ATTACHMENT A Technical Support Document

for Redesignation of the Boston-Manchester-Portsmouth (SE), NH 8-Hour Ozone (1997 Standard) Nonattainment Area

## Technical Support Document for 

# Redesignation of the Boston-Manchester-Portsmouth (SE), NH 8-Hour Ozone (1997 Standard) Nonattainment Area

September 2010

~ NEW

HAMPSHIRE DEPARTMENT OF 

# Environmental ° = Services Air Resources DivisionTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page i Table of Contents 1 . INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. . . . . .. . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . .1 2 . NATURE OF OZONEAIRQUALITY PROBLEM IN THE NORTHEAST. . . .. .. . . . . . . .. . . . . . . . . . . . . .2 2 .1 OZONE PRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. . . .. .. . . .. .. .. . . .. . . . . .. . . . . .. . . . . .. .. .. .. .. .. . . . . . . . . . . . . .2 2 .2 AIR POLLUTIONTRANSPORT MECHANISMS. . . .. .. .. .. .. .. . . .. . . . . . . . . . . . . . . . . .. .. .. . . .. .. . . . . . . . . . . . . .2 2 .2.1 High-Elevation Transport . . . . .. . . . . .. . . . . .. .. .. .. .. .. .. .. . . .. .. .. .. .. . . . . .. . . . . . . . . . . . . . . . . .. .. . . .. .. .. . . . . . . . . . . . . .5 2.2.1 .1 Aircraft Measurements . . . . . . .. . . . . .. .. . . .. .. . . .. . . . . .. . . . . .. .. .. . . . . . . . ., . . . . .. . . . . . . . . . . . . . . . . . .. .. .. . . . . . . .5 2.2.1 .2 Mt . Washington, New Hampshire .. . . . . .. . . . . .. . . . . .. . . . . . . . . . . . . . . . . . .. . . .. .. . . . . .. . . . . . . . . . .. . . .. .. .7 2 .2.1 .3 Pack Monadnock Mountain - Miller State Park, New Hampshire.. . . . . . . . .. .. . . .. .. . 9 2.2.2 Mid-Elevation Transport .. . . .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. .. . . .. .. . . .. .. .. .. .. . . . . . . . .. .. .9 2 .2.3 Low-Elevation Transport. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. . . .. .. . . . . .. . . .. .. . . .. .. .. . . .. .. . . .. .. .. .. .. . . . . . . . .. .10 2 .2.3.1 Sea Breeze. . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. . . . . .. . . . . .. . . .. .. . . . . .. .. . . .. .. .. .. .. .. .. .. . . . . . . . .. .10 2.2.3.2 Offshore Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. . . . . .. . . . . .. . . .. .. . . . . .. . . . . .. .. . . .. .. . . . . .. . . . .. .. .. .11 2 .3 THE DEVELOPMENT OF AN OZONE EPISODE. .. .. .. .. . . .. .. .. .. .. . . . . . . . . . . . . . . . . .. . . . . .. .. . . .. .. . . . .12 2.4 NOxvs. VOCCONTROL STRATEGIES EFFECTIVENESS .. . . . . . . . . . . . . . . . . . . .. .. .. . . .. . . . .. .. .. .14 3 . ATTAINMENT MODELING. . . . . . . . . . . .. . . .. .. . . .. .. . . .. .. . . .. .. .. .. .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . .. .. .15 3.1 MODELING METHODOLOGY. . .. .. . . .. .. . . .. .. . . .. .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . .. . . . . . . . .. .15 3.1 .1 Identification of Models and Domain Used . . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . .. .. . . . . . . . .. .15 3.1 .2 Emissions Processing Methodology . .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. . . . . . . . .. .17 3.1 .3 Meteorology Processing Methodology . . . .. . . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. . . . . . . . .. . 21 3.1 .4 Model Testing. . . . . . . . . . . .. . . . . .. .. .. .. .. .. .. . . . . .. . . . . .. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. . . . . . . . .. . 23 3.1 .5 Establishing Estimates of Future Design Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . .. . 25 3.2 CMAQANDCALGRIDMODELING RESULTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. . . . . 25 3.3 EPA's CAIR MODELING .. . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . 28TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page ii List of Figures Figure 2-1 Major Transport Regimes in the Northeast . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. . . .. . . . .. . . .. .. . . .. .. . . .. .. .. . . . . . .3 Figure 2-2 Typical Day/Night Ozone Cycle at Ground Level and Aloft . .. . . .. .. .. .. . . . . . . . . . . . . . . . . . . .. . . . . .4 Figure 2-3 Number of 8-Hour Ozone Events Exceeding 85 ppb. . . . . . . . . . . . . .. . . .. .. . . .. . . . . . . . . . . . . . . . . . . .. .. .. .4 Figure 2-4 How

Upper-Level Transport Works. . . . . . . . . : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. . . . . .. . . . . . . . . . . .. .. . . .5 Figure 2-5 Observed Vertical Ozone Profile Measured Above Poughkeepsie, NY . . .. .. . . .. .. . . .. .. . . .6 Figure 2-6 Aircraft Ozone Observations in the Northeast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. .. .. .. .. . . .. .. . . .7 Figure 2-7 Comparison ofAverage and Hourly Summer Ozone Concentrations.. . . . . .. .. . . .. .. . . . . .. . . . 8 Figure 2-8 Computer Model Illustration of the Low-Level Jet in the Northeast . . . . . . . . . . . . . . . . . . . . . . . . . .9 Figure 2-9 How

the Sea Breeze Works. . . . . . . . . . . . . . . .. .. .. .. . . .. .. . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Figure 2-10 Offshore Ozone Measurements fromthe Scotia Prince . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Figure 2-11 Bermuda High Synoptic Scale Transport .. . . .. .. .. .. .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Figure 3-1 Map ofthe CMAQ/CALGRID Modeling Domain . . . .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Figure 3-2 Map ofthe RPONational Domain. . . . . . . . . . .. . . . . .. . . .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Figure 3-3 QA/QCPlot of Surface Source COEmissions . . . . . .. . . .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Figure 3-4 QA/QCPlot of Surface Source VOCEmissions. . . .. . . . . .. . . . . .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Figure 3-5 QA/QCPlot of Point Source NOx Emissions. . . . . .. .. . . . . .. . . .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Figure 3-6 QA/QCPlot of Point Source S02 Emissions. . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 Figure 3-7 QA/QCPlot of Humidity Data. . .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 Figure 3-8 QA/QCPlot of Temperature Data. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Figure 3-9 QA/QCPlot of Rainfall Data .. . . .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Figure 3-10 Relative Bias between Maximum 8-Hour Ozone Concentrations Predicted 

### with CALGRID and Observed Values .. .. .. .............................. .... .. .. . . . . . . . . . . . . . . . . . . . . . . .. .. 24 Figure 3-11 Comparison of Modeled Maximum 8-Hour Ozone Concentrations . . . .. . . . . . . . . . . . . . . . . .. .. 24 Figure 3-12 CMAQSIP-Quality Modeling Results for 2009 OTB/OTW vs. 2002 Design Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. .. . . .. . . . . .. . . . . . . . . . . . . . . . . . . .. . . .. .. .. . . . . . . . . .. . . . . .. .. . . .. . .27 Figure 3-13 Plot of 2009 Estimated Design Values for the OTC2009 OTB/OTW Strategy. .. .. .. 27 Figure 3-14 Plot of Differences in Predicted Maximum 8-Hour Ozone Concentrations between 2002 Base Case and the OTC2009 OTB/OTW Strategy . .. . . .. . . . . .. .. .. .. .. . . .. .. 28 List of Tables Table 2-1 Night and Daytime Patterns of Ozone at Mt . Washington. . . . . . . . . . . . . . . . . . . . .. . . .. .. . . .. .. . . . . . . . .8 Table 3-1 Modeling Emissions Inventory: State-by-State Anthropogenic NOx . . . . . . . . . .. . . . . .. . . . . . .18 Table 3-2 CMAQMaximumModeling Statistics for 2002 Base and 2009 OTB/OTW . . . . . . . . . . . 25 Table 3-3 CALGRID MaximumModeling Statistics for 2002 Base, 2009 OTB/OTW,

and 2009 Sensitivity Runs. .. .. . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . 26 Table 3-4 Modeling Summary for New Hampshire Monitors . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . 26 Table 3-5 CAIR Modeling Results for New Hampshire for 8-hour Ozone (ppb) . . . . . . . . . . . . . . . . . . . . . 29TSDfor Redesignationofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 1



### 1. INTRODUCTION This document is provided in support of New Hampshire's request to EPA to redesignate the Boston-Manchester-Portsmouth (SE), NH nonattainment area (hereinafter referred to as the Southeast NewHampshire Nonattainment Area) to attainment status. On June 15, 2004, EPA officially classified this portion of New Hampshire as a moderate nonattainment area for the 1997 8-hour ozone Ambient Air Quality Standard (NAAQS) of 0.08 parts per million (ppm) (Federal Register, 69 FR 223857) . For several years since this classification was made, the Southeast New Hampshire Nonattainment Area has been monitoring attainment for the 8-hour ozone standard under EPA's Clean Data Policy.* This nonattainment area is therefore eligible for redesignation to attainment in accordance with the provisions of the Clean Air Act (CAA) . The information presented in this report is presented in two parts. The following section provides a conceptual description of the formation and transport of ozone in the Northeast. This information is useful in setting the context for New Hampshire's ozone redesignation request. Section 3 discusses a photochemical air quality modeling assessment that was undertaken in 2007 by New Hampshire and other Ozone Transport Region states. This modeling effort was performed in support ofstates' attainment demonstrations and for other SIP planning purposes, and is therefore not a specific component of this redesignation request. Nevertheless, it is presented here because it supports the conclusion that the improvement in New Hampshire's air quality is due to permanent, enforceable emissions control measures and is not simply an anomaly (due to cooler weather conditions, for example) .

* Using monitoring data for the period 2002-2007, EPA determined that the Southeast New Hampshire 8-hour Ozone Nonattainment Area (moderate) had reached attainment of the 8-hour ozone NAAQS. Afinal rule published on March 18, 2008 (73 FR 14387), effective on that date, suspended the requirements for this area to submit an attainment demonstration, a reasonable further progress plan, contingency measures, and other State Implementation Plan elements related to attainment of the 8-hour ozone NAAQS . This determination is consistent with EPA's Clean Data Policy, which exempts the state fromcertain SIP requirements if the area has three consecutive years of air quality data showing it meets the NAAQS, for as long as the area continues to attain the standard.TSDfor Redesignation of the Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 2

2 . NATURE OF OZONE AIRQUALITY PROBLEM INTHE NORTHEAST In order to form an effective ozone reduction plan for the State of New Hampshire, an understanding of ozone formation, source areas, wind patterns, and transport is necessary. The formation and transport of ground level ozone is a complex phenomenon affected by several variables. 2.1 Ozone Production Ozone is formed in the atmosphere when NOx combines with VOCs in the presence of sunlight. Consequently, solar energy, mixing conditions, and relative NOx and VOCconcentrations within an air mass are paramount to ozone formation. Typically, high pressure systems cause an air mass to flow downward, a phenomenon which increases ground level ozone concentrations in at least four ways: 1) the sinking motion of the air mass under high pressures stabilizes the air mass, reducing cloud formation and resulting in an increase in solar energy, thus increasing photochemical activity; 2) the sinking motion tends to keep locally produced precursor emissions nearer to the surface, thus limiting upward movement and dilution of the air mass; 3) ozone and its precursors, present at higher elevations (500 to 1500 meters) as a result of transport, are pushed down toward the ground; and 4) the sinking air raises the ground level pressure, generating more heat at ground level . The result is a greater supply of ozone and precursors at or near ground level, more reaction energy in the formof heat and sunlight, and relatively limited dilution in the air mass. Additionally, the clockwise airflowpattern around a high pressure systemtransports pollutants northward and then eastward fromthe industrial Midwest or along the Northeast Urban Corridor to New England. These meteorological conditions are typical when New

Hampshire monitors elevated levels of ground level ozone. 2.2 Air Pollution Transport Mechanisms The predominant transport patterns in the Northeast were observed and documented in a study conducted by the North American Research Strategy for Tropospheric Ozone - Northeast (NARSTO/NE) entitled "Initial Results on Transport and Mixing Based on NARSTO-Northeast Data," and dated January 28, 1997. This study identified three basic flow regimes: synoptic, channeled, and near surface (Figure 2-1) .

0 The Synopticflow

is the pattern ofairflow at higher elevations (above 2600 feet) . Synoptic flows are unaffected by large-scale frictional ground-level objects such as mountains, valleys, and lakes. Channeled

flows occur at lower elevations (650to 2600 feet) where synoptic flow patterns are interrupted by large objects such as mountains, hills, and valleys but are not affected by lower, smaller objects such as trees and buildings. Low-level

jets occur nocturnally along the eastern edge of the Appalachians. Although they somewhat resemble channeled flow, low-leveljets are compact, relatively high-speed airflows that occurjust above ground level . The speed offlow is made possible bythe compression ofconverging airflows and the frictionless surface caused by the nocturnal thermal inversion, which thejet rides on. Near-surfaceflows (below650feet) are affected by nearly all surface frictional objects, including trees and buildings.TSDfor Redesignation of the Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 3

Synoptic flows are generally from west to east, transporting pollution fromthe Midwest to the Northeast, while channeled flows generally followthe Appalachian Mountains fromsouthwest to northeast, transporting pollution from theNortheast urban corridor toward northern New England. Figure 2-1 - Major Transport Regimes in the Northeast

Synoptic (higl}level)

10 Channeled (mid-levet)

- Low-Level Jets (nocturnal)

Adapted from NARSTO 2000and Research conducted bv the Un'wersitv of Marviand Long-range (synoptic scale) transport occurs from west to east across the Appalachian Mountains. Regional scale transport in channeled flows also occurs fromwest to east through gaps in the Appalachian Mountains and in nocturnal low level jets fromsouthwest to northeast over the Northeast Corridor . Daytime sea breezes can affect local coastal areas by bringing in air pollution originally transported near the surface across water parallel to the coast (e.g ., along the Maine coastline) . Figure fromNARSTO, 2000, citing Blumenthal et al ., 1997. Absent transport, ground-level ozone concentrations increase during sunlight hours as a result of photochemical production and decrease substantially at night when ozone removal exceeds production (this is also known as diurnal variation or fluctuations within the daily cycle) . However, in areas such as New

Hampshire, which are downwind of large urban regions, ozone concentrations often rise through the evening and/or early morning hours and peak between 6:00 p.m . and 6 :00 a.m . due to transport fromupwind sources. At higher elevations, concentrations of ozone and ozone precursors may remain high at night, since there is minimal downward mixing of the atmospheric transport layers at night. During daylight hours when solar energy heats the ground, the resulting warmair near the ground begins to rise. Rising air creates an unstable atmospheric situation resulting in the upward and downward mixing of air masses (including ozone transport layers) . Thus, ground level ozone concentrations typically rise for several hours immediately after sunrise (Figure 2-2) .TSDfor Redesignation of the Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 4 Figure 2-2 - 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) . NHDES investigated weather conditions that lead to poor air days in the state. Generally, the majority of the ozone transported into the state comes fromthe Northeast corridor (Washington, DC, Baltimore, Philadelphia, New York, and Boston regions) (see Figure 2-3) . On certain days, the Boston area provides the greatest amount of ozone along the immediate New Hampshire seacoast . The non-New

England portion of the corridor provides the majority of the ozone for the remainder of New Hampshire. Air pollution contributions fromthe Midwest are significant and on some days provide the vast majority of pollution reaching New Hampshire. New

Hampshire has its worst air pollution days when low-elevation winds come from the cities to our southwest (Northeast Corridor) and mid-elevation winds come fromthe Midwest. The smoggiest days occur when there is a slow

airflowfromthe Midwest. Figure 2-3 - Number of 8-Hour Ozone Events Exceeding 85 ppb and Corresponding Wind Direction (1995-2002)

45.0- -73.0 -72.0 -71 .0

~ : - Monitor Meets the 8-Hour Ozone Standard for Health. " - Monitor Does NOT Meetthe 8-Hour, Ozone Standard )r Health

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42.0 Wind directions at the time unhealthy ozone levels were measured in New

Hampshire between 1995 and 2002: There is an overwhelming trend of winds coming into the statefromthe southwest, with the exception of the seacoast area which also suffers froma sea breeze that brings pollution fromthe Boston metro area to coastline communities. (Numbers indicate the number of unhealthy days.) Source: NHDES

-73.0 -72.0 -71 .0 LongitudeTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 5

2.2.1 High-Elevation Transport Pollution transport should not be thought ofonly as a horizontal phenomenon. Pollutants can move upwards in the air and then travel downward in sinking air currents after being transported over great distances at elevations above 2,500 feet (Figure 2-4) . Figure 2-4- How

Upper-Level Transport Works Air pollutants get picked up and carried by the upper level winds . ® Pollutants can mix down the same way they came up

Pollution Sources

2.2.1 .1 Aircraft Measurements Measurements several thousand feet above the ground may record much higher ozone overnight than that measured at ground level . For example, ozone aloft concentrations above Poughkeepsie, NY and New Haven, CT approached levels of 120 ppb or greater onthe night ofJuly 14 (Zhang &Rao, 1999) . Figure 2-5 displays the aircraft measurements above Poughkeepsie, NY around 4a.m . EST. Aircraft measurements by the NARSTO-NE during the July 1995 ozone episode also demonstrate the existence of significant transport into and within the region, contributing to exceedances of the ozone standard in Maine (Blumenthal et al ., 1997) . Several "spiral" flights a few thousand feet above Poughkeepsie, NY, Gettysburg, PA, and Shenandoah, VA, recorded ozone levels of 100 ppb or greater in the early morning (4 AM) on two days. One aircraft actually recorded an ozone concentration well above 120 ppb at an elevation of approximately 2600 feet above Poughkeepsie on July 14, 1995, when ground level ozone measured about 30 ppb. Another flight during the early morning of July 14, 1995, fromVirginia to Maine recorded ozone levels in the range of 70 to 100 ppbat an elevation of 1600 feet throughout the Northeast corridor. These elevated ozone concentrations measured in the early morning at high elevations suggest that the ozone and its precursors originated during the active times of the previous day (or days) and traveled up and away fromthe source locations. Spiral flights in the afternoon over the same threeTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 6

cities, measured uniformozone levels from ground level to 2600 feet, showing that the air had become well mixed during the day and had thus brought transported ozone aloft down to the surface. Asecond flight along the length of the entire corridor showed that ozone levels at 1600 feet had risen well above 120 ppb in the Baltimore-Washington and New York metropolitan areas. Being well above the ground, this ozone was presumably destined to be transported further downwind overnight. Figure 2-5 - Observed Vertical Ozone Profile Measured Above Poughkeepsie, NY at about 4 AM

EST on July 14,1995 1600

1200

800 w Q 400 8-hour standard

. 0 20 40 60 80 100 120 140



### fJzone (Ppb) Note. Thefipm

inchuies aver&aI hueat $5 pPb for comparingalattmeasurem=ts with the S-h= ozow

hiAAQS (observedozone data fromZhang &Rao* 1999). On behalf of the Mid-Atlantic Northeast Visibility Union (MANE-VU), additional aircraft measurements were taken to track a regional haze event in the Northeast in August of 2002 (Figure 2-6) . The aircraft measured light scattering from particles as well as ozone. Like the earlier NARSTO-NE measurements, the MANE-VU study found high levels of ozone aloft which were blowing toward the northeastern states. In most cases, the ozone measured aloft exceeded measurements collected at ground level, indicating that the ground-level ozone was not all created locally. It is also noteworthy that the preliminary measurements collected above Baltimore, MD were already rich in ozone, suggesting that a large amount of the pollutant was blowing into the region fromupwind areas. It should be noted that ozone aloft is depleted much more slowly than ozone at ground level, which comes into contact with various surfaces and obstructions. This means that, once ozone is present at high elevations, it becomes more likely to travel long distances downwind without breaking down.TSDfor Redesignationof the Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 7 

# 1) Figure 2-6 - Aircraft Ozone Observations in the Northeast 

### Ozone Concentrations in ppb fromMANEVU Flight August 14, 2002

CnriC b( MaMUW .EStt6 MEDEP .BAG Ozone measurements from aircraft observations compared to ground-based measurements. Source: MEDEP

d00 mAGL47 PMRANGE OF W IND DIRECPIONS WINDPROFILER SITES Other aircraft measurements reinforce these observations. Clarke and Ching (1983) during the summer of 1979 recorded aloft ozone concentrations of about 90 ppb transported overnight from eastern Ohio and entering into the Northeast Corridor over a region stretching fromthe lower Hudson River Valley north of New York City down across eastern Pennsylvania and into Maryland just west of Baltimore. The measurements also observed NOx aloft during the overnight hours that could contribute to additional ozone formation in the Ozone Transport Region as it mixed down to the surface in the morning. The presence of high levels of ozone and precursors aloft across a large spatial region gives rise to the concept of an "ozone reservoir" existing at nightjust above the nocturnal inversion boundary. The pollutants in this reservoir are not subject to destruction at the surface and can be transported long distances in the wind flows created by the synoptic scale weather patterns conducive to ozone formation and transport. 2.2.1 .2 Mt. Washington, New Hampshire Mt . Washington in PinkhamNotch, New Hampshire, is tall enough (elev. 6288 feet) to reach well up into the upper ozone transport layers with minimal obstruction by other terrain features. Ozone levels recorded at the summit mirror NARSTO-NE findings, showing consistently elevated levels of ozone with little diurnal 'variation during most episodes - clear evidence of long range transport. As further evidence of long range transport, Camp Dodge (elev. 2400 feet), located at the base of Mt . Washington, usually records lower ozone concentrations than those seen contemporaneously at the summit .TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainmentArea Page 8

Both monitors have no major NOx sources within 75 miles and no major sources upwind in the direction of prevailing winds for approximately 150 miles. Transport frommore distant upwind sources is the primary source of ozone monitored at these sites. Since the summit of Mt . Washington is high enough to be exposed to high elevation transport (synoptic flows), downward mixing is not a factor in creating the peak ozone values it experiences. In fact, transport time from upwind source areas appears to be the single largest factor in determining the time at which the maximumozone level occurs at the summit . Daily maximumozone levels at Camp Dodge are dependent on inversion breakup caused by downward mixing fromupper transport elevations, and thus are typically recorded during the afternoon hours. On the contrary, maximum ozone levels at the summit occur most often during the overnight hours, when no ozone is produced locally. The percent of daily one-hour ozone maxima which occur during the daylight heating hours and during the overnight hours on the summit of Mt . Washington and at Camp Dodge are listed in Table 2-1 .

Table 2-1 - Night and Daytime Patterns of Ozone at Mt . Washington Mt. Washington Percent of Hourly Maxima Percent of Hourly Maxima Monitor Location During Daylight Hours During Overnight Hours (9 a.m . to 5 p.m

.) (6 p.m . to 8 a.m

.) Summit 18% 82% Base (Camp Dodge) 80% 20% Note: Daylight heating hours are hours of the day when solar energy drives vertical mixing of transport layers The difference in ozone concentrations at the summit and base can also be seen when looking at plots of maximumozone levels at each site. The graph in Figure 2-7 is typical of summertime ozone at Mount Washington. Figure 2-7 - Comparison of Average and Hourly Summer Ozone Concentrations .

at the Base and Summit of Mt. Washington Monitor Data for Mt. Washington, NH (Summit and Base) for 1996

-IN . Wuhingtrm (ppb) -tn~vblo a -M

Washiryem +"-as+Icvbl ----C-PDAV puray. (ovb) Comparison of mountaintop

(elev. 6288 ft) ozone with mountain base (elev

. 2000± ft) hourly ozone: Often the ozone is higher in concentration at the summit dueto pollution transportfromdistant sources. Many times the ozone at the base is driven by downward mixing fromthe upper transport layers during the day: Source: NHDES (Data: AMC)TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainmentArea Page 9

2.2.1 .3 Pack Monadnock Mountain -Miller State Park, New Hampshire A similar mountaintop air pollution monitor was established in 2002 in Miller State Park at, the summit of Pack Monadnock Mountain in Peterborough, NH (elevation 2288 feet) . The mountain is located in the south-central portion of New Hampshire in an ideal location to track air pollution transport into the state. The monitor is only a short distance fromthe heavily visited and hiked Mt . Monadnock. The early findings fromthis monitor are similar to those of Mt . Washington in that when an ozone or PM2 .5 episode begins to build into the region, it is detected at higher elevations first where the stronger transport currents are located. The new Miller State Park monitor has been useful in tracking air pollution events entering the populated Merrimack Valley area (Nashua, Manchester, and Concord) . 2.2.2 Mid-Elevation Transport Mid-elevation transport is usually dominated by the effects of large topographical features, such as mountains, which redirect airflows and cause a channeling of the wind. In the Northeast, channeled airflows may occur on either side (east or west) of the Appalachian Mountain range and also between the subranges that comprise the Appalachian chain. Unhealthy air quality can be present on one side of a mountain while just a fewmiles away on the other side, the air quality is substantially cleaner. This mid-layer is generally heavily influenced by the airshed layers above and below that mix polluted, or clean air into it. Pollutants can also be injected directly into this layer by some of the very tall smoke stacks (around 1000 feet tall) commonly found in the Midwest. Mid-level transport is often affected by a phenomenon known as the low-leveljet (LLJ) . It is called "low-level" because it is lower relative to the well known Jet Stream, a high elevation airflowthat drives the movement of weather systems around the world. Recent advances in remote sensing instruments (i .e., radar profilers) have allowed the LLJ phenomena to be observed. During the overnight and early morning hours, a LLJ frequently formsjust east of the Appalachian Mountains. Once formed, the LLJ is a strong west to southwest wind flowthat develops at low altitudes just above the nocturnal boundary layer. These winds typically reach speeds of 40-50 mph and are located at approximately 1,000-2,000 feet above the ground. Figure 2-8 depicts the LLJ observed during an August 2002 ozone event. Figure 2-8 - Computer Model Illustration of the Low-LevelJet in the Northeast 9AOmb WkM(es/s) 0B/12/02 032

_. 960 mb Yind(m/s) OB/12/02 C42 The low leveljet (shown in red, orange, and yellow) normally sets up along the , eastern side of the Appalachian Mountains and flows from southwest to northeast. Source: University of MarylandTSDfor Redesignation of the Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 10

2.2.3 Low-Elevation Transport A number of one-day and multi-day transport mechanisms- have been observed along the northeastern coastal plain. Blumenthal et al ., (1997) described several transport mechanisms, including near-surface flows that act within a thousand feet of the ground and are capable of transporting ozone and its precursors along the urban corridor as far as 160miles during the daylight hours. Near surface flows are especially useful in explaining the transport and presence of the elevated ozone concentrations monitored aboard the MS Scotia Prince in the Gulf of Maine (Portland, Maine ferry to Yarmouth, Nova Scotia, Canada) . Other transport mechanisms, including boundary layer synoptic (upper level) flows and channeled (mid-level) nighttime flows are capable of transporting ozone and precursors as far as 600 kmin a 24-hour period and are responsible for longer range transport fromthe south and west (Blumenthal et al ., 1997) . Residence time (or the time a pollutant stays in the air) analysis (Wishinski and Poirot, 1995) is a technique whereby the spatial characteristics of long-termtrajectory climatology can be analyzed by keeping track of the residence time (in hours) for selected back trajectories. This was done for several New

England sites during the summers from 1989 through 1995. Back trajectories from Port Clyde, Maine showthat for days on which Maine exceeds the ozone national ambient air quality standard (NAAQS), the wind is invariably fromthe south and west. These trajectories also show that the Northeastern Corridor is principally responsible for nonattainment in New Hampshire and Maine, with areas to the south and west of the Corridor having lesser, but still significant impacts. 2.2.3.1 Sea Breeze The Atlantic Ocean produces changes in wind directions and wind speeds along the shoreline, especially in New

England. While most inland areas experience regional wind patterns with only small variations due to terrain features and other frictional effects; coastal locations are far more variable. Sea breezes develop during the heating of the day when the ground heats up, warming the onshore air mass. This air mass then rises, causing cooler air near the surface to flowin fromover the ocean (Figure 2-9) . Sea breezes are actually a subset of the NARSTO-NE near-surface flows that are driven by temperature differences between land and water, which also affects changes in mixing heights. Daytime sea breezes flowfromthe relatively cool waters of the ocean towards the coast, and diminish over a short distance due to mixing with regional wind patterns persisting further inland and with diurnal mixing. Figure 2-9 - How

the Sea Breeze Works

Sun Heats the Earth SEABREEZE

LowPressure High Pressure Hot Air Rises (- Cool Onshore Breeze The sea breeze is developed through the temperature differences between the ground and the water. As the sun warms the ground, it begins a cycle by causing the air to rise. This air cools as it moves over thewater, sinks and then blows back towards theshore.TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page I 1

Onshore breezes are the primary reason that high ozone concentrations occur along the New Hampshire coast, while substantially lower concentrations are recorded just a fewmiles farther inland. The afternoon sea breeze shifts the wind direction to the south and east, bringing ozone from over the ocean onshore. As documented by the NHDES and the Maine Department of Environmental Protection, these sea breezes develop suddenly and can drive ozone concentrations sharply upward. The offshore ozone blown in by sea breezes appears to originate fromprecursors emitted in the metropolitan Boston area. 2.2.3.2 Offshore Transport Offshore, just beyond the strongest coastal sea breezes, larger scale wind fields develop that may differ in direction from the inland regional wind pattern. Lower mixing heights, differing temperature gradients, and lower frictional effects cause this differential . Offthe New Hampshire and Maine coasts (Figure 2-10), it is not uncommon for the over-water wind field to come fromthe south, while the inland regional wind field is more fromthe southwest. This pattern allows transport of the ozone plume fromthe metropolitan Boston area to travel over the Gulf of Maine to the New Hampshire coast, even when inland wind observations suggest this should not be happening. The North Atlantic Regional Experiment (NARE) measured surface level ozone and precursor concentrations at both coastal and offshore locations in the Gulf of Maine during August and September of 1993 (Ray et al ., 1996) . The researchers observed ozone plumes in the Gulf of Maine ranging in width from55 to 93 kmand extending the entire length of the New Hampshire and Maine coastlines. The timing of the observed peak ozone concentrations, the presence of elevated ozone levels only along the coast, and lowNOx concentrations all suggest that urban plumes transported over the Gulf of Maine are brought inland by sea breezes to the coastal regions, and that regional control strategies will be needed to reduce ozone concentrations along the coast. Recent photochemical modeling utilizing the California Photochemical Grid Model (CALGRID) model (Earth Tech, 2006) serves to confirmthe presence of an urban plume moving northeastward over the Gulf ofMaine, where it is then carried by afternoon sea breezes to the coast. Along the New

Hampshire and Maine coastlines, ozone levels have not been observed to exceed the NAAQS unless there is at least a moderate westerly to southwesterly wind at the surface. Typical ozone episodes are characterized by the concentration of transported ozone and precursors in the Gulf, of Maine during the morning and mid-day hours, with afternoon sea breezes bringing high concentrations of ozone ashore in the afternoon and evening. Monitored ozone concentration data and measured wind vectors show ozone exceedances in Maine and New Hampshire to be the direct result of a large mass of both ozone and unreacted precursors being transported into the Gulf of Maine fromareas to the south and west . Here, precursors react and are then transported ashore, a conclusion supported by data collected by monitors on both the MS Scotia Prince (see Figure 2-10) in the Gulf of Maine and on land-based monitors that show significantly decreased levels of ozone at inland sites (AIRS) . Ozone air quality monitors within Maine and NewHampshire also confirm the presence and significance of transported ozone and its precursors. The ozone monitoring network in Maine extends along the coast fromthe photochemical assessment monitoring station (PAMS) located in Kittery, Maine (operated by the State of New Hampshire Department of Environmental Services) to as far north as Bar Harbor. Maximum ozone concentrations along the Maine coast almost always followa sequential pattern, with the most southerly sites monitoring daily ozone maximums in theTSDfor Redesignation of the Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 12

mid to late afternoon, and downwind sites experiencing maximum readings later in the day and into the evening hours

. Figure 2-10- Offshore Ozone Measurements from the Scotia Prince

The Scotia Prince ferry is a scheduled passenger and vehicle ferry that runs between Portland, Maine, and Yarmouth, Nova Scotia, Canada. This ferry has an ozone monitor that tracks air pollution levels during its journey between ports. The ferry often identifies distinct air pollution areas or plumes offshore over the Gulf of Maine. Source: MEDEP 2 .3 The Development of an Ozone Episode Since the late 1970s, a wealth of information has been collected concerning the regional nature of the Northeast's ground-level ozone air quality problem . Scientific studies have uncovered a rich complexity in the interaction of meteorology and topography with ozone formation and transport. The evolution of severe ozone episodes in the eastern U .S. often begins with the passage of a large high pressure area fromthe Midwest to the middle or southern Atlantic states, where it assimilates into and becomes an extension of the Atlantic (Bermuda) high pressure system (see example in Figure 2-11) . During its passage east, the air mass accumulates air pollutants emitted by large coalfired power plants and other sources located outside the region. These expansive weather systems favor the formation of ozone by creating a vast area ofclear skies and high temperatures . These two prerequisites for abundant ozone formation- are further compounded by a circulation pattern favorable for pollution transport over large distances. In the worst cases, the high pressure systems stall over the eastern United States for days, creating ozone episodes of strong intensity and long duration.TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainmentArea Page 13 Figure 2-11 - Bermuda High Synoptic Scale Transport 

### '[ Plymouth State Weather Center .'X Surface Winds (mfs) WXP flrldysis for l8Z 4JUL 99 Sea L-vel Pressure ti mb} __ 11fXP ardysis for 13Z 4JUL <J9

100010021074100610ClB 1310 1012 17U 1016 10181=0=1021 1026 LO= 1001 .7 Ht 1025.3 With the knowledge of the different transport scales into and within the region, a conceptual picture of bad ozone days emerges. After sunset, the ground cools faster than the air above it, creating a nocturnal temperature inversion. This stable boundary layer extends fromthe ground to only a few hundred meters in altitude. Above this layer, a nocturnal low leveljet can form

with higher velocity winds relative to the surrounding air. It forms fromthe fairly abrupt removal of frictional forces induced by the ground that would otherwise slow the wind. Absent this friction, winds at this height are free to accelerate, forming the nocturnal lowlevel jet. Ozone above the stable nocturnal inversion layer is likewise cut offfromthe ground, and thus it is not subject to removal on surfaces or chemical destruction fromlow level emissions. Ozone in high concentrations can be entrained in the nocturnal lowlevel jet and transported several hundred kilometers downwind overnight. The next morning as the sun heats the Earth's surface, the nocturnal boundary layer begins to break up, and the ozone transported overnight mixes down to the surface where concentrations rise rapidly, partly frommixing and partly fromozone generated locally. By the afternoon, abundant sunshine combined with warmtemperatures promotes additional photochemical production of ozone from local emissions. As a result, ozone concentrations reach their maximum levels through the combined effects of local and transported pollution. Ozone moving over water is, like ozone aloft, isolated fromdestructive forces. When ozone gets transported into coastal regions by bay, lake, and sea breezes arising fromafternoon temperature contrasts between the land and water, it can arrive highly concentrated.TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainmentArea Page 14

During severe ozone episodes associated with high pressure systems, these multiple transport features are embedded within a large ozone reservoir arriving fromsource regions to the south and west of the OTR

. Thus a severe ozone episode can contain elements of long range air pollution transport fromoutside the Northeast, regional scale transport within the OTRfromchanneled flows in nocturnal low

leveljets, and local transport along coastal shores due to bay, lake, and sea breezes. The recognition that ground-level ozone in the eastern United States is a regional problemrequiring a regional solution marks one of the greatest advances in air quality management in the United States. During the 1990s, air quality planners began developing and implementing coordinated regional and local control strategies for NOx and VOC emissions that went beyond the previous emphasis on urban-only measures. These measures have resulted in significant improvements in air quality across the OTR . Measured NOx emissions and ambient concentrations have dropped between 1997 and 2005, and the frequency and magnitude of ozone exceedances have declined within the OTR

. 2.4 NOxvs. VOCControl Strategies Effectiveness The effectiveness of a NOx-focused or VOC-focused control strategy to reduce ozone is not constant by location; rather, it is a changing chemical characteristic of an air parcel affecting a particular location. As a result, the effectiveness of a NOx or VOC-focused control strategy can vary within an air parcel as it dynamically evolves over time with transport, dispersion, and photochemical aging (NARSTO, 2000) . On a regional basis, OTAG (Ozone Transport Assessment Group), Clean Air Interstate Rule (CAIR), and other modeling studies have consistently shown that NOx reductions have the greatest impact on regional ozone concentrations, while VOCreductions have more local impacts. This is largely a result of significant naturally occurring VOC emissions (especially isoprene) in large forested regions of the eastern U .S. Real-world results from regional NOx reductions at power plants (i .e., the NOx SIP Call) are now indicating that significant ozone reductions are occurring on a regional basis as a result of regional NOx strategies. As a general rule, VOCreductions may be effective at reducing urban-scale ozone pollution in lieu of or in combination with local NOx reductions, while regional NOx controls are most effective at reducing regional ozone. While a general approach can be outlined in evaluating the potential effectiveness of NOx and VOC-focused control strategies, the optimal strategy for a specific location will depend on the particular circumstances of that location. Exceptions to a VOC-only strategy for an urban area can occur when the urban area has large natural VOCemissions, ozone is transported fromupwind, or there is recirculation of aged local pollution (e.g., sea breeze effect) . Furthermore, because the conditions causing individual ozone episodes canvary, a given urban area may change in sensitivity between a NOx and VOC-focused strategy depending on a particular episode's conditions (NARSTO, 2000) . Therefore, the appropriate combination of NOx and VOC controls at the local level depends on local circumstances with the realization that a single approach focusing on NOx- or VOC-only controls is not necessarily effective for all episode types. It is clear, however, that regional NOx reductions provide regional ozone reductions, and this will influence ozone levels being transported into local urban areas. Thus, the most effective controls for New Hampshire are NOx based regional controls with local NOx and VOCbased controls.TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 15

3 . ATTAINMENT MODELING Air quality modeling to demonstrate New Hampshire's attainment of the 8-hour ozone standard uses a regional photochemical modeling platformcapable ofestimating the distribution and magnitude of air pollutant concentrations within a reasonable range of error. Base-year and projected future year emissions inventories are used as input into the air quality model . Emission reduction strategies are applied as needed. . The results of the air quality modeling are applied in a relative sense by calculating the percent ratio of the future year modeling results (which reflect the emissions reduction strategies) to the base-year modeling results. This ratio is then applied to the observed base year design value to obtain a corresponding estimated future year design value. Known as the relative reduction factor (RRF) technique, this method follows EPA guidance; for further description see Section 3.1 .5. 3 .1 Modeling Methodology For the 8-hour ozone analyses, New Hampshire relied on the regional photochemical air quality modeling that was conducted by the New York State Department of Environmental Conservation (NYSDEC) and other modeling centers on the Community Multiscale Air Quality (CMAQ modeling platform

. In addition, New

Hampshire and other states used the California Photochemical Grid Model (CALGRID) screening-level modeling platform to evaluate additional emissions control scenarios and performsensitivity runs. The general methodologies that were used in running both of these modeling platforms for the evaluation of 8-hour ozone are described in the sections below . 3.1 .1 Identification of Models and Domain Used The SIP-quality modeling that was done for the 8-hour ozone analyses was performed on the CMAQ modeling platform . Additional modeling was done on the CALGRID screening-level platform . The CMAQand CALGRID platforms were run on the same modeling domain using a common set of model inputs . Specifically, the OTC ozone modeling domain was set up on a Lambert Conic Conformal projection and covers the eastern United States and parts of Canada. The southwest corner of the domain was set at 264 km, -888 km and the northeast corner was set to 2328 km, 1176 km

. A 12-kmgrid cell resolution was used with 172 grid cells in the east-west direction and 172 grid cells in the north-south direction. For the vertical grid definition, 22 layers were used in the CMAQ simulations. For CALGRID, processing programs were used to reformat the boundary conditions, meteorology, and emissions; these mapped the 22 layers used for CMAQto a total of nine vertical layers for the CALGRIDmodeling. The OTC CMAQ/CALGRID modeling domain is shown in Figure 3-l . The OTC 12-kmozone modeling domain is a subset of the 36-km national domain which was used by the Regional Planning Organizations (RPOs) for regional haze analysis. The 36-km

national grid is shown in Figure 3-2. For the CMAQ modeling, boundary conditions were derived fromGEOS-Chem(Goddard Earth Observing System) global atmospheric simulations by running CMAQon the 36-kmcontinental grid. For the CALGRID platform, initial conditions, side boundary conditions, and top layer concentrations were derived fromthe CMAQ boundary conditions files by means of a processing program . This programmapped the 22 vertical layers used in the CMAQsimulations to the nine layers used with CALGRID . It produced the necessary side boundary file and top layer concentration file for each modeled episode day. It also produced an initial conditions file for each episode day processed; these files could be retained so that the CALGRID user could begin aTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 16

simulation on any desired episode day . It should be noted that the default option of using 2002 boundary conditions was employed for all of the base case and future year CMAQand CALGRID simulations. Further details regarding the technical options used in the CMAQ simulations are available in NYSDEC's. technical support document TSD-ld, 8hr Ozone Modeling using the SMOKE/CMAQ system, February 1, 2006 . Additional information on the CALGRID modeling platform can be found in NHDES' Modeling Protocol for the OTCCALGRIDScreening-Level Modeling Platform for the Evaluation ofOzone, May 23, 2007.

Figure 3-1 - Map of the CMAQ/CALGRID Modeling DomainTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainmentArea Page 17 Figure 3-2- Map of the RPONational Domain 102

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3.1 .2 Emissions Processing Methodology The base year and future year emissions inventories that were used in the regional photochemical air quality modeling for the 8-hour ozone analyses were prepared by the RPOs and their contractors. These inventories were processed for input into the CMAQ air quality model using the Sparse Matrix Operator Kernel Emissions (SMOKE) model . The SMOKE modeling was performed by NYSDEC and other modeling centers, including NESCAUM and the Virginia Department of Environmental Quality (VADEQ) . Emissions processing was done for the 2002 Base Year and 2009 On The Books/On The Way (OTB/OTW) modeling scenario. The OTB/OTW scenario accounted for those emissions control measures that were either on the books or reasonably anticipated to occur. The 2002 Base Year and 2009 OTB/OTW emissions are summarized by state in Table 3-1 . Further details on the SMOKE processing that was done in support of the 8-hour ozone analyses are provided in NYSDEC's technical support document TSD-lc, Emission Processing for the Revised 2002 OTC Regional and Urban 12 km Base Case Simulations, September 19, 2006.TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 18 Table 3-1 - Modeling Emissions Inventory: State-by-State Anthropogenic NOx

State 2002

Baseline (tons/day) 2009

OTW/OTB (tons/day) Percent Reduction

from2002 Baseline Connecticut 232.16 149.41 35.64% Delaware 101 .20 91 .53 9.56% D .C. 29.13 18.30 37 .18% Maine 170.64 109.75 35.68% Maryland 548.58 312.77 42.99% Massachusetts 483.18 312.68 35.29% New Hampshire 131 .02 84.22 35.72% New Jersey 625.68 397 .32 36.50% New York 1199.32 831 .85 30.64% Pennsylvania 1614.24 1020.05 36.81% Rhode Island 89.78 57.60 35.84% Vermont 54.44 34.62 36.41% Virginia 975.74 673.39 30.99% Alabama 732.86 492.41 32.81% Arkansas 519.30 268.22 48.35% Georgia 1153.90 874.75 24.19% Kentucky 1043.23 641 .29 38.53% Illinois 1797.25 1067.17 40.62% Indiana 1329.23 926.42 30.30% Michigan 902.07 812.06 9.98% Mississippi 356 .48 271 .04 23.97% Missouri 733.00 438.76 40.14% North Carolina 1141 .21 744.30 34.78% Ohio 1379.28 848.93 38.45% South Carolina 660.35 481 .35 27.11% Tennessee 1045.52 710.79 32.02% West Virginia 902.95 432.65 52.08% I Wisconsin ~ 667.49 ~ 447.50 ~ 32.96% For the CALGRIDmodeling effort, the pre-merged SMOKE emissions files were obtained fromthe modeling centers and re-formatted for input into EMSPROC, the emissions pre-processor for the CALGRID modeling system . EMSPROC allows the CALGRID user to adjust emissions temporally, geographically, and by emissions category for control strategy analysis. The pre-merged SMOKE files that were obtained fromthe modeling centers were broken down into the biogenic, point, area, non-road, and on-road emissions categories. These files by component were then converted for use with EMSPROC, thus giving CALGRID users the flexibility to analyze a wide variety ofemissions control strategies. QA/QCplots were generated during the re-formatting of the emissions data to ensure that an accurate modeling inventory was generated for the CALGRID platform . Example emissions QA/QCplots are shown in Figures 3-3 through 3-6 .TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainment Area, Page 19 Figure 3-3 - QA/QCPlot of Surface Source COEmissions

CO Bmlsriom

: {4ou per Sq Mile) a the CLLM 2 .45 Nadding Domain UPD11$D 2002 Ban Haur 18 on July 29, 2002 SON

40 44N 4W 38N 8m 94N 92N 99W 9041 87F 84W 81W w 75R 72W 69W 0.22 0 .2 0.18 0.10 0.14 0.12 0.1 0.0e 3.07 0.0s 0 .05 : . 0 .04 0 .03 0 .02 0 .01 0 Figure 3-4 - QA/QCPlot of Surface Source VOCEmissions 8urfae WC Emissions (faoA per 3 q L{ile ) on the CALCRiD 2

.4b Modeliq Domain UPD118DTA02 Baee

soM 48N 48N 44H 42N 40N 98N 869 94u 32N Haar 18 on July 29, 2002

gas DOW 87F 84W 81W 98W 75i 42Y 69W 0 .4 0 .2 0 .15 0 .1 0 .09 0 .08 0 .07 0 .00 0 .05 0 .04 0 .03 0 .025 0 .02 1 ').015 0 .01 0,008 a.o03 0 .002 0TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 20 Figure 3-5- QA/QCPlot of Point Source NOx Emissions Polnt Souee HOx gmLafons N ns' on the CILQBID 2

.45 Hadelia` Domain UPDL'fBD OM

Due Cue H4ur 14 on July 19, 2002

B3W BOW B7R BdY all 7mP 751 7ZW on 18 14 12 10 8 8 4 2 1 0 .8 ~ 0 .8 0 .4 0 .2 ;a 0.18 ~ 0 .18 0 .14 0.12 0 .1 0 Figure 3-6- QA/QCPlot of Point Source S02 Emissions Point Sauce 902 BmissLoea ( tons) on the CLI .CRD3 2

.45 MAW

Domain UPDI'lED 2002 One Cax Hour 19 on July 19, 2002

4 2 1 0 .9 'l.8 J .7 0.8 0.5 OA 0.3 a.z 9 .1 a BaW MW am MW all 7e® 7sia zBW amTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 21

3.1 .3 Meteorology Processing Methodology The meteorological modeling that was done for the CMAQ platform was performed by the University of Maryland (UMD) in conjunction with staff at NYSDEC . UMD used the Penn State/National Center for Atmospheric Research (NCAR) 5th Generation Mesoscale Model (MM5) Version 3.6 to generate year 2002 meteorological inputs. The MM5 modeling domain was set up on a two-way nested grid that followed the RPO national domain. The 36-kmcoarse mesh grid consisted of 149 grid cells in the east-west direction and 129 grid cells in the north-south direction. The 12-kmfine mesh grid consisted of 175 grid cells in both the east-west and north-south directions. Atotal of 29 vertical layers were used in the MM5 simulations. An extensive analysis was undertaken to compare the MM5 predictions with observations for the period of May through September 2002. An assessment was made to compare MM5 outputs with surface observations from the National Weather Service and CASTNet, wind-profiler measurements from the Cooperative Agency Profilers (CAP) network, satellite cloud image data fromthe UMDDepartment of Atmospheric and Oceanic Science, and precipitation data fromthe Earth Observing Laboratory at NCAR . Technical details regarding the 2002 MM5 simulations and the assessment to compare them with observations are described in NYSDEC's Technical Support Document TSD-la, Meteorological Modeling Using Penn State/NCAR 5th Generation Mesoscale Model (MM5), February 1, 2006. For the CALGRID modeling platform, a processing programwas used to interpolate the MM5 outputs to the CALGRID modeling grid and map them to CALGRID's vertical layer structure. QA/QCplots were generated during the processing to ensure the accuracy of the interpolated data. Figures 3-7 through 3-9 showexample QA/QCplots fromthe re-formatting of the meteorological data for usewith the CALGRIDmodeling platform . Figure 3-7 - QA/QCPlot of Humidity Data

August 6, 2002 Hour 12 Humidity Layer 1 CALGRID2

.45 Modeling Domain

c 0 z U U J

400 600 800 1000 1200 1400 1600 1800 2000 2200 Humidity (ppm) soooo 28000 26000 24000 22000 20000 18000 16000 14000 12000 10000 8000 000 4000 2000 0 NHDES 7/18/O6

LCCEasting (km)TSD for Redesignation of the Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 22

Figure 3-8- QA/QCPlot of Temperature Data

August 6, 2002 Hour 18 Temperature Layer 1 CALGRID2

.45Modeling Domain

400 600 800 1000 1200 1400 1600 1800 2000 2200 LCCEasting (km) Figure 3-9 - QA/QCPlot of Rainfall Data

August 12, 2002 Hour 17

Rain CALGRID 2

.45Modeling Domain Temp (K) ' 310 306 306 302 300

1 304

298 296 294 292 290 2865 284 282 280 0 NHDES 7/23106

Rain (inches)

1 .5 1 .4 1 .3 1 .2 1 .1 1 .0 09 0 .8 0.7 0 .6 ~0 .5 i

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LCC Easting (km)TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 23

3.1 .4 Model Testing NYSDEC did an extensive quantitative analysis to evaluate predicted concentrations of ozone, as well as other gaseous and aerosol pollutants, against 2002 observations. This work is described in their technical support document TSD-le, CMAQModel Performance and Assessment, 8-Hr OTC Ozone Modeling, February 23, 2006: The authors used a wide variety of statistical metrics to assess the correlation of model predictions and observations, including:

.

.

. Correlation coefficient Normalized mean error Root mean square error Fractional error Mean absolute gross error Mean normalized gross error Mean bias Mean normalized bias Mean fractionalized bias Normalized mean bias NYSDEC also evaluated the diurnal patterns for those pollutant species that are reported hourly. With respect to 8-hour ozone, NYSDEC's model performance evaluation showed that the CMAQ model performed reasonably and that it adequately reproduced the pattern of observations, especially in urban areas and along the northeast corridor. Their analysis showed some model under-prediction during the mid-August period. Their analysis also showed that the diurnal predictions for ozone tracked fairly well with observations. Detailed tables and figures illustrating the CMAQmodeling platform's performance evaluation are shown in NYSDEC's technical support document TSD-le. NHDES performed a qualitative and quantitative assessment of the CALGRID screening platform's ability to reproduce observed ozone concentrations. To assess its performance, the CALGRID screening platformwas run for the 2002 Base Case for the July 31 to August 16, 2002 modeling episode. Predicted maximum8-hour ozone concentrations at monitor locations were compared against observations for 2002. Figure 3-10 shows the relative bias between maximum 8-hour ozone observations and predicted CALGRID 8-hour ozone concentrations for the 2002 Base Case for the episode fromJuly 30 through August 12. Figure 3-11 shows a plot of predicted 2002 Base Case ozone concentrations against 2002 observations for an example episode day. Although the CALGRID model has a tendency to over-predict, especially in the urban core areas of northern Virginia, Maryland, southeastern Pennsylvania, New York City and Boston, it does a reasonable job of reproducing the pattern ofthe 2002 maximum ozone observations.TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 24

Figure 3-10 - Relative Bias between Maximum 8-Hour Ozone Concentrations Predicted with CALGRIDand Observed Values 

## Relative Bias (CALGRID minus Observed)

Based on Model Data for July 30- August 12, 2002 2002 Base Case Emissions versus Observed Data

Green Circles are where CALGRID Underpredicts Red Triangles are where CALGRID Overpredicts

NHDES 11/21/06 Figure 3-11 - Comparison of Modeled Maximum 8-Hour Ozone Concentrations for August 13, 2002 Maamnmn8-Hour 0loone Conce~aobons Maximum 8-Hour Ozone Concentrations Gbanvatioms - 2002 Base Case CALGRID- 2002 Base Case OTC M odebmg Doanain - August 13, 2002 OTCModeling Domain - August 13, 2002

Ozone Concentrations (PPB)

-- A V; 0 to 40 40 to 50 50 to 60 60 to 70 70 to 80 80 to 90 90 to 100 100 to 150 NHDES 11/27/O6TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 25

3.1 .5 Establishing Estimates of Future Design Values In accordance with EPA guidance, future design values for regional modeling were estimated using the relative reduction factor (RRF) technique. This technique uses a statistically valid number of before-and-after modeling results for each monitoring location to calculate the RRF. Briefly, RRFs were calculated fromthe average strategy model predicted concentration divided by the average base model predicted concentration for the same grid cell location. This calculation was performed for the full ozone season (for CMAQ . A shorter, but representative period of time was used in some CALGRID modeling cases after proving to provide valid estimates based on comparisons to similar modeling for the full ozone period. In most cases, the RRF is less than 1 .0, indicating that the emission control strategy lowers the future design value. In order to relate model predictions to monitored values, the grid cells and actual monitor geographic locations must be paired. This was performed according to EPA guidance by using the maximum value of the block of the nearest 9 grid cells to each monitor location as it is overlaid on the modeling grid. The resulting RRF is then multiplied by the corresponding base 3-cycle (2000-2002, 2001-2003, 2002-2004) average design value for each monitor to calculate an estimated future year design value for comparison to the NAAQS. 

### 3.2 CMAQand CALGRID Modeling Results Statistical summaries of peak 8-hour ozone concentration for each CMAQand CALGRID model run are provided below in Tables 3-2 and 3-3. These results reflect the July 31 to August 16, 2002, modeling episode (the model was run for July 30 to August 16, but July 30 is considered to be a model warm-up day) . Included in the summary tables are peak modeled ozone concentrations for five New

Hampshire monitoring locations that routinely record elevated ozone levels (Keene, Manchester, Nashua, Portsmouth and Rye) and a more general statistic, "Grid Cell Hours" (Table 3-3), providing a dynamic domain-wide response to emission reductions. Model predicted ozone concentrations at the five New Hampshire locations are averages of a 9-grid cell area surrounding each of the monitor locations (note that these are the absolute model-predicted concentrations and not the RRF-processed estimated future year design values used to determine future attainment - these values can be found in Table 3-4 below) . In all, there are 29,584 grid cells in the modeling domain (172 x 172) . "Grid Cell Hours" is a count of the number of grid cells exceeding the indicated thresholds (80 ppb, 100 ppb, and 120 ppb) in a given hour. This value is presented in order to showthe depth of ozone exposure and how it improves under various emission reduction strategies. The maximum grid cell hour count possible is 710,016 for the full domain over a 24-hour day (172 x 172x 24), although due to nighttime hours and geographically distinct areas within the domain, maximumexpected Grid Cell Hour counts is about 400,000

. Table 3-2 - CMAQMaximum Modeling Statistics for2002 Base and 2009 OTB/OTW CMAQRun Peak 8-Hour Ozone Concentration (ppb) Keene Manchester Nashua Portsmouth Rye 2002 Base Case 85 79 87 133 133 2009 OTW/OTB 73 68 74 114 114TSDfor Redesignation of the Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 26

Table 3-3 - CALGRIDMaximum Modeling Statistics for 2002 Base, 2009 OTB/OTW, and 2009 Sensitivity Runs Peak 8-Hour Ozone Concentration (ppb) Grid Cell Hours CALGRID R

un Keene Manchester Nashua Portsmouth Rye >70ppb >85ppb >100ppb 2002 Base Case 89 100 102 130 130 86,751 30,576 8,266 2009 OTW/OTB 79 92 93 124 124 56,234 15,444 3,447 2009 NHZero-Out 77 85 95 119 119 55,686 15,307 3,441 2009 90%NOx Reduction 42 49 47 62 62 40 0 0 2009 90%

VOC Reduction 79 93 94 120 120 55,643 15,540 3,325 Note: Grid cell hours are based on the full modeling domain. Table 3-4 summarizes the modeling results for New Hampshire by listing current design values and 2009 modeled design values for all monitors in the state.

Table 3-4- Modeling Summary for New Hampshire Monitors 8-hour Ozone Design Values (ppb)

Current Predicted Design Value (DVF) AIRS ID Name Design Value (DVC) 2009

OTB/OTW CMA 2009

OTB/OTW CALGRID 330012004 Laconia 76.5 nc 66 330031002 Conway 67 nc 61 330050007 Keene 74.3 64 68 330090008 Haverhill 70.3 nc 64 330110020 Manchester 75.5 na 70 330111010 Nashua 86 74 80 330115001 Peterborough 84 73 73 330130007 Concord 74.7 nc 66 330150012 Rye 83.5 72 78 330150013 Brentwood 80 68 72 330150015 Portsmouth 68 59 63 330173002 Rochester 78.5 67 73 330190003 I Claremont 74.3 nc 67 Notes: 1 . "nc" indicates that a future design value was not calculated because of the limitation of the relative reduction factor (RRF) methodology. 2 . The Manchester monitor was not included in the CMAQresults; this is indicated by "na" in the table.TSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NHNonattainment Area Page 27

The figures belowshowthe geographical distribution of 8-hour ozone design values for the 2002 Base Case and 2009 OTB/OTW scenario for ozone monitor locations in the Ozone Transport Region. Figure 3-12 displays the CMAQ-predicted 2009 design values versus the actual 2002 design values. For comparison, Figure 3-13 shows CALGRID-predicted design values for the 2009 OTB/OTW

scenario. Figure 3-12 - CMAQSIP-Quality Modeling Results for 2009 OTB/OTW vs. 2002 Design Values OTRDomain



### 72 77 82 87 92 97 Figure 3-13 - Plot of 2009 Estimated Design Values for the OTC2009 OTB/OTW Strategy

EPISODES July 7 - 23, 2002 July 31 -August 16, 2002 DESIGN VALUES (Revised 2/23107) Average of 2000-2002, 2001-2003,2002-2004 RRFTHRESHOLDS 86 PPB, 70 PPB EMISSIONS BASE 2002 BaseTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattaimnent Area Page 28

Figure 3-14 shows the CALGRID-modeled differences (improvements) in the maximum8-hour ozone concentration between the 2009 OTB/OTW scenario and the 2002 base case. Figure 3-14 - Plot of Differences in Predicted Maximum 8-Hour Ozone Concentrations between 2002 Base Case and the OTC2009 OTB/OTW Strategy 17 16 15 14 13 12 11 10 9 80 70 60 50 40 30 20 10 00 10 20 30 40 50 60 70 80 90 100110120130140150160170 Ozone Concentrations I _1 40 30 25 20 15 Note: 10 Apositive 5 number

denotes a 3 decrease in 1 ozone conc. 'i--{ -1 -5 -10 -20 -30 NHDES 6/29/07 CALGRID 2

.45 Modeling Domain After completion of the model runs, NHDES discovered that the 2009 on-road emission estimates for New Hampshire that were inputs to the modeling had been understated (by about 10% for VOC and 15%for NOx) . To evaluate the uncertainty introduced by this situation, NHDES performed sensitivity modeling with CALGRID in which all New Hampshire on-road OTW/OTB NOx and VOC emission inputs were boosted by 25%for the July 31 to August 16, 2002, high ozone event. The results of this analysis showed that the adjusted inputs would have negligible effect on the modeled 8-hour design ozone values. 3.3 EPA's CAIR Modeling On May 12, 2005, EPA promulgated the Clean Air Interstate Rule (CAIR) . Under CAIR, 28 states across the eastern United States and the District of Columbia are expected to make reductions in NOx and S02 emissions. EPA performed technical analyses in support of CAIR, including air quality modeling to evaluate ambient levels of ozone and PM2,5 . The CAIR modeling is described in EPA's Technical Support Document for the Final Clean Air Interstate Rule, Air Quality Modeling, March 2005. The air quality modeling for ozone was performed with the Comprehensive Air Quality Model with Extensions (CAMx) version 3.10 on a modeling domain covering much of the eastern United States. Three summer 1995 meteorological episodes were used in the modeling. The analysis years and emissions scenarios that were assessed included: " 2001 Base Year . 2010 CAIRControls . 2015 BART Only " 2010Base Case . 2015 CAIRControls " 2015 Base Case 0 2015 CAIR + BARTTSDfor Redesignation ofthe Boston-Manchester-Portsmouth (SE), NH Nonattainment Area Page 29

The 2010 and 2015 Base Cases reflect expected economic growth and the anticipated benefits associated with existing emissions control programs. The CAMx model predictions were used in a relative manner. Weighted-average 1999-2003 design values were applied as the basis of the observed 8-hour ozone concentrations. Using this methodology, EPA estimated maximum8-hour ozone design values for each future-year scenario for each county in the modeling domain with an ozone monitor. Table 3-5 lists the maximum estimated future 8-hour design values for New Hampshire. These results showthat, even without the emissions benefits associated with CAIR, all New Hampshire counties were predicted to be in attainment for 8-hour ozone for the 2010and 2015 analysis years. Table 3-5 - CAIR Modeling Results for New Hampshire for 8-hour Ozone (ppb) 1999-2003 Average Estimated Maximum8-hour Future Design Value County Design Value 2010 Base 2010CAIR 2015 Base 2015 CAIR Belknap 78.0 68.5 68.2 65.8 65.0 Carroll 66.5 60.3 60.0 58.6 58.0 Cheshire 73.7 65.2 64.9 63.1 62.0 Hillsborough 85.0 76.7 76.6 74.1 73.9 Merrimack 73.0 64.8 64.6 62.3 61 .8 Rockingham 82.7 75.2 75.1 73.3 72.9 Strafford 77.3 69.2 69.1 66.8 66.5 Note: Data taken from

Appendix E ofEPA's Technical Support Documentfor the FinalCleanAir Interstate Rule, Air Quality Modeling, March 2005. References 1 . Blumenthal, D

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. Moore. Transport andmixing phenomena related to ozone exceedances in the northeast U .S . EPRI Report TR-109523, Electric Power Research Institute, Palo Alto, CA, 1997. 2. Clarke, J .F ., andJ .K.S. Ching. "Aircraft observations of regional transport of ozone in the northeastern United States." Atmos. Envt. 17, 1703-1712, 1983. 3. Earth Tech, Inc. Calgrid User Instructions. November 2006. 4. NARSTO

. AnAssessment ofTropospheric Ozone Pollution. NARSTO, July 2000 . 5. Ray, J ., R

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. and R . Poirot. Air Trajectory Residence Time Analysis Investigation of Ozone Transport Pathways: 1989-95 . 1995. 7. Zhang J. and S.T. Rao. "The role ofvertical mixing in the temporal evolution ofgroundlevel ozone concentrations." J. Applied Meteor. 38, 1674-1691, 1999.