Technical Support Document (TSD) for 2008 Ozone NAAQS Designations



### Connecticut Area Designations f or the
20 08 Ozone National Ambient Air Q uality Standard s Greater Connecticut Area

The t able below identifies the areas and associated counties or parts of counties in Connecticut that EPA
i s designat ing as no n attain ment for the 2008 o zone national ambient air quality standard s (20 08 NAAQS)

. In accordance with section 107(d) of the Clean Air Act, EPA must designate a n area ( county

or part of a county) “nonattainment” if it is violating the 2008 ozone NAAQS or if it is contributing to a
violation of the 2008 ozone NAAQS in a nearby area. The technical analyses supporting the boundaries
fo r the individual nonattainment areas are provide d below.

Final 2008 O zone Nonattainment Areas in Connecticut (state

- wide nonattainment)

Area Connecticut Recommended Nonattainment Counties EPA’s Nonattainment
Counties
New York

- N. New Jersey

- Long
Island

, NY

- NJ

- CT area Fairfield

, New Haven and
Middlesex Fairfield

, New Haven and
Middlesex
Greater Connecticut , CT 1 Hartford, Litchfield, New London, Tolland and Windham Hartford, Litchfield, New London, Tolland and Windham

EPA is designating the entire state of Connecticut as nonattainment. The analysis below provides the
basis for the nonattainment area boundar ies . It relies on an analysis of whether and which monitors are violating the 20 08 o zone NAAQS

, based on certified air quality monitoring data from 2008

- 2010 and an
evaluat ion of whether nearby areas are contributing to such violations. EPA has evaluated contribution s from nearby areas based on a weight of evidence analysis considering the factors identified below. The analysis below provides the basis for the nonattainment area boundar ies for the Greater Connecticut
ozone nonattainment area . A separate TSD has been prepared for the rest of Connectic ut. The rest of
Connecticut is also designated nonattainment for the 2008 ozone NAAQS, and is referred to as the Connecticut portion of the New York

- N. New Jersey

- Long Island , NY

- NJ

- CT ozone nonattainment

area. EPA issued guidance on December 4, 2008 that identified these factors as ones EPA would consider in determining nonattainment area boundaries and recommend ed that s tates consider these
fac tors in making their designations recommendations to EPA

. 2

1. A ir quality data ( including the design value calculated for each FRM or FEM monitor in the

area ) ; 2. Emissions and emissions

- related data ( including location of sources and population , amount of
emissions and emissions controls , and urban growth patterns) ; 3. M eteorology (weather/transport patterns) ; 4. G eography and topography (mountain ranges or other basin boundaries) ; 5. J urisdictional boundaries (e.g., counties, air districts, existing nonattainment areas, Indian country , metropolitan planning organizations (MPOs))

1 Greater Connecticut is a multijurisdictional nonattainment area that includes areas of Indian Country.

2 The December 4, 2008 guidance memorandum “Area Designations for the 2008 Revised Ozone National Ambient Air Quality Standards” refers to 9 factors. I n this technical support document we have grouped the emissions

- related factors together under the heading of “Emissions and Emissions

- Related Data

, ” which results in 5 categories of factors.2 Ground

- level ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and v olatile organic compounds (VOC) in the presence of sunlight. Because
NOx and VOC emissions from a broad range of sources over a wide area typically contribute to
violations of the ozone standard s , EPA believes it is important to consider whether there are contributing emissions from a broad geographic area. Accordingly, EPA chose to examine the 5 factors with respect

to the larger of the Combined Statistical Area (CSA) or Core Based Statistical Area (CBSA) associated with the violating monitor(s)

. 3 All da ta and information used by EPA in this evaluation are the latest available to EPA and/or provided to EPA by states or tribes.

In EPA’s designations guidance for the 2008 ozone NAAQS

, EPA recommend ed examining
CSA/C B SA s because certain factors used to establish CSAs and C B SAs are similar to the factors EPA is using in this technical analysis to determine if a nearby area is contributing to a violation of the 20 08

o zone NAAQS

. EPA used the same basic approach in the desi gnation process for the 1997 o zone NAAQS. Where a violating monitor is not located in a CSA or C B S A, EPA ’s guidance recommend ed using the boundary of the county containing the violating monitor as the starting point for considering
the nonattainment area’ s boundary.

Technical A nalysis for Greater Connecticut

Figure 1 is a map of the Greater Connecticut , CT nonattainment area . The map provides other relevant
information including the locations and design values of air quality monitors , county and other jurisdictional boundaries, CSA / CBSA boundar ies , existing 1997 ozone nonattainment boundar ies

, state borders, and major highways.

T he 2008 8

- hour ozone NAAQS, nonattainment area’s boundaries are the same as the State ’s 1997 8

- hour ozone NAAQS boundaries.

In March 2009, Connecticut recommended that the entire State of Connecticut be designated
nonattainment for the 2008 ozone NAAQS based on air quality data from 2006

- 2008. In its March 2009 letter, Connecticut recommended that the state be sp lit between two ozone nonattainment areas, with the same boundaries as for the 1997 ozone NAAQS. On October 28, 2011 Connecticut submitted an updated recommendation in which it recommended including all of Connecticut as part of a large multi

state nonatt ainment area that included all or portions of 17 other States. On November 23, 2011, Connecticut clarified their position that, if EPA does not agree with creating a large 18 state nonattainment area, the State of Connecticut should be split between two 2008 ozone nonattainment areas, with the same boundaries as for the 1997 ozone NAAQS. On February 27, 2012, Connecticut submitted a response to EPA’s 120

- day letter, dated December 9, 2011. This February 2012 response reiterated the Connecticut position o n a “super

- regional” nonattainment area , but did not rescind the November 23, 2011 clarifying recommendation

. EPA’s position on “super

- regional” nonattainment
areas for ozone is discussed below.

After considering all available information

, EPA is designating Hartford , Litchfield

, New London,
Tolland and Windham Counties a s “ nonattainment ” for the 20 08 o zone NAAQS as part of the Greater
Connecticut are a

. EPA is designating t he remaining three counties in Connecticut (Fairfield, New

3 Lists of CBSAs and CSAs and their geographic components are pr ovided at www.census.gov/population/www/metroareas/metrodef.html . The lists are periodically updated by the Office of Management and Budget. EPA used the most recent update, bas ed on 2008 population estimates, issued on December 1, 2009 (OMB Bulletin No. 10

- 02).3 Haven, and Mi ddlesex counties) as nonattainment , but join ing these counties with the New York

- N. New Jersey

- Long Island , NY

- NJ

- CT ozone nonattainment area

. Our rational is explained below.

Because Connecticut, in its clarifying recommendation of November 23, 2011 recommende d that all areas in the State be designated nonattainment and included in one of two diff erent nonattainment areas,
EPA focused its analysis on whether the boundaries for Connecticut ’s proposed nonattainment areas for
the 2 008 eight

- hour ozone NA AQS are supported by available data. EPA is designating the areas as requested in the November 23, 2011 letter from Connecticut

, in the absence of information strongly supporting that one or more of the counties should be included in an area different tha n the one recommended by the State.

Table 1 . State 's Recommended and EPA ’ s Final Designated Nonattainment Counties for Greater
Connecticut and Connecticut Portion of the New York

- N. New Jersey

- Long Island , NY

- NJ

- CT
Ozone Nonattainment Area s

Area State

- Recommended
Nonattainment Counties EPA Nonattainment Counties

Greater Connecticut

, CT Hartford Hartford

Litchfield Litchfield

New London New London

Tolland Tolland

Windham Windham

New York

- N. New Jersey

- Long Island

,

NY

- NJ

- CT area Fairfield Fairfield

New Haven New Haven

Middlesex Middlesex

Factor Assessment



### Factor 1 : Air Q uality D ata

For this factor , we considered 8

- hour o zone design values (in parts per million ( ppm ) ) for air quality
monitors in counties in the Greater Connecticut area based on data for the 2008

- 2010 period (i.e., the 2010 design value, or DV) , which are the most recent years with fully

- certified air quality data

. A
monitor’s DV is the metric or statistic that indicates whether that monitor attains a specified air quality
standard. The 2008 o zone NAAQS are met when the annual f ourth

- highest daily maximum 8

- hour average concentration, averaged over 3 years is 0.075 ppm or less

. A DV is only valid if minimum data completeness criteria are met

. See 40 CFR part 50 App endix P . Where several monitors are located in a county (or a designated nonattainment area or maintenance area ), the DV for the county or area is determined by the monitor with the highest level. All ozone data referenced in this TSD was submitted by the State, and are from Federal Reference Method monitors, sited and operated in accordance with
40 CFR Part 58

. (See letter to EPA dated November 23, 2011.)4 The 2010 DVs for the o zone NAAQS for counties in the Greater Connecticut ozone nonattainment area
and the Connecticut Portion of the New York

- N. New Jersey

- Long Island , NY

- NJ

- CT ozone
nonattainment area are shown in Table s 2a and 2b

.

Table 2 a . Air Quality Data for the Greater Connecticut Ozone Nonatt ainment Area

County State Recommended
Nonattainment? 2008

- 2010 D esign V alue ( ppm )
Hartford Yes 0.0 74
Litchfield Yes 0.0 73 4

New London Yes 0.0 76
Tolland Yes 0.0 79
Windham Yes No monitor in county

Table 2 b . Air Quality Dat a for the Three Counties of the Connecticut Portion of the New York

N. New Jersey

- Long Island , NY

- NJ

- CT Ozone Nonattainment Area

County State Recommended
Nonattainment? 2008

- 2010 Design Value (ppm)
Fairfield Yes 0.081
New Haven Yes 0.076
Middlesex Yes 0.077

EPA believes that since Connecticut has recommended , and EPA is designating the entire state as nonattainment

, air quality is not a significant factor for determining in which nonattainment area these counties should be placed , since all counties in the state are nonattainment

. Therefore, this factor did not play a significant role in this evaluation

.



### Factor 2: Emissions and Emissions

- Related Data

EPA evaluated emissions of ozone precursors ( NO
x and VOC ) and other emissions

- related data that provide information on near

- by areas contributing to violating monitors.

Emissions Data

EPA evaluated county

- level emission s data for NO
x and VOC derived from the 200 8 National Emissions Inventory (NEI), version 1.5

. This is the most recently available NEI. (See http://www.epa.gov/ttn/chief/net/2008inventory.html

. ) Significant emissions levels in a nearby area
would indicate the potential for the area to contribute to observed violations.

Table s 3 a and 3 b show emissions of NO
x and VOC (given in tons per year (tpy) ) for violating and potentially contributing counties in the State of Connecticut

.

4 2008

- 2010 ozone data used to compute the Design Value for Litchfield County is incomplete. 40 CFR part 50 App endix P requires a monitoring site to meet a 3

- year data c ompleteness of 90 percent. The Litchfield County monitor is meeting a 3

- year data completeness of 89 percent.5 Table 3 a

. Total 2008 NO
x and VOC Emissions for the Greater Connecticut Ozone Nonattainment
Area

County State Recommended
Nonattainment ? NO
x (tpy) VOC (tpy)

Hartford Yes 20

, 253 20

, 808
Litchfield Yes 3

, 429 6

, 115
New London Yes 8

, 558 9

, 160
Tolland Yes 3

, 553 3

, 764
Windham Yes 3

, 469 3

, 626
Areawide: 39

, 262 43

, 473

Table 3 b . Total 2008 NO
x and VOC Emissions for the Three Counties of the Connecticut Portion
of the New York

- N. New Jersey

- Long Island , NY

- NJ

- CT Ozone Nonattainment Area

County State Recommended
Nonattainment? NO
x (tpy) VOC (tpy)

Fairfield Yes 24,983 22,700
New Haven Yes 20,789 19,705
Middlesex Yes 4,484 5,130 Three County Total : 50,256 47,535

This factor indicates that these counties are likely contributing to nonattainment at one or more monitors within the county or at monitors in nearby counties. It does not provide any indication of which monitors are most likely affected by emissions from these counties. Therefore, this factor did not play a significant role in this evaluation

.

Population density and degree of urbanization

EPA evaluated the population and vehicle use characteristics and trends of the area as indicators of the probable location and magnitude of non

- point source emissions . These include ozone

- creating
emissions from on

- road and off

- road vehicles and engines, consumer products, residentia l fuel combustion, and consumer services. Areas of dense population or commercial development are an indicator of area source and mobile source NO
x and VOC emissions that may contribute to ozone formation. Rapid population or VMT growth (see below) in a county on the urban perimeter signifies increasing integration with the core urban area, and indicates that the associated area source and mobile source emissions may be appropriate to include in the nonattainment area. Table s 4 a and 4 b show the population , population density, and population growth information for each county in the state

.

Table 4 a . Population and Growth for the Greater Connecticut Ozone Nonattainment Area

County State
Recommended
Nonattainment? 2010 Population 2010 Population Density ( 1000 pop/sq mi) Absolute change in population (2000

- 2010) Population % change (2000

- 2010) Hartford Yes 894

, 014 1

. 19 35

, 575 4.1
Litchfield Yes 189

, 927 0.20 7

, 313 4.0
New London Yes 274

, 055 0.39 14

, 519 5. 6
Tolland Yes 152

, 691 0.37 15

, 839 11. 6
Windham Yes 118

, 428 0.23 9

, 236 8. 5
Areawide: 1

, 629

, 115 82

, 4826 Source s : U.S. Census Bureau population estimates for 2010 as of August 4, 2011

Table 4 b . Population and Growth for the Three Counties of the Connecticut Portion of the New
York

- N. New Jersey

- Long Island , NY

- NJ

- CT Ozone Nonattainment Area

County State
Recommended
Nonattainment? 2010 Population 2010 Population Density (1000 pop/sq mi) Absolute change in population (2000

- 2010) Population % change (2000

- 2010) Fairfield Yes 916,829 1.41 32,348 3.7
New Haven Yes 862,477 1.39 37,492 4.5
Middlesex Yes 165,676 0.43 10,061 6.5
Sources: U.S. Census Bureau population estimates for 2010 as of August 4, 2011

The population in the Greater Connecticut ozone nonattainment area is growing modestly and the population density is rather high, since the area includes the State capital of Hartford. This factor
indicates that the counties with the highest population density are likely contributing to nonattainment at
one or more monit ors within the county or at monitors in nearby counties. It does not provide any indication of which monitors are most likely affected by emissions from these counties. Therefore, this factor did not play a significant role in this evaluation

.

Traffic and commuting patterns

EPA evaluated the commuting patterns of residents in the area, as well as the total Vehicle Miles Traveled (VMT) for each county . In combination with the population/ population density data and the location of main transportation ar teries ( Figure 1 ) , this information helps identify the probable location
of non

- point source emissions. A county with high VMT and/or a high num b er of commuters is generally an integral part of an urban area and indicates the presence of motor vehicle emis sions that may contribute to ozone formation. Rapid population or VMT growth in a county on the urban perimeter signifies increasing integration with the core urban area, and indicates that the associated area source and mobile source emissions may be appr opriate to include in the nonattainment area. Table s 5 a and 5 b
show 200 8 VMT for Connecticut

.

Table 5 a . Traffic for the Greater Connecticut
Ozone Nonattainment Area

County State Recommended
Nonattainment? 2008 VMT* (million miles)
Hartford Yes 8,330
Litchfield Yes 1,258
New London Yes 2,916
Tolland Yes 1,499
Windham Yes 1,202
Areawide: 15,205
* MOBILE model VMTs are those inputs into the NEI version 1.5.

Table 5 b . Traffic for the Three Counties of the Connecticut
Portion of the New York

- N. New Jersey

- Long Island , NY

- NJ

- CT
Ozone Nonattainment Area

County State Recommended
Nonattainment? 2008 VMT* (million miles) Fairfield Yes 7,8037 New Haven Yes 7,248

Middlesex Yes 1,394

* MOBILE model VMTs are those inputs into the NEI version 1.5.

This factor indicates that the counties with the highest VMT are likely contributing to nonattainment at one or more monitors within the county or at monitors in nearby counties. It does not provide any indication of which monitors are most likely affected by emissions from these counties. Therefore, this
factor d id not play a significant role in this evaluation

.



### Factor 3 : Meteorology (weather/transport patterns)

EPA evaluate d meteorological data to help determine how meteorological conditions, such as weather,
and transport patterns, affect the fate and transp ort of precursor emissions contributing to ozone
formation in Connecticut

. In addition, Connecticut, in its February 2012 letter, did point out that Connecticut receives its ozone via several different meteorological conditions. EPA agrees that meteorolog y does affect ozone in Connecticut, but since the entire state is nonattainment EPA does not believe this is a significant factor for purposes of determining in w hich nonattainment area a particular
Connecticut county should be placed. Therefore, this factor did not play a significant role in this
evaluation

.



### Factor 4 : Geography/topography (mountain ranges or other air basin boundaries)

The geography/topography analysis evaluates the physical features of the land that might affect th e air shed and, therefore, the distribution of ozone over the area

. The Greater Connecticut ozone nonattainment area does not have any geographical or topographical barriers significantly limiting air pollution transport within its air shed. Connecticut in its February 2012 letter did point out that Connecticut is on Long Island Sound, but since the entire state is nonattainment and both nonattainment
areas border the S ound we do not believe this is a relevant factor for purposes of determinin g in w hich nonattainment area a particular Connecticut county should be placed. Therefore, this factor did not play a significant role in this evaluation

.



### Factor 5 : Jurisdictional boundaries

Once the general areas to be included in the nonattainment area were determined, EPA consider ed existing jurisdictional boundaries for the purposes of providing a clearly defined legal boundary and carrying out the air quality planning and enforcement functions for nonattainment areas. Examples of jurisdictional boundaries include existing/prior nonattainment areas for ozone or other urban

- scale pollutants, counties, air districts, townships, metropolitan planning organizations, state lines, Reservations, urban gro wth boundary, etc. Where existing jurisdictional boundaries are not adequate to describe the nonattainment area, other clearly defined and permanent landmarks or geographic

c oordinates were considered.

The Greater Connecticut ozone nonattainment area has previously established nonattainment boundaries
associated with 1997 8

- hour ozone N AAQS. The state has recommended, in its most recent clarifying letter to EPA dated November 23, 2011, that the boundary for nonattainment areas for the 2008 ozone NAAQS be the same as those that exist for the 1997 8

- hour NAAQS. Connecticut’s reasoning was t o

“ avoid unnecessary confusion among Connecticut’s regulated community and the general public that8 may otherwise result from having three distinct nonattainment area bou ndaries within Connecticut for
the 2008 8

- hour ozone NAAQ S

. ” This is the most significant factor for purposes of determining in

w hich nonattainment area a particular Connecticut county should be placed.

T he Greater Connecticut ozone nonattainment area also includes areas of Indian country

. A s defined at
18 U.S.C. 1151 , “Indian country” refers to: “(a) all land within the limits of any Indian reservation under the jurisdiction of the United States Government, notwithstanding the issuance of any patent, and, including rights

- of

- way running through the reservation, (b) all dependent Indian communities within the borders of the United States whether within the original or subsequently acquired territory thereof, and whether within or without the limits of a state, and (c) all Indian allotments, the Indian titles to which have not been exting uished, including rights

- of

- way running through the same.” EPA recognizes the sovereignty of tribal governments, and has attempted to take the desires of the tribes into account in establishing appropriate nonattainment area boundaries.

Two tribes’ areas of Indian country are included in the Greater Connecticut ozone nonattainment area: Mashantucket Pequot Tribe of Connecticut and the Mohegan Indian Tribe of Connecticut. Neither Tribe submitted a designation recommendation for the 2008 ozone NAAQS. EPA has concluded that all of Connecticut, including areas of Indian Country, are nonattainment for the 2008 ozone NAAQS.

EPA Position on the Connecticut Recommendation of a “Super

- Regional” Ozone Nonattainment Area for the 2008 Ozone NAAQS

In a letters dated October 28, 2011 and February 23, 2012, Connecticut recommended that EPA designate the entire State as part of a large multi

- state nonattainment area including all or portions of 17 other states, and the District of Columbia. EPA does n ot believe that creation of a super

- regional nonattainment area to address pollution transport is the appropriate approach. As an initial matter, section 107(d)(1) provides that areas designated nonattainment should include any “nearby” area contributing t o a violation of the NAAQS. We believe that broad super

- regional areas go beyond this by including areas that are not necessarily “nearby” but contribute to nonattainment through long

- range transport. The CAA has separate provisions to address this phenom enon. Section 110(a)(2)(D) requires states to address ozone transport that contributes to a violation of the NAAQS in another State. In addition, section 184, creates the northeast ozone transport region and also grants EPA authority to
establish addition al transport regions, as appropriate. Finally, we note that the approach taken by EPA is consistent with the approach Congress specified for serious and above areas for the 1

- hour NAAQS, where in section 107(d)(4)A), Congress set the CMSA boundaries as the presumptive boundaries of the
nonattainment area. In Catawba Co. v. EPA 5 , the Court upheld that “contribute” under §107(a)(1)(A) of the CAA does not necessarily mean “any contribution” to nonattainment but rather a degree of contribution sufficient to d eem an area nonattainment, that is, sufficient enough to warrant designation as nonattainment. “Section 107(d) is ambiguous as to how EPA should measure contribution and what degree of contribution is sufficient to deem an area nonattainment ...” Catawba Coun ty v. EPA , 571
F.3d 20 , 39 (D.C. Cir. 2009) (Internal citation omitted but with emphasis added)

. “Thus, reasonably exercising the discretion that Congress delegated to it, EPA interpreted “contribute” to mean “sufficiently contribute,” and then applied the C/MSA presumption and nine

- factor test precisely to identify those areas that meet that definition.” Id.

5 Catawba County v. EPA , 571 F.3d 20, (D.C. Cir. 2009)9 

### Conclusion

Based on the assessment of factor s described above

, EPA is adopting the same nonattainment boundaries in Connecticut for the 2008 ozone NAAQS as for the 1997 ozone NAAQS, to avoid unnecessary confusion

, and to aide in planning, permitting, transition and enforcement. All of Connecticut (including Indian Country) is designated as nonattainment for the 2008 ozone NAAQS.
Based on ou r analysis of the factors above, we do not see a compelling reason to reject the State’s
recommendation for inclusion in the Greater Connecticut, CT ozone nonattainment area the following
counties : Ha rtford, Litchfield, New London, Tolland and Windham . The remaining three Connecticut counties (Fairfield, New Haven, and Middlesex counties) will be joined with the multi

- state New York

N. New Jersey

- Long Island , NY

- NJ

- CT ozone nonattainment area and are f ully discussed in the technical support document for that area. (See separate TSD .)

Figure 1. Map of Greater Connecticut , CT Ozone Nonattainment Area10