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 Connecticut portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT Area

The t able below identifies the areas and associated counties or parts of counties in Connecticut that EPA intends to designate 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 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 tech nical analysi s supporting the boundaries fo r the individual nona ttainment areas are provided below.

Intended Ozone Nonattainment Areas in Connecticut (state

- wide nonattainment)

Area Connecticut Recommended Nonattainment Counties EPA’s Intended Nonattainment Counties Connecticut portion of the New York

- Newark

- Bridgeport, NY

NJ

- CT area Fairfield

, New Haven and Middlesex Fairfield

, New Haven and Middlesex

Greater Connecticut 1 area Hartford, Litchfield, New London, Tolland and Windham Hartford, Litchfield, New London, Tolland and Windham

EPA intends to designate the entire state of Connecticut as nonattainment. The analysis below provides the basis for intended nonattainment area boundar ies. It relies on our 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 evaluation 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 intended nonattainment area boundar ies for the Connecticut portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area

. A separate TSD has been prepared for the rest of Connecti c ut. The rest of Connecticut will also be designated nonattainment for the 2008 ozone NAAQS, and referred to as the 2008 Greater Connecticut 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 factors 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) ;

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. In this technical support document we have grouped the emissions

- related factors together under the headin g of “Emissions and Emissions

- Related Data

, ” which results in 5 categories of factors.2

5. J urisdictional boundaries (e.g., counties, air districts, existing nonattainment areas, Indian country , metropolitan planning organizations (MPOs))

Ground

- level ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NO x ) and volatile organic compounds (VOC) in the presence of sunlight. Because NO x 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 Base d Statistical Area (CBSA) associated with the violating monitor(s)

. 3 All data 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 NAAQ S

, 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 designation 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 p oint for considering the nonattainment area’s boundary.

Technical A nalysis for Connecticut Portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area

Figure 1 is a map of the Connecticut Portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT intended nonattainment area . The map provides information

, including the locations and design values of air quality monitors , county and other jurisdictional boundaries, CSA / CBSA boundar ies , existing nonattainment boundar ies and state borders, and major highways.

For purposes of the 1997 8

- hour ozone NAAQS, the area’s boundaries were the same as the State initially recommended for the 2008 ozone NAAQS and the same as the area we intend to designate as nonattainment for the 2008 ozone NAAQS.

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 split 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 recomm ended including all of Connecticut as part of a large multi

state non attainment 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

no nattainment area

, the State of Connecticut should be split between two 2008 ozone nonattainment

areas , with the same boundaries as for the 1997 ozone NAAQS. All ozone data reference d in the recommendations submitted by the State are from Federal Referen ce Method monitors

, sited and operated in accordance with 40 CFR Part 58

. (See letter to EPA dated November 23, 2011.)

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

- 02).3

After considering these recommendation s and b ased on EPA's technical analysis described below, EPA intends to designate Fairfield, New Haven, and Middlesex counties a s “ nonattainment ” for the 20 08

o zone NAAQS

. EPA intends to include these three counties as part of the larger tri

- state New York

Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area

. We intend to designate t he remaining counties in Connecticut ( Hartford, Litchfield, New London, Tolland and Windham Counties ) as the Greater Connecticut area

. The main issue at hand is how to “split” the counties in Connecticut between two nonattainment areas : The New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area , and the Greater Connecticut area . Information for the Greater Connecticut are a is in a separate TSD.

Because Connecticut, in its clarifying recommendation of November 23, 2011

, is recommending that al l areas in the State be designated nonattainment and included in one of two different nonattainment areas, EPA focused its analysis on whether the boundaries for Connecticut ’s proposed nonattainment areas for the 2 008 eight

- hour ozone NAAQS are supported by available data. EPA intends to designate the areas as requested , in the aforementioned letter from Connecticut

, in the absence of information strongly supporting that one or more of the counties should be included in an area different than the one

reco mmended by the State. In sum, Connecticut recommended two nonattainment areas: The New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area , and the Greater Connecticut area. Information for the Greater Connecticut area is in a separate TSD.

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

- Newark

- Bridgeport, NY

- NJ

- CT and Greater Connecticut Ozone Nonattainment Area s

Area State

- Recommended

Nonattainment Counties EPA Intended Nonattainment Counties

Connecticut Portion of the New York

- Newark

Bridgeport, NY

- NJ

- CT

area Fairfield Fairfield

New Haven New Haven

Middlesex Middlesex

Greater CT Hartford Hartford

Litchfield Litchfield

New London New London

Tolland Tolland

Windham Windham4

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 Connecticut Portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area counties 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 whethe r 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 monito r with the highest level.

The 2010 DVs for the o zone NAAQS for counties in the Connecticut Portion of the New York

- Newark

Bridgeport, NY

- NJ

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

.

Table 2 a . Air Quality Data in the Three Counties of the Connecticut Portion of the New York

Newark

- Bridgeport, NY

- NJ

- CT Ozone Nonattainment Area

County State Recommended Nonattainment? 2008

- 2010 D esign V alue ( ppm ) Fairfield Yes 0.081 New Haven Yes 0.076 Middlesex Yes 0.077

Table 2 b . Air Quality Data for the Greater Connecticut Ozone Nonattainment Area

County State Recommended Nonattainment? 2008

- 2010 Design Value (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

Fairfield, New Haven, and Middlesex Counties show violation s of the 2008 o zone NAAQS , t herefore these counties are inclu ded in the nonattainment area

. EPA believes that since Connecticut has recommended the entire state be nonattainment, air quality is not important for purposes of determining in which of the two nonattainment areas these counties should be placed.

4 2008

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

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

- year data completeness of 89 per cent.5 

### 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 areas contributing to violating monitors.

Emissions Data

EPA evaluated county

- level emission 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. We will also consider any additional information we receive on changes to emissions levels that are not reflected in recent inventories. These changes include emissions reductions due to permanent and enforceable emissions controls that will be in place before final designations are issued and emissions increases due to new

sources.

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 Connecticut Portion of the New York

- Newark

- Bridgeport, NY

NJ

- CT , and the Greater CT ozone nonattainment areas.

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

- Newark

- Bridgeport, 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

Table 3 b . Total 2008 NO x and VOC Emissions 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

EPA believes that this factor is not important for purposes of determining in which of the two nonattainment areas these counties should be placed.6

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, residential fuel combustio n, 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 in the Three Counties of the Connecticut Portion of the New York

- Newark

- Bridgeport, 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

Three County Total : 1,944,982 79

, 901
Source s : U.S. Census Bureau population estimates for 2010 as of August 4, 2011

Table 4 b . 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 82,482 Sources: U.S. Census Bureau population estimates for 2010 as of August 4, 2011

The population in the Connecticut Portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT Ozone Nonattainment Area is growing modestly and the population density is rather high, since the area includes the I

- 95 corridor

. EPA believes that this factor is not important for purposes of determining in which of the two nonattainment areas these counties should be placed.

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 c ombination with the population/ population density data and the location of main transportation arteries ( Figure 1 ) , this information helps identify the probable location of non

- point source emissions. A county with high VMT is generally an integral part of an urban area and indicates the presence of motor vehicle emissions 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 appropriate to include in the nonattainment area. Table s 5 a and 5 b shows total 2008 VMT

.7

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

- Newark

- Bridgeport, NY

- NJ

- CT

Ozone Nonattainment Area
County State Recommended

Nonattainment? 2008 VMT*

(million miles) Fairfield Yes 7,803 New Haven Yes 7,248 Middlesex Yes 1,394

Three County total : 16,445 * MOBILE model VMTs are those inputs into the NEI version 1.5.

Table 5 b

. 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.

EPA believes that this factor is not important for purposes of determining in which of the two nonattainment areas these counties should be placed.



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

EPA evaluate d meteorological data to help determine how meteorological conditions, such as weather, transport patterns and stagnation conditions, would affect the fate and transport of precursor emissions contributing to ozone formation. During the ozone season the win ds are generally southwesterly. The only area downwind of Connecticut that is recommended to be nonattainment is the Dukes County area of Massachusetts

. EPA believes that this factor is not important for purposes of determining in which of the two

nona ttainment areas these counties should be placed.



### 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 the air shed and, therefore, the distribution of ozone over the area

. The Connecticut Portion of the New York

Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area does not have any geographical or topographical barriers significantly limiting air pollution transp ort within its air shed.

EPA believes that this factor is not important for purposes of determining in which of the two nonattainment areas these counties should be placed.8 

### 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, urban growth boundary, etc. Where existing jurisdictional boundaries are not adequate to describe the nonattainment area, other clearly defined and permanent landmarks or geographic c oordinates are considered.

The Connecticut Portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area has previously established nonattainment boundaries associated with the 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 to “ avoid unnecessary confusion among Connecticut’s regulated community and the general public that may otherwise result from having thre e distinct nonattainment area boundaries within Connecticut for the 2008 8

- hour ozone NAAQ .” This is the most important factor for determining which Connecticut counties are to be in which Connecticut nonattainment area.

There are no tri bes in the three county area of Connecticut Portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area.

EPA Position on the Connecticut Recommendation of a “Super

- Regional ” Ozone Nonattainment Area for the 2008 Ozone NAAQS

In a letter dated October 28, 2011, 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 . Section 107(d) of the Clean Air A ct ( CAA ) requires EPA to designate as nonattainment all areas violating the ozone NAAQS and any nearby areas that are contributing to a violation in another area. Under the designation provision, only "nearby" areas that contribute to the violation must b e included as p art of the nonattainment area. There are other provisions of the CAA that address longer range transport of ozone pollutions, such as sections 110(a)(2)(D), 126, and 184. The phenomenon of ozone transport must be balanced against the need to have smaller areas that can focus on local control measures. We note that most of the States that Connecticut seeks to include as part of this large nonattainment area did not make a similar request. While a few other states did request that EPA design ate a broad area in the eastern part of the United States as nonattainment, each of those recommendations varied from the others. In the absence of broad agreement among a large group of states to create such a large nonattainment area, demonstrating a co mmitment to work together to address both long

- range and local transport of emissions, we do not intend to designate a large nonattainment area as suggested by Connecticut.



### Conclusion

Based on the assessment of factor s described above

, especially Factor 5, EPA preliminarily proposes to keep the nonattainment boundaries in Connecticut the same for the 2008 ozone NAAQS as for the 1997 ozone NAAQS, both to avoid confusion and for ease in planning, permitting, transition and enforcement for the 2008 ozone NAAQS

. EPA conclud es that Connecticut’s Fairfield, New Haven, and Middlesex9

Countie s meet the C AA criteri on for inclusion as part of the tri

- state New York

- Newark

- Bridgeport, NY

- NJ

- CT ozone nonattainment area

. The rest of Connecticut will also be nonattainment for the 2008 ozone NAAQS, but part of another nonattainment area called Greater Connecticut. ( See separate TSD for this area.)

Figure 1. Map of Connecticut Portion of the New York

- Newark

- Bridgeport, NY

- NJ

- CT Ozone Nonattainment Ar ea