1



## Memorandum

To: Docket

Re: Final Technical Support Document

- Oregon State Implementation Plan and Interstate Transport Requirements for the 2006 24

- hour Fine Particulate Matter National Ambient Air Quality Standards

Date: November 1 9 , 2014

Table of Contents

I. Interstate Transport and Oregon

A. Summary of Action

B

. Summary of Oregon Submittal

C. Summary of EPA Evaluation and Conclusion

II. Transport Assessment Methodology

A. Discussion of Nona ttainment and Maintenance Receptor Selection Methodology

B . Factors Considered in Transport Analysis for Nonattainment and Maintenance
Receptors

I II . Transport Assessment for Nona ttainment Receptors

A. Introduction
B. Transport to We stern States

1

. California

2

. Montana

3

. Idaho

4. Utah

C . Transport to Eastern States

I V. Transport Assessment for Maintenance R eceptors

A. Introduction

B

. Transport to Western States

1

. California

2

. Montana

3

. Utah

C . Transport to Eastern States

V. Appendix

– PM 2.5 IMPROVE Data2

1. Overview of IMPROVE Monitoring Network Sites

2. Idaho and Idaho/Oregon Border

- IMPROVE Data for the Years 2009

- 2013

3. Montana

- IMPROVE Data for the Years 2009

- 2013

4 . Nevada

- IMPROVE Data for the Years 2009

- 2013

5

. Utah

- IMPROVE Data for the Years 2009

- 2013
6. Wyoming

- IMPROVE Data for the Years 2009

- 2013

7 . California/Oregon Border

- IMPROVE Data for the Years 2009

- 2013

8. Oregon/Washington Border

- IMPR OVE Data for the Years 2009

- 2013

I . Interstate Transport and Oregon

I. A. Summary of Action

Background:

Section 110(a) (1) of the Clean Air Act ( CAA ) requires each state to submit to the Environmental Protection Agency (EPA), within three years (or such shorter period as the Administrator may prescribe) after the promulgation of a primary or secondary National Ambient Air Quality Standard (NAAQS) or any revision thereof, a State Implementation Plan (SIP) that provides for the “implementation, maintenance, and enforceme nt” of such NAAQS. The EPA refers to these specific submittals as “infrastructure” SIPs because they are intended to address basic structural SIP requirements for new or revised NAAQS. For the 2006 24

- hour PM 2.5 NAAQS, these

infrastructure SIP s were due o n September 21, 2009.

CAA s ection 110(a)(2) includes a list of specific elements that “[ e ] ach such plan submission”

must meet. The interstate transport provisions in CAA section 110(a)(2)(D)(i) (also called “good neighbor” provisions) require each state to submit a SIP that contains adequate provisions prohibiting air emissions that will have certain adverse air quality effects in other states. CAA section 110(a)(2)(D)(i) identifies four distinct elements related to the im pacts of air pollutants transported across state lines. In this action, the EPA is addressing the first two elements of this section, specified at CAA section 110(a)(2)(D)(i)(I)

– the requirement that a state SIP :

“ contain adequate provisions

—

(i) prohi biting, consistent with the provisions of this subchapter, any source or other type of emissions activity within the State from emitting any air pollutant in amounts which

will

—

(I) contribute significantly to nonattainment in, or interfere with maintenance by,
any other State with respect to any such national primary or secondary
ambient air quality standard ”1

On June 28, 2010, Oregon submitted a SIP revision to meet various CAA section 110(a)(2) infrastructure requirements for multiple NAAQS. Oregon’s SIP submittal cover letter indicated

the SIP revision included the “Oregon SIP Infrastructure for Addressing the Interstate Transport of Ozone and Fine Particulate Matter” to address the interstate transport requirements of CAA section 110(a)(2)(D)(i) for the 8

- hour ozone and PM 2.5 NAAQS (2010 Interstate Transport SI P). 1 Oregon’s June 28, 2010, submittal included public process documentation for the 2010 Interstate Transport SIP and documentation of a duly noticed public hearing on the 2010 Interstate Transport SIP held on December 22, 2009. Oregon subsequently notifi ed the EPA that a clerical error was made and that the 2010 Interstate Transport SIP had not been attached to the June 28, 2010 cover letter. The State transmitted the 2010 Interstate Transport SIP to the EPA on December 23, 2010. We find that the process followed by the State in adopting the SIP

submittal complies with the procedural requirements for SIP revisions under CAA section 110

and the EPA’s implementing regulations.

Action:

In this action, we are approving the Oregon SIP as meeting the requirements of CAA section 110(a)(2)(D)(i)(I) for the 2006 24

- hour PM 2.5 NAAQS. We believe that it is reasonable to conclude that, based on the weight of the evidence, emissions from sources in Oregon do not significantly contribute t o nonattainment or interfere with maintenance of the 2006 24

- hour

PM 2.5 NAAQS.

I. B

. Summary of Oregon Submittal

To address whether emissions from sources in Oregon significantly contribute to nonattainment

or interfere with maintenance of the 2006 24

- hou r PM 2.5 NAAQS in another state, Oregon stated in the 2010 Interstate Transport SIP that meteorological and other characteristics of any areas designated nonattainment for the 2006 24

- hour PM 2.5 NAAQS in the border states of Washington, Idaho, Nevada, and C alifornia support a finding that emissions from Oregon sources do not significantly contribute to nonattainment in, or interfere with maintenance of, the

PM 2.5 NAAQS in other states. Oregon explained that the closest 2006 24

- hour PM 2.5 designated nonattainment areas in neighboring states are the Tacoma area (Pierce County) in Washington; the Chico area (portions of Butte County) in California, and the Cache Valley area in Southeast Idaho (portions of Cache County, Utah and Franklin County, Idaho). Oregon argued in the 2010 Interstate Transport SIP that the area of highest Oregon emission densities (Portland Metro area) is separated from these 2006 24

- hour PM 2.5 nonattainment areas by significant distances and major mountain ranges up to approximate ly 7000 feet. Oregon identified one exception

– the Portland, Oregon

- Vancouver, Washington metro area, which shares a common air shed between Oregon and Washington. Oregon, however, noted that both Portland, Oregon and Vancouver, Washington are in attainme nt with the 2006 24

- hour PM 2.5 NAAQS.

1 Oregon’s submission addresses the interstate transport requirements of the 1997 PM 2.5 NAAQS, the 1997 ozone NAAQS, the 2006 24

- hour PM 2.5 NAAQS, and the 2008 ozone NAAQS. In this action, the EPA is only taking action with respect to CAA section 110(a)(2)(D)(i)(I) for the 2006 24

- hour PM 2.5 NAAQS.2

Oregon described typical seasonal wind patterns during the winter when PM 2.5 levels are the highest. It noted that wind speeds are typically variable with the majority of wind speeds occurring at less than 8 miles per hour, and a significant portion of low winds at less than 5 miles per hour. Oregon explained that these low wind speeds and air stagnation conditions do not lend themselves to long distance air pollution transport, and noted that the Portland area can

exp erience high wind speeds in the winter travelling through the Columbia River Gorge east of Portland that are not conducive to the buildup of air pollution. Oregon concluded that general meteorology supports the conclusion that high winter time 24

- hour PM 2. 5 levels in Pacific Northwest communities are typically dominated by area emission sources.

Oregon’s 2010 Interstate Transport SIP also pointed to its CAA section 110 infrastructure SIP to show that Oregon Department of Environmental Quality (ODEQ) has th e ability to participate as needed in future studies on regional air pollution issues, or collaborate with other states if air quality concerns are identified that require a case

- specific evaluation of interstate transport, and also ensures the legal mecha nism for ODEQ to take action as needed to reduce emissions to help attain compliance with Federal NAAQS. Oregon’s 2010 Interstate Transport SIP stated that that high PM 2.5 levels that threaten the 2006 24

- hour PM 2.5 NAAQS are investigated as needed to

iden tify contributing sources, including any potential role of interstate transport.

Finally, Oregon asserted that it had consulted with air agencies in Washington, Idaho, Nevada, and California and other agencies to evaluate case

- specific air quality problem s that may involve regional transport of air pollution. These staff

- level communications indicated no impacts on

PM 2.5 concentrations in other states caused by transport from Oregon, providing additional support for Oregon’s assertion that emissions from O regon sources do not significantly

contribute to nonattainment or interfere with maintenance of the 2006 24

- hour PM 2.5 NAAQS in

other states.

The Oregon submittal concluded that

, based on the weight of the evidence, including the significant role meteorol ogy and topography play in the conditions that lead to 24

- hour PM 2.5 NAAQS violations in the Pacific Northwest and the west in general

, the nature of the 24

- hour

PM 2.5 problems in states bordering Oregon, and the great distances between Oregon and the

area s experiencing 24

- hour PM 2.5 problems, it is reasonable to conclude that the Oregon SIP meets the interstate transport requirements of the CAA for the 2006 24

- hour PM 2.5 NAAQS

.

I. C

. Summary of EPA Evaluation and Conclusion

T o determine whether the CAA section 110(a)(2)(D)(i)(I) requirement is satisfied , the EPA must

determine whether a s tate’s emissions contribute significantly to nonattainment or interfere with

maintenance in other states

. If this factual finding is in the negative, then CAA section

1 10(a)(2)(D)(i)(I) does not require any substantive changes to a state’s SIP to impose additional emissions controls to alleviate interstate transport

. Consistent with the EPA ’ s approach in the

eastern United States ( 1998 NOx SIP c all , the 2005 CAIR

, and the 2011 Transport Rule ), we are evaluating potential interstate transport from Oregon to other states with respect to specific3

monitors identified as having nonattainment and/or maintenance problems, which we refer to as “receptors.” 2

It is importa nt to note that on August 21, 2012, the U.S. Court of Appeals for the DC Circuit issued a decision to vacate the Transport Rule. See EME Homer City Generation, L.P. v. E.P.A.,

696 F.3d (DC Cir. 2012) cert. granted , 2013 U.S. Lexis 4801 (2013). The DC Circ uit also

ordered the EPA to continue implementing CAIR in the interim. However, on April 29, 2014, the U.S. Supreme Court reversed and remanded the D.C. Circuit’s ruling and upheld the EPA’s approach in the Transport Rule. EPA v. EME Homer City Generatio n, L.P ., 134 S.Ct. 1584 (2014). The Supreme Court generally upheld the EPA’s approach in the Transport Rule

, and on

October 2 3 , 2014, the DC Circuit lifted the stay on the Transport Rule. 3

While our evaluation is consistent with the Transport Rule approach, t he State of Oregon was not covered by either CAIR or the Transport Rule, and the EPA made no determinations in either rule regarding whether emissions from sources in Oregon significantly contribute to

nonattainment or interfere with maintenance of the 2006 24

- hour PM 2.5 NAAQS in another state

, nor did it attempt to quantify Oregon’s obligation

. 4

Evaluation :

In this action, w e have evaluated the information available and have determined that no single piece of information is by itself disposit ive of the issue. Instead, the total weight of all the evidence taken together is used to evaluate whether Oregon emissions significant ly contribut e to
nonattainment or interfere with maintenance of the 2006 24

- hour PM 2.5 NAAQS in any other

state.

We believe that the Oregon 2010 Interstate Transport submittal provides important information

on the meteorology, topography, and violating areas in surrounding states and that this information generally supports a conclusion that emissions from sources in Or egon do not significantly contribute to nonattainment or interfere with maintenance of the 2006 24

- hour

PM 2.5 NAAQS in any other state

. In order to reach a conclusion, however, we believe it is

necessary to supplement the information provided in the Idaho 2010 Interstate Transport

submittal with a review of the monitors in other states that are appropriate nonattainmen t and maintenance receptors. We also have reviewed monitor ing data collected at National Parks and

wilderness areas (class I areas) in the west which we believe may be considered representative of background ( data provided in s ection V. Appendix to this TSD). In addition, we have review ed

technical documentation produced by the EPA and states during the designations and attainment planning processes for the PM 2.5 NAAQS under part D , title I of the CAA . This technical

documentation addresses atmospheric science, meteorology, topography and sources of PM 2.5 in

Ore gon and surrounding states in the west . While this information was developed for SIPs under part D, title I of the CAA, we believe the information help s inform our evaluation of interstate transport requirements at CAA section 110(a)(2)(D)(i)(I) for the 2 006 24

- hour PM 2.5 NAAQS

.

2 See NO

x SIP Call, 63 FR 57371 (October 27, 1998); CAIR, 70 FR 25172 (May 12, 2005); and Tr ansport Rule or

Cross

- State Air Pollution Rule, 76 FR 48208 (August 8, 2011).

3 USCA Case #11

- 1302, Document # 1518738, Filed 10/23/2014.

4 Ibid.4

Our supplemental analysis is provided in s ections II and III below.

Conclusion:

Based on the following weight of the evidence , we conclude that the Oregon SIP meets the requirements of CAA section 110(a)(2)(D)(i )(I) for the 2006 24

- hour PM 2.5 NAAQS:

 The evidence in the 2010 Oregon Interstate Transport submittal that shows the significant role
meteorology, topography and distance play in the conditions that lead to violations of the 24

- hour

PM 2.5 standard in bordering western states

.

 The evidence from monitor ing data collected at National Parks and wilderness areas (class I
areas) in the west that indicates there are low background levels of PM 2.5 in class I areas located

between Oregon and identified recep tors , and in the west in general, at the times when violations
in the west typically occur (winter months )

.

 The evidence from technical support documents produced by the states and the EPA through the
designations and attainment planning process for the NAAQS that indicates violations of the 24

- hour PM 2.5 standard in the western states are generally driven by wintertime inversion
meteorology in areas impacted by major mountain ranges including the Cascade Range , the

W asatch Front, the Sierra Nevada Range

, and other significant topography.

II. Transport Assessment Methodology

II. A. Discussion of Nona ttainment and Maintenance Receptor Selection Methodology

On September 25, 2009, the EPA issued a guidance memorandum 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 PM 2.5 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 ( PM 2.5 ) National Ambient Air Quality Standards (NAAQS)

, ” September 25, 2009 ( “ 2006 24

- hour PM 2.5 NAAQS Infrastructure Guidance” or “Guidance” ). 5 The Guidance

rec ommends that each state explain in its SIP submission for section 110(a)(2)(D)(i)(I) SIP

whether or not emissions from sources in the state contribute significantly to nonattainment or interfere with maintenance of the NAAQS in any other state, and to addr ess any such impacts if they exist

. See Guidance at 3 , 4. The Guidance states as follows:

The state ’ s conclusion must be supported by 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

5 Available at: http://www.epa.gov/ttn/caaa/t1/memoranda/20090925_harnett_pm25_sip_110a12.pdf5

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 e missions on nearby nonattainment areas, and evaluating the air quality impact and potential mitigation strategies. 6

T o determine whether the CAA section 110(a)(2)(D)(i)(I) requirement is satisfied

, the EPA must

determine whether a s tate’s emissions contri bute significantly 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. If, however, the evaluation

reveals that emiss ions 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 mitigate 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 the EPA’ s approach in the 1998 NOx SIP c all , the 2005 CAIR

, and the

2011 Transport Rule, 7 the EPA is ev aluating these impacts with respect to specific monitors identified as having nonattainment and/or maintenance problems, which we refer to as “receptors.” 8 The EPA notes that no single piece of information is by itself dispositive of the issue. Instead, t he total weight of all the evidence taken together is used to evaluate significant

contributions to nonattainment in, or interference with maintenance of

, the 2006 24

- hour PM 2.5 NAAQS in another state.

A receptor may be a downwind location that is currently violating the 2006 24

- hour PM 2.5 NAAQS, has violated in the past, is projected to violate in the future, or may have trouble maintaining the NAAQS in the future. Nonattainment and maintenance receptors can be identified using future year modeling, recent ambient data, or both.

If appr opriate future year modeling is not available

, 9 nonattainment and maintenance receptors can be identified using recent ambient air quality monitoring data. For this action, we evaluated

the three most recent consecutive three

- year periods for which comple te, quality

- assured and certified air quality data were available (covering a five

- year period) to calculate “design

values” 10 for those period. We evaluated the design values for monitors located in the following

western states

, which were not included in the modeling domain for the Transport Rule: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. 11

6 Guidance at 3.

7 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).

8 Air quality designations are not relevant to the methodology for identifying these “receptors.”

9 Available modeling data should be evaluated for the intended purpose. If modeling data is used to establish

nonattainment and/or maintenance rec eptors, it should be for an appropriate future year (within the time frame of downwind attainment dates) and model performance should be shown to be acceptable for the upwind and downwind areas being considered.

10 “Design value” means the “calculated conc entration according to the applicable appendix of [40 CFR part 50] for the highest site in an attainment or nonattainment area.” 40 CFR 58.1 (definitions).

11 We did not evaluate des ign values for Alaska or Hawaii

.6

Because the EPA uses the most recent three

- year design value period for purposes of promulgating air qu ality designations and redesignations, it is logical to use the most recent 3

- year 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 years

of data. This methodology is conceptually similar ( although not identical) to the methodology

that the EPA used in the Transport Rule to identify “nonattainment” and “maintenance”

receptors.

In this action w e have applied the following methodology:

Similar to the Transport Rule analysis, we examined ambient data which spanned a five

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

three

- year design value periods at the time of our analysis a re 200 9

- 20 11

, 2010

- 20 12 , and 20 11

- 20 1 3

. 12

1) N onattainment receptors are those sites that are violating the NAAQS in the most recent

three

- year period (2011

- 2013)

. 13

2) Maintenance receptors are those receptors that show attainment in the most recent three

year design value period ( 2011

- 2013 ) but violated the NAAQS in at least one of the previous two periods ( 2009

- 2011 and/or 2010

- 2012 )

.

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

. Also informing this list was the EPA’s AirData

website: http://www.epa.gov/airquality/airdata/

.

The western receptors identified using this methodology and analy zed in this action are shown in

T able 1 below. Receptors with 24

- hour PM 2.5 design values above the 24

- hour PM 2.5 standard of 35μg/m 3 for the most recent three

- year period ( 20 11

- 201 3 ) are listed as nonattainment receptors. Receptors with 24

- hour PM 2.5 design values at or below the 24

- hour PM 2.5 standard of 35μg/m 3

for the most recent three

- year period ( 2011

- 2013 )

, but above the standard for at least one of the previous three

- year periods ( 2009

- 2011 or 2010

- 20 12 )

, are listed as maintenance receptors.

To evaluate the potential for significant contribution to nonattainment in other states

, the EPA

first evaluated potential transport to the western states with identified nonattainment receptors :

12 As noted above, the EPA can consider dat a from these years for states in the western United States as such data is not impacted by the remanded CAIR.

13 When evaluating recent design values, it is not necessary to average the design values together to create a five

year weighted average. Weighte d average data is only necessary when projecting modeling data to the future, since modeled projections are generally based on only a single year (or less) of modeled meteorology.7

California, Montana, Idaho , and Utah

. 14 To evaluate the potential for interference with

maintenance in other states

, the EPA evaluated potential transport to the western states with

identified maintenance receptors : California

, Montana, and Utah

. 15

Table 1: List of Western Counties with Daily PM 2.5 Nonattainment or Maintenance Receptors

State County 2006 NAAQS 24

- hr

PM 2.5 NAAQS designated

nonattainment area Site 24

- hr standard ( μg/m 3 )

2009

- 2011 2010

-

2012 2011

-

2013 Receptor

Type

California Fresno San Joaquin Valley 060190011 58 NA 59 NA 62 NA Nonattainment

California Fresno San Joaquin Valley 060195001 54 NA 54 NA 58 NA Nonattainment

California Fresno San Joaquin Valley 060195025 48 NA 53 NA 63 NA Nonattainment

California Imperial 060250005 38 NA 32 A 42 NA Nonattainment

California Inyo 060271003 36 NA 33 A 38 NA Nonattainment

California Kern San Joaquin Valley 060290014 62 NA 58 NA 65 NA Nonattainment

California Kern San Joaquin Valley 060290016 55 NA 47 NA 60 NA Nonattainment

California Kings San Joaquin Valley 060310004 46 NA 43 NA 49 NA Nonattainment

California Kings San Joaquin Valley 060311004 57 NV 54 NA 60 NA Nonattainment

California Los Angeles Los Angeles

- South

Coast Air Basin 060370002 36 NA 31 NV 28 A Maintenance

California Madera San Joaquin Valley 060392010 55 NV 51 NA 52 NA Nonattainment

California Merced San Joaquin Valley 060470003 43 NA 41 NA 42 NA Nonattainment

California Merced San Joaquin Valley 060472510 39 NA 40 NA 49 NA Nonattainment

California Riverside Los Angeles

- South

Coast Air Basin 060658005 39 NA 37 NA 38 NA Nonattainment

California Sacramento Sacramento 060670006 35 A 31 A 36 NA Nonattainment

California San Joaquin San Joaquin Valley 060771002 38 NA 36 NA 45 NA Nonattainment

California San Joaquin San Joaquin Valley 060772010 41 NV 38 NA 37 NA Nonattainment

California Stanislaus San Joaquin Valley 060990005 50 NA 44 NA 51 NA Nonattainment

California Stanislaus San Joaquin Valley 060990006 51 NA 49 NA 53 NA Nonattainment

California Tulare San Joaquin Valley 061072002 47 NA 47 NA 56 NA Nonattainment

Idaho Ada 160010010 19 A 27 A 53 NA Nonattainment

Idaho Franklin Logan 160410001 50 NA 47 NA 42 NA Nonattainment

Idaho Lemhi 160590004 38 NA 38 NA 38 NA Nonattainment

Idaho Shoshone 160790017 38 NA 38 NA 40 NA Nonattainment

Montana Lewis and

Clark 300490026 37 NA 33 A 29 A Maintenance

Montana Silver Bow 300930005 39 NA 34 A 39 NA Nonattainment

Oregon Crook 410130100 31 A 31 A 39 NA Nonattainment

Oregon Klamath Klamath Falls 410350004 39 NA 35 A 40 NA Nonattainment

Oregon Lake 410370001 36 NA 34 A 56 NA Nonattainment

Oregon Lane Oakridge 410392013 39 NA 38 NA 40 NA Nonattainment

Utah Box Elder Salt Lake City 490030003 40 NA 37 NA 37 NA Nonattainment

14 As this analysis focuses on interstate transport, EPA did not evaluate the impact of Oregon emissions on receptors

within Oregon

. 15 Using the methodology described, no receptors were identified in Arizona, Colorado, Nevada, New Mexico, Washington, and Wyoming.8

State County 2006 NAAQS 24

- hr

PM 2.5 NAAQS designated

nonattainment area Site 24

- hr standard ( μg/m 3 )

2009

- 2011 2010

-

2012 2011

-

2013 Receptor

Type

Utah Cache Logan 490050004 42 NA 37 NA 46 NA Nonattainment

Utah Davis Salt Lake City 490110004 40 NA 34 A 35 A Maintenance

Utah Salt Lake Salt Lake City 490350003 50 NA Nonattainment

Utah Salt Lake Salt Lake City 490353006 45 NA 38 NA 41 NA Nonattainment

Utah Salt Lake Salt Lake City 490353010 41 NA 35 A 39 NA Nonattainment

Utah Utah Provo 490490002 35 A 29 A 45 NA Nonattainment

Utah Utah Provo 490494001 41 NA 32 NV 44 NA Nonattainment

Utah Utah Provo 490495008 38 NA 41 NV 42 NV Nonattainment

Utah Utah Provo 490495010 42 NA 35 A 46 NA Nonattainment

Utah Weber Salt Lake City 490570002 41 NA 37 NA 40 NA Nonattainment

Utah Weber Salt Lake City 490571003 37 NA 33 A 35 A Maintenance NA = Not attaining; A = attaining; NV = incomplete data; Blank = monitor not operating

Data sources: AirTrends http://www.epa.gov/airtrends/values.html and AirData http://www.epa.gov/airquality/airdata/

Note: receptors with design values (DV) that would otherwise attain the 24

- hour PM 2.5 standard from 2011 to 2013 but for flagged wildfire exceptional events are excluded from this list (i.e. Ravalli, Montana DV = 27 μg/m 3 ; Missoula, Montana DV = 24 μg/m 3 ; and Jackson, Oregon DV = 34 μg/m 3 ).

II. B

. Factors Considered in Transport Analysis for Nona ttainment and M aintenance

R eceptors

Consistent with the recommendations in the Guidance, the EPA reviewed multiple factors to evaluate the weight of the evidence. The EPA evaluated emission inventory data

, ambient

monitorin g data , and meteorological condi tions within the S tate of Oregon

. Emission inventories used in the Transport Rule modeling analysis provide the following amounts of NOx and SO 2 emissions for Oregon in 2012: 189,886 tons of NOx and 36,494 tons of SO 2

. 16 The monitored

ambient PM 2.5 concentrations for receptors in the State of Oregon are shown in Table 1 above.

In addition, the EPA reviewed PM 2.5 m onitoring data at National Parks and wilderness areas in the west that the EPA believes may be considered representative of western regi onal background

levels of PM 2.5 . We reviewed five years of data collected at the IMPROVE 17 monitoring network

at specific National Parks and wilderness areas ( c lass I areas ) in Idaho and on the Idaho/Oregon

border ( Craters of the Moon National Monument

, Sawtooth Wilderness , Hells Canyon

Wilderness , and Starkey ), in Utah (Bryce Canyon National Park

, Canyonlands , Capitol Reef

16 See “Emissions 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.

17 The Interagency Monitoring of Protected Visual Environments (IMPROVE) program i s 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 State implementation pl ans for the protection of visibility in c lass 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 visibil ity impairment. http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx9

National Park , and Zion )

, in Nevada ( Jarbidge Wilderness and Great Basin National Park )

, at the

California

- Oregon border (Crater Lake National Park , Lava Beds National Monument, and

Lassen Volcanic National Park )

, and at the Oregon

- Washington border ( Mount Hood Wilderness and the Columbia River Gorge). 18

Ambient PM 2.5 monitoring data, as well as c hemical 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 PM 2.5 d ata from each of the se monitoring sites in

section V. Appendix to this TSD. The data provided is for the 2009

- 2013 period for each day

when measurements occurred at these c lass I monitors

. This provides information about region al background level s of PM 2.5 in the states surrounding Oregon , and as discussed below, provides

information about levels of PM 2.5 at areas located between Oregon and specific ally identified nonattainment and maintenance receptors

. We note that t he chemical composition of the PM 2.5 in these areas is also available on the IMPROVE website

. 19

Most of the elevated levels of PM 2.5 in the western states are measured during the winter months. For example, in 2011 and 2012, each exc e e dance of the 2006 24

- hour PM 2.5 NAAQS in Salt Lake City occurred in either December or January of those years. 20 Monitor values are

accessible on the EPA’s AirData website

. IMPROVE monitoring sites evaluated indicate low background PM 2.5 levels during the winter months for each of the years from 2009 through 2013

. For example, the PM 2.5 values for January and December of 2010 at Bryce Canyon National

Park , Utah are below 3μg/m 3

. See F igure 1 below. While there are variations in the data,

i ncluding peaks during non

- winter months

, we believe the data provided in section V. Appendix

to this TSD generally indicates that PM 2.5 levels in c lass I areas, as monitored by the IMPROVE network, are generally low at the times when areas in the west are typically experiencing

elevated 24

- hour PM 2.5 levels (winter months ).

18 See section V. Ap

pendix to this TSD

. 19 http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx

20 Monitoring data is accessible on the EPA’s AirData website at http://www.epa.gov/airtrends/values.html 2013 Design Value Report for PM 2.5

.10

Figure 1: IMPROVE PM 2. 5 Data for Bryce Canyon National Park for the Year 201 0

In addition, the EPA reviewed technical information

, such as meteorological conditions

, topography, distance, and monitored ambient data related to each of the areas with nonattainment and maintenance receptors in the potentially impacted western states to evaluate the factors that

cause or contribute to the elevated PM 2.5 levels at these locations

.

We discuss our evaluation of the factors with respect to each identified nonattainment and

maintenance receptor in the following sections. Please note that some states contain both identified nonattainment receptors and main tenance receptors, specifically: California, Montana,

and Utah. Therefore an evaluation for receptors i n these states appear s in both section s III and IV

below.

I II . Transport Assessment for Non a ttainment Receptors

IV. A. Introduction

Based on the methodology for selecting nonattainment receptors described in section II.A above

, we evaluated nona ttainment receptors in the following western states: California, Montana,

Idaho , and Utah

. 21 We have also addressed the nearest eastern receptor evaluated in the Transport Rule modeling domain. 22

I II

. B

. Transport to Western States

21 As this analysis focuses on interstate transport, we did not evaluate the impact of Oregon emissions on nonattainment receptors within Oregon

. 22 Madison County, Illinois. See “ Technical Support Document (TSD) for the final Transport Rule, Docket ID No.

EPA

- HQ

- O AR

- 2009

- 0491, June 28, 2011

.11

III.B.1. California

Eastern California

/ Inyo County Nonattainment Receptor (Site 060271003)

County Site Name Description

Inyo Keeler This s ite is affected primarily is by crustal sources.

M assive erosion from Owens dry lake; in Owens Valley

.

The EPA identified a single nonattainment receptor in Inyo County, specifically the Keeler monitor, which is located adjacent to the Owen s Lake Bed. (See Figures 2 through 4 below).

The Owens Lake Bed is surrounded by steep terrain.

Figure 2 : Keeler Dun es 23

T he Owens Valley Planning Area (OVPA) is located in Inyo County in eastern

- central California. It is situated at the south end of the deep, long, narrow Owens Valley with the Sierra Nevada to the west (max imum elev ation 14,495 feet), the Inyo Mount ains to the east (max imum

elev ation 14,246 feet ), and the Cos o Range to the south ( max imum elev ation 8,160 f eet). The predominantly dry, alkaline Owens Lake bed is approximately eight miles south of the

23 htt p://www.gbuapcd.org/owenslake.htm12

community of Lone Pine on U.S. Highway 395, 60 miles north of the city of Ridgecrest, and 35 miles west of Death Valley. The bed of Owens Lake is defined as the area below 3,600 feet above mean sea level (all elevations will be given in feet above mean sea level). The lake bed

extends about seventeen miles north and south and ten miles east and west and covers an area of approximately 110 square miles (70,000 acres).

Figure 3 : Owens Lake Dust ID Network Map13

Owens Lake is th e largest single source of PM 10 in the United States. 24 Water was first diverted from the Owens River to the City of Los Angeles in 1913, and by 1926 Owens Lake was dry. Today, the Owens lakebed produces enormous amou nts of windblown dust in exceeda nce of federal air pollution standards for particulate matter. Monitoring and research conducted for more than 20 years, as well as three previous State Implementation Plans (SIPs), has determined

that wind

- blown dust from the dry bed of Owens Lake is the dominant cause of NAAQS

violations for PM 10 in the area. 25 Based on the above

- described information about the proximity of this receptor to the large, eroding dry bed of Owens Lake, the distance from Oregon to this receptor (> 350 miles), and the significant intervening terrain, as described above, we believe it

is reasonable to conclude tha t emissions from Oregon sources do not significantly contribute to

nonattainment of the 2006 24

- hour PM 2.5 NAAQS at this receptor.

Figure 4 : Owens Lake Contour Map

24 Ibid.

25 Final 2008 Owens Valley PM 10 P lanning Area Demonstration of Attainment State Implementation Plan, January
28, 2008. http://www.gbuapcd.org/ovpm10sip.htm14

Southern California

/Riverside County Nonattainment Receptor (Riverside) (Site 060658005)

The high 24

- hour PM 2.5 concentrations in the South Coast Air Basin and at the Riverside nonattainment receptor are mainly due to the secondary formation of smaller particulates resulting from mobile, stationary and area source emissions of precursor gases (i.e., NOx, SOx, ammonia ( NH 4 ), and VOC s ) that are converted to PM in the atmosphere. Speciated PM 2.5 data at the Central Los Angeles Site (C E LA) and the Rubi doux site (RIVR) indicate that o rganic c arbon,

a mmonium n itrate, and a mmonium s ulfate constitute the major components at each site . See Figures 5 and 6 below. 24

- hour PM 2.5 design value trends show strong downward trend s at all

sites in the Sou th Coast Basin. 26 See Figur e 7 below.

Figure 5 : Speciated data for the Central Los Angeles Site 27

26 Joe Cassmassi, Scientific, Tec hnical & Modeling Peer Review ( STMPR ) Advisory Group Meeting, September 22,

2011

. 27 STMPR Item # 5

- 2008 PM 2.5 Air Quality Characterization, January 19, 2012. Bong

- Mann Kim

.15

Figure 6 : Speciated data for Roubidoux site at Riverside 28

28 Ibid.16

Figure 7 : 24

- hour PM 2.5 Design Value Trends

PM 2.5 is essentially a combustion generated pollutant due to the volume of traffic flow and numbers of sources (both point and area) in the regio n. It is important to note that the areas with the highest concentrations are directly downwind of a n area with major ammonia source s associated with dairies and poultry farming. 29

The South Coast Air Quality 2012 Air Quality Management Plan 30 air quality p rojections show that the emission control strategy outlined in the plan will result in air quality improvement at each of the nonattainment receptors in the plan , and that each of these sites will attain the

standard in 2014 or sooner

. See Figure 8 below.

29 Final 2012 Air Quality Management Plan (AQMP), Appendix V

– Modeling and Attainment Demonstrations February, 2013.

30 http://www.aqmd.gov/home/library/clean

- air

- plans17

Figure 8 : Maximum 24

- Hour Avera ge PM 2.5 Design Concentrations: 2008 Baseline, 2014

, and 2014 Controlled 31

Based on the air quality trends and projections that indicate that th e above

- referenced emission

strategy will be effective in reducing 24

- hour PM 2.5 levels at this receptor, the distance from Oregon to this receptor (approximately 600 miles ), and the significant intervening terrain including the Sierra Nevada and Cascade Ranges ( see Figure 9 below)

, we believe it is

reasonable to conclude that emissions from Oregon do not significantly contribute to

nonattainment of the 2006 24

- hour PM 2.5 NAAQS at the Riverside receptor.

Central California

/ Fresno, Kern, Kings, Madera, Merced, San Joaquin, Stanislaus and Tulare

Counties Nonattainment Rece ptors (Sites: see table 2 below)

Table 2: Central California

– San Joaquin Valley Nonattainment Receptor Sites

County Nonattainment Receptor Sites

Fresno 060190011, 060195001, 060195025

Kern 060290014, 060290016 Kings 060310004, 060311004

Madera 060392010

Merced 060470003, 060472510 San Joaquin 060771002, 060772010

Stanislaus 060990005, 060990006

Tulare 061072002

31 Source: South Coast Air Quality Management District. http://www.aqmd.gov/home/library/clean

- air

- plans18

PM 2.5 levels in the San Joaquin Valley are generally highest in the months of January, Februa ry, November and December. PM 2.5 bui lds up in episodes of several days or weeks. See Figure 1 0

below. These episodes generally occur during periods with stagnation, cool temperatures, high humidity, and low mixing depths. 32 The peak day composition of PM 2.5 at Baker s field is

p rimarily ammon ia nitrate (67%) and organic carbon (16%). See Figure 1 1 below.

Figure 9 : Map of California 33

32 Nature of PM 2.5 in the San Joaquin Valley , Karen Magliano, California Air Resources Board, Technical Symposium

. April 27, 2012

. 33 Source: University of Texas. http://www.lib.utexas.edu19

Figure 1 0 : Monthly Average PM 2.5 Concentration in Bakersfield California 34

Figure 1 1 : 2008

– 2010 Peak Day Composition in Bakersfield 35

34 Source: South Coast Air Quality Management District. http://www.aqmd.gov/home/library/clean

- air

- plans

35 Ibid.20

The primary sources of PM 2.5 in the region are diesel engines (nitrate), gasoline engines (nitrate), and agricultural activities (ammonium) which contr ibute regionally. Wood smoke (o rganic

c arbon) and diesel engines ( e lemental c arbon) contribute to the elevated 24

- ho ur levels of PM 2.5 in urban areas.

Based on the evidence discussed above, that PM 2.5 builds up in episodes of several days or weeks, during periods with stagnation and low mixing depths, the distance from Oregon to these receptors (> 300 miles), low background levels of PM 2.5 at class I sites between Oregon and this

receptor at the time when these exceedances generally occur, 36 and the significant intervening terrain, including the Sierra Nevada Range ( see Figure 9 above), we believe it is reasonable t o conclude that emissions from Oregon do not significantly contribute to nonattainment of the

2006 24

- hour PM 2.5 NAAQS at these receptors.

California/Mexico Border

– Imperial County Nonattainment Receptor (Site 060250005)

L evels of PM 2.5 in Imperial County that exceed the 2006 24

- hour PM 2.5 NAAQS are recorded at
the Calexico

– Ethel Street monitoring site, which is located near the Mexican Border ( see Figure 1 3 below). The elevated levels of PM 2.5 occur primarily in the wintertime, and seven of

the ni ne values above the level of 35 μg/m 3 in the years 200 8

- 2010 occur in December or January ( See Table 3 below).

Table 3: Calexico

- Ethel Street: Dates of PM 2.5 Values Above 35 μg/m 3 (2006

- 2010)

Year Date s 2008 January 4, and December 22, 25

2009 September 4, and December 12, 21, 24

2010 June 28, and December 4

T he levels of PM 2.5 measured at the Brawley and El Centro monitoring sites are always lower

– usually much lower

– than those measured at the Calexico Ethel Street monitor on days when th e
PM 2.5 levels at the Calexico Ethel Street monitor exceed 35 μg/m 3 . S ee Figure s 1 3 and 1 4 b elow. Because these nearby monitors do not show similar increases in monitored values, it appears that

t he elevated PM 2.5 is being influenced by a source near the C alifornia/Mexico Border.

Based on the above

- described information, distance from Oregon to this California receptor (approximately 1000 miles), and significant intervening topography , including the Sierra Nevada Range (see Figure 9 above) , we believe it is reasonable to conclude that emissions from Oregon

do not significantly contribute to nonattainment of the 24

- hour PM 2.5 standard at this receptor.

36 IMPROVE mon itoring data at Crater Lake, OR, Lava Beds National Monument, CA and Lassen Volcanic National Park, CA

. See section V. Appendix to this TSD.21

Figure 13 : PM 2.5 Monitoring Sites in Imperial County California22

Figure 14 : PM 2.5 levels (μg/m 3 ) at Imperial PM 2.5 Monitoring Sites

, 2006

- 2010, for days of

elevated 24

- hour PM 2.5

Northern California

– Plumas County Nonattainment Receptor (Site 0600631006)

County Site Description

Plumas Quincy This receptor violated the 2006 24

- hour PM 2.5 NAAQS in the most recent design value period (2011

- 2013) but was in attainment of the

24

- hour PM 2.5 NAAQS in the three previous design value periods.

The EPA identified a single nonattainment receptor in Northern California

– the Plumas County receptor located in Quincy. While this receptor is located in an area that is designated attainment

for the 2006 24

- hour PM 2.5 NAAQS, portions of Plumas County are being considered in the designations process for the 2012 annual PM 2.5 NAAQS. 37 We note tha t we are not evaluating

37 EPA Technical Support Document for California for the 2012 Primary Annual PM 2.5 NAAQS. http://www.epa.gov/pmdesignations/2012standards/eparesp/09_CA_120TSD_20140818.pdf 0 10 20 30 40 50 60 70 Calexico -Ethel

El Centro

Brawley23

interstate transport requirements for the 2012 annual PM 2.5 NAAQS in this action, however, we believe that the information developed as part of the designations process for the 2012 annual

PM 2.5 NAAQS is informative for our evaluati on of this receptor for purposes of interstate transport requirements for the 2006 24

- hour PM 2.5 NAAQS. 38

A letter from the Northern Sierra Air Quality Management District, dated June 18, 2014, cites wood burning for residential heating in wood stoves and fireplaces, open burn piles for yard waste disposal, and prescribed burning in nearby federal lands performed by the U.S. Forest Service and a railroad switching yard as the sources affecting PM 2.5 concentrations in Portola,

located in Plumas County, 32 mi les from Quincy

. 39 El evated PM 2.5 in the winter months in

Portola is generally considered related to emissions from residential wood burning. The letter

cite d the diurnal pattern of PM 2.5 concentrations that peak around the two times people use their

wood stoves most: from 5:00 pm to 12:00 am, and from 5:00 am to 8:00 am. With respect to the Quincy receptor, the Northern Sierra Air Quality Management District indicated that similar diurnal patterns are found in Quincy, but not to the same degree. The lette r stated that “emissions in Quincy are also mainly from wood burning appliances (as supported by diurnal PM 2.5 concentration patterns), although Sierra Pacific Industries maintains a biomass

- fired cogeneration facility in Quincy that emitted an 2010

- 2012 a verage of 44 tons per year of total particulate matter.” 40

The population of Plumas County is 19,940. 41 The county lies in the northern Sierra Nevada Mountains near the southern border of the Cascade Range

. The topography of Plumas County is highly variable, including mountain peaks (> 7,000 ft

. ) and valleys with extreme slop es and

differences in altitude. 42 This topography affects and directs airflow, causing shallow vertical mixing, and creating areas of hig h pollutant concentrations by hindering dispersion. 43 Quincy is located in a small and isolated mountain valley at approximately 5000 feet elevation. 44 Prevailing winds in Quincy are from the west, and much of the time there is no measureable wind in Quincy, as indicated by wind roses developed by Northern Sierra Air Quality Management

District. 45

Based on the nature of the PM 2.5 probl em in general at this receptor as described above, the

distance from Oregon to this receptor (approximately 150 miles), low background levels of PM 2.5 at class I sites between Oregon and this receptor at the time when these exceedances generally

38 EPA Technical Support Document for California for the 2012 Primary Annual PM 2.5 NAAQS. http://www.epa.gov/pmdesignations/2012standards/eparesp/09_CA_120TSD_20140818.pdf

39 2012 Northern Sierra Air Quality Management District letter dated June 18, 2 014

. http://www.epa.gov/pmdesignations/2012standards/rec/r9carec2.pdf

40 Ibid at page 4.

41 2010 Census.

42 EPA Technical Support Document for California for the 2012 Primary Annual PM 2.5 NAAQS. http://www.epa.gov/pmdesignations/2012standards/eparesp/09_CA_120TSD_ 20140818.pdf

43 2012 Northern Sierra Air Quality Management District letter dated June 18, 2014

. http://www.epa.gov/pmdesignations/2012standards/rec/r9carec2.pdf

44 Ibid. at page 2.

45 Ibid. at Attachment 6, page 13.24

occur, 46 and s ignificant intervening terrain as described above , we believe it is reasonable to

conclude that emissions from Oregon do not contribute significantly to nonattainment of the 24

- hour PM 2.5 standard at this receptor.

Figure 15 : Topographical Map of Plumas County 47

III.B.2 . Montana

Silver Bow County Nonattainment Receptor (Butte) (Site 300930005)

Elevated levels of PM 2.5 in the Butte area also occur primarily in the winter months. 48 The Butte area is topographically prone to wintertime temperature inversions, as it is situated in a mountain

46 IMPROVE monitoring data at Crater Lake, OR, Lava Beds National Monument, CA and Lassen Volcanic National Park, CA

. See section V. Appendix to this TSD.

47 EPA Technical Support Document for California for the 2012 Primary Annual PM 2.5 NAAQS. http://www.epa.gov/pmdesignations/2012standards/eparesp/09_CA_120TSD_20140818.pdf

48 In 2009 and 2010, the only recent years in wh ich the Butte maintenance receptor violated the 2006 PM 2.5 NAAQS, each exceedance of the NAAQS occurred in either December or January. Monitor values are accessible on EPA’s
AirData website, http://www .epa.gov/airquality/airdata/

.25

valley. The mountains of the Lewis Range and the Bitteroot Range , part of the R ocky Mountains, are situated to the west of Butte, between Oregon and this receptor. See Figure 1 6

below. The tallest peaks in the Bitteroot Range reach 7,000 to 11,000 feet. Speciation data indicates that emissions from wood smoke are the primary contri butor to exceedances of the

PM 2.5 standard in Butte. 49 These factors indicate that high levels of PM 2.5 in Butte build as emissions become trapped in the mountain valley du ring wintertime inversions. 50

Given the characteristics of the elevated PM 2.5 levels at this receptor, air quality data indicating that regional background levels of PM 2.5 are generally low during the time periods of elevated

PM 2.5 at this receptor

, 51 the intervening topography be tween Oregon and this receptor, as described above

, and the distance from Oregon to this receptor (> 200 miles), we believe it is

reasonable to conclude that emissions from Oregon sources do not contribute significantly to

nonattainment of the 2006 24

- hour PM 2.5 NAAQS at this receptor.

Figure 1 6 : Map of M ontana 52

49 Ward, T., Lange, T

. , “The impact of wood smoke on ambient PM 2.5 in northern Rocky Mountain valley communities.” Environmental Pollution 158 (2010) 723

– 729

. 50 Ibid.

51 Craters of the Moon, ID, Sawtooth National Forest, ID, Sula Peak Wilderness Area, MT, Gate of the Mountains Wilderness Area, MT. See section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Result s/HazePlanning.aspx

52 Source: University of Texas. http://www.lib.utexas.edu26

I II .B.3

. Idaho

Franklin County/Cache County Nonattainment Receptor (Logan) (Site 490050004 )

See discussion of Cache County/Franklin County in section III.B.4. Utah below.

Shoshone County Nonattainment Receptor (Pinehurst) (Site 160790017 )

The EPA identified a single nonattainment receptor in Shoshone County, Idaho, namely the receptor located in Pinehurst. Idaho Department of Environmental Quality has identified

Pinehurst as an area of concern for PM 2.5

. 53 A portion of Shoshone County (West Silver Valley)

is being considered in the designations process for the 2012 annual PM 2.5 NAAQS. 54 We note that we are not evaluating interstate transport requirements for the 2012 annual PM 2.5 NAAQS in this action, however, we believe that the inform ation developed as part of the designations process for the 2012 annual PM 2.5 NAAQS is informative for our evaluation of this receptor for purposes of interstate transport requirements for the 2006 24

- hour PM 2.5 NAAQS. 55

Shoshone County is a rural county i n the northern panhandle of Idaho. The area is sparsely populated and is home to rugged mountainous terrain. Residential wood combustion in the cold, winter months is most responsible for elevated particulate matter in the area, while prescribed burning i n the late autumn and in the spring also contributes substantially. Smoke from wildfires can affect the area in the summer. Smoke from crop residue burning is a minor contributor to

PM 2.5 at this receptor

. 56

The Pinehurst monitor measures high values in t he winter due to a combination of residential wood combustion, low wind speeds, and low mixing heights. In the springtime prescribed burning contributes to elevated PM 2.5 . The monitor generally records lower values in the summer except for occasional impac ts from wildfires. In the autumn season the monitor is again influenced by prescribed burning. 57

Pinehurst is located in a partially obstructed topographic bowl within the Silver Valley. 58 The Silver Valley is also the location of the Bunker Hill Superfund site which is a large mining site

that has been undergoing remediation since the 1980s. The mining site currently has only minor

emissions associated with movement of product from the unde rground mining sites. The analysis developed for the 2012 annual PM 2.5 NAAQS designations process supports a conclusion that the majority o f the emissions impacting PM 2.5 levels, in general, are generated from residential wood combustion in close proximity to the Pinehurst monitor. Secondarily, emissions from prescribed burning generated in and around the Silver Valley are also expected t o contribute to elevated

PM 2.5 levels

. 59

53 https://www.deq.idaho.gov/media/662796

- nonattainment_map .pdf

54 EPA Technical Support Document for Idaho for the 2012 Primary Annual PM 2.5 NAAQS. http://www.epa.gov/pmdesignations/2012standards/eparesp/10_ID_120NAATSD.pdf

55 Ibid at page 5.

56 Ibid. at page 5.

57 Ibid. at page 8.

58 Ibid. at page 29.

59 Ibid. at page 29.27

Topography plays a significant role in channeling winds along valleys in partic ular meteorological situations. See Figure 17 below.

Figure 17 : Pinehurst Monitor within West Silver Valley Topography

In West Silver Valley the predominant wind directions are southwe sterly and westerly, but during pollution episodes the wind can also be southerly or northeasterly. During calm, wintertime weather conditions, cold surface temperatures, low wind speeds, and constrained vertical mixing deve lop in concert with each other. The deep, narrow mountain valley significantly magnifies this ef fect rela tive to other nearby areas. The combination of these meteorological effects and the mountainous terrain con fine the geographical area that could contribute emissions to the pollution episode in West Silver Valley. It is h ypothesized that the parti cular terrain features around Pinehurst limit mixing in Pinehurst even more so than the rest of the West Silver Valley. 60

60 Ibid. at page 34.28

Light westerly winds are often associated with high PM 2.5 at the receptor because the monitor is

located on the east side of town. The light westerly winds collect wintertime residential wood

combustion PM 2.5 and carry it to the monitor to the east where it is constrained within the eas t side of the topographic bowl. At night cold air drainage winds follow the stream valleys from the hig her te rrain around West Silver Valley and into river valley. These winds could bring smoke from smoldering prescri bed burns from higher elevation into West Silver Valley. Stronger down

valley northeast winds clear the valley of pollution, while at other ti mes weak northeast winds advect pollution to the monitor. 61 During cold stagnant periods when PM 2.5 is the highest, the mountainous terrain strongly limit the ability of the already weak transport winds to bring pollution from outside areas into the valley

. 62

Given the characteristics of the elevated PM 2.5 levels at this receptor, air quality data indicating that regional background levels of PM 2.5 are generally low during the time periods of elevated

PM 2.5 at this receptor

, 63 the intervening topography betw een Oregon and this receptor, as

described above

, and the distance from Oregon to this receptor (> 100 miles), we believe it is

reasonable to conclude that emissions from Oregon sources do not contribute significantly to

nonattainment of the 2006 24

- hour PM 2.5 NAAQS at this receptor.

Lemhi County Nonattainment Receptor (Salmon) ( Site 160590004 )

The EPA identified a single nonattainment receptor in Lemhi County, Idaho. Lemhi County population is 7,936. The largest city and county seat is Salmon.

The highest point is Bell Mountain at 11,612 feet above mean sea level (MSL), and the lowest point is the Salmon River at approximately 3,000 feet above MSL. The river cuts through the center of Lemhi County before turning west. The county’s eastern border with Beaverhead County

, Montana , is the continental divide

. See Figure 18 below.

The Salmon area is currently listed by the Idaho Department of Environmental Quality as an area

of concern for PM 2.5. 64 Information from the State of Idaho indicates that local emissions, including from woodstoves, contribute to primary PM 2.5 that results in elevated daily PM 2.5 values during stable weather events associated with strong inversions.

The highest values at this recept or were also associated with significant wildfires in 2012. Despite the impacts of wildfire in 2012, Idaho Department of Environmental Quality recognizes that residential wood burning in combination with winter inversions meteorology are impacting

the Salm on receptor. The topography of the area is significant. The Salmon receptor is located in a mountain valley surrounding by significant terrain. The Bitteroot Range, part of the Rocky Mountains, is situated between Oregon and this receptor.

61 Ibid. at page 34.

62 Ibid. at page 36.

63 Craters of the Moon, ID, Sawtooth National Forest, ID, Sula Peak Wilderness Area, MT, Gate of the Mountains Wilderness Area, MT. See section V. Appendix to this TSD and http://vista.cira.colostate.ed u/TSS/Results/HazePlanning.aspx

64 https://www.deq.idaho.gov/media/662796

- nonattainment_map.pdf29

Figure 18 : Map of Idaho30

Given the characteristics of the elevated PM 2.5 levels at this receptor, air quality data indicating that regional background levels of PM 2.5 are generally low during the time periods of elevated

PM 2.5 at this receptor

, 65 the intervening topography between Oregon and this receptor, as

described above

, and the distance from Oregon to this receptor (> 100 miles), we believe it is

reasonable to conclude that emissions from Oregon sources do not contribute significantly to

non attainment of the 2006 24

- hour PM 2.5 NAAQS at this receptor.

Ada County Nonattainment Receptor (Boise) (Site 160010010 )

Ada County is identified as an area of concern for PM 2.5 by the Idaho Department of Environmental Quality. 66 Ada County is in southwest Idaho and Boise is the county’s most populace city. This receptor is in the western Treasure Valley, a basin with surrounding mountainous topography. The Boise Front, approximately 6,000 feet above MSL is located to

the north

. The Owyhee Mount ains are situated to the southwest . Temperature inversions in Ada County occur in the winter months. These stagnation events are cited by Idaho Department of Environmental Quality as impacting the area with respect to particulate matter pollution. 67

Source s of PM 2.5 and precursors are shown in the Table 4 below.

Table 4: Annual E m issions by Source C ategory

— 2015 (tons per year) 68

Source Type NOx SO2 VOC PM10 PM2.5 TC

Point 355.6 65.7 268.1 169.1 142.6 68.5

Area 900.0 23.6 14,551.2 21,107.4 3,651.3 7,806.1

On

- road 5,856.6 33.4 2,939.7 283.0 193.0 246.0

Non

- road 1,979.8 28.2 1,480.7 196.9 185.8 172.7 Biogenic 202.3 0.0 12,802.5 0.0 0.0 0.0

Total 9,294.3 150.9 32,042.2 21,756.4 4,172.7 8,293.3

The design value for the period 2011

- 2013 at this receptor exceeded the 2006 24

- hour PM 2.5 NAAQS, however the previous three design value periods attained the 2006 24

- hour PM 2.5 NAAQS. 69 IMPROVE data from the Hells Canyon and Starkey class I areas are generally low during the times of elevated 24

- hour PM 2.5 levels at the Ada County receptor. 70

65 Craters of the Moon, ID, Sawtooth National Forest, ID, Sula Peak Wilderness Area, MT, Gate of the Mountains Wilderness Area, MT. See section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Result s/HazePlanning.aspx

66 https://www.deq.idaho.gov/media/662796

- nonattainment_map.pdf

67 See Northern Ada County Carbon Monoxide maintenance Plan and Redesignation R equest

68 Source: Idaho Department of Environmental Quality.

69 EPA Airdata.

70 See section V. Appendix to this TSD.31

Given the characteristics of the elevated PM 2.5 levels at this receptor, air quality data indicating that regional background levels of PM 2.5 are generally low during the time periods of elevated

PM 2.5 at this receptor

, 71 and the intervening topography between Oregon and this receptor, we believe it is reasonable to conclude that emissions from Oregon sources do not contribute significantly to nonattainment of the 2006 24

- hour PM 2.5 NAAQS at this receptor.

I II

. B

. 4

. Utah

Utah County Nonattainment Receptor s (Provo ) (Site s 490490002, 490494001, 490495008

, 490495008 )

A large portion of Utah County is designated as the Provo 2006 24

- hour PM 2.5 nonattainment

area ( Provo NAA)

. 72 The Provo nonattainment receptor s identified are 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. See Figure 1 9 below. The Wasatch Mountain Range rises from the valley f loor to approximately 7,000 to over 9,000 ft. MSL and defines the eastern boundaries of both the Salt Lake Valley to the north and the Utah Valley to the south. These valleys are bound on their respective western sides by the Oquirrh Mountains

which also h ave heights of 7,000 ft. MSL to well over 9,000 ft. MSL. North of Salt Lake County, the Wasatch Mountain Range continues to act as a barrier to the east, while the Great Salt Lake serves as the western boundary. 73

Elevated levels of PM 2.5 at these receptor s occur primarily in the winter months. 74 The levels of

elevated PM 2.5 at these receptor s are driven by inversion meteorology which traps pollutants and leads to exceedances, as noted in the discussion of these receptors below. 75 During the winter

m onths, levels of PM 2.5 at background monitoring sites located north and west of this receptor 76
are very low, generally below 3μg/m 3

, and the vast majority of the PM 2.5 in the urban area is generated within the area and trapped during winter inversion meteo rology

.

71 Craters of the Moon, ID, Sawtooth National Forest, ID, Sula Peak Wilderness Area, MT, Gate of the Mountains Wilderness Area, MT. See section V. Appendix to t his TSD and http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx

72 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document,

December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf

. 73 Ibid. at page 48.

74 For example, in 2011 and 201 2, each exceedance of the 2006 PM 2.5 NAAQS in Salt Lake City occurred in either December or January of those years. Monitor values are accessible on EPA’s AirData website, http://www.epa.gov/airquality /airdata/

. 75 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document,

December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf . At page 48.

76 IMPROVE monitoring network at Craters of the Moon, ID, Sawtooth National Forest , ID and Jarbidge

Wilderness Area , NV. See section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx32

Figure 1 9 : Monitoring Network with Counties and Topography 77

During inversions, the Provo NAA features stagnant air masses and calm to light winds. As the

airshed is essentially capped, PM 2.5 is formed in

- situ (and trapped) via fresh emission sources and

77 Source: Utah Department of Environmental Quality. 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document, December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD /tsd_4.0_4.8_4.8.2_r08_UT.pdf

. a t page 19.33

secondary chemistry. Transport of air masses between Salt Lake City and Provo receptors can occur during inversions, as there is a 4.75

- mile gap in the mountains separating these airsheds

which is below the approximate average inversion height for these areas. 78

Speciation data from wintertime PM 2.5 exceedance days from 2004

- 2006 showed the average composition of PM 2.5 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 primary and secondarily

formed PM 2.5 that violate the 2006 24

- hour PM 2.5 NAAQS during stable weather events associated with strong inversions. 79

B ased on the meteorology, topography and characteristics of the PM 2.5 levels during time periods

when the 24

- hour PM 2.5 standard is exceeded as described above, as well as the low levels of background PM 2.5 during these time periods at IMPROVE monitors in the class I areas near these

receptor s and Oregon 80 it is reasonable to conclude that emissions from Oregon do not significantly contribute to nonattainment of the 2006 24

- hour PM 2.5 NAAQS at t hese receptor s

.

Box Elder, Salt Lake and Weber Counties Nonattainment Receptors (Greater Salt Lake City ) (Sites 490030003, 490350003, 490353006, 490353010, 490570002)

All of Salt Lake c ounty an d portions of Box Elder and Weber c ounties are designated as part of the Salt Lake City (SLC) 2006 24

- hour PM 2.5 nonattainment area (NAA)

. 81 The EPA identified nonattainment receptors in each of the three counties. The SLC NAA and these nonattainment

receptors are situated in a valley bordered on the w est by the Stansbury Mountains, 82 Promontor y Mountains and Great Salt Lake, and on the e ast by the Wasatch Front. Like the other low

- lying valleys just west of the Wasatch Front, the topography of the Salt Lake valley makes it prone to temperature inversions. See Figure 1 9 above.

A western topographic airshed barrier for eastern Box Elder County involves the Promontory Mountains and North Promontory Mountains. 83 The Promontory Mountains are located approximately 24 miles west of both Brigham City and Ogden and show approximate altit udes of 5,600 ft. (MSL) in the south (extending into the Great Salt Lake), areas of over 6,000 ft. (MSL) in the middle, and 5,000 ft. to the North where they meet the southern end of the North Promontory Mountains. The southern end of the North Promontory Mountains are approximately

78 Ibid. at page 41.

79 Ibid. at page 34.

80 IMPROVE monitoring network at Jarbidge Wilderness Area, NV, Crater Lake, OR, and Lava Beds National
Monument, CA. See section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx

81 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document,

December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf

. At page 25.

82 The Quqirrh Mountains lie between the Wasatch Front and the Stansbury Mountains. However, EPA determined that some area located west of the Quqirrh Mountains should still be considered part of the SLC nonattainment area.

83 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document,

December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf . At page 48.34

5,000 ft. (MSL) and are also approximately 5,000 ft. (MSL) to the north (northwest of Howell, UT.) 84

The Stansbury Mountains are located approximately 17 miles west of Tooele City (approximately 43 miles southwest of Salt Lake C ity) and show approximate altitudes of 8,300 ft. (MSL) in the south, areas 7,000 ft. (MSL) to over 9,500 ft. (MSL) in the middle, and 5,000 ft. (MSL) to the North where they meet the Great Salt Lake. Also, an impediment to airflow in this

area includes the South Mountain ridge located at the southern end of the Tooele Valley. This ridge essentially connects the Stansbury Mountains to the Oquirrh Mountains and has a maximum height of approximately 6,500 ft. (MSL). Therefor e, it is likely that Salt Lake Count y is contributing to Utah C ounty’s high concentration PM 2.5 violations and that U tah C ount y is contributing to Salt Lake C ounty’s high concentration PM 2.5 violations. 85

During inversions, the SLC 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, PM 2.5 is formed in

- situ (and trapped) via fresh em ission sources and secondary chemistry. 86 Speciation data from wintertime PM 2.5 exceedance days from 2004

- 2006 showed the

average composition of PM 2.5 in Salt Lake City is 58% ammonium nitrate, 31% carbon and organic compounds, 8% ammonium sulfate, and 2% c rustal. Several factors, including significant amounts of emissions from mobile, point and area sources

, contribute to primary and secondarily formed PM 2.5 that violate the 2006 24

- hour PM 2.5 standard during stable weather events associated with strong inv ersions. 87

B ased on the meteorology, topography and characteristics of the PM 2.5 levels during time periods

when the 24

- hour PM 2.5 standard is exceeded, as described above, as well as the low levels of background PM 2.5 during these time periods at IMPROVE monito rs at class I areas near this receptor and Oregon 88 it is reasonable to conclude that emissions from Oregon do not significantly contribute to nonattainment of the 2006 24

- hour PM 2.5 NAAQS at t hese receptor s

.

Cache County / Franklin County Nonattainment Receptor (Logan) (Site 490050004 )

Portions of Cache County, Utah and Franklin County , Idaho make up the Cache Valley, a mountain valley straddling the Utah

- Idaho border. Portions of these two counties are also designated as part of the Logan UT

- ID 2006 24

- hour PM 2.5 , cross

- state nonattainment area ( Cache Valley NAA)

. 89 See Figure 20 below.

84 Ibid. at page 48.

85 Ibid. at page 49.

86 Ibid. at page 34.

87 Ibid. at page 53.

88 IMPROVE monitoring network at Jarbidge Wilderness Area, NV, Crater Lake, OR, and Lava Beds National
Monument, CA. See section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx

89 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document,

December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf . At page 2.35

Figure 20 : Location map showing the Cache Valley and the boundaries for Franklin County, Idaho, and Cache County, Utah. 90

Limited chemical speciation data indicates the 24

- hour PM 2.5 problem is dominated by ammonium nitrate aerosol similar to nonattainment areas along the Wasatch F ront in and near

90 Source Utah Department of Environmental Quality.36

Salt L ake City. 91 The chemical speciation monitor in Bountiful is closest to the Cache Valley

an d is considered broadly representative of conditions in the Cache Valley. 92 The ridge dominated synoptic meteorology during PM 2.5 cold pool episodes features weak transport winds and near calm surface winds. As a result, transport of PM 2.5 and precursors f rom the rural regions at the domain periphery is limited . In addition, most of the observed Wasatch Front and Cache Valley PM 2.5 is formed in

- situ (and trapped) via fresh emission sources and secondary chemistry. 93

Residential heating emissions from woodstoves, emissions from agricultural activities, and

mobile source emissions contribute to primary and secondarily formed PM 2.5 that violate the 24

- hour standard during stable weather events associated wi th extremely strong inversions. T hese emissions and the related effects are limited to the Cache Valley, as they are trapped there due to temperature inversions, low wind, and significant topography. 94

The most prominent topographical features impacting the Cache Valley as a whole include : (1) the eastern boundary of the v alley which is composed of the Wasatch

- Cache National Forest, the Bear River Mountain Range, and Monte Cristo Mountain Range, and (2) the western boundary which is composed of the northern section of the Wasatch Mountain Range and the Wellsville Mountain Range. The mountains to the east rise to approximately 8,300 feet MSL and to the

west the mountains rise to approximately 9,900 feet MSL. However, the valley floor only ranges in altitude from approximately 4,500 feet MSL to 5,200 feet MSL from south to north respectively. 95

The Wellsville Mountains, Bear River Mountains, and northern Wasatch mountains converge in southern Cache County , Utah to form a topographical barrier between the Cache Valley and other adjacent Utah co unties such as Box Elder and Weber. As with the southern area of the Cache Valley, the mountain ranges of the northern area of the Cache Valley, bordering the eastern and western portions of Franklin County, effectively meteorologically isolate Franklin County from Bannock, Bear Lake, Caribou, and Oneida Counties in Idaho. 96

EPA Region 10 Positive Matrix Factor ( PMF ) receptor modeling identified 11 factors contributing to elevated wintertime 24

- hour PM 2.5 levels at the Bountiful monitoring site including nitrate rich (56%), ammonium chloride (15%), wood smoke (10%), organic pyrolysis rich (6%), sulfate rich (5%) and smaller contributions by other identifi ed factors (gasoline vehicles, two soil factors, fireworks, iron rich, and urban unidentified).

Based on the meteorology, topography and characteristics of the PM 2.5 levels during time periods

when the 24

- hour PM 2.5 standard is exceeded, as described above, as well as the low levels of background PM 2.5 during these time periods at IMPROVE monito rs at clas s I areas near this

91 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document,

December 2008. http://www.epa.gov/pmdesignations/2006 standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf . At page 9.

92 Ibid. at page 14

- 15.

93 Ibid. at page 14

- 15.

94 Ibid. at page 17

- 18.

95 Ibid. at page 17

- 18.

96 Ibid. at page 7.37

receptor and Oregon 97 it is reasonable to conclude that emissions from Oregon do not significantly contribute to nonattainment of the 2006 24

- hour PM 2.5 NAAQS at this receptor.

I II

. C . Transport to Eastern States

The EPA has also considered potential PM 2.5 transport from Oregon emission sources to the nearest potential receptor located in the eastern , midwestern, and southern states within the domain of the modeling analysis for the Transport Rule (76 FR 48208)

. The receptor nearest to Oregon evaluated in the Transport Rule modeling analysis is Madison County

, Illinois

. We note,

t he Transport Rule modeling did not analyze the contribution of Oregon sources to Madison County, Illinois. Thus, we have analyzed the magnitude of Oregon’s SO 2 and NOx emissions relative to states found to have emissions that significantly contribute to nonattainment at that

receptor. The EPA also considered the distance from Oregon to Madison County, Illinois relative to states found to significant ly contribute there.

We believe that the following factors support a finding that emissions from O r egon sources do

not significantly contribute to nonattainment of the 2006 24

- hour PM 2.5 NAAQS at the Madison County, Illinois receptor: (1) the relatively small magnitude of the emission inventory of PM 2.5 precursors (SO 2 and NOx) in Oregon as detailed in the paragraph below , combined with (2) the relatively long distance between the s tate of Oregon and th is receptor (> 1000 miles)

. The EPA

believes that these factors also support a finding that emissions from Oregon sources do not significantly contr ibute to nonattainment of the 2006 24

- hour PM 2.5 NAAQS at any of the other Transport Rule receptors f a rther east.

In the Transport Rule analysis

, the EPA did not quantify the PM 2.5 contributions from Oregon to Illinois or any of the other Eastern nonattainment and maintenance receptors modeled as part of the Transport Rule . However, we can make a qualitative conclusion abou t the likely contribution

from Oregon to Illinois and point s f a rther east by comparing the Oregon emissions to a state that

was modeled in the Transport Rule

. Minnesota was modeled for the Transport Rule , and was found below the threshold of significant c ontribution to downwind nonattainment and

interference with maintenance of the 24

- hour PM 2.5 NAAQS for all receptors modeled for the Transport Rule

. We ha ve evaluated the relative amounts of PM 2.5 precursor (SO 2 and NOx)

emissions in Oregon compared to th e amounts of PM 2.5 precursor emission in Minnesota, as

modeled in the “2012 Transport Rule Base Case.”

The emission inventories used in the Transport Rule modeling analysis indicate that SO 2 emissions in Idaho are about 33 % of SO 2 emissions in Minnesota and NOx emissions in Idaho

are about 52 % of NOx emissions in Minnesota. Specifically, t he Transport Rule 2012 Base C ase inventories 98 provide the following statewide emissions inventory data for these two states : 36,494 tons of SO 2 and 189,886 tons of NOx from Oregon emission sources , compared to
109,940 tons of SO 2 and 364,052 tons of NOx from Minnesota emission sources

. Even though the relationship between upwind emissions and downwind secondary PM 2.5 formation is not

97 IMPROVE monitoring network at Jarbidge Wilderness Area, NV, Crater Lake, OR, and L ava Beds National
Monument, CA. See section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx

98 See “Emissions 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

- 2.38

linear, we would expect the Oregon PM 2.5 contribution to Illinois to be much less than that of

Minnesota and well below the 1% threshold applied in the initial screening stage of the T ransport

R ule

. In addition, Oregon is a much greater distance away from Madison County, Illinois than

Minnesota ( > 1000 miles vs approximately 300 miles)

. The distance from Oregon to the other eastern receptors is even greater, and therefore, the expected impact somewhat smaller.

Given all of these factors, the EPA believes it is reasonable to conclude that emissions from Oregon sources do not contribute significantly to nonattainment of the 2006 24

- hour PM 2.5 NAAQS at identified receptors in any eastern state

.

I V. Transport Assessment for Maintenance Receptors

I V. A. Introduction

Based on our methodology for selecting ma intenance receptors described in s ection II.A above,

we have evaluated maintenance receptors in the following w estern states: California , Montana,

and Utah. We also evaluated the nearest easte rn receptor evaluated in the Transport Rule modeling domain. 99

I V. B. Transport to Western State s

IV.B.1. California

Southern California

– Los Angeles County Maintenance Receptor (Site 060370002)

The high 24

- hour PM 2.5 concentrations in the South Coast Air Basin and at this maintenance

receptor are mainly due to the secondary formation of smaller particulates resulting from mobile, stationary and area source emissions of precursor gases (i.e., NOx, SOx, ammonia ( NH 4 ), an d

VOC s ) that are converted to PM in the atmosphere. Speciated PM 2.5 data at the Central Los Angeles Site (C E LA) and the Rubi doux site (RIVR) indicate that o rganic c arbon, a mmonium

n itrate, and a mmonium s ulfate constitute the major components at each site

. See Figures 2 0 and

21 below. 24

- hour PM 2.5 design value trends show strong downward trend s at all sites in the

Sou th Coast Basin. 100 See Figur e 2 2 below.

99 Madison County, Illinois. See “ Technical Support Document (TSD) for the final Transport Rule, Docket ID No.

EPA

- HQ

- O AR

- 2009

- 0491, June 28, 2011

. 100 Joe Cassmassi, Scientific, Technical & Modeling Peer Review ( STMPR ) Advisory Group Meeting, September
22, 2011

.39

Figure 2 1 : Speciated data for the Central Los Angeles Site 101

101 STMPR Item # 5

- 2008 PM2.5 Air Quality Characterization, January 19, 2012. Bong

- Mann Kim

.40

Figure 2 2 : Speciated data for Roubidoux site at Riverside 102

102 Ibid.41

Figure 2 3 : 24

- hour PM 2.5 Design Value Trends

PM 2.5 is essentially a combustion generated pollutant due to the volume of traffic flow and numbers of sources (both point and area) in the region. It is important to note that the areas with the highest concentrations are directly downwind of a n area with major ammonia source s associated with dairies and poultry farming. 103

The South Coast Air Q uality 2012 Air Quality Management Plan 104 air quality projections show that the emission control strategy outlined in the plan will result in air quality improvement at each of the nonattainment receptors in the plan , and that each of these sites will attai n the

standard in 2014 or sooner

. See Figure 2 4 : Maximum 24

- Hour Average PM 2.5 Design Concentrations: 2008 Baseline, 2014 and 2014 Controlled

.

103 Final 2012 Air Quality Management Plan (AQMP), Appendix V

– Modeling and Attainment Demonstrations February, 2013.

104 http://www.aqmd.gov/home/library/clean

- air

- plans42

Figure 2 4 : Maximum 24

- Hour Avera ge PM 2.5 Design Concentrations: 2008 Baseline, 2014

, and 2014 Controlled 105

Based on the air quality trends and projections that indicate that th e above

- referenced emission

strategy will be effective in reducing 24

- hour PM 2.5 levels at these receptors, the distance from Oregon to these receptor s (> 500 miles), and the significa nt intervening terrain including the Sierra Nevada and Cascade Ranges ( See Figure 9 above) we believe it is reasonable to conclude

that emissions from Oregon do not interfere with maintenance of the 2006 24

- hour PM 2.5 NAAQS at these receptors.

I V.B. 2

. Montana

Lewis and Clark County Maintenance Receptor (Helena) (Site 300490026)

Elevated levels of PM 2.5 in the Helena area occur primarily in the winter months. 106 The Helena Valley is topographically prone to cold pool inversion conditions during the winter months. 107
The mountains of the Lewis Range and the Bitteroot Range are situated to the west of Helena, between Idaho and this receptor. See Figure 25 below. Speciation data indicates that emissions from wood smoke are the primary contributor to exceedance s of the PM 2.5 standard in Helena. 108
In the months when violations of the NAAQS occurred at the Helena receptor, the nearby Gate

105 Source: South Coast Air Quality Management District. http://www.aqmd.gov/home/library/clean

- air

- plans

106 The maintenance receptor in Helena, MT violated the 2006 PM 2.5 NAAQS only in 2010. Each of the exceedances

of the 2006 PM 2.5 standard at this receptor during 2010 occurred during the winter months, with all but one exceedance occurring in December or January. Monitor values are accessible on EPA’s AirData website, http://ww w.epa.gov/airquality/airdata/

. 107 Johnson, J. “Case Study of a Persistent Cold Pool in the Helena Valley.” NOAA. November 21, 2000.

108 Ward, T., Lange, T

. , “The impact of wood smoke on ambient PM 2.5 in northern Rocky Mountain valley

communities.” Environme ntal Pollution 158 (2010) 723

– 729

.43

of the Mountains Wilderness Area monitor did not exceed 2 μg/m 3

. 109 All of these factors taken together indicate that high levels of PM 2.5 in Helena build as emissions become trapped during

wintertime inversions.

Figure 25 : Map of Montana 110

Given the characteristics of the elevated PM 2.5 levels at this receptor, air quality data indicating that regional background levels of PM 2.5 are generally low at IMPROVE monitors in class I areas near this receptor 111 during the time periods of elevated PM 2.5 , and the intervening topography between Oregon and this receptor (the Bitteroot Range, part of the Rocky Mountains) we believe it is reasonable to conclude that emissions from Oregon sources do not

interfere with maintenance of the 2006 24

- hour PM 2.5 standard s at this receptor location.

IV.B. 3

. Utah

Davis and Weber Counties Maintenance Receptors (Greater Salt Lake City) (Sites 490110004

and 490571003)

We note that the EPA identified both nonattainment and maintenance receptors in Greater Salt Lake City. Therefore, we have included our evaluation in both sections.

109 The Gate of the Mountains IMRPOVE monitor is located roughly 17 miles from Helena, MT. The IMPROVE

monitor data can be found in section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx

110 Source: University of Texas. http:// www. lib.utexas.edu

111 Craters of the Moon, ID, Sawtooth National Forest, ID, Sula Peak Wilderness Area, MT, Gate of the Mountains Wilderness Area, MT. See section V. Appendix to this TSD and http://vista.cira.colost ate.edu/TSS/Results/HazePlanning.aspx44

Portions of Davis and Weber c ounties are designated as part of the Salt Lake City (SLC) 2006

24

- hour PM 2.5 nonattainment area (NAA)

. 112 The EPA identified maintenance receptors in these

two counties. The SLC NAA and these maintenance receptors are situated in a valley bordered

on the w est by the Stansbury Mounta ins, 113 Promontory Mountains and Great Salt Lake, and on

the e ast by the Wasatch Front. Like the other low

- lying valleys just west of the Wasatch Front, the topography of the Salt Lake valley makes it prone to temperature inversions. See Figure 26

below.

A western topographic airshed barrier for eastern Davis County involves the Promontory Mountains and North Promontory Mountains. 114 The Promontory Mountains are located approximately 24 miles west of both Brigham City and Ogden and show approximate altitudes of 5,600 ft. (MSL) in the south (extending into the Great Salt Lake), areas of over 6,000 ft. (MSL) in the middle, and 5,000 ft. to the North where they meet the southern end of the North Promontory Mountains. The southern end of the North Promontory Moun tains are approximately 5,000 ft. (MSL) and are also approximately 5,000 ft. (MSL) to the north (northwest of Howell, UT.) 115

The Stansbury Mountains are located approximately 17 miles west of Tooele City (approximately 43 miles southwest of Salt Lake City) and show approximate altitudes of 8,300 ft. (MSL) in the south, areas 7,000 ft. (MSL) to over 9,500 ft. (MSL) in the middle, and 5,000 ft. (MSL) to the North where they meet the Great Salt Lake. Also, an impediment to airflow in this

area includes the Sou th Mountain ridge located at the southern end of the Tooele Valley. This ridge essentially connects the Stansbury Mountains to the Oquirrh Mountains and has a maximum height of approximately 6,500 ft. (MSL). Therefore, it is likely that Salt Lake County

is contributing to Utah County’s high concentration PM 2.5 violations and that Utah County is contributing to Salt Lake County’s high concentration PM 2.5 violations. 116

During inversions, the SLC NAA becomes a closed airshed (save for potential transport betwe en 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, PM 2.5 is formed in

- situ (and trapped) via fresh emission sources and secondary chemistry. 117 Speciation data from wintertime PM 2.5 exceedance days from 2004

- 2006 showed the average composition of PM 2.5 in Salt Lake City is 58% ammonium nitrate, 31% 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 primary and

112 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document,

December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf

. 113 The Quqirrh Mountains lie between the Wasatch Front and the Stans bury Mountains. However, EPA determined that some area located west of the Quqirrh Mountains should still be considered part of the SLC nonattainment area.

114 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Documen t,
December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf

. at page 48.

115 Ibid. at page 48.

116 Ibid. at page 49.

117 Ibid. at page 34.45

secondarily formed PM 2.5 that violate the 2006 24

- hour PM 2.5 standard during stable weather events associated with strong i nversions. 118

Figure 26 : Monitoring Network with Counties and Topography 119

118 Ibid. at page 53.

119 Source: Utah Department of Environmental Quality. 2006 24

- Hour PM 2.5 NAAQS Designations (74 FR 58688, November 13, 2009), Technical Support Document, December 2008. http://www.epa.gov/pmdesignations/2006standards/final/TSD/tsd_4.0_4.8_4.8.2_r08_UT.pdf . At page 19.46

Based on the meteorology, topography and characteristics of the PM 2.5 levels during time periods

when the 24

- hour PM 2.5 standard is exceeded, as described above, as well as the low levels of background PM 2.5 during these time periods at IMPROVE monito rs at class I areas near this receptor and Oregon 120 we believe it is reasonable to conclude that emissions from Oregon do

not interfere with maintenance of the 2006 24

- hour PM 2.5 NAAQ S at these receptors.

I V. C. Transport to Eastern States

The EPA has also considered potential PM 2.5 transport from Oregon emission sources to the nearest potential receptor located in the eastern , midwestern, and southern states within the

domain of the modeling analysis for the Transport Rule (76 FR 48208)

. The receptor nearest to Oregon evaluated in the Transport Rule modeling analysis is Madison County, Illinois. We note, the Transport Rule modeling did not analyze the contribution of Oregon sources to Madison County, Illinois. Thus, we have analyzed the magnitude of Oregon’s SO 2 and NOx emissions relative to states found to have emissions that significantly contribute to nonattainment at that receptor. The EPA also considered the distance from Oreg on to Madison County, Illinois relative to states found to significantly contribute there.

We believe that the following factors support a finding that emissions from Oregon sources do

not interfere with maintenance of the 2006 24

- hour PM 2.5 NAAQS at the Madison County,

Illinois receptor: (1) the relatively small magnitude of the emission inventory of PM 2.5 precursors (SO 2 and NOx) in O r egon as detailed in the paragraph below, combined with (2) the relatively long distance between the state of Oregon and this receptor (> 1000 miles). The EPA believes

that these factors also support a finding that emissions from Oregon sources do not interfere with

maintenance of the 2006 24

- hour PM 2.5 NAAQS at any of the other Transport Rule receptors

farther east.

In the Transport Rule analysis, the EPA did not quantify the PM 2.5 contributions from Oregon to Illinois or any of the other Eastern receptors modeled as part of the Transport Rule. However, we can make a qualitative conclusion about the likely contributi on from Oregon to Illinois and points farther east by comparing the Oregon emissions to a state that was modeled in the Transport Rule. Minnesota was modeled for the Transport Rule, and was found below the threshold of significant contribution to downwind nonattainment and interference with

maintenance of the 24

- hour PM 2.5 NAAQS for all receptors modeled for the Transport Rule. We

have evaluated the relative amounts of PM 2.5 precursor (SO 2 and NOx) emissions in Oregon compared to the amounts of PM 2.5 prec ursor emission in Minnesota, as modeled in the “2012 Transport Rule Base Case.”

The emission inventories used in the Transport Rule modeling analysis indicate that SO 2 emissions in Oregon are about 33 % of SO 2 emissions in Minnesota and NOx emissions in

O r egon are about 52 % of NOx emissions in Minnesota. Specifically, the Transport Rule 2012

120 IMPROVE monitoring network at Craters of the Moon, I D, Sawtooth National Forest , ID and Jarbidge

Wilderness Area , NV. See section V. Appendix to this TSD and http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx47

Base Case inventories 121 provide the following statewide emissions inventory data for these two

states: 36,494 tons of SO 2 and 189,886 tons of NOx from Oregon emission sources, compared to
109,940 tons of SO 2 and 364,052 tons of NOx from Minnesota emission sources. Even though the relationship between upwind emissions and downwind secondary PM 2.5 formation is not linear, we would expect the Oregon PM 2.5 contrib ution to Illinois to be much less than that of

Minnesota and well below the 1% threshold applied in the initial screening stage of the Transport

Rule

. In addition, Oregon is a much greater distance away from Madison County, Illinois than

Minnesota (> 1000 miles vs approximately 300 miles). The distance from Oregon to the other eastern receptors is even greater, and therefore, the expected impact somewhat smaller.

Given all of these factors, the EPA believes it is reasonable to conclude that emissions fro m Oregon sources do not interfere with maintenance of the 2006 24

- hour PM 2.5 NAAQS at identified receptors in any eastern state.

V. Appendix

– PM 2.5 IMPROVE Data

1. Overview and Map of IMPROVE Monitoring Sites

IMPROVE Monitoring Program Overview

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

est ablished in 1985 to aid the creation of Federal and State implementation plans for the protection of visibility in class I areas ( 156 national parks and wilderness areas ) as stipulated in

the 1977 amendments to the Clean Air Act

. 122

The objectives of IMPROVE include: (1) establi shing current visibility and aerosol conditions in mandatory class I areas; and (2) identifying chemical species and emission sources responsible for existing man

- made visibility impairment.

The particulate monitoring portion of the IMPROVE program measures the concentration of the fine (PM 2.5 ) particles for mass, optical absorption, major and trace elements, organic and elemental carbon, and nitrate and of PM 10 particles for mass. Prior to 2000, IMPROVE sites collect two samples per week, on Wednesday and Saturday. With the implementation of the Regional Haze Rule the IMPROVE program changed to a 1

- in

- 3 day schedule.

121 See “Emissions 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.

122 http://vista.cira.colostate.edu/improve/Overview/IMPROVEProgram_files/frame.htm48

IMPROVE Monitoring Data

The data for this report was obtained from the website http://views.cira.colostate.edu/web/

. The graphs in this report show the PM 2.5 (fine) mass monitor values from 2009 to 2013 at selected IMPROVE monitoring locat ions.

Additional data, such as the chemical composition data in the graph shown below, is also

available as the http://views.cira.colostate.edu/web/ site, using the composition tool.

State National Parks, Monuments and Wilderness Areas (identifier on IMPROVE Network Map)

Idaho (and Idaho/Oregon Border) Craters of the Moon National Monument (69), Sawtooth

Wilderness (70), Hells Canyon Wilderness (77), Starkey (76)

Montana Sula Peak (71) , Cabinet Mountains W ilderness Area (75) , Gate

of the Mountains W ilderness Area (74)

Nevada Jarbidge Wilderness Area (68)

, Great Basin National Park (116)

Utah Bryce Canyon National Park (51), Canyonlands (50), Capitol

Reef National Park (52), Zi on (49) Wyoming Bridger Wilderness (65) , North Absaroka W ilderness A rea (67) , Yellowstone N ational Park 2 (66)

California

- Oregon Border Crater Lake (86), Lava Beds National Monument (87), Lassen Volcanic National Park (90) Oregon/Washington Border Mount Hoo d (85)

, Columbia River Gorge (112)

Source: http://vista.cira.colostate.edu/improve/Overview/IMPROVENetworkExp.htm49 

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### 2. Idaho and Idaho/Oregon Border

– IMPROVE Data for the Years 200 9

- 2013

Craters of the Moon National Monument , ID

Sawtooth Wilderness , ID51

Hells Canyon Wilderness , ID

Starkey, OR52



### 3. Montana

- IMPROVE Data for the Years 200 9

- 2013

Sula Peak, MT

Cabinets Mountains Wilderness , MT53

Gates of the Mountains Wilderness, MT



### 4. Nevada

- IMPROVE Data for the Years 200 9

- 2013

Jarbidge Wilderness , NV54

Great Basin National Park , NV



### 5. Utah

– IMPROVE Data for the Years 2009

- 2013

Bryce Canyon National Park , UT55

Canyonlands National Park, UT

Capitol Reef National Park , UT56

Zion Canyon, UT



### 6. Wyoming

- IMPROVE Data for the Years 200 9

- 201 3

Bridger Wilderness , WY57

North Absaroka Wilderness, WY



### Yellowstone National Park 2, WY58



### 7. California/Oregon Border

– IMPROVE Data for the Years 200 9

- 201 3

Crater Lake National Park, OR

Lava Beds National Monument, CA59

Lassen Volcanic National Park, CA



### 8 . Oregon /Washington Border

– IMPROVE Data for the Years 200 9

- 201 3

Mount Hood Wilderness, OR60

Columbia River Gorge, OR



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