Comment Attachment Page A-3 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



## FIGURE 1. Proposed Areas of N onattainment for 8-Hour Ozone NAAQS in New Hampshire (2008 NAAQS)


# STATE OF NEW HAMPSHIRE

Recommended Ozone

Nonattainment Areas (2008 Standard)

Southeast New Hampshire Nonattainment Area

Attainment Areas Presidential Range NH Rural Transport Area
Monadnock Highlands NH Nonattainment Area Areas in Coos County above 5000 feet in elevation

Areas above 2000 feet in elevation

1/6/2009 Possible 8-hrBndys (2008) with Counties.gsm Pelham Hudson

Nashua Hollis Brookline Mason New Ipswich Rindge Windham

Salem Atkinson Newton South Hampton Seabrook Hampton North Hampton Rye Ports mouth New Castle

Hampstead Derry San down Dan Ville Kings

ton East Kings ton Kens

ington

Hamp ton Falls Exeter Strat ham Brent Wood Fremont

Epping Newmarket
Newfields Green land Newing ton Durham Madbury Dover

Rollingsford Sommersworth Rochester

Barrington Milton

Farmington

Strafford

Nottingham Lee Northwood

Deerfield

Raymond Candia

Auburn
Chester

London Derry Manchester Hookset Concord

Allens town Bow Pembroke Hopkinton

Weare

Goffstown

Bedford

Amherst Merrimack

Litchfield New Boston

Lynde borough Mt. Vernon

Milford Wilton Temple Dunbarton

Fitzwilliam Richmound Winchester Hinsdale

Chesterfield

West moreland Keene

Swanzey
Troy Jaffrey Dublin Marl borough Roxbury Harrisville

Peter borough

Sharon

Greenland Frances town Hannock Benning ton Deering Antrim Stoddard

Nelson Sullivan Gilsum

Surry Walpole Acworth Lempster

Langdon Charles town

Alstead Marlow Washington Hillsborough Henniker Bradford Warner Newbury Goshen Unity Claremont Cornish

Plantfield

Lebanon

Hanover

Enfield

Enfield

Grantham

Croydon

Newport Sunapee Springfield Grafton

Orange

Danbury Alexandria

Wilmot

New London

Sutton Salibury Andover

Hill Bristol Hebron Bridge water New Hampton Meredith

Sanbornton

Franklin

Northfield

Webster Canterbury

Loudon

Epsom Pittsfield Gilmanton Belmont Tilton Laconia Gilford

Alton

Barnstead New Durham

Brook field

Middle town Wakefield Wolfboro Moulton borough Tuftonboro Ossipee Lyme

Orford

Piermont

Haverhill Bath

Warren Benton

Wentworth

Dorchester Groton Rumney

Ellsworth

Woodstock Lincoln Easton Landaff Monroe Lyman
Lisbon Sugar Hill Franconia Bethlehem Littleton
Carroll

Livermore

Waterville Valley
Thornton

Campton

Plymouth Holderness

Ashland Sandwich

Hebron Albany

Tamworth Freedom

Effingham Conway

Madison Eaton Hebron

Jackson Chatham Beans Purchase Sargents Purchase Crawfords Purchase Low&Burbanks Grant

Beans Grant Martins Loc.

Greens Grant

Pinkhams Grant

Hales Location Dalton Whitefield Jefferson Lancaster North Umberland Kilkenny

Randolph Berlin

Gorham Shelburne Sucess Milan Stark Stratford

Columbia

Colebrook Stewartstown

Dixville

Millsfield

Odell

Dummer Cambridge Errol Wentworths Location

Second College Grant Dixs Grant Atkinson & Gilmanton

Academy Grant Clarksville Pittburg

Ervings Location

COOS

GRAFTON

CARROLL

SULLIVAN

CHESHIRE MERRIMACK STRAFFORD

HILLSBOROUGH ROCKINGHAM BELKNAP

# ATTACHMENT A

Comments Received Regarding New Hampshire’s 8-Hour Ozone Nonattainment Area BoundariesComment Attachment Page A-2 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009Comment Attachment Page A-3 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009Comment Attachment Page A-4 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009Comment Attachment Page A-5 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009Comment Attachment Page A-6 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009Comment Attachment Page A-7 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009Comment Attachment Page A-8 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

# ATTACHMENT B

TECHNICAL ATTACHMENT Rationale for New Hampshire’s 8-Hour Ozone Nonattainment Area BoundariesTechnical Attachment Page B-2 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009 

# Rationale for New Hampshire’s 8-Hour Ozone Nonattainment Area Boundaries

The recommendations contained in this letter are fully compliant with Section 107(d)(1)(A) of the Clean Air Act (“CAA”) which de fines a nonattainment area as any area that (1) does not meet the ozone National Ambien t Air Quality Standard (“NAAQS”), or (2) contributes to ambient ozone violations in a nearby area. These boundaries exercise the flexibility allowed in the guidance, consid ering: population, populati on density, projected growth, existing air quality, prevailing mete orology, and metropolitan planning organization boundaries. In addition, geographic emission dens ities and airflow trajectories were also considered. Table B1 contains the most recent 3-years of quality assured monitoring data for ozone in New Hampshire. These monitors are marked in Figure B1 along with the recommended nonattainment area boundaries.

According to the New Hampshire recommendation, there will be three separate nonattainment areas in the state, the largest of which is the s outheastern New Hampshire area that encompasses the state’s la rgest cities and areas of population growth. The second area considers the highlands in the Monadnock re gion of southwestern New Hampshire, where mountaintop monitored ozone levels have exceeded the ozone standard, but the monitored ozone levels at lower elevations do not. The third area represents the remo te mountains surrounding Mt. Washington in the northern portion of the stat e. This high elevation monitor is far removed from population centers and well above the overn ight inversion layers , making it a good choice as a Rural Transport Area. More discussion for each of the three areas can be found below.


## TABLE B1. 2006 – 2008 8-Hour Ozone Design Values by Monitor, in parts-per-billion (ppb) Location Monitor ID 2006-08 Design Value 2006 4 th Max 2007 4 th Max 2008 4 th Max Southeast NH Area Manchester 330110020 68 68 74 64 Nashua 330111011 73 73 81 67 Portsmouth 330150014 73 73 78 69 Rye 330150016 79 76 86 75 Monadnock Highlands Miller State Park 330115001 78 78 81 76 Presidential Range Mt. Washington Summit 330074001 76 69 85 75 Camp Dodge 330074002 61 59 61 65 Attainment Areas Claremont 330190003 68 64 76 66 Concord 330131007 70 69 74 67 Keene 330050007 69 67 73 68 Laconia 330012004 70 67 75 70 Lebanon 330090010 67 63 72 68


### Values in bold exceed the 8-hour ozone NAAQS threshold of 75 parts per billion.Technical Attachment Page B-3 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B1. Proposed Areas of Nonattainment for 8-Hour Ozone NAAQS in New Hampshire (2008 NAAQS)



# STATE OF NEW HAMPSHIRE

Ozone Nonattainment Areas (2008 Standard)

Potential 8-Hour Nonattainment Areas

Attainment Areas Areas in Coos County above 5000 feet in elevation



### Areas above 2000 feet in elevation

Pelham Hudson

Nashua Hollis Brookline Mason New Ipswich Rindge Windham

Salem Atkinson Newton South Hampton Seabrook Hampton North Hampton Rye Ports mouth New Castle

Hampstead Derry San down Dan Ville Kings

ton East Kings ton Kens

ington

Hamp ton Falls Exeter Strat ham Brent Wood Fremont

Epping Newmarket
Newfields Green land Newing ton Durham Madbury Dover

Rollingsford Sommersworth Rochester

Barrington Milton

Farmington

Strafford

Nottingham Lee Northwood

Deerfield

Raymond Candia

Auburn
Chester

London Derry Manchester Hookset Concord

Allens town Bow Pembroke Hopkinton

Weare

Goffstown

Bedford

Amherst Merrimack

Litchfield New Boston

Lynde borough Mt. Vernon

Milford Wilton Temple Dunbarton

Fitzwilliam Richmound Winchester Hinsdale

Chesterfield

West moreland Keene

Swanzey
Troy Jaffrey Dublin Marl borough Roxbury Harrisville

Peter borough

Sharon

Greenland Frances town Hannock Benning ton Deering Antrim Stoddard

Nelson Sullivan Gilsum

Surry Walpole Acworth Lempster

Langdon Charles town

Alstead Marlow Washington Hillsborough Henniker Bradford Warner Newbury Goshen Unity Claremont Cornish

Plantfield

Lebanon

Hanover

Enfield

Enfield

Grantham

Croydon

Newport Sunapee Springfield Grafton

Orange

Danbury Alexandria

Wilmot

New London

Sutton Salibury Andover

Hill Bristol Hebron Bridge water New Hampton Meredith

Sanbornton

Franklin

Northfield

Webster Canterbury

Loudon

Epsom Pittsfield Gilmanton Belmont Tilton Laconia Gilford

Alton

Barnstead New Durham

Brook field

Middle town Wakefield Wolfboro Moulton borough Tuftonboro Ossipee Lyme

Orford

Piermont

Haverhill Bath

Warren Benton

Wentworth

Dorchester Groton Rumney

Ellsworth

Woodstock Lincoln Easton Landaff Monroe Lyman
Lisbon Sugar Hill Franconia Bethlehem Littleton
Carroll

Livermore

Waterville Valley
Thornton

Campton

Plymouth Holderness

Ashland Sandwich

Hebron Albany

Tamworth Freedom

Effingham Conway

Madison Eaton Hebron

Jackson Chatham Beans Purchase Sargents Purchase Crawfords Purchase Low&Burbanks Grant

Beans Grant Martins Loc.

Greens Grant

Pinkhams Grant

Hales Location Dalton Whitefield Jefferson Lancaster North Umberland Kilkenny

Randolph Berlin

Gorham Shelburne Sucess Milan Stark Stratford

Columbia

Colebrook Stewartstown

Dixville

Millsfield

Odell

Dummer Cambridge Errol Wentworths Location

Second College Grant Dixs Grant Atkinson & Gilmanton

Academy Grant Clarksville Pittburg

Ervings Location



### COOS

GRAFTON

CARROLL

SULLIVAN

CHESHIRE MERRIMACK STRAFFORD

HILLSBOROUGH ROCKINGHAM BELKNAP (Based on monitored design values for the period 2006-2008) 

### Ozone Monitors below 75ppb Ozone Monitors above 75ppb Mountain-top Ozone Monitors above 75ppbTechnical Attachment Page B-4 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


### As requested in EPA’s guidance (and consiste nt with how designati ons are identified in Part 81 of the Code of Federal Regulations), attainment/nonattainm ent information is provided in Table B2. This information, along with digitized longitude and latitude coordinates for mapping purposes, and electronic versions of this da ta and associated maps will be provided.



## TABLE B2. Proposed Designations of Areas of 8-Hour Ozone NAAQS Nonattainment in New Hampshire

NEW HAMPSHIRE – OZONE (8-HOUR STANDARD) Designation Classification 

# Designated Area Type Type Southeast New Hampshire Nonattainment Area: Nonattainment TBD *



### Hillsborough County: Includes only the following towns: Amherst Nonattainment TBD * 

### Bedford Nonattainment TBD * 

### Brookline Nonattainment TBD * 

### Goffstown Nonattainment TBD * 

### Hollis Nonattainment TBD * 

### Hudson Nonattainment TBD * 

### Litchfield Nonattainment TBD * 

### Lyndeborough Nonattainment TBD * 

### Manchester Nonattainment TBD *


### Mason Nonattainment TBD * 

### Merrimack Nonattainment TBD * 

### Milford Nonattainment TBD *


### Mt. Vernon Nonattainment TBD * 

### Nashua Nonattainment TBD * 

### New Boston Nonattainment TBD * 

### Pelham Nonattainment TBD *


### Weare Nonattainment TBD * 

### Wilton Nonattainment TBD * 

### Merrimack County: Includes only the following towns: Hooksett Nonattainment TBD * 

### Rockingham County: Nonattainment TBD * 

### Strafford County: Nonattainment TBD *



### * - Classification of the Southeast New Hampsh ire Nonattainment Area will be determined in coordination with classification effort s for Massachusetts and Rhode Island.Technical Attachment Page B-5 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009 

## TABLE B2. Proposed Designations of Areas of 8-Hour Ozone NAAQS Nonattainment in New Hampshire (continued)

NEW HAMPSHIRE – OZONE (8-HOUR STANDARD) Designation Classification 

# Designated Area Type Type Presidential Range NH Rural Transport Area: Nonattainment Rural Transport

Includes only the following areas Above 5000 feet elevation (msl): Coos County: Boot Spur Nonattainment Rural Transport Mt. Adams Nonattainment Rural Transport Mt. Clay Nonattainment Rural Transport Mt. Jefferson Nonattainment Rural Transport Mt. Madison Nonattainment Rural Transport Mt. Monroe Nonattainment Rural Transport Mt. Quincy Adams Nonattainment Rural Transport Mt. Washington Nonattainment Rural Transport

Monadnock Highlands NH Nonattainment Area: Nonattainment Marginal

Includes only the following areas Above 2000 feet elevation (msl): Cheshire County: Bald Mountain Nonattainment Marginal Fletcher Mountain Nonattainment Marginal Hodgeman Hill Nonattainment Marginal Hubbard Mountain Nonattainment Marginal Jackson Hill Nonattainment Marginal Mt. Monadnock Nonattainment Marginal Osgood Hill Nonattainment Marginal Pitcher Mountain Nonattainment Marginal Hillsborough County: Burton Peak Nonattainment Marginal Crotched Mountain Nonattainment Marginal Holt Peak Nonattainment Marginal North Pack Monadnock Mtn Nonattainment Marginal Pack Monadnock Mtn Nonattainment Marginal

Rest of State AttainmentTechnical Attachment Page B-6 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009 

## Evaluation of the Degree of No nattainment in New Hampshire

The recommended boundaries for the South east New Hampshire Nonattainment Area were developed in consultation w ith EPA Region I and are consistent with the flexibility allowed in the guidance. EPA Region I specifically request ed justification for not being fully inclusive of the Boston-Worcester-Manchester CSA boundaries and why the state seeks to designate its nonattainment areas separately from the Massachus etts and Rhode Island portions of the CSA. The explanation that follows is consistent with the nine factors specified in Section 107(d)(1)(A) and the Ozone Transport Region provisions of the Clean Air Act, and considers benefits likely to be achieved for the requirements.

Nine Factors for Evaluating Designation Boundaries 1. Air Quality data 2. Emissions data 3. Population density and degree of urbanization 4. Traffic and commuting patterns 5. Growth rates and patterns 6. Meteorology and transport patterns 7. Geography and topography 8. Jurisdictional boundaries (counties, existing nonattainment area boundaries, MPOs, etc.) 9. Level of control of emission sources



### New Hampshire’s analyses started with the id entification of areas within the State that are actually in violation of the 8-hour ozone standard (see figu re B2 below). After examining the attainment status with updated monitoring da ta for the period 2006 through 2008, only the Rye monitor at Odiorne Point State Park violates the standard for regular population based monitors (Table B1). Because of the coastal effect drivi ng Ordiorne Point ozone levels higher than nearby Portsmouth, NHDES concludes that all towns borderi ng the Atlantic coast are also likely in violation of the new ozone standard. In additi on, mountain-top monitors at Miller State Park (Pack Monadnock Mountain), and Mt. Washingt on also exceed the NAAQS, but represent mountain highlands and transpor t layers rather than populatio n exposure. Each of these mountain areas had violations extrapolated to similar terrain in the immediate areas. It makes sense to separate the highlands from the co re Southeast New Hampshire nonattainment area because they represent differing patterns of influe nce and this allows the state to reach further into adjoining counties on a scientifically sound basis.Technical Attachment Page B-7 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



## FIGURE B2. Areas of Violation of the 8-Hour Ozone NAAQS in New Hampshire



# STATE OF NEW HAMPSHIRE

Ozone Areas of Violation

(2008 Standard)

Estimated 8-Hour Areas of Violation

Attainment Areas

Pelham Hudson

Nashua Hollis Brookline Mason New Ipswich Rindge Windham

Salem Atkinson Newton South Hampton Seabrook Hampton North Hampton Rye Ports mouth New Castle

Hampstead Derry San down Dan Ville Kings

ton East Kings ton Kens

ington

Hamp ton Falls Exeter Strat ham Brent Wood Fremont

Epping Newmarket
Newfields Green land Newing ton Durham Madbury Dover

Rollingsford Sommersworth Rochester

Barrington

Milton

Farmington

Strafford

Nottingham Lee Northwood

Deerfield

Raymond Candia

Auburn
Chester

London Derry Manchester Hookset Concord

Allens town Bow Pembroke Hopkinton

Weare

Goffstown

Bedford

Amherst Merrimack

Litchfield New Boston

Lynde borough Mt. Vernon

Milford Wilton Temple Dunbarton

Fitzwilliam Richmound Winchester Hinsdale

Chesterfield

West moreland Keene

Swanzey
Troy Jaffrey Dublin Marl borough Roxbury Harrisville

Peter borough

Sharon

Greenland Frances town Hannock Benning ton Deering Antrim Stoddard

Nelson Sullivan Gilsum

Surry Walpole Acworth Lempster

Langdon Charles town

Alstead Marlow Washington Hillsborough Henniker Bradford Warner Newbury Goshen Unity Claremont Cornish

Plantfield

Lebanon

Hanover

Enfield

Enfield

Grantham

Croydon

Newport Sunapee Springfield Grafton

Orange

Danbury Alexandria

Wilmot

New London

Sutton Salibury Andover Hill Bristol Hebron Bridge water New Hampton Meredith

Sanbornton

Franklin

Northfield

Webster Canterbury

Loudon

Epsom Pittsfield Gilmanton Belmont Tilton Laconia Gilford

Alton

Barnstead New Durham

Brook field

Middle town Wakefield Wolfboro Moulton borough Tuftonboro Ossipee Lyme

Orford

Piermont

Haverhill Bath

Warren Benton

Wentworth

Dorchester Groton Rumney

Ellsworth

Woodstock Lincoln Easton Landaff Monroe Lyman
Lisbon Sugar Hill Franconia Bethlehem Littleton
Carroll

Livermore

Waterville Valley
Thornton

Campton

Plymouth Holderness

Ashland Sandwich

Hebron Albany

Tamworth Freedom

Effingham Conway

Madison Eaton Hebron

Jackson Chatham Beans Purchase Sargents Purchase Crawfords Purchase Low&Burbanks Grant

Beans Grant Martins Loc.

Greens Grant

Pinkhams Grant

Hales Location Dalton Whitefield Jefferson Lancaster North Umberland Kilkenny

Randolph Berlin

Gorham Shelburne Sucess Milan Stark Stratford

Columbia

Colebrook Stewartstown

Dixville

Millsfield

Odell

Dummer Cambridge Errol Wentworths Location

Second College Grant Dixs Grant Atkinson & Gilmanton

Academy Grant Clarksville Pittburg

Ervings Location



### COOS

GRAFTON

CARROLL

SULLIVAN

CHESHIRE MERRIMACK STRAFFORD

HILLSBOROUGH ROCKINGHAM BELKNAP (Based on monitored design values for the period 2006-2008) 

### Mountain-top Ozone Monitors above 75ppb Ozone Monitors above 75ppbTechnical Attachment Page B-8 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009 

## 1. Southeast New Hampshire Nonattainment Area Discussion

As a starting point in defining the core Southeast New Hampshire nonattainment area, New Hampshire started with EPA guidance. In its December 4, 2008 memorandum from Robert J. Meyers, the U.S. Environmental Protection Agency (“EPA”) proposed the use of the most recent Core Based Statistical Areas (“CBSAs”) or Combined Statistical Areas (“CSAs” - which includes two or more CBSA’s) as presumptiv e 8-hour ozone nonattainment area boundaries. While the intent of designating areas as nonattai nment large enough to capture both the areas that violate the standard and the sources that cause the violations is ideal, applying the concept in the real world is often complicated. CBSAs and CSAs are defined by socio-economic patterns proximate to urban centers rath er than by factors which dete rmine air quality, but they are attractive for nonattainment area bou ndaries because they are predef ined political boundaries that represent urban proximity. Application of CBS As/CSAs work well in regions of the country where transport of the offending pollutant doesn’t pass from region to region as it does in the Northeast U.S. Because the wind can easily dir ect pollutants outside of the metropolitan area boundaries, the use of CBSAs/CSAs to derive nonattainment area boundari es can result in a designation that is too small on the upwind si de and too large on the downwind side.

In fact, the presumptive norm would extend the New Hampshire portion into very rural downwind counties where pollution control programs could only produce very small reductions whose benefits would blow with the wind away from the areas that need the benefit. Further, The New Hampshire Department of Transpor tation and the state’s Regional Planning Commissions have expressed concerns about needing to expand their programs at significant cost while only producing mini mal benefits at best. New Hampshire Department of Transportation estimates that it would cost them upwards of $0.25 million to establish the modeling ability to add the require d conformity analyses to the full extent of the CSA, with annual costs of up to $50,000. These additional costs come at a time of great financial distress. Further, the Department of Trans portation has advised us that the vast majority of the towns to be added to fill out the full county presumptiv e boundary are extremely rural and represent only a tiny fraction of the emissions of the prev iously defined 8-hour nonattainment area.

In the interest of formi ng better consistency between past 1-hour ozone Serious nonattainment areas with present 8-hour ozone boundaries, NHDES feels it is appropriate to ensure both areas are fully inclusive of and ma ximize the ability of the states Metropolitan Planning Organizations (“MPO’s”) to contribute to modeling for conformity. All towns from the Boston CSA that are excluded in this recommenda tion fall outside of the New Hampshire MPOs and would require new accommodations for planning and modeling for conformity determinations (Figure B4). In addition, the towns excluded from the designation have significantly lower nitrogen oxides (“NOx”) emissi on densities than those areas contained within the recommended boundaries (Figure B5). As a result, the area proposed for designation captures the vast majority of the state’s emissi ons, and much of those emission areas not falling within the boundaries lie on the downwind edge of the CSA and have ozone design values safely below the NAAQS (Table B3).

The boundaries are however fully inclusive of previously designated 8-hour ozone nonattainment areas and areas formerly classifi ed as serious nonattainment for 1-hour ozone standard (Figure B3). Because of the low-levels of emissions in the towns that fall within the CSA boundaries but do not fall within our propo sed nonattainment area boundaries, we expect negligible additional benefit towards improved air quality in the region if these towns were to beTechnical Attachment Page B-9 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



### included within the nonattainment area. Furthe r, these areas are primarily located on the downwind edge of the region exceeding the ozone standard and are unlikely to contribute to exceedances in the area. Including these towns would provide administrative completeness with the presumptive norm, but would come at a cost to the communities and to the state with virtually zero additional benefit.

Merrimack Station, the state’s largest single source emitter of NOx, resides in the town of Bow, which has been excluded from the New Ha mpshire recommended nona ttainment area. The power plant in that town is already maxi mally controlled for oxide s of nitrogen (“NOx”) through the use of selectiv e catalytic reduction on both of its boilers (as part of the NOx Budget Rule in an approved State Implementation Pl an (“SIP”) revision) and has electrostatic precipitators (“ESPs”) to control particle emissi ons. By state law, the facility is required to install a wet scrubber system for sulfur dioxide and mercury emission reductions and have it operational by 2013. The plant is also required to fulfill OTR and MANE-VU requirements. There is no additional benefit to including the power plant within th e designated area.

In New Hampshire, local pollution controls are important to prevent air quality degradation, however th e greatest success in recent years in reducing ozone has come from super-regional and national air pollution control programs. Programs such as the federal NOx SIP Call for power plants and the Low Emissi on Vehicle program for automobiles has been unprecedented in the air quality bene fits they provided and there is room to take these programs further. It should be clearly noted that regard less of boundary designations, all portions of New Hampshire will continue to operate under Oz one Transport Region requirements, Ozone Transport Commission emission control strategies, state-wide permitting and offset requirements, state-wide Onboard Diagnostic requ irements for mobile sources, and state-wide Stage 1 requirements. In addition, all of Hillsborough, Merrimack, Rockingham, and Strafford Counties will continue to have reformul ated gasoline and Stage 2 requirements.

EPA’s guidance indicates that the rationale for the presumptive CSA or CBSA boundary is the need to consider emission controls over a larger area due to the pervasive nature of ozone and the transport of ozone and its precursors. However, this important goal is met if all contributing areas within a CSA are designated as a non-attainment area, with the same ozone classification, 1 

### even if they are not w ithin the same non-attainment area. Rhode Island and eastern Massachusetts are likely to be classified by EPA at the same level based on the severity of their ozone violations. New Hampshire’s ozon e concentrations will likely allow the state to designate its nonattainment area in a less severe classification than eastern Massachusetts. However, New Hampshire intends to request that EPA classify its Southeastern New Hampshire non-attainment area at the same level as desi gnated for eastern Massach usetts. Thus, eastern Massachusetts, Rhode Island and southern portions of New Hampshire would be subject to Clean Air Act control requirements commensura te with their uniform classification.

New Hampshire is strongly committed to work ing with other states within the Ozone Transport Region to address air quality on a re gional basis. The Ozone Transport Commission member states are engaged in an ongoing regional attainment planning process for the 2008 ozone standard. That process incl udes coordinated development of emissions inventories, joint

1 Ozone non-attainment areas are classified based on the le vel of severity of their ozone problem. The Clean Air Act requires certain emission control measures based on cla ssifications. Southeastern New Hampshire, Eastern MA and Rhode Island are “moderate” non-attainment areas under th e 1997 standard. EPA will issue classifications for nonattainment areas under the 2008 ozone standard in 2010.Technical Attachment Page B-10 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


### ozone attainment modeling, and the development of recommended control stra tegies for all states within the OTC. New Hampshire, Massachusetts , and Rhode Island are actively engaged in this OTC planning process. Thus, the coordinated planning efforts that would be one of the advantages of a three-state non- attainment area are already in place. In addition, New Hampshire Massachusetts, and Rhode Island intend to furthe r consult with each other, and with Region 1 EPA staff, to identify any addi tional State Implementation Plans and attainment issues on which the three states may be able to coordinate.

The Clean Air Act and SIPs are designed to be implemented on a state-by-state basis. Each state must prepare its own SIP and conduct public hearings on proposed SIP revisions and adopt controls through its own re gulatory process. Thus, state jurisdictional issues support single-state SIPs, unless there is a go od rationale for a multi-state area.

A single multi-state SIP would be administra tively more complex fo r each of the three states and require the commitment of additional staff resources. This is particularly true in New Hampshire because, in addition to the Southeast New Hampshire non-attainment areas, the state is also proposing two other areas that will need to be addressed. Preparing one State Implementation Plan that covers all pertinent New Hampshire non-attainment areas will require less staff time than preparing one SIP for New Ha mpshire only areas and a separate multi-state SIP for Southeastern New Hampshire. Under pr esent budgetary constraints, the use of limited staff resources is an important consideration.Technical Attachment Page B-11 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B3. Proposed Areas of Nonattainment for 8-Hour Ozone NAAQS Compared to CMSA a nd Existing 1-Hour Ozone Serious Nonattainment Area Boundaries in New Hampshire



# STATE OF NEW HAMPSHIRE
Ozone Nonattainment Areas

Current 8-Hour Southeast New Hampshire Moderate Area
Former 1-Hour Serious Nonattainment Areas
New Recommended 8-Hour Ozone Nonattainment Area

Attainment Areas

Pelham Hudson

Nashua Hollis Brookline Mason New Ipswich Rindge Windham

Salem Atkinson Newton South Hampton Seabrook Hampton North Hampton Rye Ports mouth New Castle

Hampstead Derry San down Dan Ville Kings

ton East Kings ton Kens

ington

Hamp ton Falls Exeter Strat ham Brent Wood Fremont

Epping Newmarket
Newfields Green land Newing ton Durham Madbury Dover

Rollingsford Sommersworth Rochester

Barrington Milton

Farmington

Strafford

Nottingham Lee Northwood

Deerfield

Raymond Candia

Auburn
Chester

London Derry Manchester Hookset Concord

Allens town Bow Pembroke Hopkinton

Weare

Goffstown

Bedford

Amherst Merrimack

Litchfield New Boston

Lynde borough Mt. Vernon

Milford Wilton Temple Dunbarton

Fitzwilliam Richmound Winchester Hinsdale

Chesterfield

West moreland Keene

Swanzey
Troy Jaffrey Dublin Marl borough Roxbury Harrisville

Peter borough

Sharon

Greenland Frances town Hannock Benning ton Deering Antrim Stoddard

Nelson Sullivan Gilsum

Surry Walpole Acworth Lempster

Langdon Charles town

Alstead Marlow Washington Hillsborough Henniker Bradford Warner Newbury Goshen Unity Claremont Cornish

Plantfield

Lebanon

Hanover

Enfield

Enfield

Grantham

Croydon

Newport Sunapee Springfield Grafton

Orange

Danbury Alexandria

Wilmot

New London

Sutton Salibury Andover

Hill Bristol Hebron Bridge water New Hampton Meredith

Sanbornton

Franklin

Northfield

Webster Canterbury

Loudon

Epsom Pittsfield Gilmanton Belmont Tilton Laconia Gilford

Alton

Barnstead New Durham

Brook field

Middle town Wakefield Wolfboro Moulton borough Tuftonboro Ossipee Lyme

Orford

Piermont

Haverhill Bath

Warren Benton

Wentworth

Dorchester Groton Rumney

Ellsworth

Woodstock Lincoln Easton Landaff Monroe Lyman
Lisbon Sugar Hill Franconia Bethlehem Littleton
Carroll

Livermore

Waterville Valley
Thornton

Campton

Plymouth Holderness

Ashland Sandwich

Hebron Albany

Tamworth Freedom

Effingham Conway

Madison Eaton Hebron

Jackson Chatham Beans Purchase Sargents Purchase Crawfords Purchase Low&Burbanks Grant

Beans Grant Martins Loc.

Greens Grant

Pinkhams Grant

Hales Location Dalton Whitefield Jefferson Lancaster North Umberland Kilkenny

Randolph Berlin

Gorham Shelburne Sucess Milan Stark Stratford

Columbia

Colebrook Stewartstown

Dixville

Millsfield

Odell

Dummer Cambridge Errol Wentworths Location

Second College Grant Dixs Grant Atkinson & Gilmanton

Academy Grant Clarksville Pittburg

Ervings Location

COOS

GRAFTON

CARROLL

SULLIVAN

CHESHIRE MERRIMACK STRAFFORD

HILLSBOROUGH ROCKINGHAM BELKNAP

2/18/2008 1_8-hrBndys with Counties.gsmTechnical Attachment Page B-12 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B4. Map of New Hampsh ire Metropolitan Planning Organizations and Regional Planning Commissions

Boundary of the Metropolitan Planning Organizations (MPOs)Technical Attachment Page B-13 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B5. New Hampshire-NOx Emission Density

137 147 157 122 132 142

0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 

## Total Area Source and Mobile NOx Emissions 2002 Base Case August 12, 2002

NOx Emissions (Tons)

NHDES 2/18/09 CALGRID 2.45 Modeling Domai n 

## (Tons per 144 km 2 

## )

Area enclosed by white dots is the area recommended by New Hampshire as the Southeast New Hampshire Nonattainment Area.

Relative geographic emission density estimates a re based on modeling inventories for the OTC Photochemical Modeling Domain for 8-hour ozone modeling initiative.Technical Attachment Page B-14 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



## TABLE B3. Towns in the New Hampshire Portio n of the CBA that are Not Included in the Recommende d New Hampshire Area of Influence

County Town 2007 Census

Pop. 2000 Census

Pop. Growth Rate (%/yr) 2007 Pop. Density (#/sqmi) Ozone DV (ppb) nearest monitor Notes**

State Totals 1,312,256 1,235,786 0.92 137.4 -- -- 

### Belknap County Totals 61,048 56,325 1.2 152 70 All portions subject to State-wide permitting and offset requirements, OTR Requirements, OTC Controls, OBD and Stage 1 

### Alton 5,070 4,503 1.8 80 70 Remote and downwind, low population density, low emissions 

### Barnstead 4,567 3,886 2.5 109 70 Remote and downwind, low population density, low emissions 

### Belmont 7,161 6,720 0.9 234 70 Remote and downwind, low population density, low emissions 

### Center Harbor 1,104 997 1.5 82 70 Remote and downwind, low population density, low emissions 

### Gilford 7,397 6,803 1.2 190 70 Remote and downwind, low population density, low emissions 

### Gilmanton 3,513 3,055 2.1 62 70 Remote and downwind, low population density, low emissions 

### Laconia 16,950 16,411 0.5 835 70 Remote and downwind 

### Meredith 6,616 5,942 1.6 165 70 Remote and downwind, low population density, low emissions 

### New Hampton 2,228 1,950 2.0 61 70 Remote and downwind, low population density, low emissions 

### Sanbornton 2,869 2,591 1.5 60 70 Remote and downwind, low population density, low emissions 

### Tilton 3,573 3,467 0.4 313 70 Remote and downwind, low population density, low emissionsTechnical Attachment Page B-15 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



## TABLE B3. Towns in the New Hampshire Portio n of the CBA that are Not Included in the Recommende d New Hampshire Area of Influence (continued)

County Town 2007 Census

Pop. 2000 Census

Pop. Growth Rate (%/yr) 2007 Pop. Density (#/sqmi) Ozone DV (ppb) nearest monitor Notes**

State Totals 1,312,256 1,235,786 0.92 137.4 -- -- Hillsborough County Totals 402,302 380,841 0.8 457 -- All portions subject to State-wide permitting and offset requirements, OTR Requirements, OTC Controls, OBD, RFG, and Stage 1&2 

### Antrim 2,619 2,449 1.0 79 69 Remote, low population density, low emissions 

### Bennington 1,475 1,401 0.8 133 69 Remote, low population density, low emissions 

### Deering 2,048 1,875 1.3 66 70 Remote, low population density, low emissions 

### Francestown 1,579 1,480 1.0 52 68 Remote, low population density, low emissions 

### Greenfield 1,770 1,664 0.9 69 69 Remote, low population density, low emissions Greenville 2,188 2,224 -0.2 645 73 Low population and emissions. No growth. 

### Hancock 1,805 1,739 0.5 60 69 Remote, low population density, low emissions 

### Hillsborough 5,522 4,925 1.7 128 69 Remote, low population density, low emissions New Ipswich 5,190 4,289 3.0 159 69 Remote, low population density, low emissions 

### Peterborough 6,140 5,883 0.6 157 69 Remote, low population density, low emissions 

### Sharon 366 360 0.2 25 69 Remote, low population density, low emissions 

### Temple 1,560 1,297 2.9 67 69 Remote, low population density, low emissions 

### Windsor 233 204 2.0 28 69 Remote, low population density, low emissionsTechnical Attachment Page B-16 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



## TABLE B3. Towns in the New Hampshire Portio n of the CBA that are Not Included in the Recommende d New Hampshire Area of Influence (continued)

County Town 2007 Census

Pop. 2000 Census

Pop. Growth Rate (%/yr) 2007 Pop. Density (#/sqmi) Ozone DV (ppb) nearest monitor Notes**

State Totals 1,312,256 1,235,786 0.92 137.4 -- -- Merrimack County Totals 148,274 136,225 1.3 160

-- All portions subject to State-wide permitting and offset requirements, OTR Requirements, OTC Controls, OBD, RFG, and Stage 1&2 Allenstown 4,943 4,843 0.3 241 

### 68 Low population density, low emissions, low growth Andover 2,226 2,109 0.8 55 

### 70 Low population density, low emissions Boscawen 3,958 3,672 1.1 160 

### 70 Low population density, low emissions Bow 8,051 7,138 1.8 287 

### 70 Low population density, Power Plant well controlled with SCR, ESP, and soon to add scrubber. Bradford 1,524 1,454 0.7 43 

### 68 Remote and downwind, low population density, low emissions Canterbury 2,312 1,979 2.4 53 

### 70 Remote and downwind, low population density, low emissions Chichester 2,528 2,236 1.9 120 

### 70 Remote, low population density, low emissions Concord 42,392 40,687 0.6 659 

### 70 Remote, low to moderate population density, low emissions Danbury 1,150 1,071 1.1 31 

### 70 Remote and downwind, low population density, low emissions Dunbarton 2,610 2,226 2.5 84 

### 70 Remote, low population density, low emissions Epsom 4,567 4,021 1.9 134 

### 70 Remote, low population density, low emissions Franklin 8,735 8,405 0.6 316 

### 70 Remote and downwind, low to moderate population density, low emissions Henniker 5,063 4,433 2.0 118 

### 70 Remote, low population density, low emissions Hill 1,103 992 1.6 41 

### 70 Remote and downwind, low population density, low emissions Hopkinton 5,616 5,399 0.6 130 

### 70 Remote, low population density, low emissions Loudon 5,137 4,481 2.1 110 

### 70 Remote, low population density, low emissionsTechnical Attachment Page B-17 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

County Town 2007 Census

Pop. 2000 Census

Pop. Growth Rate (%/yr) 2007 Pop. Density (#/sqmi) Ozone DV (ppb) nearest monitor Notes**

State Totals 1,312,256 1,235,786 0.92 137.4 -- -- Merrimack County Totals 148,274 136,225 1.3 160

-- All portions subject to State-wide permitting and offset requirements, OTR Requirements, OTC Controls, OBD, RFG, and Stage 1&2 Newbury 2,076 1,702 3.1 58 

### 68 Remote and downwind, low population density, low emissions New London 4,478 4,116 1.3 199 

### 68 Remote and downwind, low population density, low emissions Northfield 5,144 4,548 1.9 179 

### 70 Remote and downwind, low population density, low emissions Pembroke 7,353 6,897 0.9 323 

### 70 Remote, low population density, low emissions Pittsfield 4,375 3,931 1.6 175 

### 70 Remote and downwind, low population density, low emissions Salisbury 1,278 1,137 1.8 32 

### 70 Remote and downwind, low population density, low emissions Sutton 1,826 1,544 2.6 43 

### 68 Remote and downwind, low population density, low emissions Warner 2,962 2,760 1.0 53 

### 70 Remote and downwind, low population density, low emissions Webster 1,856 1,579 2.5 67 

### 70 Remote and downwind, low population density, low emissions Wilmot 1,336 1,144 2.4 45 

### 68 Remote and downwind, low population density, low emissionsTechnical Attachment Page B-18 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



### Areas of Influence

In accordance with EPA guidance, New Hampshir e has investigated the influence of New Hampshire emissions on nonattainment areas within and beyond the state’s borders. As discussed above, the County of Belknap, town s in the western portion of Hillsborough County, and all towns in Merrimack County except for Hooksett were excluded from the CSA presumptive norm because of the highly rural natu re of most of the towns and because of their very low emission densities. Further, the countie s at the northern edge of the CSA presumptive norm (Belknap and Merrimack) lie on the downwind e dge of the CSA. The vast majority of the ozone episodes in the CSA have winds from the west or southwest. For these northern counties to have any effect on ozone violations to th eir south, there would need to be a north wind, something almost always associated with clean air in the region. This section examines the airflows during periods of actual ozone episodes throughout the region.

New Hampshire performed back-trajectory analyses for all of the 8-hour ozone exceedances for the proposed New Hampshire nonattainment areas as well as for other nonattainment monitors in southeastern Massachus etts and Rhode Island. The analysis included ozone data for each hour that ozone levels were equal to or greater than 75 ppb at a monitoring site for all 8-hour ozone exceedances recorded at sites in Massachusetts, Rhode Island, and New Hampshire that are likely to be in nonattain ment. The National Oceanic and Atmospheric Administration (NOAA)’s Air Resources Labo ratory HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) is a computer model used to create and map trajectories. The model uses gridded meteorologi cal data. For more information about HYSPLIT please refer to the following document: Description of the HYS PLIT 4 Modeling System by Draxler and Hess (http://www.arl.noaa.gov/documen ts/reports/arl-224.pdf).

These trajectory plots are a composite ofall episodes during 2006-2008 and use a colorcoding scheme that uses red to show low level tr ajectories that are most likely to pick up local emissions, yellow shows trajectories with some po tential to pick up local emissions, and green and blue with are at altitudes too high to pi ck up local emissions and are possibly transporting emissions from areas further upwind. For most trajectories shown here, the Canadian fires of May 24-25, 2007 were removed from the data set as exceptional events. For exceedance days in New Hampshire, every hour that exceeded 75ppb was run individually. For Massachusetts and Rhode Island trajectories, only one trajectory wa s run for each exceedance day. All trajectories produced by NHDES go back 72 hours before the measured value exceeding 75ppb.

Because of the fundamentally different airs heds and the lack of influence the New Hampshire nonattainment areas have on southeas tern Massachusetts and Rhode Island during ozone events (and vice versa), it would be inappr opriate to require New Hampshire to link it’s nonattainment area to these other states. The three states have expressed their preference to be designated individually and have agreed to meet periodically with each other and with EPA Region I to coordinate anal yses and SIP efforts.

Figure B6 shows that trajectories generall y do not cross New Hampshire and those that do cross at low elevation, do so across the sout heast corner of the state – well within the proposed nonattainment area. Al l areas within the proposed Ne w Hampshire nonattainment area demonstrate some Boston influence, but there is a greater influence from the Northeast Urban Corridor. It is interesting to not e that there is very little influe nce, if any at all, from Rhode Island to New Hampshire during these events.Technical Attachment Page B-19 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



### Figure B7 shows that trajectories from Miller St ate Park (Pack Monadnock) generally do not cross New Hampshire, but instead approach the monitor from across nearby state lines to the south and west. Trajectories indicate an extremely strong influence from the full length of the Northeast Urban Corridor and influences on occasion from the Metro Boston area and from the industrial Midwest. Trajectories for Mt. Washington on the other hand have a much stronger influence from the industrial Midwest as well as a strong influence from the Northeast Urban Corridor. Some trajectories for Mt. Washington pass through the central and southern portion of New Hampshire (areas proposed for nonattainment designation) and then make a sharp turn over northern Massachusetts and on to the Northeast Urban Corridor.

Figure B8 shows that overall, the trajectories for areas to the north of downtown Boston are similar to those of southeastern New Hampshire except that the Massachusetts areas have a bit more Midwest influence. Any trajectories passing over New Hampshire, do so in the southeastern corner. Still, the Northeast Urban Corridor is probably the dominant influence during these episodes. Again, there is relatively little influence from Rhode Island emissions at these monitors. Since the many New Hampshire trajectories pass over this region and some of the Massachusetts trajectories pass over the southeastern corner of New Hampshire, it can be concluded the two areas are of similar airsheds.

Figure B9 shows that trajectories for areas sout h, southeast, and southwest of Boston exhibit some very fundamental differences compared to those from the northern areas. These monitors show very little Boston influence and a strong influence from the southern portion of the Northeast Urban Corridor. None of the trajectories from south of Boston pass over New Hampshire at a low elevation. Since the many New Hampshire trajectories pass over this region but none of the southeastern Massachusetts trajectories pass over the southeastern corner of New Hampshire, it can be concluded that while this area can contribute to New Hampshire’s ozone exceedances, New Hampshire does not contribute to exceedances in southeastern Massachusetts. Thus these two areas are of different airsheds.

Figure B10 shows that trajectories for Rhode Island are very similar to those of Southeastern Massachusetts, having a strong influence from the southern portion of the Northeast Urban Corridor. None of the trajectories pass over New Hampshire or urban Boston at low elevations. Clearly upon close inspection, Rhode Island and New Hampshire are of fundamentally different airsheds. New Hampshire has a high degree of metro New York City and Philadelphia influence, while trajectories to Rhode Island tend to travel further over the stable influence of the ocean waters to areas further south in the corridor. By passing over the water, ozone has less interaction with ozone reducing vegetation and chemically reactive new emissions, and stays concentrated in a relatively thin vertical layer. Transporting ozone is more likely to stay intact at elevated concentrations by traveling over the water.

Trajectory analyses were also conducted by the State of Maine for monitors in their state that exceed the ozone NAAQS. The trajectory methodology used by the Maine Department of Environmental Protection (“MEDEP”) was similar to that used by NHDES, except back trajectories only went back in time 24 hours from the monitored value exceeding 75ppb. Trajectories for Kennebunkport and Acadia, Maine (Figure B11) have low elevation crossings of the southeastern portion of New Hampshire and some higher elevation crossings of the western portion of the state. Several trajectories crossing the northern portion of the state are associated with the Canadian forest fires exceptional event of May 24 and 25, 2007. In verbal communication, MEDEP concurred with NHDES that the southeastern corner of New Hamp shire was the most likely portion of the state to contribute to ozone exceedances in the state of Maine and felt that the New Hampshire proposed boundaries were likely to meet their needs.Technical Attachment Page B-20 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B6. Back Trajectories fo r 8-Hour Exceedance Days for Southeastern New Hampshi re Locations (2006-2008)

Manchester, NH Nashua, NH

Portsmouth, NH

Trajectory Elevations (meters) -85 -80 -75 -70 -85 -80 -75 -70

35 40 45

0 to 15 15 to 50 50 to 100 100 to 300 300 to 2000 

### Rye - Odiorne Point, NH -85 -80 -75 -70 -85 -80 -75 -70

35 40 45

- 8 5 - 8 0 - 7 5 - 7 0 - 8 5 - 8 0 - 7 5 - 7 0

35 40 45 - 8 5 - 8 0 - 7 5 - 7 0 - 8 5 - 8 0 - 7 5 - 7 0

35 40 45Technical Attachment Page B-21 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B7. Back Trajectories fo r 8-Hour Exceedance Days for Mountainous New Hampshire Locations (2006-2008)

Miller State Park (Pack Monadnock Mountain



# -85 -80 -75 -70 -85 -80 -75 -70

35 40 45

0 to 15 15 to 50 50 to 100 100 to 300 300 to 2000 Trajectory Elevations (meters)



## Mt. Washington (Summit)

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45
0 to 50 50 to 100 100 to 300 300 to 500 500 to 1000 1000 to 2000 2000 to 6000 Trajectory Elevations (meters)Technical Attachment Page B-22 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B8. Back Trajectories fo r 8-Hour Exceedance Days for Northeastern Massachusetts Locations (2006-2008)

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45 Chelmsford, MA Haverhill, MA

- 8 5 - 8 0 - 7 5 - 7 0 - 8 5 - 8 0 - 7 5 - 7 0

35 40 45 Lynn, MA

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45 Newbury MA

0 to 15 15 to 50 50 to 100 100 to 300 300 to 2000 Trajectory Elevations (meters)Technical Attachment Page B-23 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B9. Back Trajectories fo r 8-Hour Exceedance Days for Southeastern Massachusetts Locations (2006-2008)

Boston, MA BlueHill, MA

Fairhaven, MA Truro,MA

Trajectory Elevations (meters) 

### -85 -80 -75 -70 -85 -80 -75 -70

35 40 45

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45

35 40 45

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45

0 to 15 15 to 50 50 to 100 100 to 300 300 to 2000 -85 -80 -75 -70 -85 -80 -75 -70

35 40 45Technical Attachment Page B-24 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B10. Back Trajectories for 8-Hour Exceedance Days for Rhode Island Locations (2006-2008)

West Greenwich, RI Naragansett, RI

Providence, RI

Trajectory Elevations (meters) -85 -80 -75 -70 -85 -80 -75 -70

35 40 45

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45

-85 -80 -75 -70 -85 -80 -75 -70

35 40 45

35 40 45 0 to 15 15 to 50 50 to 100 100 to 300 300 to 2000Technical Attachment Page B-25 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## FIGURE B11. Back Trajectories for 8-Hour Exceedance Days for Southern Maine Locations (Kennebunkport and Acad ia NP) (2004-2008)

Graphics provided by MEDEPTechnical Attachment Page B-26 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009 

## 2. Presidential Range NH No nattainment Area Discussion

The Presidential Mountain Range in Northern New Hampshire is a unique and well studied area that experiences higher than expected ozone levels for an area so remote from anthropogenic pollution sources. Th e Presidential Range is a cl uster of mountains in Coos County that stand higher than ju st about everything else in the region. At 6,288 feet in elevation, Mt. Washington is the tallest mountain peak in the Presidential Range and in the entire Northeastern United States. The Presidential Range stands at the crossroads of the atmospheric jetstreams, bringing hurricane force winds and sn ow to these mountains nearly every month of the year. Winds have been measured at we ll over 200 miles per hour at the summit of Mt. Washington. So unique is this area that a scie nce observatory was built to better understand it. From the summit, you can see into Vermont, Main e, Massachusetts, and Quebec Canada. With all the grand views of forests and mountains, th ere are no views of cities or smokestacks. The pollution measured here rides on the winds from places far off. For this reason, New Hampshire recommends (pending final 2007-2009 data) that the Presidential Range NH Nonattainment area be declared as a Rural Transport Area. This nonattainment area proposal consists of all mountain peaks in the Presidentia l range at an elevation of 5000 feet and above.

The proposed Presidential Range Rural Transport Area includes only the following areas above 5000 feet elevation (mean sea level): Coos County: Boot Spur Mt. Adams Mt. Clay Mt. Jefferson Mt. Madison Mt. Monroe Mt. Quincy Adams Mt. Washington

The 2006-2008 8-hour ozone design value for Mt . Washington at 76 parts per billion is only slightly over the NAAQS. It is possi ble that once 2009 data are final that this nonattainment designation will not be necessary and thus the proposal should be retracted.

While most monitors exhibit a somewhat typi cal diurnal cycle to ozone values showing maximum levels during the late afternoon or evening, the levels at the summit of Mt. Washington are defiant of this pa ttern and are nearly fl at all day long, sometimes at moderate or worse air quality (figure B12). In fact summit concentrations dip just a little bit at the time that ozone at the base of the mountai n begins to rise. This occurs when a thermal inversion, which usually lies between the base and the summit in the morning, begins to lift and break up, allowing the pollution from above to mix down into the cleaner air below. Because this region is completely dominated by transport, ozone levels near the summits where transport mechanisms work best, are usually higher than fo und at the base of the mountain (figure B13). Being well removed from metropolitan areas and from other ozone nonattainment areas, this region meets the criterion for a Rural Transport Area designation.Technical Attachment Page B-27 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


## Figure B12 Typical Day/Night Oz one Cycle at Gro und Level and Aloft

Solar ultraviolet energy helps to create ozone which is present in high quantities late in the day. At night, there is no ultraviolet sunlight to create ozone and ground level objects and gases act to remove ozone, resulting in the curve in blue, which represents ozone at ground level. Ozone at higher elevations, conversely, is often not depleted at night and may remain at elevated concentrations throughout the day (red curve).



## Figure B13 Comparison of Ozon e Concentrations at the Base and Summit of Mt. Washington

Hourly and Summer Average Ozone Concentrations

Relative comparison of mountaintop (elev. 6288 feet) ozone with mountain base (elev. around 2000 feet) hourly ozone. Often the ozone is higher in concentration at the summit (blue line) due to pollution transport from distant sources. Many times the ozone at the base (red line) is driven by upward mixing from the upper transport layers during the day.

Source: NHDES (Data: AMC)Technical Attachment Page B-28 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



### The elevation at which thermal inversions set- up in the mountains is somewhat variable. They are often found at low elevations during the winter and higher during the summer. The elevation of thermal inversions also changes th roughout the day, starting at lower elevations and rising as the ground below warms up. Because of this , it is very difficult to set a single elevation cut off to indicate where on the mountains nonattainment exists. Because the thermal inversion heavily influences where the transport layer a bove is cut off from the ground level below, its location is important to determin ing areas that potentially mainta in ozone concentrations above the NAAQS for 8-hours or more.

Conceptually, the setup is complicated a nd a conclusion can not be reached by just looking at a single snapshot of m easurements where an instantaneous maximum is measured. As the thermal inversion rises and falls in eleva tion, the point of maximum ozone moves along with it. Elevations below this maximum ozone point see a quick drop off in ozone with decreasing elevation, however the ozone drop off at elevat ions above the peak is about 3 times more gradual. Because of this and the daily waggi ng of the maximum peak up and down the mountain sides, longer term maximum ozone averages reside at elevations close to the high elevation that the ozone peak reaches for the day. Thus, if the ozone peak varies between 3000 and 5000 feet in elevation, sustained 8-hour averages will typica lly be higher at 5000 feet than at 3000 feet.

The concept of wind fields around mountains is also important to consider when attempting to understand where maximum ozone is likely to occur. When a wind field encounters a mountain, the flow responds to the te rrain by lifting the airflow to get over the terrain and to split the airflow ar ound the terrain if a route exists that offers less resistance to lifting it further. Both the lift and wrap mechanis ms usually result in faster wind speeds. As is commonly accounted for in air pollution dispersi on modeling, a plume of pollution approaching elevated terrain has its maximum impact on the mountain at elevations above the stable plume height. The same thing occurs as the transport plume of pollution meets elevated terrain. Just how much higher depends on a number of factor s including wind speed. The higher the wind speed, the more the lifting. For this reason, aircraft measuremen ts and atmospheric soundings away from mountain areas will of ten produce data that suggests altitudes for ozone peaks that will be somewhat lower in elevation than actually measured on the mountain side. Typically in the Northeast, the transport layer can be f ound between 2500 and 3500 feet, but as the terrain rises, so does the elevation of impact.

Another contributing factor to the proposed designation of 5000 foot and above in the Presidential Range as a Rural Tr ansport Area, is the fact that the mount ain ridge averages between 4500 and 5200 feet in elevation. Air pollu tion plumes approaching the range will lift up the mountain ridge to this point and then be able to wrap arou nd the peaks. Because of this, maximum ozone for this region may be at a lowe r elevation rather than at the summit of Mt. Washington on most days of the year. The airm ass is also pulled downward on the leeward side of the ridge.

There are very little data co llected specifically for Mt. Washington and the Presidential Range, thus one needs to be cautious in draw ing conclusions on the full applicability of thresholds derived from limited datasets. Single snapshot observations only reflect on the conditions of the moment while critical trans port mechanisms can vary by the hour or even minutes in some cases. Actual measurements have been provided to NHDES and are discussed below:Technical Attachment Page B-29 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


### Figure B14 shows measurements from a University of Maryland flyby on August 13, 2002 during studies for regional haze. As is typical for the area, a morning inversion sets up at a fairly low elevation of around 2000 to 3300 feet, trap ping relatively clean air below it. The peak of the transport layer sets up just above the in version at about 3500 feet. As the day’s warming progresses, the inversion lifts in elevation and levels-o ut allowing some ozone from the transport layer above to begin spilling dow n to the ground. As this occurs , the transport layer lifts along with the point of maximum oz one to higher elevations.



## Figure B14 Aircraft fly-by of Mt . Washington for 09:19 – 09:43 am on August 13, 2002 (University of Maryland)

Figure B15 below, shows how this might look at ground level on the mountain. According to Figure B15, elevated ozone values are measured down to elevations of 2674 feet during the early morning hours of July 29 of 1993. Ho wever, later in the day, that level lifts to between 4774 feet and 5676 feet in elevation (nearly identical w ith the elevations estimated by NHDES based on the physics of the flows around the local terrain). Once averaged over an extended period (similar to the 8-hour NAAQS), maxi mum sustained ozone levels occur close to the 4774 foot in elevation mark on th e mountain during this event.

While each event differs and these two snaps hots provide only limited data, they fit the NHDES model. It would of course be more helpfu l to have more extensive data with enhanced interim elevation and temporal da ta, but it is almost immaterial as to what specific elevation threshold is applied for nonattain ment designation. Whether it s hould be higher or lower is less important than the designation of a reasonable re presentative area as nonattainment that has an actual monitor to track its progress. Othe r than Mt. Washington, none of the candidate mountains have emission sources to control and the sources that drive the ozone violations are not anywhere nearby.Technical Attachment Page B-30 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009



## Figure B15 Appalachian Mounta in Club Auto Road Transect Study for July 29-30, 1993

(Ground-based measurements – AMC 1993)Technical Attachment Page B-31 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009 

## 3. Monadnock Highlands NH No nattainment Area Discussion

The Monadnock Highland region in Southweste rn New Hampshire is another unique region with elevated measured oz one levels. This region of the state contains several mountains that rise on the western fringe of where the northeastern ozone plume typically enters the state from the southwest. This southwest to northeas t mountain range helps to channel the transport flow northeastward toward the Southeast New Ha mpshire nonattainment area discussed above. At 2288 feet in elevation, Pack Monadnock Mountai n lies on the eastern edge of this range and happens to be located toward the middle of the transport flow. The mountain also stands at the northern end of the low-level jet that forms overni ght, transporting air pollu tion at relatively high velocities from along the urba n corridor that extends from Boston to New York City, Philadelphia, Baltimore, Washington, and from as far away as North Carolina. The monitoring equipment on this mountain was placed here as a special purpose monitor to capture the air quality entering the state so that air polluti on transport could be be tter researched and understood.

Several similarly sized mountains lie very nearby to the north and south. These mountains are included in the nonattainment designa tion because of size and proximity. Just to the west lies Mt. Monadnock, the most heavily hiked mountain in the northeast U.S. This mountain stands about 1000 feet taller than Pack Monadnock and despite be ing further west it has also been included in this designation because of its higher altitude . To be conservative, several other mountain peaks to the north of Mt . Monadnock are also included in the designation due to their similar size to Pack Monadnock de spite the growing distan ce between the transport corridor and the terrain’s location. While more hi gh terrain lies further to the north and west, a reasonable cut-off is created at the Cheshire County line as this boundary is already far enough off the transport corridor that NAAQS exceedance s are not expected ther e. Historic data collected at a former monitoring site on the su mmit of Mt. Sunapee in Sullivan County supports this determination.

Elevation cut-offs for this region are conceptu ally the same as for the Presidential Range, however this region lies largely below the transport layer, thus increasing elevation produces increasing ozone, provided the location is approp riate to capture the transport plume. As described before, ozone concentrat ions below the transport layer dr op off rapidly, so there can be a sharp decline in ozone as elev ation decreases. Should there be substantial local emissions surrounding these mountains, ground level ozone would work its way upward during the afternoon hours, dominating the effect of tran sport from above. However, the Monadnock region is sparsely populated and de void of major air po llution sources, thus is heavily dominated by the transport layer down-mixing effect. As stat ed before, the transport layer in the Northeast usually sets up between 2500 and 3500 feet and ri ses with terrain. Si nce the terrain through much of the Monadnock highlands is below this level, down mixing from the transport layer becomes a dominant factor. Therefore, applying a gradient factor of 1 part per billion per 55 vertical feet 2 

### from the monitor station at 2288 feet fr om 78 parts per billion to 75 parts per billion produced an estimated elevation of 2124 feet. To simplify the threshold, we propose to round it down to 2000 feet for the purposes of defining nonattainment in the Monadnock Highlands.

2 Gradient factor may vary but the factor applied here has basis as being consistent with recently observed aircraft measurements in the Northeast (including data posted in Figure B11 above).Technical Attachment Page B-32 Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009


### For designation purposes all terrain above 2000 feet in elevation in Cheshire and western Hillsborough Counties should be desi gnated as marginal nonattainment. This includes:

The proposed Monadnock Highlands Nonattainment Area includes only the following areas above 2000 feet elevation (msl):

Cheshire: Bald Mountain Fletcher Mountain Hodgeman Hill Hubbard Mountain Jackson Hill Mt. Monadnock Osgood Hill Pitcher Mountain

Hillsborough: Burton Peak Crotched Mountain Holt Peak North Pack Monadnock Mtn Pack Monadnock Mtn