25 Transport of air masses between the Salt L ake City and Provo NAAs can occur during inversions, as there is a 4.75

- mile gap in the mountains sep arating these airsheds that is below the approximate average inversion height for these areas. 26 Speciation data from wintertime PM2.5 exceedance days from 2004

- 2006 showed the average composition of PM2.5 in Provo is 71% ammonium nitrate, with 21% carbon and organic compounds, 8% ammonium sulfate, and 2% crustal. Several factors, including significant amounts of emissions from mobile, point , and area sources , contribute to ambient levels of primary and secondaril y formed PM2.5 that violate the standard during stable weather events associated with strong inversions. **IV . C. Transport to Other Western States** 

**– Nevada, California,**  **Oregon, Washington, Idaho and Montana**  **IV. C.1**  **. Nevada**  PM2.5 formation at the nonattainment receptor in Nevada is discussed in detail in Appendix B and is summarized below. Elevated PM2.5 levels in the Reno area occur during wintertime stagnation episodes

. The highest values are generall y measured in January and December. 27 W ildfires in June and July of 2008 had a large impact on PM2.5 concentrations in this area ; however, the Washoe County Health District has flagged the affected data as exceptional events. 28 The IMPROVE PM2.5 monitoring data for the Nevada sites , shown in Appendix D , show very low levels of PM2.5 (below 3μg/m 3 ) for the months of January and December for each of the ye ar s from 2006 through 2010

. We also note that Nevada areas are even further away than the

25 Id. 26 Id. at 41. 27 Washoe County, Nevada Air Quality Trends (2002

- 2011). http://www.co.washoe.nv.us/repository/files/4/Washoe

- County
- Air

- QualityTrends

- 2002
- 2011.pdf 28 Washoe County, Nevada Air Quality Trends (2002

- 2011). http://www.co.washoe.nv.us/repository/files/4/Washoe

- County
- Air

- QualityTrends

- 2002
- 2011.pdf14

Utah areas and more dispersion of New Mexico’s emis sions would be expected compared to the Utah anal ys is. The local nature of the PM2.5 levels during time perio d when the standard is exceeded and the low levels of background PM2.5 during these time periods support our finding that emissions from the state of New Mexico do not contribute significantly to nonattainment of the PM2.5 standard at these nonattainment receptors. **I V.**  **C.2 .**  **California** Transport to nonattainment receptors in California is discussed in detail in Appendix B and is summarized below. We note that California areas are even further away than the Utah areas , there are more terrain blocking features (mountains and mountain ranges) and more dispersion of New Mexico’s emissions (less potential impacts) would be expected compared to the Utah an al ys is. We also note that general transport winds are west to east in California which would not ty picall y provide transport of New Mexico’s emissions.
Northern California

– Butte, Sacramento , and Sutter Counties In Northern California, monitored excee dances of the PM2.5 standard appear to result from complex topography and localized emissions occurring during wintertime temperature inversions with low winds that persist for several days in an area that trap s emissions. The speciation data from high concentration days indicates that as much as 75% of the concentrations are due to organic carbon, which also indicates that residential wood burning emissions are the dominant source. 29 Given the factors that indicate the elevated PM2.5 levels at these loc ations are caused b y local emission s , which occur during wintertime temperature inversions with low winds that persist for several days in an area that trap s emissions , tog ether with complex topography and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico sources do not significantly contribute to nonattainment of the 2006 24

- hour PM2.5 NAAQS at these receptor locations

. Central California

– Fresno, Kern, Kings, Merced, San Joaquin, Stanislaus , and Tulare Counties In Central California, the monitored exceedances of the PM2.5 standard appear to result from complex topography and localized emissions occurring during wintertime temperature inversions with low winds that persist for several days in an area that trap s emissions to gether with complex topography. The speciation data from high concentration days indicate high levels of secondary nitrate . On some days elevated levels of organic carbon indicate that residential wood burning also contributes to elevated levels of PM2.5
. Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , which occur during winte rtime temperature inversions with low winds that persist for

29 ARB Almanac website (2006) http://www.arb.ca.gov/ei/maps/statemap/cntymap.htm)15

several days in an area that traps emissions , tog ether with complex topography and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico sources do not significantly contribute to nonattainment of the 2006 24
- hour PM2.5 standard at th ese receptor location s . Southern California

– Lo s Angeles, Riverside, and San Bernardino Counties PM2.5 in Southern California is essentially a combustion

- generated pollutant and is associated with the volume of traffic, and numbers of sources (both point and area) located in the region

. It is important to note that the areas with the highest concentrations of PM2.5 are directl y downwind of an area with majo r ammonia source s associated with dairies and poultry farming

. Eastern California

– Inyo County Elevated levels of PM2.5 in Inyo County are measured at a single monitor, the Keeler monitor, which is located adjacent to the Owen s Lake Bed. The Owens Lake Bed is surrounded b y steep terrain. EPA believes that given the proximity of the monitor to a large loc al source of particulate matter and the nearb y terrain , it is reasonable to conclude that emissions from New Mexico sources do not significantly contribute to nonattainment of the 2006 24
- hour PM2.5 standard at this monitor. California/Mexico Border

– San Diego County The La Posta receptor is classified as a nonattainment receptor, based on a single measured PM2.5 value of 114 μg/m 3 measured o n June 1, 2010. All other measured values of PM2.5 at the La Posta monitoring site are very low. On June 1, 2010, the La Posta monitor recorded the highest measured value in the entire state of California, and 99% of the PM2.5 values for the rest of the State were below 20 μg/m 3

. The monitoring site is located over 7 00 miles from New Mexico

. The monitored PM2.5 levels at the two operating monitors in Imperial County , which is located just east of San Diego County and the La Posta monitor and far west of New Mexico , on June 1, 2010 were 7.12μg/m 3 and 10.2μg/m 3

. The level of PM2.5 measured at the L a Posta monitor on June 1, 2010 appears to be from local sources , which supports our finding that emissions from New Mexico sources do not significantly contribute to the elevated PM2.5 levels at this location

. **IV. C**  **. 3**  **. Oregon**  PM2.5 monitoring data from the Crater Lake National Park and Lava Beds IMPROVE monitoring site 30 are representative of regional background PM2.5 in southern Oregon , and is consistently

low (below 3μg/m 3 ) in the wintertime . The available data for each of the three areas with nonattainment receptors, discussed below, indicate that the cause of elevated PM2.5 levels is local. We note that Oregon areas are even further away than the Utah areas and more dispersion of New Mexico’s emissions would be expected compared to the Utah anal ys is.

30 See Appendix D of this TSD.16

Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , which occur during wintertime temperature inversi ons with low winds that persist for several days in an area that traps emissions, together with complex topography , the low background levels of PM2.5 in the area, and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico sources do not significantl y contribute to nonattainment of the 2006 24
- hour PM2.5 standard at th ese receptor locations

. Klam ath County (Klamath Falls) A portion of Klamath County is designated nonattainment for the 2006 PM2. 5 NAAQS. Klamath Falls is a relativel y small urban community located in and supporting a vast rural area in south

central Oregon. The s tate of Oregon ’s analysis includes a 2005 emission inventory that shows that wood stove emissions are the most significant source of emissions. Additional air quality monitoring data provide supporting evidence that residential wood combustion emissions are the primary cause of exceedance days. Data show that exceedances occur during winter months, at a time when w oodstoves are contributing to smoke in the area. Exceedances occurred from December through January , corresponding directly with the winter wood heating season, indicating the exceedances ( except for flagged wildfire events ) are a seasonal occurrence. Speciation data analysis indicates most of the PM2.5 comes from elemental and organic carbon, ty pical indicators of combustion activities such as wood burning. Meteorological data from Klamath Falls show that low wind speeds dominate during violating days, and the Klamath Falls area experiences frequent winter

- time nocturnal inversions, when PM pollution can build up over time. Diurnal concentrations of PM2.5 are observed by hourl y light scatter data that correspond closely with night

- time use of woodstoves

. Night

- time inversions coupled with low wind speeds strongl y suggest that pollution in the Klamath Falls area is a localized effect heavily influenced b y the use of woodstoves. EPA Region 10’s Positive Matrix Factor receptor modeling identified the 6 factors contributing to elevated wintertime PM2.5 including wood smoke (65%), organic p yrolysis rich (23%) , and smaller contributions by

other identified factors (nitrate rich, soil, sulfate rich, and urban unidentified). Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , which occur during wintertime temperature inversions with low winds that persist for several days in an area that traps emissions, together with complex topography and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico sources do not significantly contribute to nonattainment of the 2006 24
- hour PM2.5 standard at th ese receptor locations

. Lane County (Oakridge) A portion of Lane County is designated nonattainment for the 2006 PM2.5 NAAQS.17

EPA’s technical anal ys is points to residential home heating , using wood burning appliances , as the main contributors to fine particle pollution in this area. EPA Region 10’s P ositive M atrix F actor receptor modeling identified seven factors which c ontribut e to elevated wintertime PM2.5 including wood smoke (76%), organic p yrol ys is rich (15%) , as well as smaller contributions by other identified factors (gasoline vehicles, iron rich, sulfate rich, sea salt, and soil). PM2.5 monitoring data from the Crater Lake National Park and Lava Beds IMPROVE monitoring sites 31 are representative of regional background PM2.5 in southern Oregon, and are consistently

low (below 3μg/m 3 ) in the wintertime. Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , monitoring data indicating that regional levels of PM2.5 are low, and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico sources do not significantly contribute to nonattainment of the 2006 24
- hour PM2.5 standard at th ese receptor locations

. Lake County (Lakeview) EPA Region 10’s P ositive M atrix F actor receptor mo deling identified seven factors contributing to PM2.5 including wood smoke (67%), organic p yrolysis rich (13%), nitrate rich (7%), soil (5%) , and smaller contributions by other identified factors (sulfate rich and urban unidentified)

. PM2.5 monitoring data from the Crater Lake National Park and Lava Beds IMPROVE monitoring sites 32 are representative of regional background PM2.5 in southern Oregon, and are consistently

low (below 3μg/m 3 ) in the wintertime. Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , the monitoring data , which indicate that regional levels of PM2.5 are low, and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico s ources do not significantl y contribute to nonattainment of the 2006 24
- hour PM2.5 standard at th ese receptor locations

. **IV. C**  **. 4**  **. Washington**  Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico do not significantly contribute to nonattainment of the 24

- hour PM2.5 standard at either of the two nonattainment receptor location s in the s t ate of Washington. We note that Washington areas are even further away than the Utah areas and more dispersion of New Mexico’s emissions would be expected compared to the Utah anal ys is. Pierce County (Tacoma) The s tate of Washington’s analysis indicate s that wood smoke associated with home heating

31 Id. 32 Id.18

is the largest source of PM2.5 in the Tacoma

- Pierce County nonattainment area. Surface measurements at multiple sites suggest that the only design values which violate the 2006 PM2.5 NAAQS are in the core of the nonattainment area, within about 3 kilometers (km) of the South L St. monitor. Beyond about 3

- 5km, the design values drop and are well below the NAAQS.
Yakima County (Yakima) EPA Region 10’s Positive Matrix Factor receptor modeling identified 10 factors contributing to elevated wintertime PM2.5 including wood smoke (24%), nitrate rich (24%), gasoline vehicles (16%), organic p yrol ys is rich (9%), sulfate rich (7%) , and smaller contributions from other identified facto rs (iron rich, sea salt, soil, zinc rich, and urban unidentified). **IV. C**  **. 5**  **. Idaho**  EPA believes that the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions combined with the distance of the area from New Mexico support our finding that emissions from New Mexico do not contribute to nonattainment of the 24

- hour PM2.5 standard at the nonattainment receptors in the s tate of Idaho

. We note that Idaho areas are even further away than the Utah areas and more dispersion of New Mexico’s emissions would be expected compared to the Utah anal ys is. Franklin County

/Cache County P ortion s of Franklin County , Idaho and Cache County , Utah are designated as part of the Cache Valley

2006 PM2.5 , two - state, nonattainment area. Limited chemical speciation data in the Cache Valley

indicates the PM2.5 problem is dominated by ammonium nitrate aerosol

. Transport of PM2.5 and precursors from the rural regions at the domain periphery is very small and most of the observed Wasatch Front and Cache Valley PM2.5 is formed in

- situ (and trapped) via fresh locally derived emission sources and secondary chemistry

. Local heating emissions from woodstoves, emissions from agricultural activities, and mobile emis sions may contribute to violations of the PM2.5 NAAQS during stable weather events associated with extremely strong inversions as they are trapped in the Cache Valley due to temperature inversions, low wind, and local topography. Shoshone County (Pinehurs t) In formation from the s tate of Idaho indicates that emissions from woodstoves contribute to primary PM2.5 that violates the standard during stable weather events associated with strong inversions. These emissions and the related effects are limited to the c ity of Pinehurst airshed, as they are trapped there due to temperature inversions, low wind , and local topography .19

**IV.C. 6**  **. Montana**  EPA believes that the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions combined with the distance of the area from New Mexico support our finding that emissions from New Mexico do not contribute to nonattainment of the 24

- hour PM2.5 standard at the nonattainment receptor in the s tate of Montana. We note that Montana areas are even further away than the Utah areas and more dispersion of New Mexico’s emissions would be expected compared to the Utah anal ys is. Silver Bow County (Butte) Elevated levels of PM2.5 in the Butte area occur primarily in the winter months. 33 The Butte area is topographically prone to wintertime temperature inversions, as it is situated in a montane valley . Speciation data indicates that emissions from wood smoke are the primary contributor to exceedances of the PM2.5 st andard in Butte. 34 These factors indicate that high levels of PM2.5 in Butte are driven by local emissions, which become trapped and build during wintertime inversions. **IV. D. Transport to Eastern States**  EPA has also considered potential PM2.5 transport from New Mexico emission sources to the nearest potential nonattainment or maintenance receptors located in the eastern , midwestern and southern states within the domain of the modeling anal ys is for the Cross State Air Pollution Rule (CSAPR) (76 FR 48208)

. The nonattainment and/or maintenance receptor nearest to New Mexico identified in the 2012 CSAPR modeling analysis is Madison County , Illinois

. The CSAPR modeling did not analyze the contribution of New Mexico sources to Madison County, Illinois. In this action , EPA analyzed the magnitude of New Mexico ’s SO 2 and NOx emissions relative to states found to have emissions that significantly contribute to nonattainment at that receptor. EPA also considered the dis tance of New Mexico from Madison County , Illinois relative to states found to significantl y contribute there. EPA believes that the following factors support a finding that emissions from New Mexico sources do not contribute significantly to nonattainment of the 2006 24

- hour PM2.5 NAAQS at this receptor: (1) the relativel y small magnitude of the emission inventory of PM2.5 precursors (SO2 and NOx) in New Mexico , combined with (2) the relatively long distance between New Mexico and this receptor. EPA believes that these factors also support a finding that New Mexico does not contribute significantl y to nonattainment of the 2006 24

- hour PM2.5 NAAQS at any of the other CSAPR receptors f

arther east. In the CSAPR modeling, EPA did not quantify the PM2.5 contributions from New Mexico to Illinois or any of the other Eastern nonattainment and maintenance receptors. However, we can make a qualitative conclusion about the likely contribution from New Mexico to Illinois and point s f arther east by

comparing th e New Mexico emissions to a state that was modeled in CSAPR. Texas is the nearest state to New Mexico that was found to significantly contribute to

33 See Appendix E of this TSD at E. 2
. 34 Id at E.3
.20

downwind nonattainment in CSAPR. And in fact, Texas was found to contribute significantl y to the nonattainment receptor in Madison County , Illinois. The 24

- h our PM2.5 contribution from Texas to Madison County was above the 1% threshold (0.35 μg/m3) used in CSAPR to identify contributions that were considered not significant (the Texas contribution was 0.37 μg/m 3 ). EPA has evaluated the relative amounts of PM2.5 precursor (SO2 and NOx) emissions in New Mexico compared to the amounts of PM2.5 precursor emissions in Texas , as modeled in the 2012 CSAPR “base case. ” The emission inventories used in the CSAPR model ing anal ys es indicate that SO2 emissions in New Mexico are less than 5 % of SO2 emissions in Texas, and NOx emissions in New Mexico are less than 20% of NOx emissions in Texas. Specifically, the CSAPR “ 2012 Base Case ” inventories provide the following stat ewide emissions inventory data for these two states: 2 81,341 tons of NOx and 2 5, 254 tons of SO2 from New Mexico emission sources, compared to 1,501,170 tons of NOx and 712,582 tons of SO2 from Texas emission sources. 35 Even though the relationship between upwind emissions and downwind secondary PM2.5 formation is not linear, we would expect the New Mexico PM2.5 contribution to Illinois to be much less than that of Texas and well below the 1% threshold. In addition, the distance from the closest part of New Mexico to Madison County , Illinois ( approximately 800 miles) is almost twice the distance to Madison County from the closest part of Texas (415 miles )

. The distance from New Mexico to the other eastern receptors is even greater, therefore, the expected impact is even smaller. Given all of these factors, EPA believes it is reasonable to conclude that emissions of PM2.5 and PM2.5 precursors from New Mexico sources do not significantl y contribute to nonattainment of the 20 06 24
- hour PM2.5 NAAQS in any eastern state
. **V. Transport Assessment for Maintenance Receptors**  **V. A.**  **Introduction** Based on our methodology for selecting maintenance receptors in Section III.A, above (Discussion of Nonattainment and Maintenance Receptor Selection Methodology), EPA has identified maintenance receptors in only three other western states: Arizona, Utah and California

. Thus, to evaluate the potential for New Mexico emissions to interfere with maintenance in other states, we have evaluated technical information related to the maintenance receptors onl y in Arizona, Utah and California

. As this anal ys is focu ses on interstate transport, EPA did not evaluate the impact of New Mexico emissions on maintenance receptors within New Mexico

. **V. B.**  **Transport to Nearby State s**  **V.B.1 . Arizona**  Pinal County ( Cowtown) This receptor is in the West Central Pinal nonattainm ent area
. This monitoring site is a middle scale site and is only comparable to the 24

- hour NAAQS due to its close proximity

to nearby sources. Emission inventory data, combined with speciation and

35 See “E mi ssions Inventory Final Rule TSD,” Technical Support Document (TSD) for the final Transport Rule, Docket ID No. EPA

- HQ
- OAR
- 2009
- 0491, June 28, 2011, at Tables 7

- 1 and 7

- 2.21

source apportionment data, point to agricultural activities and cattle feedlots, as well as other nearb y sources of PM2.5 , as primary sources contributing to PM2.5 levels at the Cowtown monitor on days with exceedances of the 24

- hour PM2.5 NAAQS. The Cowtown monitor has a consistent PM2.5 /PM10 ratio that is lower than other nearb y sites, suggesting that the causes of Cowtown PM2.5 concentrations are different than for other locations . The correlation of the PM2.5 /PM10 ratio with PM2.5 concentrations at the Cowtown monitor suggests that PM2.5 and PM10 concentrations at the Cowtown monitoring site are generated b y the same sources. Also, the Cowtown monitor is the only site in the area with a pronounced diurnal pattern, with high PM in the morning and evening hours, further suggesting the influence of local sources. Santa Cruz County (Nogales ) This receptor is in the Nogales nonattainment area. High PM2.5 values in Nogales generall y occur under stagnant, light wind conditions during winter, and are asso ciated with southerly flow (i.e., from the direction of Mexico). Nighttime drainage flow is ty

pically from south to north along the Nogales Wash, and the narrow valley topography can trap air pollutants, especially during the evening hours when the diurnal flow is from the south, out of Nogales, Sonora , Mexico

. Measurements of PM2.5 composition show that the main emission sources are wood burning, food cooking, open burning, dust emissions, and tailpipe emissions from on

- road and off

- road vehicles

. **V.B.2. Utah**  Elevated levels of PM2.5 in the Utah nonattainment areas occur primarily in the winter months. 36 The levels of elevated PM2.5 in the S alt Lake City 2006 PM2.5 nonattainment area and the Provo 2006 PM2.5 nonattainment area are primarily due to local emissions, as noted in the discussion of Salt L ake City and Provo nonattainment areas below. Of the 17 days with measured values above the standard in 2010 in Salt L ake City , eleven days were in January (with levels up to 76μg/m 3 ), and four days were in December (with levels up to 53μg/m 3 ). The remaining two days above the standard were March 30 and April 27. During the winter months, levels of PM2.5 at background monitoring sites located north of New Mexico and south of the Utah maintenance receptors 37 are very low, generally

below 3μg/m 3 , indicating that over 90% of the PM in the urban area is locall y generated. As discussed above, this supports our finding that PM2.5 levels are not likely to be caused b y regional elevated PM2.5 levels. The factors that indicate the elevated PM2.5 levels at these locations are caused by local emissions, as well as the low levels of background PM2.5 during these time periods,

36 See Appendix E at E.1
. 37 IMPROVE monitoring network at each of six National Parks in Utah (Bryce Canyon, Zion, Capitol Reef, and Arches National Parks) and Nevada ( Jarbidge Wilderness Area and Great Basin National Park)

.22

support our finding that emissions from the state of New Mexico do not interfere with mainten ance of the 2006 24

- hour PM2.5 standard at these maintenance receptors. Box Elder, Davis, Salt Lake, Tooele, and Weber Counties (Greater Salt Lake Area) All of Davis and Salt Lake c ounties, and portions of Box Elder, Tooele , and Weber c ounties are desi gnated as part of the Salt Lake City 2006 PM2.5 nonattainment area. The SL C NAA is situat ed in a valley

bordered on the ea st by

the Stansbury Mountains, 38 the Promontory Mountains , and the Great Salt Lake, and on the we st by the Wasatch Front. During inversions, the NAA becomes a closed airshed (save for potential transport between the Salt Lake City and Provo NAAs) featuring stagnant air masses and light winds which typically oscillate back and forth within the airshed. As th e airshed is essentially capped during inversions, PM2.5 is formed in

- situ (and trapped) via fresh locall y derived emission sources and secondary chemistry

. 39 Speciation data from wintertime PM2.5 exceedance days from 2004

- 2006 showed the average composition of PM2.5 in Salt Lake City is 58% ammonium nitrate, 31% carbon and organic compounds, 8% ammonium sulfate, and 2% crustal. Several factors, including significant emissions from mobile, point and area sources , contribute to primary and secondaril y forme d PM2.5 that violate the standard during stable weather events associated with strong inversions. Utah County (Provo

- Orem) A large portion of Utah County is designated as the Provo 2006 PM2.5 nonattainment area. The Provo NAA is situated in the Utah Valley . Like the other low

- lying valleys just west of the Wasatch Front, the topography of the Utah Valley makes it prone to temperature inversions. During inversions, the Provo NAA features stagnant air masses and calm to light winds. As the airshed is es sentiall y capped, PM2.5 is formed in

- situ (and trapped) via fresh locally derived emission sources and secondary chemistry

. 40 Transport of air masses between the Salt L ake City and Provo NAAs can occur during inversions, as there is a 4.75

- mile gap in the m ountains separating these airsheds which is below the approximate average inversion height for these areas. 41 Speciation data from wintertime PM2.5 exceedance days from 2004

- 2006 showed the average composition of PM2.5 in Provo is 71% ammonium nitrate, with 21% carbon and organic compounds, 8% ammonium sulfate, and 2% crustal. Several factors, including significant mobile, point , and area sources contribute to ambient levels of primary and secondaril y formed PM2.5 that violate the standard during stable weather events associated with strong inversions.

38 The Quqirrh Mountains lie between the Wasatch Front and the Stansbury Mountains. However, EPA de termined that some area located west of the Quqirrh Mountains should still be considered part of the SLC nonattainment area. 39 2006 24
- Hour PM2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document, December 2008, Index 583

- 669 at 40. 40 Id. 41 Id. at 41.23

**V.B. 3**  **. California** Transport to maintenance receptors in California is discussed in detail in Appendix C and summarized below. We note that California areas are even further away than the Utah and Arizona areas, there are more terrain blocking features (mountains and mountain ranges) and more dispersion of New Mexico’s emissions (less potential impacts) would be expected compared to the Arizona and Utah analyses. We als o note that general transport winds are west to east in California which would not ty picall y provide transport of New Mexico’s emissions.
Northern California

/San Francisco Bay

Area

– Alame da, Solano, and Santa Clara County Receptors The receptors in these counties are in the San Francisco Bay airshed . The monitored values of PM2.5 that exceed the standard likel y reflect localized sources because they occur during wintertime temperature inversions with low winds that persist for several days, allowing directl y emitted and secondary PM2.5 to build up over a few days. The Bay Area Air Quality Management District analyses show that during the winter peak season, wood burning can account for 33 to over 80 percent of the PM2.5 concentrations

. Ammonium nitrate and elemental carbon from diesel sources can also contribute to these high values

. EPA believes that the factors that indicate the elevated PM2.5 levels at these locations are caused by local emissions and the distance of the area from New Mexico support our finding that emissions from New Mexico do not interfere with maintenance of the 24

- hour PM2.5 standard at this receptor. Southern California

– Orange County (Maintenance O nl y) and Los Angeles, Riverside, San Bernardino Counties Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , regional and local flow patterns, and the location of California nonattainment areas generall y upwind of New Mexico emission sources, we believe it is reasonable to conclude that emissions from New Mexico do not interfere with maintenance of the 2006 24
- hour PM2.5 standard at this receptor. California/Mexico Border

– Imperial County The high monitored levels of PM2.5 are limited to the Calexico

– Ethel Street monitoring site, which is loc ated near the Mexican Border. The elevated PM2.5 levels occur primarily in the winter months during stagnation conditions, when long distance transport is unlikely . On days of elevated PM2.5 at the Calexico Ethel Street monitor, the levels of PM2.5 measured at the other monitors in Imperial County , the Brawley and El Centro sites , are lower on all days. The PM2.5 appears to be from a local source near the California/Mexico Border. These factors support our finding that emissions from New Mexico sources do not interfere with maintenance of the 24

- hour PM2.5 standard at this receptor.24

Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , regional and local flo w patterns, and the location of California nonattainment areas generall y upwind of New Mexico emission sources, we believe it is reasonable to conclude that emissions from New Mexico do not interfere with maintenance of the 2006 24
- hour PM2.5 standard at this receptor

. Northern California

– Sacramento County In Northern California, monitored exceedances of the PM2.5 standard likely reflect localized sources occurring during wintertime temperature inversions with low winds that persist for several days in an area that trap emissions tog ether with complex topography

. The speciation data from high concentration days indicates that the PM2.5 has a high carbon mass, which also indicates that residential wood burning emissions are the dominant source

. 42 Given the factors that indicate the elevated PM2.5 levels at these locations are caused b y local emissions , which occur during wintertime temperature inversions with low winds that persist for several days in an area that trap emissions , tog ether with complex topography and the distance of the area from New Mexico , we believe it is reasonable to conclude that emissions from New Mexico do not interfere with maintenance of the 2006 24
- hour PM2.5 standard at th ese receptor s . **V.C . Transport to Eastern States**  EPA has also considered potential PM2.5 transport from New Mexico emission sources to the nearest potential nonattainment or maintenance receptors located in the eastern , midwestern and southern states within the domain of the modeling anal ys is for the Cro ss State Air Pollution Rule (CSAPR) (76 FR 48208)

. The nonattainment and/or maintenance receptor nearest to New Mexico identified in the 2012 CSAPR modeling analysis is Madison County , Illinois

. The CSAPR modeling did not analyze the contribution of New Mexico sourc es to Madison County, Illinois. Thus, EPA anal yzed the magnitude of New Mexico ’s SO 2 and NOx emissions relative to states found to have emissions that significantl y contribute to nonattainment at that receptor. EPA also considered the distance of New Mexico from Madison County , Illinois relative to states found to significantly contribute there. EPA believes that the following factors support a finding that emissions from New Mexico sources do not interfere with maintenance of the 2006 24
- hour P M2.5 NAAQS at this receptor: (1) the relatively small magnitude of the emission inventory of PM2.5 precursors (SO2 and NOx) in New Mexico , combined with (2) the relativel y long distance betw een New Mexico and this receptor. EPA believes that these factors also support a finding that New Mexico emissions do not interfere with maintenance of the 2006 24

- hour PM2.5 NAAQS at any of the other CSAPR receptors f arther east. In the CSAP R modeling, EPA did not quantify the PM2.5 contributions from New Mexico to Illinois or any of the other Eastern nonattainment and maintenance receptors. However, we can make a qualitative conclusion about the likely contribution from New Mexico to Illinois and points f arther east by

comparing the New Mexico emissions to a st ate that was modeled in

42 ARB Almanac website (2006) http://www.arb.ca.gov/ei/maps/statemap/cntymap.htm)25

CSAPR. Texas is the nearest state to New Mexico that was found to significantly contribute to downwind nonattainment in CSAPR. And in fact, Texas was found to contribute significantl y to the nonattainment receptor in Madison County , Illinois. The 24

- h our PM2.5 contribution from Texas to Madison County was above the 1% threshold (0.35 μg/m 3 ) used in CSAPR to identify contributions that were considered not significant (the Texas contribution was 0.37 μg/m 3 ). EPA has evaluated the relative amounts of PM2.5 precursor (SO2 and NOx) emissions in New Mexico compared to the amounts of PM2.5 precursor emissions in Texas, as modeled in the 2012 CSAPR “base case. ” The emission inventories used in the CSAPR modeling anal ys es indicate that SO2 emissions in New Mexico are less than 5 % of SO2 emissions in Texas, and NOx emissions in New Mexico are less than 20% of NOx emissions in Tex as. Specifically , the CSAPR “ 2012 Base Case ” inventories provide the following statewide emissions inventory data for these two states: 2 81,341 tons of NOx and 2 5, 254 tons of SO2 from New Mexico emission sources, compared to 1,501,170 tons of NOx and 712,582 tons of SO2 from Texas emission sources. 43 Even though the relationship between upwind emissions and downwind secondary PM2.5 formation is not linear, we would expect the New Mexico PM2.5 contribution to Illinois to be much less than that of Texas and well b elow the 1% threshold. In addition, the distance for New Mexico to Illinois is approximately twice the distance as from Texas to Illinois. The distance from the closest part of New Mexico to Madison County , Illinois ( approximately 800 miles) is more than twice the distance to Madison County from the closest part of Texas (415 miles ) . The distance from New Mexico to the other eastern receptors is even greater, and therefore, the expected impact even smaller

. Given all of these factors, EPA believes it is reasonable to conclude that emissions of PM2 .5 and PM2.5 precursors from New Mexico sources do not interfere with maintenance of the 2006 24

- hour PM2.5 NAAQS in any eastern state
.

43 See “E mi ssions Inventory Final Rule TSD,” Technical Support Document (TSD) for the final Transport Rule, Docket ID No. EPA

- HQ
- OAR
- 2009
- 0491, June 28, 2011, at Tables 7

- 1 and 7

- 2.