### MEMORANDUM UNITED STATES ENVIRONMENTAL PROTECTION AGENCY RESEARCH TRIANGLE PARK, NC 27711



## JAN 

## 2Z2015 OFFICE OF AIR QUALITY PU\NNING AND STANDARDS



### SUBJECT: Information onthe Interstate Transport "Good Neighbor" Provision for the 2008 Ozone National Ambient Air Quality Standards (NAAQS) under Clean Air Act (CAA) Section 110(a)(2)(D)(i )
FROM:



### TO: Regional Air

### Division Directors, Regions 1-10 Thepurpose ofthis memorandum is to provide information to states regarding state implementation plans (SIPs) to address the interstate transport "Good Neighbor'' Provision ofthe Clean AirAct (CAA) as it pertains tothe 2008 ozone National AmbientAir Quality Standards (NAAQS). This information consists of:

• Discussion ofelements that have been usedpreviously to address interstate transport, and • The EPA's preliminary air quality modeling data

### for ozone for the year 2018. The EPA anticipates that

### this 

### information, togetherwith additional steps described below, will be helpful to states developing "GoodNeighbor" SIPs for the 2008 ozone NAAQS. The EPA and states are behind schedule in 

### addressing the "GoodNeighbor" Provisionfor the 2008 ozone standards, due to factors such as the EPA'sreconsideration ofthe standards and protracted litigation relatedto previous actions [mostrecently the Cross-State Air PollutionRule (CSAPR)] underthe "GoodNeighbor" Provision. This document ispartofthe process ofworking with states to offer support and information to enable the EPA and states to move forward to address the requirements ofthe "GoodNeighbor" Provision for this NAAQS as soon as possible.
In addition to the information being shared today, the EPA will hold a webinar in early February and a workshop inthe spring of2015. The webinar will focus on the content ofthis memo and the attached preliminary air quality modeling data. For.the workshop, the EPA plans to facilitate discussions with states on: (1) available emission controls; (2) potential**state-by~state** 

### electric generating unit (EGU) nitrogen oxides (NOx) reductions based on those controls; and (3) potential EGU emissions budgets informed bythose reductions. More information onthe webinar and workshop will be 

### forthcoming. The EPA's goal is to provide information and to initiate discussions that will 

### inform state development and EPA review of"GoodNeighbor" SIPs, and, where appropriate, to facilitate state efforts to supplement orresubmittheir "Good Neighbor" SIPs. At this 

### time, there are anumber ofstates that may nothave submitted "GoodNeighbor" SIPs for the 2008 ozone NAAQS. In addition, there are anumber

Internet**Add~Bss** (URL) • http://www.epa.gov**R~lecmecyGI•bl•** • Printed with Vegetabl& OU Based Inial on Recycled Paper (Minimum 25% Postoonsumer)ofpending "GoodNeighbor" SIPs for the 2008 ozone NAAQS that the EPA will review and take action on. While ourgoal is to facilitate SIP development, the EPA also recognizes its backstop role inthe SIP development process-that is, ourobligation to develop andpromulgate federal imp1ementation plans, as appropriate. We plan to take this action, ifnecessary. It is our intention that any federal rule developed to satisfy this obligation would provide ample opportunity for states to pursue alternatives. 

### The "Good Neighbor" Provision

Under CAA sections llO(a)(l) and 110(a)(2), each state1 is required to submit a SIP2 that provides for**~he** implementation, maintenance and enforcement ofeach primary or secondaryNAAQS. Moreover, section llO(a)(l)requires each state to make this newSIP submission within 3 years after promulgation ofa new orrevised NAAQS.3 This type ofSIP submission is commonly referredto as an "infrastructure SIP." The conceptual purpose ofaninfrastructure SIP submissionisto assure that the state's SIP contains the necessary structural requirements for the implementation ofthe new orrevised NAAQS, whether by establishing that the SIP already contains or sufficiently addresses the necessary provisions, orby making a substantive SIP revisionto update the SIP.
CAA section llO(a)(2)(D)(i)(I) requires each state in its SIPto prohibit emissions that will significantly contribute to nonattainment ofa NAAQS, or interfere withmaintenance ofa NAAQS, 

### in a downwind state. Under section llO(a)(2)(D)(i)(I), each state is requiredto submitto the EPAnew orrevised SIPs that "containadequate provisions- prohibiting, consistent withthe provisions ofthis subchapter, any source or othertype ofemissions activity withinthe state from emitting any air pollutant in amounts whichwill

... contribute significantly to nonattainmentin, or interfere withmaintenance by, any other state withrespectto any suchnational primary or secondary ambientair quality standard." Forpurposes ofthis document, we refer to section 110(a)(2)(D)(i)(I) asthe "GoodNeighbor Provision" and to SIP revisions addressing this requirement as "GoodNeighbor SIPs."


### ElementsThat HaveBeenUsed Previously to Address the "Good Neighbor" Provision
The EPAnotesthat a consistent framework for addressing transport for certainNAAQS, involving a numberofbasic steps, has been developed in several previous federal rulemakings.4 These basic steps include: (1) identifying downwind 

### air quality problems, (2) identifying upwind states thatcontribute enoughto**~ose** downwindair quality problemsto warrant further review and analysis, (3) identifying

1The tenn "state" as used in this memorandumhas the same meaning as provided in CAA section 302(d). These CAA sections and this information may also apply, as appropriate underthe Tribal Authority Rule (TAR) in 40 CFRpart49, to an Indian tribe thatreceives adetermination ofeligibility for treatment in a similarmanner as a state for purposes of administering atribal air quality managementprogram under section 110(a )"ofth.e CAA. Tribes should lookto th.e TAR and engage their respective EPA regional offices in discussing how this information may impactthe development and approvability oftheir tribal implementation plans (TIPs). We encourage states to provide outreach and engage indiscussions with tribes about their SIPs as they arebeing developed. · 2 In the CAA and in this memorandum, "plan," "SIP" and "TIP" may, depending on context, refer either to (i) all orpart of the existing state (ortribal) implementation plan (i.e., the collection ofall submissions previously approved bythe EPA as meeting CAA requirements) or (ii) a submission that adds to or modifies the existing plan as directed by section 11O(a){l). 3 The Administratormay specify a shorterperiod. 4 See for example, Finding ofSignificant Contribution and Rulemaking for Certain States in the Ozone TransportAssessment Group Region for Purposes ofReducing Regional Transport ofOzone. 63 FR 57356 (October 27, 1998); Clean AirInterstate Rule (CAIR) Final Rule. 70 FR25162 (May 12, 2005); CSAPRFinal Rule. 76 FR48208 (August 8, 2011).
2

### the emissions reductions necessary to prevent an identifiedupwind state from contributing significantly to those downwind air 

### quality problems and (4) adoption ofpennanent and enforceable measures needed to achieve those emissions reductions.
Efforts to address ozone transport by the EPA and states under the "Good Neighbor" Provisionhave focused onreductions ofNOxas the precursorpollutant for which emissions in upwind states have the greatest impacts ontransported ozone.5


### In 

### CSAPR, downwind air 

### quality problems were assessed based on modeled future air 

### quality concentrations for a year aligned With attainment deadlines for a particularNAAQS. The assessment of future air

### quality conditions generally accounted for on-the-books emissions reductions6 

### and the most up-to-date forecast offuture baseline emissions. The locations ofdownwind air quality problems were identified as those receptors that were projected to be unable to attain or maintain 

### the standard. More detail onthe methods for identifying problem receptors in CSAPR is 

### contained inthe attachment. CSAPR used a screening threshold (1 percent ofthe NAAQS) to identify contributing upwind states 

### warranting further review and analysis. States whose air 

### quality impact1 to at least one downwind problemreceptor 

### was greater than 

### or equal to the threshold were identified as needing further evaluation for actions to address transport. States whose air 

### quality impacts to all downwind problemreceptors were belowthis threshold were identified as states not requiring further evaluation for actions to address transport-that is, these states had 

### no emissions reduction obligation under the "Good Neighbor" Provision.
In 

### orderto quantify emissions reductions needed to eliminate significant contributions to a downwind air quality problem, CSAPR's apportionment ofresponsibility evaluated air

### quality and included consideration ofcost, an approach that was recently upheld by the U.S. Supreme Court.8

### The selection ofcost criteriawas infonnedby airquality considerations. For example, the approach inCSAPRfor sulfur dioxide contributions to 

### fine particulate matter (PM2.5) 

### placed states into two groups based on differing air 

### quality considerations at downwind receptors. For states within each group, however, a uniform cost level 

### was used to determine needed emissions reductions.

The EPA'spreliminary air

### quality modeling analysis (see 

### attachment and the Air

### Quality Modeling Technical Support Documentfor the 2008 Ozone NAAQS TransportAssessment located at 

### www.epa.gov/airtransport) applies the CSAPR approachto the 2008 ozone NAAQS, including the approach for identifying nonattainment and maintenance receptors and for identifying upwind states that contribute to these receptors based on the 1percent screening threshold. Following the CSAPR approach, a state could either demonstrate that its contribution is belowthe screening threshold, or it could evaluate the scope ofits transport obligation and identify measures to achieve any needed emissions reductions. The discussions atthe spring 2015 workshop are intended to help states with their evaluation ofsuch emissions reductions.

s See discussion inpreamble to the CSAPRFinal Rule. 76 FR48222 (August 8, 2011). 6 The exceptionbeing CAIR, which CSAPRwas designed to replace andtherefore was not considered on-the-books. 7 Forozone the impacts would include those from volatile organic compowtds (VOC) and NOx, and from all sectors. 8 EPA v. EMEHomer City Generation, L.P., 134 S. Ct. 1584, 1606-07 (2014). 

### 3CSAPRand its predecessortransport rules, the NOx SIP Call and CAIR, were designed to address the collective contributions from the 37 states inthe EasternU.S. and were not formally evaluated for applicability to the 11 states inthe Western U.S.9 The EPA'spreliminary modeling indicates thatmost western states contribute less than 1percentto downwind nonattainment ormaintenance receptors, a level the EPA considered to not need further evaluationfor actions to address transport in CSAPR. There are a few receptors inthe West where 1to 3 western states may contribute amounts potentially exceeding the 1 percentthreshold (See Technical SupportDocument). Due to the possibility that additional considerations may impact the EPA's and state's evaluation oftransport from these potentially linked states 

### inthe Western U.S., we expectthatthe EPA and states will continue to evaluate these westerntransport linkages (not included in the attachment) on a case-by-case basis. We recommend that states consult with theirEPA regional offices regardingthese specific situations.
ForFurther Information
Ifyouhave any questions concerning this information, please contactTim Smith, at (919) 541-4718, smith.tim@epa.gov, orGobeail McKinley, at (919) 541-5246, mcldnley.gobeail@epa.gov.
Attachment

9 Forthe purposes ofthis information document, we include the 37 states and the District ofColumbiainthe region from Texas northward to NorthDakota and eastward to the East Coast as comprisingthe Eastern U.S. The Western U.S. refers to the 11 states in the contiguous U.S. west ofthose states (AZ, CA, CO, ID, MT, NM, NV, OR, UT, WA and WY).


### 4

### Attachment

Air QualityModelingResults 

### A. Backgro1Jnd The EPA performed photochemica1 air

### quality modeling to project ozone concentrations at air quality monitoring sites to 

### 2018, the moderate area attainmentdate for the 2008 ozone National Ambient Air Quality Standards (NAAQS), and to 

### estimate state-by-state contributionsto those 2018 concentrations. We thenused the air

### quality modeling results, and themethods we used for Cross-State Air Pollution Rule (CSAPR), to 

### identify ozone monitoring sites expected to be nonattainment or maintenance receptors for the 2008 ozone NAAQS in 2018. We used the contribution information to quantify projectedinterstate contributions from emissions ineach upwind state to ozone concentrations at

### each identified 2018 nonattainment and maintenance receptorin downwind states. The EPA's air 

### quality modeling used the 2011-based air quality modeling platform. This platform includes emissions for a 2011 base year and a 2018 future base case as well as meteorology for 2011. The 2011 meteorology 

### was used in air quality model simulations for both 2011 and 2018. We selected 2011 as the base yearbecause it reflected the most currentNational Emissions Inventory (NEI) available. Details on the construct and evaluation ofthe 2011-based air

### quality modeling platform are provided inthe Air Quality Modeling Technica1 Support Document for the 2008 OzoneNAAQS Transport Assessment (AQMTSD). The 2011 base year emissions in the 2011-based air quality modeling platformwere derived from the 2011 NEI, as described inthe Technical Support Document: Preparation ofEmissions Inventories for the Version 6.0, 2011 Emissions Modeling Platform. 10 

### This document also describes the control and growth assumptions by source type 

### that were used'to create the 2018 base case emissions inventory. 11 

### The EPA released the 2011 and 2018 emissions inventory for public review on

10 Available on the EPA's website at: http://www.epa.gov/ttnchiellemch. 11 For electric generatingunits (EGUs), the 2018 base case emissions were obtained from the Integrated Planning Model (IPM version 5.13, http://www.epa.govlpowersectormodeling/BaseCasev51 3.html). The 2018 base case EGU projections include the Acid Rain Program, Clean Air Interstate Rule (CAIR), and Mercury andAir Toxics Standards. The base case does not include CSAPR, the proposed Clean PowerPlan orthe proposed 2015 ozone NAAQS, because ofthe time the projections were developed. 

### 1November 27, 2013 (78 FR70935), and January 14, 2014 (79 FR2437), respectively. The air quality modeling presented inthis transport information document pre-dated, and therefore does notreflect, comments received from this public reviewprocess ofthe 2011 and 2018 emissions inventories. We note that the EPAplans to re-model2011 and 2018 to provide updated projections of2018 design values and contributions, using revised inventories createdinresponse to comments onthis public review process and other emissions updates. The EPA used the Comprehensive

### Air Quality Model withExtensions (CAMx version 6.10) 12 for modeling the 2011 base year and 2018 base case emissions scenarios to identify sites withprojected nonattainment and maintenanceproblems in 2018. As shown inFigure 1, the air quality model runs
were performed for a modeling domainthat covers the 48 states inthe contiguous U.S. along with adjacent portions ofCanadaand Mexico. The spatial resolution (i.e., grid size) for this modeling domain is 12 km x 12 km. The 2011 and 2018 scenarios were also bothmodeled for the full year with 2011 meteorology.

12 Environ, April4, 2014 (http://www.camx.com). 

### 2 '•

### Figure 1. 

### Air quality modeling domain (area within the purple lines).



### B. Identification of Future Nonattainment andMaintenance Receptor Sites The ozone predictions from the 2011 and 2018 CAMx model runs were used to project ambient (i.e., measured) ozone design values to 2018 following the approach described inthe EPA's draft informationfor attainment demonstrationmodeling. 13 We selected 2011 as the base year to reflect the
mostrecentNEI, and we selected 2018 to coincide withthe attainment date for moderate areas under the 2008 ozone NAAQS. The draft modeling informationrecommends using 5-yearweighted average

13 The December 3, 2014, draft ozone, fine particulate matter and regional haze SIP modeling guidance is available at http://www.epa.gov/ttnlscramlguidance/guide/Draft

_03-P M-RH _Modeling_Guidance-2014.pdf

3ambient design values 14 centered onthe base year as the starting point for projecting design values to the future. Because 2011 is the base year ofemissions, we started with the average ambient 8-hour ozone design values for the period 2009 through 2013 (i.e., the average ofdesign values for 2009-2011, 2010- 2012 and 2011-2013). The 5-year weighted average ambient design value at each site was projected to 2018 using model-predicted Relative Response Factors (RRFs) 15 which were calculatedbased on procedures described inthe draft modeling information. The 2018 projected average ozone design values were evaluated to identify those sites with design values that exceedthe 2008 ozone NAAQS. 16 Those sites with 2018 average design values that exceedthe NAAQS are projectedto 

### be nonattainment in 2018. We followed the CSAPR approach to identify sites withprojected maintenance problems in 2018 (76 FR48208). 

### As part ofthe approach for identifying sites withprojected future maintenance problems, the highest (i.e., maximum) ambient design value from the 2011-centered 5-yearperiod (i.e., the maximum ofdesign values from 2009-2011, 2010-2012 and 2011-2013) was projected

### to 2018 for each site using the site-specific RRFs. Monitoring sites with a 2018 maximum designvalue that exceeds the NAAQS are projectedby the CSAPR approach to have a maintenanceproblem in2018. Thebase year ambient andprojected 2018 average and maximum design values at

### all monitoring sites are provided inthe AQMTSD. In 2018 there are 11 projected nonattainment sites and 18 projected maintenance sites inthe East 

### (See Table 1). These are the sites that are indicated from the EPA's preliminary modeling as warranting the evaluation ofcontributions from upwind states.**~e** projected 2018 nonattainment sites inthe East are located infour nonattainment areas: Baltimore, MD; New York City, NY (sites 

### in bothNY and CT); Dallas, TX; and Houston, TX. Note that several ofthese nonattainment areas also contain additional sites that are projected as maintenance receptors. Also, there

are several projected maintenance-only areas 

### inthe East: Holland, MI; Louisville, KY; Philadelphia, PA (including sites inbothNJ and PA); St. Louis, MO; and Sheboygan, WI 

### (See Table 2).

14 The air quality design value for a site is the 3-year average annual fourth-highest daily maximum 8-hour average ozone concentration. 15 Inbrief, the RRF for a particular location is the ratio ofthe 2018 ozone model prediction to the 2011 ozone model prediction. The RRFs were calculated using model outputs for the Maythrough September period. 16 In determining compliance with the NAAQS, ozone design values are truncated to integer values. For example, a design value of75.9ppb is truncated to 75 ppb which is attainment. Inthis manner, design values at or above 76.0 ppb are considered nonattainment. 

### 4

### Table 1. Ambient and 2018 projected average and maximum 8-hour ozone design values (DVs) at 2018 nonattainment receptors in theEast (nonattainment receptors have a 2018 average design value of2: 76.0 ppb). Units are ppb.
2009- 2009- 2013 Avg 2013 Max 2018 Avg 2018 Max State County Site ID DVs DVs DVs DVs Connecticut Fairfield 90013007 84.3 89.0 76.7 81.0 Connecticut Fairfield 90019003 83.7 87.0 77.5 80.6 Maryland Harford 240251001 90.0 93.0 79.4 82.1 NewYork Suffolk 361030002 83.3 85.0 78.2 79.8 Texas Brazoria 480391004 88.0 89.0 80.5 81.4 Texas Denton 481210034 84.3 87.0 77.0 79.5 Texas Harris 482010024 80.3 83.0 76.4 79.0 Texas Harris 482011034 81.0 82.0 76.6 77.6 Texas 

### Harris 482011039 82.0 84.0 77.7 79.6 Texas Tarrant 484392003 87.3 90.0 79.7 82.2 Texas Tarrant 484393009 86.0. 86.0 78.3 78.3



### Table2. Ambient and 2018 projected average and maximum 8-hourozone design values (DVs) at 2018 maintenance receptors intheEast (maintenance receptors have a 2018 maximum design value of

### 2: 76.0 ppb ). Units are ppb.
2009- 2009- 2013 Avg 2013 Max 2018 Avg 2018 

### Max State County Site ID DVs DVs DVs DVs Connecticut Fairfield 90010017 80.3 83.0 74.1 76.6 Connecticut New Haven 90099002 85.7 89.0 75.8 78.8 Kentucky Jefferson 211110067 82.0 85.0 73.7 76.4 Michigan Allegan 260050003 82.7 86.0 74.5 77.5 Missouri Saint Charles 291831002 82.3 86.0 74.1 77.4 NewJersey Camden 340071001 82.7 87.0 72.3 76.0 NewJersey Gloucester 340150002 84.3 87.0 74.0 76.3 New York Richmond 360850067 81.3 83.0 74.6 76.2 Pennsylvania Philadelphia 421010024 83.3 87.0 74.7 78.0 Texas Collin 480850005 82.7 84.0 75.0 76.2 Texas Dallas 481130069 79.7 84.0 73.7 77.7 Texas Dallas 481130075 82.0 83.0 75.2 76.1 Texas Denton 481211032 82.7 84.0 75.1 76.3 52009- 2009- 2013Avg 2013 

### Max 2018Avg 2018Max State County Site ID 

### DVs DVs DVs DVs Texas Harris 482010029 83.0 84.0 75.4 76.3 

### Texas Harris 482010055 81.3 83.0 75.0 76.6 

### Texas Tarrant 484390075 82.0 83.0 75.5 76.4 

### Texas Tarrant 484393011 80.7 83.0 74.2 76.3 Wisconsin Sheboygan 551170006 84.3 87.0 75.4 77.8



### C. Quantification of Interstate Ozone Contributions 

### The EPA performednationwide, 17 

### state-level ozone source apportionment modeling using the CAMx Ozone Source Apportionment Technology/Anthropogenic Precursor Culpability Analysis (OSAT/APCA) technique 18 

### to quantify the contribution of2018 base 

### case nitrogen oxides (NOx} 

### and volatile organic compound (VOC} emissions from all sources in each state to projected 2018 ozone concentrations at airquality monitoring sites. In

### the source apportionment model run, we trackedthe

ozone formed from each ofthe following contribution categories (i.e., "tags"):

• States- anthropogenic NOx and VOC emissions from each state tracked individually (emissions from all anthropogenic sectors in a given state were combined},

• Biogenics- biogenic NOx and VOC emissions domainwide (i.e., not by state),

• Boundary Concentrations- concentrations transported into the nationwide modeling domain,

• Tribes-the aggregate ofemissions from those tribal lands for which we havepoint source inventory data in the 2011 NEI (i.e., we did not model the contributions from individual tribes), and

• Other-- combinedemissions from wild and prescribed fires, offshore emissions from marine vessels, offshore drilling platforms and anthropogenic emissions from the portions ofCanada and Mexico within the modeling domain.

17 As shown inFigure 1, the EPA's nationwide modeling includes the 48 contiguous states. 18 As part ofthis technique, ozone formed from reactions between biogenic VOC and NO,. with anthropogenic NO,. and VOC are assigned to the anthropogenic emissions. 6The CAMx OSAT/APCA model run was performed for the period May 1through September 30 using the projected 2018 base case emissions and 2011 meteorology for this timeperiod. The hourly contributions 19 from eachtag were processedto obtain the 8-hour average contributions corresponding to the time period ofthe 8-hour daily maximum concentration on each day inthe 2018 model simulation. This step was performed for those model grid cells containing monitoring sites inorder to obtain 8-hour average contributions for each day atthe location ofeach site. The model-predicted contributions were then applied in a relative sense to quantify the contributions to the 2018 average design value ateach site. First, the daily 8-hour contributions were averaged across the subset ofdays with 2018 model predictions exceedingthe 2008 ozone NAAQS (i.e., 8-hr daily**maximum~** 76 ppb). For those sites with fewer 

### than 

### 5 predicted exceedance days in 2018, we averaged the contributions for the top five concentrations days.2

# ° For each site, the multi-day average contribution from eachtag was normalized by the sum ofthe contributionfrom all tags, combined. The resulting fractional contributions
ateach site were then applied to the 2018 average design value to quantify (i.e., "apportion") the design value into contributions from each tag. This process was performedfor each monitoring site with a projected 2018 design value. Additional details onthe source apportionment modeling and the calculation ofcontributions can

### be found in the AQMTSD. The resulting 2018 contributions from each tag to each monitoring site are provided 

### inthe AQMTSD. The largest contributions from each state to 2018 downwind nonattainmentreceptors and to downwind maintenancereceptors are provided in Table 3.

19 Contributions from anthropogenic emissions under ''NOx-limited" and "VOC-Iimited" chemical regimes were combined to obtain the net contribution from NOx and VOC anthropogenic emissions in each state. 20 Ifa site did nothave at least 5 days with a modeled 2018 8-hour daily maximum**concentration~** 60 ppb, then contributions were not calculated atthe monitor.


### 7Table 3. Largest ozone contributions from each state to downwind 2018 projected nonattainment and to 2018 projected maintenance receptors. Units are ppb. Largest Contribution to Largest Contribution to a 2018 Nonattainment a 2018 Maintenance

Site in Downwind Site inDownwind Upwind State States States Alabama 1.06 1.39 Arizona 1.478 0.44 Arkansas 1.25 2.19 California 0.23 1.168 Colorado 0.35 0.33 Connecticut 0.41 0.08 Delaware 0.63 2.46 District of Columbia 0.69 0.29 Florida 0.87 1.05 Georgia 0.71 0.73 Idaho 0.09 0.22 lllinois 0.87 22.29 Indiana 1.93 11.41 Iowa 0.62 0.89 Kansas 0.70 1.15 Kentucky 1.94 2.40 Louisiana 3.38 4.37 Maine 0.01 0.00 Maryland 2.59 6.96 Massachusetts 0.21 0.12 Michigan 1.48 3.63 Minnesota 0.43 0.34 Mississippi 0.83 1.52 Missouri 1.53 4.12 Montana 0.14 0.17 Nebraska 0.36 0.56 Nevada 0.70 0.44 New Hampshire 0.03 0.02 NewJersey 921 9.95 NewMexico 0.26 0.20 New York 16.05 16.14 North Carolina 0.57 0.55 North Dakota 0.13 0.19 Ohio 4.06 4.41 Oklahoma 1.50 2.59 Oregon 0.69 0.73 Pennsylvania 9.85 18.76 Rhode Island 0.04 0.03 8**~gemConbibutionto ~gest**  Conbibutionto a 2018 Nonattainment a 2018 Maintenance

Site 

### in Downwind Site in Downwind Upwind State States States South Carolina 0.36 0.35 South Dakota 0.09 0.12 Tennessee 0.69 0.99 Texas 0.92 2.74 Utah 0.29 1.43 8 Vermont 0.02 0.02 

### Virginia 4.42 3.27 Washington 0.21 0.13 WestVirginia 2.79 2.88 Wisconsin 0.34 2.49 Wyoming 0.37 

### 1.29- 8 These four western states (i.e., AZ, CA, UT, and WY) contribute above the 1percentthresholdto projected 2018 nonattainment ormaintenance sites in the West, as identified in the AQMTSD. 

### Table 4 indicates the projected state "linkages" to downwind 2018 nonattainmentreceptors in the Eastern U.S.21

### identified inthe air 

### quality modeling using a threshold of 1percent ofthe 2008 ozone NAAQS (0.76 ppb), consistent with CSAPR. Table 

### 5provides the same information for states that contribute at

### orabove the 1percentthreshold to identified 2018 maintenance receptors inthe Eastern U.S. (States 

### inthe Eastern 

### U.S. 

### that are not listed inthese tables contribute below 1percent at

### all receptors).

21 Forthe purposes ofthis information document, we include the 37 states and the District ofColumbia in the region from Texas northward toNorth Dakota and eastwardto the East Coast as comprisingthe Eastern U.S. The Western U.S. refers to the 11 states inthe contiguous U.S. west ofthose states (AZ, CA, CO, ID, MT, NM, NV, OR, UT, WA and WY). 

### 9

### Table4. Ozone contributions atorabove a 1 percentthreshold from upwind states to 2018 nonattainmentreceptors in the EasternU.S. Units areppb.
2018 Nonattainrnent Upwind States- Part 1(AL through MS) Receptors County Site ID 

### AL AR 

### PL IL IN 

### KY LA MD M1 MS Fairfield, CT 90013007 2.11 0.93 Fairfield, CT 90019003 2.60 Harford, MD 240251001 1.93 1.95 0.86 Suffolk, NY 361030002 0.79 1.02 1.50 1.49 Brazoria, TX 480391004 1.00 0.88 3.25 0.81 Denton. TX 481210034 1.06 0.95 3.13 Harris, TX 482010024 0.87 2.24 Harris, TX 482011034 1.06 0.81 3.39 Harris, TX 482011039 1.25

# ~ 0.84 Tarrant,TX 484392003 0.82 0.97 Tarrant, TX 484393009 1.19
Number ofLinkages=> 2 6 1 3 2 I 7 3 3 2

2018 Nonattainment Upwind States -Part2 (MO through WV) Receptors County Site ID MO NJ NY 

### OH OK PA TX 

### VA 

# wv Fairfield, Cf 90013007 6.72 15.58 1.92 9.86 1.92 0.97 Fairfield, Cf 90019003 8.17 16.06 1.50 9.30 2.17 0.89 Harford, MD 240251001 4.07 6.93 0.92 4.43 2.80 Suffolk, NY 361030002 9.21 2.52 9.79 0.80 1.72 0.99 Brazoria, TX 480391004 1.20 0.77 Denton. TX 481210034 1.12 Harris. TX 482010024 Harris, TX 482011034 1.53 1.51 Harris, TX 482011039 1.06 0.99 Tarrant, TX 484392003 1.22 Tarrant, TX 484393009 1.25
Number ofLinkages => 3 3 2 4 6 4 2 4 4



### 10

### Table 5. Ozone contributions ator above a 1 percentthreshold from upwind states to 2018 maintenance receptors in theEastern U.S. Units areppb.

2018 Maintenance Receptors Upwind States- Part 1 (ALthrough LA) County Site ID AL AR DE FL IL

# ~lA KS KY LA Fairfield, CT 90010017 0.79 New Haven, CT 90099002 0.81 Jefferson, KY 211110067 1.09 . 11.42 Allegan MI 260050003 2.19 22.30 8.17 0.89 1.15 SaintCharles, MO 291831002 0.87 1.53 7.07 0.78 Camden,NJ 340071001 1.85 1.33 1.66 0.87 Gloucester, NJ 340150002 2.47 0.86 1.01 1.22 Richmond,NY 360850067 1.14 0.90 1.21 Philadelphia,PA 421010024 1.36 0.78 2.01 2.41 Collin, TX 480850005 1.06 1.91 Dallas, TX 481130069 1.07 1.55 Dallas, TX 481130075 1.13 

### 1.55 Denton, TX 481211032 1.40 3.05 Harris, TX 482010029 0.77 1.05 4.32 Harris, TX 482010055 1.40 0.82 4.37 Tarrant, TX 484390075 0.94 ! 1.03 2.33 Tarrant, TX 484393011 1.87 0.99 2.55 SheboyRan. WI 551170006 15.87 7.92 0.88 1.12
Number ofLinkages => 3 9 4 l 8 9 1 4 4 lO

2018 Maintenance Receptors Upwind States- Part 2 (MD through 1N) County Site ID MD MI MS MO NJ NY 

### OH OK PA 

### TN Fairfield CT 90010017 2.01 7.64 15.49 1.93 9.28 NewHaven, CT 90099002 1.74 5.58 16.15 1.86 8.70 Jefferson. KY 211110067 1.23 3.93 Allegan.MI 260050003 4.13 1.70 SaintCharles, MO 291831002 0.89 0.77 Camden, NJ 340071001 1.58 0.95 1.54 4.42 18.76 Gloucester, NJ 340150002 6.97 1.03 1.34 3.71 16.20 Richmond, NY 360850067 3.59 9.95 2.10 16.19 Philadelphia, PA 421010024 5.14 1.38 3.84 1.00 Collin, TX 480850005 

# =tHH Dallas, TX 481130069 Dallas, TX 481130075 112018 Maintenance Receptors Upwind States- Part 2 (MD through TN) County Site ID MD MI MS MO NJ NY OH OK PA TN Denton, TX 481211032 1.22 Harris, TX 482010029 0.79 Harris, TX 482010055 1.52 0.95 Tarrant, TX 484390075 2.59 Tarrant, TX 484393011 0.81 2.55 Sheboygan, WI 551170006 3.64 1.81 1.64
Number ofLinkages=> 5 4 2 5 4 4 7 9 5 2

2018 Maintenance Receptors Upwind States

- Part 3 TXthrough WI County Site ID TX VA 

# wv WI Fairfield, CT 90010017 1.88 0.87 NewHaven, CT 90099002 1.39 0.83 Jefferson, KY 211110067 Allegan,MI 260050003 2.75 2.49 Saint Charles, MO 291831002 2.38 Camden, NJ 340071001 1.45 1.17 Gloucester, NJ 340150002 0.97 2.95 2.23 Richmond, NY 360850067 3.28 2.03 Philadelphia, PA 421010024 1.01 2.39 2.88 Collin, TX 480850005 Dallas, TX 481130069 Dallas, TX 481130075 Denton, TX 481211032 Harris TX 482010029 Harris TX 482010055 Tarrant, TX 484390075 Tarrant, TX 484393011 Sheboygan, WI 551170006 2.26
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