Comment Attachment Page A-3 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

FIGURE 1. Proposed Areas of Nonattainment 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

Derry Hampstead

San

down Dan

Ville Kings

ton

East

Kings

ton

Kens

ington

Hamp

 ton

 Falls

Exeter

Strat

Brent ham

Fremont Wood

Epping Newmarket

Newfields Green

 land

Newing

ton

Durham

MadburyDover

Rollingsford

Sommersworth

Rochester

Barrington

Milton

Farmington

Strafford

Nottingham Lee

Northwood

Deerfield

Raymond

Candia

Auburn

Chester

London

Derry

Manchester

Hookset

Concord

Allens Bow town

Pembroke

Hopkinton

Weare

Goffstown

Bedford

AmherstMerrimack

Litchfield

New

Boston

Lynde

borough

Mt.

Vernon

Milford

Wilton

Temple

Dunbarton

Richmound Fitzwilliam

Winchester

Hinsdale

Chesterfield

West

moreland Keene

Swanzey

Troy Jaffrey

Marl Dublin

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 Boundaries 
Comment Attachment Page A-2 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 
Comment Attachment Page A-3 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 
Comment Attachment Page A-4 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 
Comment Attachment Page A-5 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 
Comment Attachment Page A-6 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 
Comment Attachment Page A-7 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 
Comment 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 Boundaries 
Technical 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 defines a nonattainment area as any area that 

(1) does not meet the ozone National Ambient Air Quality Standard (“NAAQS”), or (2) 

contributes to ambient ozone violations in a nearby area. These boundaries exercise the 

flexibility allowed in the guidance, considering: population, population density, projected 

growth, existing air quality, prevailing meteorology, and metropolitan planning organization 

boundaries. In addition, geographic emission densities 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 southeastern New Hampshire area 

that encompasses the state’s largest cities and areas of population growth. The second area 

considers the highlands in the Monadnock region 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 remote mountains surrounding 

Mt. Washington in the northern portion of the state. This high elevation monitor is far removed 

from population centers and well above the overnight 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 

4th Max 

2007 

4th Max 

2008 

4th 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

Derry Hampstead

San

down Dan

Ville Kings

ton

East

Kings

ton

Kens

ington

Hamp

 ton

 Falls

Exeter

Strat

Brent ham

Fremont Wood

Epping Newmarket

Newfields Green

 land

Newing

ton

Durham

MadburyDover

Rollingsford

Sommersworth

Rochester

Barrington

Milton

Farmington

Strafford

Nottingham Lee

Northwood

Deerfield

Raymond

Candia

Auburn

Chester

London

Derry

Manchester

Hookset

Concord

Allens Bow town

Pembroke

Hopkinton

Weare

Goffstown

Bedford

AmherstMerrimack

Litchfield

New

Boston

Lynde

borough

Mt.

Vernon

Milford

Wilton

Temple

Dunbarton

Richmound Fitzwilliam

Winchester

Hinsdale

Chesterfield

West

moreland Keene

Swanzey

Troy Jaffrey

Marl Dublin

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 75ppb
Technical Attachment Page B-4 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

As requested in EPA’s guidance (and consistent with how designations are identified in 

Part 81 of the Code of Federal Regulations), attainment/nonattainment information is provided in 

Table B2. This information, along with digitized longitude and latitude coordinates for mapping 

purposes, and electronic versions of this data 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) 

Designated Area Designation Classification 

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 Hampshire Nonattainment Area will be determined in 

coordination with classification efforts 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) 

Designated Area Designation Classification 

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 Attainment 
Technical Attachment Page B-6 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

Evaluation of the Degree of Nonattainment in New Hampshire 

The recommended boundaries for the Southeast New Hampshire Nonattainment Area 

were developed in consultation with EPA Region I and are consistent with the flexibility allowed 

in the guidance. EPA Region I specifically requested 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 Massachusetts 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 identification of areas within the State that 

are actually in violation of the 8-hour ozone standard (see figure B2 below). After examining the 

attainment status with updated monitoring data 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 driving Ordiorne Point ozone levels higher than nearby 

Portsmouth, NHDES concludes that all towns bordering the Atlantic coast are also likely in 

violation of the new ozone standard. In addition, mountain-top monitors at Miller State Park 

(Pack Monadnock Mountain), and Mt. Washington also exceed the NAAQS, but represent 

mountain highlands and transport layers rather than population 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 core Southeast New Hampshire nonattainment area 

because they represent differing patterns of influence 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

Derry Hampstead

San

down Dan

Ville Kings

ton

East

Kings

ton

Kens

ington

Hamp

 ton

 Falls

Exeter

Strat

Brent ham

Fremont Wood

Epping Newmarket

Newfields Green

 land

Newing

ton

Durham

MadburyDover

Rollingsford

Sommersworth

Rochester

Barrington

Milton

Farmington

Strafford

Nottingham Lee

Northwood

Deerfield

Raymond

Candia

Auburn

Chester

London

Derry

Manchester

Hookset

Concord

Allens Bow town

Pembroke

Hopkinton

Weare

Goffstown

Bedford

AmherstMerrimack

Litchfield

New

Boston

Lynde

borough

Mt.

Vernon

Milford

Wilton

Temple

Dunbarton

Richmound Fitzwilliam

Winchester

Hinsdale

Chesterfield

West

moreland Keene

Swanzey

Troy Jaffrey

Marl Dublin

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 75ppb
Technical 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 presumptive 8-hour ozone nonattainment area boundaries. 

While the intent of designating areas as nonattainment 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 rather than by factors which determine air quality, but they are 

attractive for nonattainment area boundaries because they are predefined political boundaries that 

represent urban proximity. Application of CBSAs/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 direct pollutants outside of the metropolitan area 

boundaries, the use of CBSAs/CSAs to derive nonattainment area boundaries can result in a 

designation that is too small on the upwind side 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 Transportation and the state’s Regional Planning 

Commissions have expressed concerns about needing to expand their programs at significant 

cost while only producing minimal 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 required 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 Transportation has advised us that the vast majority of the towns to 

be added to fill out the full county presumptive boundary are extremely rural and represent only 

a tiny fraction of the emissions of the previously defined 8-hour nonattainment area. 

 In the interest of forming 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 maximize 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 recommendation 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”) emission 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 emissions, 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 classified 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 proposed nonattainment area boundaries, we expect 

negligible additional benefit towards improved air quality in the region if these towns were to be 
Technical Attachment Page B-9 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

 

included within the nonattainment area. Further, 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 Hampshire recommended nonattainment area. 

The power plant in that town is already maximally controlled for oxides of nitrogen (“NOx”) 

through the use of selective catalytic reduction on both of its boilers (as part of the NOx Budget 

Rule in an approved State Implementation Plan (“SIP”) revision) and has electrostatic 

precipitators (“ESPs”) to control particle emissions. 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 the designated area. 

In New Hampshire, local pollution controls are important to prevent air quality 

degradation, however the 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 Emission Vehicle program for automobiles has been 

unprecedented in the air quality benefits they provided and there is room to take these programs 

further. It should be clearly noted that regardless of boundary designations, all portions of New 

Hampshire will continue to operate under Ozone Transport Region requirements, Ozone 

Transport Commission emission control strategies, state-wide permitting and offset 

requirements, state-wide Onboard Diagnostic requirements for mobile sources, and state-wide 

Stage 1 requirements. In addition, all of Hillsborough, Merrimack, Rockingham, and Strafford 

Counties will continue to have reformulated 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 within 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 ozone 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 designated for eastern Massachusetts. Thus, eastern 

Massachusetts, Rhode Island and southern portions of New Hampshire would be subject to Clean 

Air Act control requirements commensurate with their uniform classification. 

New Hampshire is strongly committed to working with other states within the Ozone 

Transport Region to address air quality on a regional basis. The Ozone Transport Commission 

member states are engaged in an ongoing regional attainment planning process for the 2008 

ozone standard. That process includes coordinated development of emissions inventories, joint 

1

 Ozone non-attainment areas are classified based on the level of severity of their ozone problem. The Clean Air Act 

requires certain emission control measures based on classifications. Southeastern New Hampshire, Eastern MA and 

Rhode Island are “moderate” non-attainment areas under the 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 strategies 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 further consult with each other, and with Region 1 

EPA staff, to identify any additional 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 regulatory process. Thus, state jurisdictional issues support 

single-state SIPs, unless there is a good rationale for a multi-state area. 

A single multi-state SIP would be administratively more complex for 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 Hampshire only areas and a separate multi-state 

SIP for Southeastern New Hampshire. Under present 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 and 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

Derry Hampstead

San

down Dan

Ville Kings

ton

East

Kings

ton

Kens

ington

Hamp

 ton

 Falls

Exeter

Strat

Brent ham

Fremont Wood

Epping Newmarket

Newfields Green

 land

Newing

ton

Durham

MadburyDover

Rollingsford

Sommersworth

Rochester

Barrington

Milton

Farmington

Strafford

Nottingham Lee

Northwood

Deerfield

Raymond

Candia

Auburn

Chester

London

Derry

Manchester

Hookset

Concord

Allens Bow town

Pembroke

Hopkinton

Weare

Goffstown

Bedford

AmherstMerrimack

Litchfield

New

Boston

Lynde

borough

Mt.

Vernon

Milford

Wilton

Temple

Dunbarton

Richmound Fitzwilliam

Winchester

Hinsdale

Chesterfield

West

moreland Keene

Swanzey

Troy Jaffrey

Marl Dublin

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.gsm
Technical Attachment Page B-12 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

FIGURE B4. Map of New Hampshire 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 Domain

(Tons per 144 km2) 

Area enclosed by white dots is the area 

recommended by New Hampshire as the 

Southeast New Hampshire Nonattainment 

Area. 

Relative geographic emission density estimates are 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 Portion of the CBA that are 

Not Included in the Recommended 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 

emissions 
Technical Attachment Page B-15 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

TABLE B3. Towns in the New Hampshire Portion of the CBA that are 

Not Included in the Recommended 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 emissions 
Technical Attachment Page B-16 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

TABLE B3. Towns in the New Hampshire Portion of the CBA that are 

Not Included in the Recommended 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 emissions 
Technical 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 

emissions 
Technical 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 Hampshire 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, towns 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 nature of most of the towns and because of their 

very low emission densities. Further, the counties at the northern edge of the CSA presumptive 

norm (Belknap and Merrimack) lie on the downwind edge 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 their 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 Massachusetts 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 nonattainment. The National Oceanic and Atmospheric 

Administration (NOAA)’s Air Resources Laboratory HYSPLIT (HYbrid Single-Particle 

Lagrangian Integrated Trajectory) is a computer model used to create and map trajectories. The 

model uses gridded meteorological data. For more information about HYSPLIT please refer to 

the following document: Description of the HYSPLIT 4 Modeling System by Draxler and Hess 

(http://www.arl.noaa.gov/documents/reports/arl-224.pdf). 

These trajectory plots are a composite of all episodes during 2006-2008 and use a colorcoding scheme that uses red to show low level trajectories that are most likely to pick up local 

emissions, yellow shows trajectories with some potential to pick up local emissions, and green 

and blue with are at altitudes too high to pick 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 was 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 airsheds and the lack of influence the New 

Hampshire nonattainment areas have on southeastern Massachusetts and Rhode Island during 

ozone events (and vice versa), it would be inappropriate 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 analyses and SIP efforts. 

Figure B6 shows that trajectories generally do not cross New Hampshire and those that 

do cross at low elevation, do so across the southeast corner of the state – well within the 

proposed nonattainment area. All areas within the proposed New Hampshire nonattainment area 

demonstrate some Boston influence, but there is a greater influence from the Northeast Urban 

Corridor. It is interesting to note that there is very little influence, 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 State 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 south, 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 Hampshire 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 for 8-Hour Exceedance Days for 

Southeastern New Hampshire 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

-85 -80 -75 -70

-85 -80 -75 -70

35

40

45

-85 -80 -75 -70

-85 -80 -75 -70

35

40

45
Technical Attachment Page B-21 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

FIGURE B7. Back Trajectories for 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 for 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

-85 -80 -75 -70

-85 -80 -75 -70

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 for 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

45
Technical 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 2000
Technical 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 Acadia NP) (2004-2008) 

Graphics provided by MEDEP 
Technical Attachment Page B-26 

Rationale for Proposed 8-hour Ozone Nonattainment Area Boundaries March 12, 2009

 

2. Presidential Range NH Nonattainment 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. The Presidential Range is a cluster of mountains in Coos 

County that stand higher than just 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 snow to these mountains nearly every month of 

the year. Winds have been measured at well over 200 miles per hour at the summit of Mt. 

Washington. So unique is this area that a science observatory was built to better understand it. 

From the summit, you can see into Vermont, Maine, Massachusetts, and Quebec Canada. With 

all the grand views of forests and mountains, there 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 Presidential 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 possible 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 typical 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 pattern and are nearly flat 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 mountain 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 found 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 Ozone Cycle at Ground 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 Ozone 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 throughout 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 above is cut off from the ground level below, its 

location is important to determining areas that potentially maintain ozone concentrations above 

the NAAQS for 8-hours or more. 

Conceptually, the setup is complicated and a conclusion can not be reached by just 

looking at a single snapshot of measurements where an instantaneous maximum is measured. As 

the thermal inversion rises and falls in elevation, 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 elevations above the peak is about 3 times more 

gradual. Because of this and the daily wagging 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 typically 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 terrain by lifting the airflow to get over the 

terrain and to split the airflow around the terrain if a route exists that offers less resistance to 

lifting it further. Both the lift and wrap mechanisms usually result in faster wind speeds. As is 

commonly accounted for in air pollution dispersion 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 factors including wind speed. The higher the wind 

speed, the more the lifting. For this reason, aircraft measurements and atmospheric soundings 

away from mountain areas will often 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 found 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 Transport Area, is the fact that the mountain ridge averages 

between 4500 and 5200 feet in elevation. Air pollution plumes approaching the range will lift up 

the mountain ridge to this point and then be able to wrap around the peaks. Because of this, 

maximum ozone for this region may be at a lower elevation rather than at the summit of Mt. 

Washington on most days of the year. The airmass is also pulled downward on the leeward side 

of the ridge. 

There are very little data collected specifically for Mt. Washington and the Presidential 

Range, thus one needs to be cautious in drawing conclusions on the full applicability of 

thresholds derived from limited datasets. Single snapshot observations only reflect on the 

conditions of the moment while critical transport 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, trapping relatively clean air below it. The peak 

of the transport layer sets up just above the inversion at about 3500 feet. As the day’s warming 

progresses, the inversion lifts in elevation and levels-out allowing some ozone from the transport 

layer above to begin spilling down to the ground. As this occurs, the transport layer lifts along 

with the point of maximum ozone 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. However, later in the day, that level lifts to 

between 4774 feet and 5676 feet in elevation (nearly identical with 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), maximum sustained ozone levels occur close to 

the 4774 foot in elevation mark on the mountain during this event. 

While each event differs and these two snapshots provide only limited data, they fit the 

NHDES model. It would of course be more helpful to have more extensive data with enhanced 

interim elevation and temporal data, but it is almost immaterial as to what specific elevation 

threshold is applied for nonattainment designation. Whether it should be higher or lower is less 

important than the designation of a reasonable representative area as nonattainment that has an 

actual monitor to track its progress. Other 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 Mountain 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 Nonattainment Area Discussion 

The Monadnock Highland region in Southwestern New Hampshire is another unique 

region with elevated measured ozone 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 northeast mountain range helps to channel the transport 

flow northeastward toward the Southeast New Hampshire nonattainment area discussed above. 

At 2288 feet in elevation, Pack Monadnock Mountain 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 overnight, transporting air pollution at relatively high 

velocities from along the urban 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 pollution transport could be better researched and 

understood. 

Several similarly sized mountains lie very nearby to the north and south. These 

mountains are included in the nonattainment designation 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 being 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 despite the growing distance between the transport 

corridor and the terrain’s location. While more high 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 exceedances are not expected there. Historic data 

collected at a former monitoring site on the summit of Mt. Sunapee in Sullivan County supports 

this determination. 

Elevation cut-offs for this region are conceptually 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 appropriate to capture the transport plume. As 

described before, ozone concentrations below the transport layer drop off rapidly, so there can be 

a sharp decline in ozone as elevation 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 transport from above. However, the Monadnock 

region is sparsely populated and devoid of major air pollution sources, thus is heavily dominated 

by the transport layer down-mixing effect. As stated before, the transport layer in the Northeast 

usually sets up between 2500 and 3500 feet and rises with terrain. Since 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 feet2 from the monitor station at 2288 feet from 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 designated 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