4.3.4

4.3.4 Air Quality
Air quality impacts are likely to occur during construction for the proposed partial-build and build
alternatives as a result of the actions of disturbing soil, clearing timber, and paving. Concurrently, the
internal combustion engines in the construction equipment used for the project, such as excavators, dozers,
and dump trucks, would also contribute emissions of regulated air pollutants within the area of construction.
Emissions from these activities are estimated to produce localized impacts on air qualiry, especially far
particulate matter (dust). These impacts were estimated far each partial-build and build alternative using
emission rate calculations, emission rate models and dispersion modeling techniques.
Air quality impacts from construction activities are expected to be major and adverse for particulate matter
with aerodynamic diameters ofup to 10 microns (PMio) sulfur dioxide (SOz), moderate and adverse for
nitrogen oxides (NOX), minor and adverse for carbon monoxide (CO) and volatile organic compounds
(VOC), and negligible and adverse for benzene at various locations for each of the partial-build and build
alternatives. These activities may cause reductions in visibility and increased pollutant deposition that are
considered ruajar. The location of the highest impacts is likely to occur predominantly within the immediate
viciniry of the active construction area (approximately 1,000 ft [300 m]), dissipating rapidly with distance.
Consequently, as the active construction area would proceed over the length of the project for the 5-year and
15-year construction periods for the Partia]-Build Alternative to Bushnell and the Northern Shore Corridor,
respectively, so too would the location of the maximum air quality impacts of these pollutants. Generally,
the areas requiring the greatest volume of earthwork (i.e., highest intensity of construction activiry) were
found to have the highest impacts of these pollutants to air quality. Impacts to visibility would be major and
adverse at low elevations near the construction area, but are expected to decline rapidly with height. Impacts
to sulfur and nitrogen deposition would be minor and adverse for every partial-build and build alternative.
Once the roadway is open to traffic, the internal combustion engines in the vehicles traversing the road
would produce emissions of regulated air pollutants. Emissions of NOX, VOC and CO from motor vehicles
have the greatest potential to impact the local air qualiry. Using projected traffic volume information,
emission rate models, and air dispersion and deposition modeling techniques, the potential concentration
impacts from tail-pipe emissions are shown to be negligible for the partial-build and build alternatives.
Potential impacts of NOX and VOC on the total annual emissions in the Park are minor for the Northern
Shore Corridar (Primitive and Principal Park Roads) and negligible for all other alternatives. Potential
impacts of CO on the total annual emissions in the Park are minor far the Northern Shore Corridor for the
Principal Park Road, but negligible for all other alternatives. Potential effects of tail-pipe emissions on
visibiliry are estimated to be negligible once the road alternatives are in operation. Additional nitrogen and
sulfur deposition rates associated with tail-pipe emissions from traffic for tbe partial-build and build
alternatives were also evaluated within the GSMNP (specifically at Clingmans Dome) and are estimated to
be negligible.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-115
North Shore Road Final Environmental Impact Statement

4.3.4.1 Methodology for Assessing the Impacts of the Proposed Alternatives
Air qualiry concentration impacts are evaluated by pollutant type per the Clean Air Act (CAA) and NAAQS
that are used for measuring the quality of air on a regional scale, and are considered protective of human
health and the environment. The list of air pollutants is commonly referred to as the criteria air pollutants.
In addition to criteria pollutants, exhaust from internal combustion equipment includes various compounds
that are considered to be toxic. One of the most prevalent toxic compounds in vehicle exhaust is benzene.
Therefore, benzene emissions were also analyzed. Specifically, the pollutants evaluated are:
■ Nitrogen Dioxide (NOz)
■ Sulfur Dioxide (SOz)
■ Particulate Matter-10 micron (PMio) 2.5 micron (PMzs)
■ Total Suspended Particulate —100 micron (NC standard only)
■ Carbon Monoxide (CO)
■ Volatile Organic Compounds (VOC)
■ Benzene
Emission rates for each of these pollutants were developed far the construction activities and for the vehicle
traffic traversing the finished road based on published emission estimating techniques. The methods for
estimating these emissions are discussed in further detail below. The emission rates were subsequently used
as a basis for predicting air concentrations of these pollutants (except VOC) over the study area. Predictions
of air concentrations were made by executing an air dispersion model that takes into account not only the
emission rates of each of these pollutants, but also the local meteorology, topography, precipitation, and
spatial location in the Park. The presence of these pollutants in the air over a sustained period not only affect
human health but also park resources by causing reduced visibility and increased deposition rates of nitrogen
and sulfur compounds in the area. These secondary effects were also modeled far the study area, including
the Clingmans Dome area, which is especially sensitive to acid deposition phenomena.
4.3.4.1.1 Construction Emissions
Emission rates from the internal coinbustion engines and from fugitive dust-generating construction
activities were developed using USEPA's AP-42 Compilation of Air Pollutant Emission Factors, USEPA's
NONROAD2004 emission rate model for vehicle emissions, and other published e�nission estimating
techniques. Emissions rate estimates were developed for each of three phases of construction: clearing and
grubbing (tree removal); earthwork (cut and fill), and laying the roadbed (gravel and asphalt paving). An
approximate construction plan was developed for each phase based on productivity rates of the construction
equipment. Tl�e intensiry of construction during the cut and fill phase was estimated based on preliminary
earthwork cut and fill data (using functional designs) and the average equipment productiviry for various
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-116
North Shore Road Final Environmental Impact Statement

construction equipment (average excavating rate of 90 yd3 per hour [70 m3/hr]). Construction emissions
were developed and modeled for each roadway segment, taking into account the geographic location,
average elevation changes along the segment, and projected haul distances to and from the segment.
Emissions occurring within active construction areas were subsequently modeled using the USEPA and
NPS-approved CALPUFF modeling system. To define the construction emissions for the model, emissions
from both the intemal combustion engines and the fugitive dust-generating construction activities were
added together. The total emissions were assumed to occur within an active construction zone that covers
approximately 3000 m� (30 m x 100 m) during a 24-hour period. The CALPUFF modeling system compiles
this emission source information with a complex set of input data including meteorological data, elevation
data, average humidity factors, and a coardinate grid system of receptor points. Concentrations for each
regulated air pollutant are calculated by CALPiJFF over an array of receptors and for appropriate time-
averaging period as defined by the air quality standards. Maximum concentrations from each segment and
each build alternative were compiled and compared to the NAAQS concentration, Class I PSD increment
concentrations, and North Carolina Acceptable Ambient Levels (AAL). Secondary atmospheric chemical
reactions were also modeled evaluate the effects on visibility and quantify the potential nitrogen and sulfur
deposition effects. Deposition rates were developed and compared to the Deposition Analysis Thresbolds
(DAT) calculated per NPS guidance.
In addition, NPS completed a near field visible plume analysis using the USEPA VISCREEN model. This
model is mare appropriate for assessing impacts close to the source of emissions and can estimate the effects
from the primary pollutants of NOx, fugitive, PM�o, and, and PM2.5 emissions from the diesel construction
equipment. The VISCREEN model calculates the change in the color difference index (delta E) and the
contrast between the plume and the viewing background. Values of delta E and plume contrast are based on
the concentrations of fine pri�nary particulates (including soot), NOz, and the geometry of the observer,
target, plume, and the position of the sun. Plume contrast results from an increase or decrease in light
transmitted from the viewing background through the plume to the observer. The threshold values of a
detectable plume are a delta E greater than 2.0 ar a contrast value of greater than (+/-) 0.05. The analysis
followed NPS Federal Land Managers' Air Quality Related Values Work Group (FLAG) recommendations
and applied the visual range corresponding to natural conditions at GSMNP of ] 14 mi (183 km) to generate
the hourly estimates of delta E and plume contrast.
For the near-field visibility analysis using VISCREEN, two vistas far the Partial-Build Alternative to
Bushnell and the Northern Shore Corridor were analyzed. The first was a generalized close vista view of the
construction site from a trail 2 mi (3 km) away. The second generalized vista was from the distance from
Clingmans Dome to the construction site approximately 8 mi (13 km) away. The generalized construction
source site was characterized as a virtual point source in the VISCREEN model to replicate the area source
nature of the construction sites. VISCREEN was run in a generalized Level 2 mode. The meteorological
conditions analyzed were based on the USEPA SCREEN3 model's default 64 one-hour combinations of six
atmospheric stabilities and associated wind speeds. Stable atmospheric conditions occur usually during the
early morning hours from sunrise until 1 to 2 hours after sunrise, and possibly the hour before sunset and are
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-117
North Shore Road Final Environmental Impact Statement

characterized by low wind speeds. Neutral and unstable atmospheric conditions occur an hour or two after
sunrises until the hour before or just prior to sunset. Neutral and unstable conditions are representative a light
wind moderate to windy conditions and are associated with a well mixed atmosphere.
4.3.4.12 Roadway Vehicle Emissions
Air emission rates from future roadway vehicles were estimated using USEPA's MOBILE 6.2 emission
factor model. This model calculates emission rates for a wide selection of vehicle types primarily based on
their size and whether they are gasoline or diesel powered. Specific factors regarding vehicle maintenance,
average vehicle age, condition, and vehicle emission control system tampering rates were obtained from the
NCDENR. This model also accounts for projected improvements to fuel combustion efficiency and overall
vehicle performance expected to be realized by the time that construction is completed. The emission factor
data obtained from the MOBILE model were subsequently used with future projected vehicle traffic volumes
for each build alternative to develop the peak hourly emission rates over the roadway. Seasonal factors are
also taken into account in both the emission factor model and the projected volume of vehicle traffic.
Similar to the construction phase emissions, the effects of air dispersion on the peak predicted vehicle
emissions was modeled using the CALPLTFF modeling system. The CALPUFF model provides estimates of
the ambient concentrations of each regulated air pollutant over a grid of receptor locations in the study area
using actual meteorological data, topographical elevation data, and spatial location within the Park.
Additionally, the CALPUFF model was implemented to predict the secondary effects that emissions could
have on visibility and acid deposition rates of nitrogen and sulfur. Emissions were developed for each
roadway segment and defined in the CALPUFF model as "line" sources, taking into account the elevation
changes across the segment. The CALPLTFF modeling system calculated the maximum concentrations and
deposition rates within the study area and within sensitive areas in the Park (e.g., Clingmans Dome area).
The maximum concentrations predicted for each proposed alternative were identified and compared with the
NAAQS concentration, Class I PSD increment concentrations, and North Carolina AAL for each altemative.
The deposition rates of acid gases predicted by CALPUFF are evaluated with respect to the DAT.
Air quality impacts were assessed in terms of type, context, duration, and intensity.
Type
Type includes whether an impact is beneficial or adverse for a specified pollutant. Beneficial impacts are
changes that result in decreases in amounts of a pollutant while adverse impacts are changes that result in
increases in amounts of a pollutant. Beneficial visibility impacts would involve improved visibility, while
adverse impacts would deteriorate views.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-118
North Shore Road Final Environmental Impact Statement

Context/Duration
Air quality impacts are evaluated in terms of the potential far short-term effects to occur within the near-field
vicinity of the emission source, and, for those emissions that are estimated to persist over a sustained period,
the potential far long-term effects on the regional air quality around the emission source are also evaluated.
The short-term impacts are generally those which occur within a 1-hour, 24-hour, or 3-month time period.
The location of the maximum short-term impacts is usually governed by the emission source dimensions,
emission rate, and surrounding topography. The long-term regional impacts are typically evaluated over a
period of 1-year or 5-year period. The regional impacts incorporate the effects of atmospheric mixing,
transport, and secondary chemical reactions in the atmosphere. The location of the maximum impacts over
the long-term is generally a function of the prevailing wind direction for the region.
Intensity
Impact categories are used to assess potential airborne pollution impacts on: (1) human health (linked to the
amount of projected emissions and national air quality health-based standards); and (2) Park resources
(linked to current and projected air quality and resource impacts). The impact levels utilize ambient
concentration values that are loosely based on some of the emissions thresholds found in the PSD and
Conformity sections of the CAA, as applicable, as well as the rationale in setting the NAAQS. While these
emissions thresholds do not apply here in the same strict regulatory sense as in the CAA, they do reflect
potential levels of concern.
Existing conditions are particularly important in air qualiry impact and impairment determinations, because
of the potentially large degree of current irnpact caused by air pollution coming from outside the Park. In
many cases, the degree to which air pollution has currently affected Park resources will directly affect the
amount of additional emissions that can be added before "impairment" to these resources occurs. Sometimes
(as with visibility) a very clean current condition provides a higher likelihood that a small amount of added
air pollution emissions would produce a perceptible visual impact. In other cases (as with atmospheric
deposition), an already high amount of current deposition (relative to natural background deposition levels)
would also create a high likelihood that a small additional amount of emissions would cause resource
impacts.
Impact levels are characterized as"likely" when one ar more of the criteria in the "proposed action" category
are true. Current condition information is used as a modifier to adjust the impact upward or downward
taking into account the weight of evidence and management objectives.
No/Negligible
Negligible impacts may occur when current air quality conditions in the Park are characterized as follows:
■ SUM06 ozone < 8 ppm-hrs. far the 3-month summer season
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-119
North Shore Road Final Environmental Impact Statement

■ Deposition of wet N(NO3-N +NH4-N) is less than 1 kg/ha/yr, and wet SO4 is less than 3 kg/ha/yr.
Annual average visibiliry conditions (in units of deciview) are better than or equal to estimated natural
conditions.
And the air quality metrics from the proposed actions are characterized as follows:
■ Predicted emissions result in a decrease in emissions of pollutants for which the study area is designated
non-attainment.
■ Predicted emissions increases are less than 50 tons per year (TPY) (45 tonnes per year [tpy]) for
pollutants for which the study area is designated attainment.
■ Predicted concentrations of regulated air pollutants do not exceed the NAAQS or PSD increment
concentrations.
■ Predicted (i.e., modeled) visibiliry, nitrogen, and sulfur are below thresholds listed in NPS FLAG and
DAT guidance.
■ No perceptible visibiliry impacts are likely (no visible smoke, plume, or haze).
Minor
Air qualiry impacts that are minor can occur when the current air quality conditions in the Park are
characterized as:
■ SUM06 ozone between 8-15 ppm-hrs. for the 3-month summer season.
Deposition of wet N(NO3-N +NH4-N) is above 1 kg/ba/yr, and wet SO4 is above 3 lcg/ha/yr, and
insufficient evidence of deposition sensitive or nutrient sensitive ecosystems exists.
■ Annual average visibility conditions (in units of deciview) are more than one but less than or equal to
one and one-half times estimated natural conditions.
And the air quality metrics from the proposed actions are characterized as follows:
■ Predicted emissions increases are between 1 and 5 TPY (0.91 and4.5 tpy) for pollutants for which the
study area is designated non-attainment ar maintenance.
Predicted emissions increases are between 50 and 100 TPY (45 and 9l tpy) for pollutants for which the
study area is designated attainment.
■ Predicted concentrations of regulated air pollutants do not exceed the NAAQS or PSD increment
concentrat�ons.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-120
North Shore Road Final Environmental Impact Statement

■ Predicted (i.e., modeled) visibility, nitrogen, and sulfur are approaching (between 90-100 percent) of
thresholds listed in NPS FLAG and DAT guidance.
■ Perceptible visibiliry impacts occur, but are only visible from a small area of the Park, are of short
duration (less than one day) and visible to only a few Park visitors on the days that they occur.
Moderate
Air quality impacts that are moderate can occur when the current air quality conditions in the Park are
characterized as:
■ SUM06 ozone between 15-25 ppm-hrs. for the 3-month summer season.
■ Deposition of wet N(NO3-N +NH4-N) is above 1 kg/t�a/yr, and wet SO4 is above 3 kg/ha/yr, and
sensitive ecosystems are present in the Park that could likely be impacted in some way (change to
physical, chemical, or biological processes) from deposition.
Annual average visibility conditions (in units of deciview) are more than one and on�half but less than
ar equal to three times estimated natural conditions.
And the air quality metrics from the proposed actions are characterized as follows:
■ Predicted emissions increases are above 5 TPY (4.5 tpy) far pollutants for which the study area is
designated non-attainment ar maintenance.
■ Predicted emissions increases are between 100 and 250 TPY (91 and 227 ryp) for pollutants for which
the study area is designated attainment.
■ Predicted concentrations of regulated air pollutants do not exceed the NAAQS, but may exceed PSD
increment concentrations.
■ Predicted (i.e., modeled) visibility, nitrogen, and sulfur exceed thresholds listed in NPS FLAG and DAT
guidance, but NPS does not believe impacts will harm integrity of the resources.
■ Perceptible visibility impacts occur, and are visible from several areas of the Park, between one and
several days, and many Park visitors may observe them on the days that they occur.
Major
Air quality impacts that are major can occur when the current air quality conditions in the Park are
characterized as:
■ SUM06 ozone > 25 ppm-hrs. for the 3-month summer season.
■ Deposition impacts to Air Quality Related Values have been documented in the Park.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-121
North Shore Road Final Environmental Impact Statement

■ Visibility conditions are worsening (trending downward based on the Government Performance and
Results Act [GPRA] 10-year trends information) at the Park.
And the air quality metrics from the proposed actions are characterized as follows:
■ Predicted emissions increases are above conformiry deminimus levels for pollutants for which the study
area is designated non-attainment or maintenance.
■ Predicted emissions increases are above 250 TPY (227 tpy) for pollutants for which the study area is
designated attainment.
■ Predicted concentrations of regulated air pollutants may exceed both the NAAQS and PSD increment
concentrations.
■ Predicted (i.e., modeled) visibility, nitrogen, and sulfur exceed thresholds listed in NPS FLAG and DAT
guidance, and NPS believes impacts will harm integrity of the resources.
■ Perceptible visibility impacts occur, and are visible from many areas of the Park, many days over the
course of a year, ar are visible to a majariry of Park visitors on the days that they occur.
4.3.4.2 Summary of Impacts
The results of this analysis indicate that the impacts during the construction phase of the project for the
partial-build and build alternatives would be major for PM�o, and SOz, ��noderate for NOx, minor for CO and
VOC, and negligible for benzene during construction. Impacts to visibility would be major during
construction, but limited to elevations below 322 ft (100 m). Deposition of sulfur and nitrogen within the
region are estimated to be small in magnitude, but major for all partial-build and build alternatives during
construction due to the existing deposition rates. Air quality impacts are adverse, unless otherwise noted.
The maximum potential impacts from construction are temparary, short-term increases in ambient
concentrations that are confined to the active construction area. Long-range transport of pollutants is not
estimated to occur to an appreciable degree because the emissions are generated near ground level, whether
they originate from the internal combustion engines of the construction equipment or from the dust-
generating actions associated with clearing, excavation, grading or paving. Furthermore, the mountainous
terrain has a tendency to hinder the transport of air pollutants to areas beyond the construction area.
Results for the construction period from each alternative, therefore, are comparable. Although the
construction period varies between the alternatives (2 years for Laurel Branch, 5 years for the Partial-Build
Alternative to Bushnell, and l 5 years for the Northern Shore Corridor), the air quality thresholds used for
measuring tbe intensity of the air qualiry impacts are given in terms of concentrations for periods of 1 year or
less. The emissions from construction activities are not expected to aggregate in one particular area. Rather
they are estimated to remain localized around the active construction site, especially during cut and fill
phases of construction. As construction progresses over the length of the project, so too would the location
of the maximum air quality impacts. From a long-term and regional scale perspective, the emissions
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-122
North Shore Road Final Environmental Impact Statement

occurring as a result of construction will contribute to the influx of emissions originating from sources
located outside the Park.
After the road is built, the primary source of air emissions would be the vehicles tra�ersing the road.
Emissions of tail-pipe pollutants were modeled for each of the partial-build and build alternatives and are
shown to have negligible impacts of PMio, PMzS, SOz, CO, and benzene. Impacts ofNOx and VOC are also
negligible for the partial-build alternatives but minor far the full build Northern Shore Corridor alternatives.
Impacts to visibility and deposition are estimated to be negligible for each alternative. The analysis includes
emissions from idling vehicles in parking areas far the Laurel Branch and Partial-Build Alternative to
Bushnell alternatives, where they are likely to congregate. While maximurn changes in ambient
concentrations are predicted to occur in the local proximity to the road, from the large-scale regional
perspective, the emissions will contribute to the large influx of air pollutants from outside the Park.
Following an examination of the traffic growth projections, vehicle miles traveled for the area, and other
factors, NCDOT issued a draft report titled Transportation Conformity Analysis for the North Shore Road in
the Great Smoky Mountains National Park (Haywood and Swain Counties) in December 2006 (NCDOT
2006). Associated interagency coardination and consultation associated is discussed in Section 5.10. The
analysis was conducted for the baseline routes of the Partial-Build Alternative to Bushnell (Principal Park
Road) and the Northern Shore Corridor (Principal Park Road) as potential worst-case alternatives. The
procedures required a comparison of future projected regional traffic emissions (2030) with a level estimated
for a base year of 2002. (The method of comparing future traffic emissions against levels for a base year was
done for this conformity determination in the absence of a Motor Vehicle Emissions Budget for the area.)
The draft report indicates that the projected future vehicle emissions are expected to be lower than 2002
levels and, therefore, the partial-build and build alternatives conform to the regional plan to attain the 8-hour
ozone standard.
4.3.4.2.1 No-Action
The No-Action Alternative would not change ambient levels of regulated air pollutants in the study
corridors. There would be no short-term or long-term impacts from the No-Action Alternative.
4.3.4.22 Monetary Settlement
The Monetary Settlement Alternative would not change ambient levels of regulated air pollutants in
GSMNP. Tl�ere are no anticipated short-term or long-term impacts to air quality.
4.3.4.2.3 Laurel Branch Picnic Area
Air quality impacts for the Laurel Branch Picnic Area are estimated to be major for PM�o and SOz, moderate
for NOx, minor for VOC and CO, and negligible for benzene during the construction phase. Impacts on
visibiliry are estimated to be major and the effects of deposition of sulfur and nitrogen within the region are
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-123
North Shore Road Final Environmental Impact Statement

determined to be major during the construction phase. Elevated ambient air concentrations of these
pollutants can be expected to occur within the limited area (approximately 1,000-foot [approximately 300-m]
radius) of the active construction zone, declining rapidly with distance from the location of the active
construction equipment.
Over the 2-year duration of the construction period, it is estimated that 1.1 tons (1.0 t) of PMio will be
emitted from the construction engines and fugitively from construction activities. Maximum ambient air
concentrations of PM�o within 1,000 ft(300 m) of the construction zone are predicted to be near 31 µg/m3 on
a 24-hour average, which is well below the NAAQS (150 µg/m3) but geater than the Class I PSD Increment
(8 µg/m3). The annual average concentration of PM�o is predicted to be about 2. ] µg/m3, which is below the
Class I PSD Increment (4 µg/m3) and well below the NAAQS (50 µg/m3). Maximum ambient air
concentrations of SOz within 1,000 ft(300 m) of the construction zone are predicted to be near 7.3 µg/m3 on
a 24-hour average, which is well below the NAAQS (365 µg/m3) but greater than the Class I PSD Increment
(5 µg/m3). The annual average concentration of SOz is predicted to be about 0.5 µg/m3, which is below both
the Class I PSD Increment (2 µg/m3) and the NAAQS (80 µg/m3). Estimated maximum concentrations and
total emission rates for all pollutants including NOX, VOC, CO and benzene during construction are shown in
Table 4-13. Major impacts to visibiliry include an estimated maximum reduction in visibiliry of 12 dv in the
active construction area. The maximum value represents a view at or near ground level and limited
additional analysis at elevated heights (approximately 30 m, representing the height of the tree ]ine) indicates
that change in visibility is likely to be about four times less. Effects on nitrogen and sulfur deposition of 0.05
kg/ha/yr and 0.01 kg/ha/yr, respectively, are determined to be major and adverse when considered in relation
to existing conditions in GSMNP.
After construction is completed, emissions are estimated to occur primarily from motor vehicles traversing
the access road and potentially congregating in the parking lot. Access to the Laurel Branch Picnic Area
would be via a short loop road that ties into existing Lake View Road. Traffic volumes on this loop road are
projected to be very low and could result in very small, localized, and temporary concentrations slightly
above background levels. Impacts to air quality in the GSMN P for the operational phase of this alternative
are expected to be negligible. Effects on visibility (0.003 dv) and deposition rates of nitrogen and sulfur
(0.00014 kg/ha/yr and 0.000008 kg/ha/yr, respectively) within the GSMNP are estimated to be negligible.
The tail-pipe and fugitive emission rate of PMio combine far a total of approximately 0.33 tons (0.30 t) per
year. Estimated maximum concentrations and total emission rates for all pollutants including NOx, SOz, CO,
VOC and benzene for the partial-build and build alternatives once they are fully operational are shown in
Table 4-14.
4.3.4.2.4 Partial-Build Alternative to Bushnell
Partial-Build Alternative to Bushnell (Primitive Park Road)
Air qualiry impacts for the Partial-Build Alternative to Bushnell (Primitive Park Road) are estimated to be
majar for PMio and SOz, moderate for NOX, minor for VOC and CO, and negligible for benzene during the
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-124
North Shore Road Final Environmental Impact Statement

Table 4-13. Construction Phase Emissions within 1,000 feet (300 meters) of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build to Southern Option Northern Shore Southern Option Southern Option Southern Option
Time Type Bushnell at Forney Creek Corridor at Forney Creek at Hazel/Eagle Crossing
(baseline) Embayment (baseline) Embayment Creek Fontana Dam
Annual --- 9.0 �ag/m3 Decrease of 6.2 �ag/m3 Decrease of Decrease of Increase of
Average 0.8 �ag/m3 0.5 ug/m3 0.3 ug/m3 0.8 ug/m3
Annual
Primitive "' 11.8 tons/yr 1.6 fewer tons/yr 14.7 tons/yr 0.5 fewer tons/yr 1.8 fewer tons/yr 02 fewer tons/yr
Total Park (10.7 metric (1.5 fewer metric (13.3 metric (0.5 fewer metric (1.6 fewer metric (02 fewer metric
Road: tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
Construction --- 59 tons 8 fewer tons 221 tons 8 fewer tons 27 fewer 3 fewer tons
Total (54 metric tons) (7 metric tons) (201 metric tons) (7 metric tons) (24 metric tons) (3 metric tons)
NOx
Annual 3.8 ug/m3 8.4 �ag/m3 Decrease of 8.2 �ag/m3 Decrease of Decrease of Increase of
Average 1.0 �ag/m3 0.5 ug/m3 0.3 ug/m3 0.5 ug/m3
Annual
Principal 2.� tons/yr 12.2 tons/yr 32 fewer tons/yr 16.8 tons/yr 1.1 fewer tons/yr 1.3 fewer tons/yr 02 fewer tons/yr
Total Park (11.1 metric (2.9 fewer metric (15.2 metric (1.0 fewer metric (12 fewer metric (02 fewer metric
Road: tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
Construction 5.4 tons 61 tons 16 fewer tons 252 tons 17 fewer tons 19 fewer tons 3 fewer tons
Total (4.8 metric tons) (56 metric tons) (15 metric tons) (229 metric tons) (15 metric tons) (17 metric tons) (3 metric tons)
Annual --- 0.9 ug/m3 Decrease of 0.6 �ag/m3 Decrease of Decrease of No change
Average 0.1 �ag/m3 0.1 ug/m3 0.1 ug/m3
9.3 ug/m3 Decrease of 6.3 ug/m3 Decrease of Decrease of No change
24-hour --- 0.6 ug/m3 0.3 ug/m3 02 ug/m3
85 �ag/m3 Decrease of 61 ug/m3 Decrease of Decrease of No change
3-hour Primitive 6 Ng/m3 3�ag/m3 3 ug/m3
SOz Park
Annual Road: --- 1.1 tons/yr 0.16 fewer tons/yr 1.3 tons/yr 0.04 fewer tons/yr 0.15 fewer tons/yr 0.02 fewer tons/yr
Total (1.0 metric (0.15 fewer metric (12 metric (0.04 fewer metric (0.14 fewer metric (0.02 fewer metric
tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
--- 5.3 tons 0.8 fewer tons 20 tons 0.6 fewer tons 2.2 fewer tons 0.3 fewer tons
Construction � � � � � � � � � � �
Total 4.9 metric tons 0.7 fewer metric 18 metric tons 0.6 metric tons 2.0 metric tons 0.3 metric tons
tons)
Environmental Consequences - 4-125
North Shore Road Final Environmental Impact Statement

Table 4-13. Construction Phase Emissions within 1,000 feet (300 meters) of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build to Southern Option Northern Shore Southern Option Southern Option Southern Option
Time Type Bushnell at Forney Creek Corridor at Forney Creek at Hazel/Eagle Crossing
(baseline) Embayment (baseline) Embayment Creek Fontana Dam
Annual 0.5 ug/m3 0.7 ug/m3 No change 0.7 �ag/m3 No change No change No change
Average
7.3 Ng/m3 7.6 ug/m3 Decrease of 7.2 Ng/m3 Decrease of Decrease of Increase of
24-hour 0.7 ug/m3 0.3 �g/m3 0.3 �ag/m3 0.1 ug/m3
60 Ng/m3 70 Ng/m3 Decrease of 70 Ng/m3 Decrease of Decrease of 5 No change
3-hour 3 3 s
Principal � 1�9�m 4 �ag/m ug/m
SOZ Park 025 tons/yr 1.1 tons/yr 0.16 fewer tons/yr 1.3 tons/yr 0.04 fewer tons/yr 0.15 fewer tons/yr 0.02 fewer
Annual Road �0.23 metric (1.0 metric (0.15 fewer metric (1.2 fewer metric (0.04 fewer metric (0.14 fewer metric tons/yr
Total tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.02 fewer metric
tons/yr)
0.5 tons 5.6 tons 1.4 fewer tons 22 tons 1.4 fewer tons 1.5 fewer tons 0.3 fewer tons
Construction � � � � � � � � � � � � �
Total 0.5 metric 5.1 metric tons 1.3 metric tons 20 metric tons 1.3 metric tons 1.4 metric tons 0.3 metric tons
tons)
Annual --- 4.8 ug/m3 Decrease of 3.6 Ng/m3 Decrease of Decrease of No change
Average 1.0 ug/m3 0.5 ug/m3 0.2 �g/m3
24-hour --- 49 Ng/m3 Decrease of 40 Ng/m3 Decrease of Decrease of Decrease of
9�ag/m3 4 ug/m3 3 ug/m3 2 ug/m3
Primitive --- 4.5 tons/yr 1.2 fewer tons/yr 6.6 tons/yr 0.35 fewer tons/yr 1.3 fewer tons/yr 0.04 fewer
Annual Park (4.1 metric (1.1 fewer metric (6.0 metric (0.32 fewer metric (12 fewer metric tons/yr
Total Road: tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.04 fewer metric
tons/yr)
--- 23 tons 6.0 fewer tons 100 tons 5.3 fewer tons 19 fewer tons 0.6 fewer tons
Construction
PM 10 Total (21 metric tons) (5 fewer metric (91 metric tons) (4.9 fewer metric (18 fewer metric (0.6 fewer metric
tons) tons) tons) tons)
Annual Principal 2.1 ug/m3 4.6 ug/m3 Decrease of 5.4 �ag/m3 Decrease of Decrease of No change
Average Park 1.3 ug/m3 0.6 ug/m3 0.5 ug/m3
Road:
24-hour 31 ug/m3 48 ug/m3 Decrease of 57 Ng/m3 Decrease of Decrease of Decrease of
13 Ng/m3 7 ug/m3 6 ug/m3 2 Ng/m3
0.5 tons/yr 4.8 tons/yr 2.0 fewer tons/yr 8.3 tons/yr 0.7 fewer tons/yr 0.7 fewer tons/yr 0.04 fewer
Annual (0.5 metric (4.4 metric (1.8 fewer metric (7.5 metric (0.6 fewer metric (0.6 fewer metric tons/yr
Total tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.04 fewer metric
tons/yr)
Environmental Consequences - 4-126
North Shore Road Final Environmental Impact Statement

Table 4-13. Construction Phase Emissions within 1,000 feet (300 meters) of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build to Southern Option Northern Shore Southern Option Southern Option Southern Option
Time Type Bushnell at Forney Creek Corridor at Forney Creek at Hazel/Eagle Crossing
(baseline) Embayment (baseline) Embayment Creek Fontana Dam
PM 10 1.1 tons 24 tons 10 fewer tons 125 tons 10 fewer tons 11 fewer tons 0.6 fewer tons
Construction � � � � � � � � � � � � �
Total 1.0 metric 22 metric tons 9.3 metric tons 114 metric tons 9.3 metric tons 10 metric tons 0.6 metric tons
tons)
--- 1.7 tons/yr 0.3 fewer tons/yr 2.4 tons/yr 0.3 fewer tons/yr 0.4 fewer tons/yr 0.02 fewer
Annual (1.6 metric (0.3 fewer metric (2.2 metric (0.3 fewer metric (0.4 fewer metric tons/yr
Total Primitive tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.02 fewer metric
Park tons/yr)
Road:
Construction --- 8.6 tons 1.7 fewer tons 36 tons 1.7 fewer tons 6.0 fewer tons 0.3 fewer tons
Total (7.8 metric tons) (1.5 metric tons) (32 metric tons) (1.5 metric tons) (5.4 metric tons) (0.3 metric tons)
PM 2.5 0.25 tons/yr 1.8 tons/yr 0.7 fewer tons/yr 2.9 tons/yr 0.7 fewer tons/yr 0.7 fewer tons/yr 0.02 fewer
Annual (0.23 metric (1.6 metric (0.6 fewer metric (2.6 metric (0.6 fewer metric (0.6 fewer metric tons/yr
Total Principal tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.02 fewer metric
Park tons/yr)
Road: 0.5 tons 9.0 tons 3.3 fewer tons 43 tons 3.3 fewer tons 3.7 fewer tons 0.3 fewer tons
Construction
Total (0.5 metric (82 metric tons) (3.0 metric tons) (39 metric tons) (3.0 metric tons) (3.3 metric tons) (0.3 metric tons)
tons)
Annual "-' 4.8 Ng/m3 Decrease of 3.6 Ng/m3 Decrease of Decrease of No change
Average 1.0 �g/m3 0.5 ug/m3 0.2 ug/m3
24-hour 49 Ng/m3 Decrease of 40 Ng/m3 Decrease of Decrease of Decrease of
9 ug/m3 4 Ng/m3 3 ug/m3 2�ag/m3
Primitive
Park 4.5 tons/yr 1.2 fewer tons/yr 6.6 tons/yr 0.35 fewer tons/yr 1.3 fewer tons/yr 0.04 fewer
Annual Road: (4.1 metric (1.1 fewer metric (5.9 metric (0.32 fewer metric (12 fewer metric tons/yr
TSP Total tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.04 fewer metric
tons/yr)
Construction --� 23 tons 6 fewer tons 100 tons 5.3 fewer tons 19 fewer tons 0.6 fewer tons
Total (21 metric tons) (5 metric tons) (91 metric tons) (4.9 metric tons) (18 metric tons) (0.6 metric tons)
Annual Principle 2.1 ug/m3 4.6 Ng/m3 Decrease of 5.4 �g/m3 Decrease of Decrease of No change
Average Park 1.3 ug/m3 0.6 Ng/m3 0.5 ug/m3
Road:
24-hour 30.6 Ng/m3 48 Ng/m3 Decrease of 57 ug/m3 Decrease of Decrease of Decrease of
13 �ag/m3 7 ug/m3 6�ag/m3 2 ug/m3
Environmental Consequences - 4-127
North Shore Road Final Environmental Impact Statement

Table 4-13. Construction Phase Emissions within 1,000 feet (300 meters) of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build to Southern Option Northern Shore Southern Option Southern Option Southern Option
Time Type Bushnell at Forney Creek Corridor at Forney Creek at Hazel/Eagle Crossing
(baseline) Embayment (baseline) Embayment Creek Fontana Dam
TSP 0.5 tons/yr 4.8 tons/yr 2.0 fewer tons/yr 8.3 tons/yr 0.7 fewer tons/yr 0.7 fewer tons/yr 0.04 fewer
Annual (0.5 metric tons/ r
tons/yr) (4.4 metric (1.8 fewer metric (7.5 metric (0.6 fewer metric (0.6 fewer metric y
Total tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.04 fewer metric
tons/yr)
Construction 1.1 tons 24 tons 10 fewer tons 125 tons 10 fewer tons 11 fewer tons 0.6 fewer tons
Total (1.0 metric �22 metric tons) (9.3 metric tons) (114 metric tons) (9.3 metric tons) (10 metric tons) (0.6 metric tons)
tons
8-hour� --- 142 ug/m3 Decrease of 97 ug/m3 Decrease of Decrease of Increase of
12 ug/m3 6�g/m3 2�ag/m3 7�ag/m3
--- 1045 Ng/m3 Decrease of 707 ug/m3 Decrease of Decrease of Decrease of
1-hour� 91 Ng/m3 45 ug/m3 42 ug/m3 9 Ng/m3
Primitive
Park --- 6.8 tons/yr 0.9 fewer tons/yr 8.7 tons/yr 0.3 fewer tons/yr 1.1 fewer tons/yr 1.9 fewer tons/yr
Annual Road:
Total (6.1 metric (0.8 fewer metric (7.9 fewer metric (0.3 fewer metric (1.0 fewer metric (1.7 fewer metric
tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
Construction --- 34 tons 4.7 fewer tons 130 tons 4.7 fewer tons 16 fewer tons 1.9 fewer tons
Total (31 metric tons) (4.3 metric tons) (118 metric tons) (4.3 metric tons) (15 metric tons) (1.7 metric tons)
CO g-hour* 72 ug/m3 134 �ag/m3 Decrease of 127 �ag/m3 Decrease of Decrease of Increase of
10 ug/m3 5 Ng/m3 9 ug/m3 2�g/m3
472 ug/m3 920 �ag/m3 Decrease of 916 ug/m3 Decrease of Decrease of Decrease of
1-hour� 69 ug/m3 35 ug/m3 76 ug/m3 3�ag/m3
Principal 1.6 tons/yr 7.0 tons/yr 0.6 fewer tons/yr 9.8 tons/yr 0.6 fewer tons/yr 0.7 fewer tons/yr 0.1 fewer tons/yr
Annual Park
Total Road: (1.5 metric (6.3 metric (0.5 fewer metric (8.8 metric (0.5 fewer metric (0.6 fewer metric (0.1 fewer metric
tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
32 tons 35 tons 9.6 fewer tons 147 tons 9.6 fewer tons 11 fewer tons 2.0 fewer tons
Construction � � � � � � � � � � � � �
Total 2.9 metric 32 metric tons 8.7 metric tons 134 metric tons 8.7 metric tons 10 metric tons 1.8 metric tons
tons)
--- 1.0 tons/yr 0.1 fewer tons/yr 1.3 tons/yr 0.05 fewer tons/yr 0.19 fewer tons/yr 0.01 fewer tons/yr
Annual (0.9 metric (0.1 fewer metric (1.2 metric (0.05 fewer metric (0.17 fewer metric (0.01 fewer metric
Total Primitive tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
Park
VOCs Road:
Construction --- 5.0 tons 0.5 fewer tons 19.5 tons 0.75 fewer tons 2.8 fewer tons 0.15 fewer tons
Total (4.5 metric tons) (0.45 metric tons) (17.5 metric tons) (0.68 metric tons) (2.5 metric tons) (0.14 metric tons)
Environmental Consequences - 4-128
North Shore Road Final Environmental Impact Statement

Table 4-13. Construction Phase Emissions within 1,000 feet (300 meters) of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build to Southern Option Northern Shore Southern Option Southern Option Southern Option
Time Type Bushnell at Forney Creek Corridor at Forney Creek at Hazel/Eagle Crossing
(baseline) Embayment (baseline) Embayment Creek Fontana Dam
VOCs 0.2 tons/yr 1.0 tons/yr 0.3 fewer tons/yr 1.5 tons/yr 0.11 fewer tons/yr 0.12 fewer tons/yr 0.02 fewer tons/yr
Annual
Total (0.2 metric (0.9 metric (0.3 fewer metric (1.4 metric (0.10 fewer metric (0.11 fewer metric (0.02 fewer metric
Principal tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
Park
Road: 0.4 tons 5.0 tons 1.5 fewer tons 22.5 tons 1.7 fewer tons 1.8 fewer tons 0.30 fewer tons
Construction � � � � � � � � � � � 0.27 metric tons
Total 0.4 metric 4.5 metric tons 1.4 metric tons 20.4 metric tons 1.5 metric tons 1.6 metric tons � �
tons)
Annual --- 0.010 �g/m3 Decrease of 0.006 ug/m3 No change No change No change
Average 0.001 �ag/m3
--- 0.012 tons/yr 0.002 fewer tons/yr 0.014 tons/yr 0.0007 fewer 0.002 fewer tons/yr 0.0002 fewer
Annual Principal (0.011 metric (0.002 fewer metric (0.013 metric tons/yr (0.002 fewer metric tons/yr
Total Park tons/yr) tons/yr) tons/yr) (0.006 fewer metric tons/yr) (0.0002 fewer
Road: tons/yr) metric tons/yr)
Construction "' 0.06 tons 0.008 fewer tons 0.21 tons 0.01 fewer tons 0.03 fewer tons 0.003 fewer tons
Total (0.05 metric tons) (0.007 metric tons) (0.19 metric tons) (0.01 metric tons) (0.03 metric tons) (0.003 metric
tons)
Benzene Annual 0.005 ug/m3 0.008 Ng/m3 Decrease of 0.008 Ng/m3 No change No change Increase of 0.001
Average 0.001 Ng/m3 �g/m3
0.002 tons/yr 0.012 tons/yr 0.003 fewer tons/yr 0.016 tons/yr 0.004 fewer tons/yr 0.004 fewer tons/yr 0.0002 fewer
(0.002 metric (0.011 metric (0.003 fewer metric (0.015 metric (0.004 fewer metric (0.004 fewer metric tons/yr
Annual Principal tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) (0.0002 fewer
Total Park metric tons/yr)
Road:
0.005 tons 0.06 tons 0.016 fewer tons 0.24 tons 0.02 fewer tons 0.02 fewer tons 0.003 fewer tons
Construction 0.003 metric
Total (0.005 metric (0.05 metric tons) (0.015 metric tons) (0.22 metric tons) (0.02 metric tons) (0.02 metric tons) �
tons) tons)
Environmental Consequences - 4-129
North Shore Road Final Environmental Impact Statement

Table 4-14. Operational Emissions of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build Southern Option Northern Southern Option Southern Option Southern
Time Type to Bushnell at Forney Creek Shore at Forney Creek at Hazel/Eagle Option
(baseline) Embayment Corridor Embayment Creek Crossing
(baseline) Fontana Dam
Annual --- 2.46E-03 �ag/m3 No change 2.69E-03 Decrease of Decrease of No change
Average Primitive ug�m3 5.0E-04 �ag/m3 4.0E-05 ug/m3
Park -__ 0.42 tons/yr 0.08 fewer tons/yr 1.0 tons/yr 0.05 fewer tons/yr 0.07 fewer tons/yr 0.05 fewer
Annual Road:
Total (0.38 metric (0.07 metric (0.9 metric (0.05 metric (0.06 metric tons/yr (0.05
tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) metric tons/yr)
NOx
Annual 3.53E-03 ug/m3 2.46E-03 ug/m3 No change 2.69E-03 Decrease of Decrease of No change
Average Principal I�g�m3 5.0E-04 �ag/m3 4.0E-05 �g/m3
Park 0.03 tons/yr 0.46 tons/yr 0.10 fewer tons/yr 3.3 tons/yr 0.14 fewer tons/yr 0.33 fewer tons/yr 0.16 fewer
Annual Road:
Total (0.03 metric (0.42 metric (0.09 metric (3.0 metric (0.13 metric (0.30 metric tons/yr (0.15
tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) metric tons/yr)
Annual --- 6.52E-05 Ng/m3 No change 7.73E-05 Decrease of Decrease of No change
Average ug/m3 1.35E-05 Ng/m3 1.6E-06 ug/m3
8.76E-04 �g/m3 No change 9.99E-04 Decrease of Decrease of No change
24-hour �g/m3 1.65E-04 �ag/m3 3.6E-05 �ag/m3
Primitive
3-hour Park "- 3.18E-03 Ng/m3 No change 3.99E-03 Decrease of Decrease of No change
Road: I�g�m3 5.9E-04 ug/m3 1.6E-04 ug/m3
--- 0.004 tons/yr 0.001 fewer 0.018 0.0008 fewer 0.0012 fewer 0.0009 fewer
Annual (0.0004 metric tons/yr tons/yr tons/yr (0.0007 tons/yr (0.0011 tons/yr (0.0008
Total tons/yr) (0.001 metric (0.016 metric metric tons/yr) metric tons/yr) metric tons/yr)
tons/yr) tons/yr)
SOZ
Annual 2.38E-05 ug/m3 6.52E-05 Ng/m3 No change 7.73E-05 Decrease of Decrease of No change
Average ug/m3 1.35E-05 �g/m3 1.6E-06 �g/m3
1.85E-04 ug/m3 8.76E-04 ug/m3 No change 9.99E-04 Decrease of Decrease of No change
24-hour �g/m3 1.65E-04 ug/m3 3.6E-05 ug/m3
Principal 5.83E-04 ug/m3 3.18E-03 Ng/m3 No change 3.99E-03 Decrease of Decrease of No change
3-hour Park Road �ag/m3 5.9E-04 �ag/m3 1.6E-04 �ag/m3
0.0002 tons/yr 0.005 tons/yr 0.001 fewer 0.050 0.0020 fewer 0.0050 fewer 0.0024 fewer
Annual (0.0002 metric (0.005 metric tons/yr tons/yr tons/yr (0.0018 tons/yr (0.0045 tons/yr (0.0022
Total tons/yr) tons/yr) (0.001 metric (0.045 metric metric tons/yr) metric tons/yr) metric tons/yr)
tons/yr) tons/yr)
Environmental Consequences - 4-130
North Shore Road Final Environmental Impact Statement

Table 4-14. Operational Emissions of the Partial-Build and Build Alternatives
Pollutant Averaging Road �aurel Branch Partial-Build Southern Option Northern Southern Option Southern Option Southern
Time Type to Bushnell at Forney Creek Shore at Forney Creek at Hazel/Eagle Option
(baseline) Embayment Corridor Embayment Creek Crossing
(baseline) Fontana Dam
Annual --- 9.29E-06 No change 6.23E-03 �g/m3 Decrease of 1.4E- Decrease of No change
Average �ag/m3 03 Ng/m3 2.7E-04 �g/m3
24-hour --- 1.07E-04 No change 6.85E-02 �g/m3 Decrease of Decrease of No change
Primitive ug�m3 6.4E-03 �g/m3 1.2E-05 �g/m3
Park Road: ___ 4.8 tons/yr 0.92 fewer tons/yr 22 tons/yr 0.90 fewer tons/yr 1.5 fewer tons/yr 1.0 fewer
Annual (4.4 metric (0.83 metric (20 metric (0.82 metric tons/yr) (1.4 metric tons/yr
Total tons/yr) tons/yr) tons/yr) tons/yr) (0.91 metric
PM 10 tons/yr)
Annual 7.98E-06 ug/m3 9.29E-06 No change 2.05E-05 �ag/m3 Decrease of 8.0E- Decrease of No change
Average �ag/m3 07 �ag/m3 12E-06 ug/m3
24-hour 4.53E-05 �ag/m3 1.07E-04 No change 2.40E-04 �ag/m3 Increase of 1.2E-05 Decrease of No change
Principal u9�m3 Ng/m3 4.9E-05 ug/m3
Park Road: 0.001 tons/yr 0.016 tons/yr 0.003 fewer 0.046 tons/yr 0.002 fewer tons/yr 0.005 fewer 0.002 fewer
Annual (0.001 metric (0.014 metric tons/yr (0.042 metric (0.002 metric tons/yr (0.004 tons/yr (0.002
Total tons/yr) tons/yr) (0.003 metric tons/yr) tons/yr) metric tons/yr) metric tons/yr)
tons/yr)
Annual Primitive --- 1.0 tons/yr .19 fewer tons/yr 4.7 tons/yr 020 fewer tons/yr 0.30 fewer tons/yr 020 fewer
Park Road: (0.91 metric (0.17 metric (4.3 metric (0.18 metric tons/yr) (027 metric tons/yr (0.18
Total tons/yr) tons/yr) tons/yr) tons/yr) metric tons/yr)
PM 2.5 Principal 0.00044 tons/yr 0.008 tons/yr 0.002 fewer 0.08 tons/yr 0.003 fewer tons/yr 0.008 fewer 0.004 fewer
Annual Park Road: �0.00040 metric (0.007 metric tons/yr (0.07 metric (0.003 metric tons/yr (0.007 tons/yr (0.004
Total tons/yr) tons/yr) (0.002 metric tons/yr) tons/yr) metric tons/yr) metric tons/yr)
tons/yr)
Environmental Consequences - 4-131
North Shore Road Final Environmental Impact Statement

Table 4-14. Operational Emissions of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build Southern Option Northern Southern Option Southern Option Southern
Time Type to Bushnell at Forney Creek Shore at Forney Creek at Hazel/Eagle Option
(baseline) Embayment Corridor Embayment Creek Crossing
(baseline) Fontana Dam
Annual --- 9.29E-06 �g/m3 No change 2.05E-05 �g/m3 Decrease of 8.0E- Decrease of No change
Average 07 ug/m3 12E-06 ug/m3
Primitive --- 1.07E-04 �ag/m3 No change 2.40E-04 ug/m3 Increase of 1.2E-05 Decrease of No change
24-hour Park �g/m3 4.9E-05 ug/m3
Road: ___ 4.8 tons/yr 0.92 fewer tons/yr 22 tons/yr 0.9 fewer tons/yr 1.5 fewer tons/yr 1.0 fewer tons/yr
Annual
Total (4.4 metric (0.83 metric (20 metric (0.82 metric tons/yr) (1.4 metric (0.91 metric
tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
TSP Annual 7.98E-06 ug/m3 9.29E-06 ug/m3 No change 2.05E-05 �g/m3 Decrease of 8.0E- Decrease of No change
Average 07 ug/m3 1.2E-06 ug/m3
24-hour Principal 4.53E-05 ug/m3 1.07E-04 ug/m3 No change 2.40E-04 �g/m3 Increase of 1.2E-05 Decrease of 3 No change
Park ug/m 4.9E-05 ug/m
Road: 0.001 tons/yr 0.016 tons/yr 0.003 fewer tons/yr 0.046 tons/yr 0.002 fewer tons/yr 0.005 fewer 0.002 fewer
Annual tons/ r 0.004 tons/ r 0.002
(0.001 metric (0.014 metric (0.003 metric (0.042 metric (0.002 metric Y i Y i
Total tons/yr) tons/yr) tons/yr) tons/yr) tons/yr) metric tons/yr) metric tons/yr)
8-hour� --- 1.57 Ng/m3 No change 1.57 �ag/m3 Decrease of Decrease of No change
0.41 ug/m3 0.06 �g/m3
Primitive 6.46 ug/m3 No change 6.46 �ag/m3 Decrease of Decrease of No change
1-hour� Park 3.61 �g/m3 0.12 ug/m3
Road:
Annual "' 7.3 tons/yr 1.3 fewer tons/yr 27 tons/yr 1.2 fewer tons/yr 1.8 fewer tons/yr 1.2 fewer tons/yr
Total (6.7 metric (1.2 metric tons/yr) (24 metric (1.1 metric tons/yr) (1.6 metric (1.1 metric
CO tons/yr) tons/yr) tons/yr) tons/yr)
8-hour� 1.19 ug/m3 1.57 ug/m3 No change 1.57 �ag/m3 Decrease of Decrease of No change
0.41 ug/m3 0.06 ug/m3
Principal 2•99 u9�m3 6.46 Ng/m3 No change 6.46 �ag/m3 Decrease of Decrease of No change
1-hour� Park 3.61 ug/m3 0.12 �ag/m3
Road:
Annual 0.52 tons/yr 7.3 tons/yr 1.5 fewer tons/yr 64 tons/yr 2.7 fewer tons/yr 6.5 fewer tons/yr 3.1 fewer tons/yr
Total (0.47 metric (6.7 metric (1.3 metric tons/yr) (58 metric (2.4 metric tons/yr) (5.9 metric (2.8 metric
tons/yr) tons/yr) tons/yr) tons/yr) tons/yr)
Environmental Consequences - 4-132
North Shore Road Final Environmental Impact Statement

Table 4-14. Operational Emissions of the Partial-Build and Build Alternatives
Pollutant Averaging Road Laurel Branch Partial-Build Southern Option at Northern Southern Option at Southern Option Southern
Time Type to Bushnell Forney Creek Shore Forney Creek at Hazel/Eagle Option
(baseline) Embayment Corridor Embayment Creek Crossing
(baseline) Fontana Dam
Annual Primitive '-' 0.47 tons/yr 0.08 fewer tons/yr 1.4 tons/yr 0.07 fewer tons/yr 0.10 fewer tons/yr 0.07 fewer
Park (0.43 metric (0.07 metric tons/yr) (1.3 metric (0.06 metric tons/yr) (0.09 metric tons/yr (0.06
Total Road tons/yr) tons/yr) tons/yr) metric tons/yr)
VOCs 0.044 tons/yr 0.40 tons/yr 0.07 fewer tons/yr 3.7 tons/yr 0.15 fewer tons/yr 0.37 fewer tons/yr 0.18 fewer
Annual Principle (0.04 metric (0.36 metric (0.06 metric tons/yr) (3.3 metric (0.14 metric tons/yr) (0.33 metric tons/yr (0.16
Total Park tons/yr) tons/yr) tons/yr) tons/yr) metric tons/yr)
Road
Annual --- 1.64E-04 No change 1.94E-04 Decrease of 3.0E-05 Decrease of 4.0E- No change
Average ug/m3 �ag/m3 �ag/m3 06 Ng/m3
Primitive
Park ___ 0.014 tons/yr 0.002 fewer tons/yr 0.044 tons/yr 0.0019 fewer tons/yr 0.0030 fewer 0.0021 fewer
Annual Road (0.012 metric (0.002 metric tons/yr) (0.040 metric (0.0017 metric tons/yr (0.0027 tons/yr
Total tons/yr) tons/yr) tons/yr) metric tons/yr) (0.0019 metric
tons/yr)
Benzene
Annual 2.49E-04 �g/m3 1.64E-04 No change 1.94E-04 Decrease of 3.0E-05 Decrease of 4.0E- No change
Average ug/m3 �g/m3 �ag/m3 06 Ng/m3
Principle
Park 0.0011 tons/yr 0.010 tons/yr 0.002 fewer tons/yr 0.12 tons/yr 0.0052 fewer tons/yr 0.0081 fewer 0.0056 fewer
Annual Road � � ( y) (0.11 metric (0.0047 metric tons/yr tons/yr
0.0010 metric 0.009 metric 0.002 metric tons/ r
Total tons/yr) tons/yr) tons/yr) tons/yr) (0.0073 metric (0.0051 metric
tons/yr) tons/yr)
Environmental Consequences - 4-133
North Shore Road Final Environmental Impact Statement

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Environmental Consequences — 4-134
North Shore Road Final Environmental Impact Statement

construction phase. Impacts on visibility are estimated to be major and the effects of deposition of sulfur and
nitrogen within the region are determined to be major during the construction phase. Elevated ambient air
concentrations of these pollutants can be expected to occur within the limited area (approximately 1,000-foot
[approximately 300-m] radius) of the active construction zone, declining rapidly with distance from the
location of the active construction equipment.
Over the 5-year duration of the construction period, it is estimated that 23 tons (21 t) of PMio will be emitted
from the construction engines and fugitively from construction activities. Maximum ambient air
concentrations of PMio within roughly ],000 ft(300 m) of the construction zone are predicted to be near 49
µg/m3 on a 24-hour average, which is well below the NAAQS (150 µg/m3) but greater than the Class I PSD
Increment (8 µg/m3). The annual average concentration of PM�o is predicted to be about 4.8 µg/m3, which is
also greater than the Class I PSD Increment (4 µg/m3), yet well below the NAAQS (50 ug/m3). Maximum
ambient air concentrations of SOz within 1,000 ft(300 m) of the construction zone are predicted to be near
9.3 µg/m3 on a 24-hour average, which is well below the NAAQS (365 µg/m3) but greater than the Class I
PSD Increment (5 µg/m3). The annual average concentration of SOz is predicted to be about 0.7 µg/m3,
which is below both the Class 1 PSD Increment (2 µg/m3) and the NAAQS (80 µg/m3). Estimated maximum
concentrations and total emission rates for all pollutants including NOX, CO, VOC and benzene during
construction are shown in Table 4-13. Major impacts to visibility include an estimated maximum reduction
in visibility of ] 3 dv in the active construction area. The maximum value represents a view at or near ground
level and limited additional analysis at elevated heights (approximately 100 ft [30 m], representing the height
of the tree line) indicates that change in visibility is likely to be about four times less. The VISCREEN
analysis indicates that a plume will likely be visible to visitors from a location 2 mi (3 km) from the
construction area during the early morning and late afternoon. From mid-morning through late afternoon, no
plume will likely be visible to visitors. For visitors located approximately 8 mi (13 km) from the
construction area (the approximate distance from Clingmans Dome), a visible plume would only be observed
from sunrise until approximately l to 2 hours after sunrise. Visitors would not observe a visible plume from
a location at this distance from mid-morning through sunset. Effects on nitrogen and sulfur deposition rates
of 0.07 kg/halyr and O.OI 5 kg/ha/yr, respectively, are determined to be major and adverse when considered
in relation to existing conditions in GSMNP.
Emissions occurring after construction is completed would likely be limited to tail-pipe emissions from
motar vehicles traversing the road and potentially congregating in ihe parking lots. Projected iraffic volumes
for this alternative are small. Increases in ambient air concentrations of regulated air pollutants would be
temporary, localized and negligible in magnitude. Air quality impacts are expected to be negligible once the
road is opened and fully operational. The annual average concentration of PM�o is predicted to be about
0.000009 µg/m3, well below botb the Class I PSD Increment (4 µg/m3) and NAAQS (50 µg/m3). Tail-pipe
and fugitive emission rates of PMio combine for a total of approximately 7.5 tons (6.8 t) per year, a
negligible impact, but greater than total annual emissions far the Principal Park Road. Effects on visibility
(0.002 dv) and deposition rates of nitrogen and sulfur within the GSMNP are estimated to be negligible
(0.00014 kg/ha/yr and 0.000008 kg/ha/yr). Estimated maximum concentrations and total emission rates for
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-135
North Shore Road Final Environmental Impact Statement

all pollutants including NOx, SOz, CO, VOC and benzene for the partial-build and build alternatives once
they are fully operational are shown in Table 4-14.
Southern Option at Forney Creek Embayment (Primitive Park Road)
These options primarily differ from the baseline Partial-Build Alternative to Bushnell due to their location.
The construction intensity and a�erage rate of emissions are similar to the baseline route, but the alignment
puts the construction activity further from the center of the Park. These impacts are estimated to occur in
proximity to the construction area. Estimated concentrations and total emissions are somewhat reduced from
the baseline route. However, this option requires the construction of a bridge, which requires construction
equipment to remain within a relatively small area over a longer time frame. The effect of this could be a
more sustained source of air emissions during bridge construction. Although this could result in slightly
higher ambient concentrations compared with those occurring during construction of the baseline route, they
would likewise be temporary. Estimated maximum concentrations and total emission rates for all pollutants
during construction are shown in Table 4-13.
With respect to the vehicle emissions after the construction is complete, this option would decrease the
distance and average time it would take far motor vehicles to reach Bushnell. Consequently, long-term
emissions from traffic traversing the Southern Option at Forney Creek Embayment are expected to be
slightly less than the baseline route due to the shorter route and average time that motor vehicles are
operating in the Park. Estimated maximum concentrations and total emission rates for all pollutants for the
partial-build and build alternatives, including southern options once they are fully operational are shown in
Table 4-14.
Partial-Build Alternative to Bushnell (Principal Park Road)
The magnitude of air qualiry impacts associated with the construction period for the Partial-Build Alternative
to Bushnell (Principal Park Road) are predicted to be nearly the same as those staYed above for the Primitive
Park Road with impacts estimated to be inajor for PMio, SOz, visibiliry (maximum value of 13 dv), and
deposition of nitrogen and sulfur (0.07 kg/ha/yr and 0.015 kg/ha/yr, respectively) during the construction
phase. Estimated maximum concentrations and total emission rates for all pollutants during construction are
shown in Table 4-13.
With respect to the vehicle emissions after the construction is complete, this option would decrease the
distance and average time it would take for motor vehicles to reach Bushnell. Consequently, total long-term
emissions from traffic traversing the Southern Option at Forney Creek Embayment are expected to be
slightly less than the baseline route due to the shorter route and average time that motar vehicles are
operating in the Park. Short-term impacts to air quality in the nearby vicinity of the road would be
negligible. Effects on visibility (0.002 dv) and deposition rates of nitrogen and sulfur within the GSMNP are
estimated to be negligible (0.001 kg/ha/yr and 0.00004 kg/haJyr). Fugitive emissions of PMio occurring as
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-136
North Shore Road Final Environmental Impact Statement

road dust under this option are substantially less than emissions for the Primitive Park Road. Tail-pipe and
fugitive emission rates of PMio combine for a total of approximately 0.02 tons (0.018 t) per year. Estimated
maximum concentrations and total emission rates far all pollutants including NOx, SOz, CO, VOC and
benzene for the partial-build and build alternatives once they are fully operationa] are shown in Table 4-14.
The draft air quality conformiry analysis indicates that the projected future vehicle emissions far the Partial-
Build Alternative to Bushnell (Principal Park Road) are expected to be lower than 2002 levels and, therefore,
this alternative conforms to the regional plan to attain the 8-hour ozone standard (NCDOT 2006).
Southern Option at Forney Creek Embayment (Principal Park Road)
These options primarily differ from the baseline Partial-Build Alternative to Bushnell due to their location.
The construction intensiry and average rate of emissions are similar to the baseline route, but the alignment
puts the construction activiry further from the center of the Park. These impacts are estimated to occur in
proximity to the construction area. Estimated concentrations and total emissions are somewhat reduced from
the baseline route. However, this option requires the construction of a bridge, which requires construction
equipment to remain within a relatively small area over a longer time frame. The effect of this could be a
more sustained source of air emissions during bridge construction. Although this could result in slightly
higher ambient concentrations compared with those occurring during construction of the baseline route, they
would likewise be temporary. Estimated maximum concentrations and total emission rates for all pollutants
during construction are shown in Table 4-13.
As discussed for the Primitive Park Road, this option would decrease the distance and average time it would
take for motar vehicles to reach Bushnell. Consequently, the long-term emissions from traffic traversing the
Southern Option at Forney Creek Embayment are expected to be slightly less than the baseline route.
Estimated maximum concentrations and total emission rates for all pollutants for the partial-build and build
alternatives including southern options once they are fully operational are shown in Table 4-14.
4.3.4.2.5 Northern Shore Corridor
Northern Shore Corridor (Primitive Park Road)
Air quality impacts during the construction phase of the Northem Shore Corridor (Primitive Park Road) are
estimated to be major for PMio and SOz, moderate for NOX, minar for VOC and CO, and negligible for
benzene. Impacts on visibility are estimated to be major and the effects of deposition of sulfur and nitrogen
within the region are determined to be majar during the construction phase. Elevated ambient air
concentrations of these pollutants can be expected to occur within the limited area (approximately 1,000-foot
[approximately 300-m] radius) of the active construction zone, declining rapidly with distance from the
location of the active construction equipment.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-137
North Shore Road Final Environmental Impact Statement

Over the ] 5-year duration of the construction period, it is estimated that 100 tons (91 t) of PM�o will be
emitted from the construction engines and fugitively from construction activities. Average ambient air
concentrations of PM�o within roughly 1,000 ft(300 m) of the construction zone are predicted to be near 40
µg/m3 on a 24-hour average, which is well below the NAAQS (l 50 ug/m3) but greater than the Class I PSD
Increment (8 µg/m3). The annual average concentration of PMio is predicted to be about 3.6 µg/m3, which is
also below the Class I PSD Increment (4 µg/m3) and the NAAQS (50 µg/m3). Construction for some
segments may result in annual average concentrations that are slightly greater than the Class I PSD
Increment. Maximum ambient air concentrations of SOz within ],000 ft[300 m] of the construction zone are
predicted to be near 6.3 µg/m3 on a 24-hour average, which is well below the NAAQS (365 µg/m3) but
greater than the Class I PSD Increment (5 µg/m3). The annual average concentration of SOz is predicted to
be about 0.6 µg/m3, which is below both the Class I PSD Increment (2 µg/m3) and the NAAQS (80 µg/m3).
Estimated maximum concentrations and total emission rates for all pollutants including NOX, CO, VOC and
benzene during construction are shown in Table 4-13. Major impacts to visibility include an estimated
maximum reduction in visibility of 9.5 dv in the active construction area. The maximum value represents a
view at or near ground level and limited additional analysis at elevated heights (approximately 30 m,
representing the height of tbe tree line) indicates that change in visibility is likely to be about four times less.
The VISCREEN analysis indicates that a plume will likely be visible to visitars from a location 2 mi (3 km)
from the construction area during the early moming and late afternoon. Prom mid-morning through late
afternoon, no plume will likely be visible to visitors. For visitors located approximately 8 mi (] 31�rn) from
the construction area (the approximate distance from Clingmans Dome), a visible plume would only be
observed from sunrise until approximately 1 to 2 hours after sunrise. Visitors would not observe a visible
plume from a location at this distance from mid-morning through sunset. Effects on nitrogen and sulfur
deposition rates of 0.07 kg/ha/yr and 0.015 kg/ha/yr, respectively, are determined to be major and adverse
when considered in relation to existing conditions in GSMNP.
After the roadway construction is completed, air qualiry impacts from vehicles traveling the Northern Shore
Corridor (Primitive Park Road) are estimated to be minor for NOX and VOC, and negligible for PMio� PMzs,
SOz, CO, and benzene. Effects of vehicle exhaust emissions on nitrogen deposition rates, sulfur deposition
rates, and visibility conditions in the Park are estimated to be negligible. Vehicle miles traveled through the
Park would be greater tban tbe Partial-Build Alternative to Bushnell or the Laurel Branch Picnic Area,
resulting in a greater increase in net emissions within the Park over an extended period. It is for this reason
that the impacts for NOX and VOC are minor. Estimated maximum concentrations and total emission rates
for all pollutants including NOx, SOz, CO, VOC and benzene for the partial-build and build alternatives once
they are fully operational are shown in Table 4-14.
Southern Option at Forney Creek Embayment, Southern Option at Hazel and Eagle Creek Embayments, and Southern
Option Crossing the Fontana Dam (Primitive Park Road)
These options only differ from the baseline Northern Shore Corridor due to their location. The construction
intensity and average rate of emissions are very similar to the baseline route, but the alignment puts the
construction activiry further from the center of the Park. These impacts are estimated to occur in proximity
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-138
North Shore Road Final Environmental Impact Statement

to the construction area. Estimated concentrations and total emissions are somewhat reduced from the
baseline route. However, the two southern options at the embayments of Forney, Hazel, and Eagle creeks
require the construction of a bridge, which requires construction equipment to remain within a relatively
small area over a longer time frame. The effect of this could be a more sustained source of air emissions
during bridge construction. Although this could result in slightly higher ambient concentrations compared
with those occurring during construction of the baseline Northern Shore Corridor route, they would likewise
be temporary. Estimated maximum concentrations and total emission rates for all pollutants during
construction are shown in Table 4-13.
Once the roadway is opened to traffic, the southern options offer a shorter route and, consequently, would
result in a reduced average in vehicle iniles traveled compared with the Northern Shore Corridor. This
results in a lower estimated net increase in emissions from vehicular traffic. Estimated maximum
concentrations and total emission rates for all pollutants for the partial-build and build alternatives including
southern options once they are fully operational are shown in Table 4-14.
Northern Shore Corridor (Principal Park Road)
Air quality impacts for the Northern Shore Corridor (Primitive Park Road) are estimated to be major for
PMio and SO2, moderate for NOx, minor for VOC and CO, and negligible for benzene during the
construction phase. Impacts on visibiliry are estimated to be major and the effects of deposition of sulfur and
nitrogen within the region are determined to be major during the construction phase. Elevated ambient air
concentrations of these pollutants can be expected to occur within the limited area (approximately 1,000-foot
[approximately 300-m] radius) of the active construction zone, declining rapidly with distance from the
location of the active construction equipment.
Over the 15-year duration of the construction period, it is estimated that 125 tons (113 t) ofPMiowill be
emitted from the construction engines and fugitively from construction activities. Average ambient air
concentrations of PM�o within 1,000 ft(300 m) of the construction zone are predicted to be near 57 µg/m3 on
a 24-hour average, which is well below the NAAQS (l 50 µg/m3) but greater than the Class I PSD Increment
(8 µg/m3). The annual average concentration of PMio is predicted to be about 52 µg/m3, which is slightly
above the Class I PSD Increment (4 µg/m3) yet is well below the NAAQS (50 µg/m3). Maximum ambient
air concentrations of SOz within 1,000 ft (300 m) of tbe construction zone are predicted to be near 7.2 µg/m3
on a 24-hour average, which is well below the NAAQS (365 µg/m3) but greater than the Class I PSD
Increment (5 µg/m3). The annual average concentration of SOz is predicted to be about 0.7 µg/m3, which is
below both the Class I PSD Increment (2 µg/m3) and the NAAQS (80 µg/m3). Estimated maximum
concentrations and total emission rates for all pollutants including NOx, CO, VOC and benzene during
construction are shown in Table 4-13. Majar impacts to visibiliry include an estimated maximum reduction
in visibility of 9.5 dv in the active construction area. The maximum value represents a view at or near
ground level and limited additional analysis at elevated heights (approximately 30 m, representing the height
of the tree line) indicates that tbe change in visibility is likely to be about four times less. The VISCREEN
analysis indicates that a plume will likely be visible to visitars from a location 2 mi (3 km) from the
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-139
North Shore Road Final Environmental Impact Statement

construction area during the early morning and late afternoon. From mid-morning through late afternoon, no
plume will ]ikely be visible to visitors. For visitors located approRimately 8 mi (l 3 km) from the
construction area (the approximate distance from Clingmans Dome), a visible plume would only be observed
from sunrise until approximately 1 to 2 hours after sunrise. Visitors would not observe a visible plume from
a location at this distance from mid-maming through sunset. Effects on nitrogen and sulfur deposition rates
of 0.1 kg/haJyr and 0.2 kg/ha/yr, respectively, are determined to be major and adverse when considered in
relation to existing conditions in GSMNP.
After the roadway construction is completed, air qualiry impacts from vehicles traveling the Northern Shore
Corridor (Principal Park Road) are estimated to be minor for NOx, VOC, and CO and negligible for PMio,
PM2.5, SOz, and benzene. The evaluation of emissions show a much lower leve] of emissions of particulate
matter (dust) generated as road dust when comparing this option with the Primitive Park Road. Effects on
visibiliry (0.002 dv) and deposition rates of nitrogen and sulfur within the GSMNP are estimated to be
negligible (0.001 kg/ha/yr and 0.00004 kg/ha/yr). Vehicle miles traveled through the Park would be greater
than the Partial-Build Alternative to Bushnell or Laurel Branch Picnic Area, resulting in a greater increase in
net emissions within the Park over an extended period. Estimated maximum concentrations and total
emission rates for all pollutants including NOX, SOz, CO, VOC and benzene far the partial-build and build
alternatives once they are fully operational are shown in Table 4-14.
The draft air quality conformity analysis indicates that the projected future vehicle emissions for the
Northern Shore Corridor (Principal Park Road) are expected to be lower than 2002 levels and, therefore, this
alternative conforms to the regional plan to attain the 8-hour ozone standard (NCDOT 2006).
Southern Option at Forney Creek Embayment, Southern Option at Hazel and Eagle Creek Embayments, and Southern
Option Crossing the Fontana Dam (Principal Park Road)
These options only differ from the baseline Northern Shore Corridor due to their location. The construction
intensity and average rate of emissions are very similar to the baseline route, but the alignment puts the
construction activity further from the center of the Park. These impacts would be temporary and are
estimated to occur within close proximiry to the construction area. Estimated concentrations and total
emissions are somewhat reduced from the baseline route. However, the two southern options at the three
embayments of Forney, Hazel and Eagle creeks include the construction of a bridge, which requires
construction equipment to remain within a relatively small area over a longer time frame. The effect of this
could be a mare sustained source of air emissions during bridge construction. Although this could result in
slightly higher ambient concentrations compared with those occurring during construction of the baseline
Northern Shore Corridor route, they would likewise be temporary. The magnitude of the predicted impact
concentrations are nearly the same as those provided above far the baseline option. Estimated maxitnum
concentrations and total emission rates for all pollutants during construction are shown in Table 4-13.
Over the long term, the southern options offer a shorter route and, consequently, would result in a reduced
average in vehicle miles traveled compared with the Northern Share Corridar. This results in a lower
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-140
North Shore Road Final Environmental Impact Statement

estimated net increase in emissions from vehicular traffic. Estimated maximum concentrations and total
emission rates for all pollutants for the partial-build and build alternatives including southem options once
they are fully operational are shown in Table 4-14.
4.3.4.2.6 Cumulative Impacts
In recent years, monitoring and research has shown that airborne pollutants originating from emission
sources located outside the Park and transported into the Park are impacting streams, soils, vegetation,
visibility, visitor enjoyment and public health. Winds coming into the southern Appalachian Mountains have
been shown to carry pollutants originating from as far away as the Tennessee, Ohio, and Mississippi River
valleys and the industrial cities of the Southeast and Midwest. The complex mountainous terrain of the
GSMNP, combined with predominant weather patterns, tend to collect and trap air pollutants entrained in
currents entering the Park. Products of fossil fuel combustion include nitrogen oxides, sulfur dioxide and
particulate matter that chemically convert in the atmosphere to secondary pollutants such as ozone (smog),
sulfates, and nitrates which hinder visibility and increase deposition rates of nitrogen, sulfur, and particulate
matter within the Park, especially at higher elevations.
Air quality impacts, while majar for PM�o and SOz and moderate for NOX during the construction phases of
the partial-build and build alternatives, are estimated to occur in proximity to the active construction areas.
This is due in large part to the mountainous terrain of the Park where topography can play a significant role
to impede long-range transport and air dispersion. Air dispersion modeling of projected emissions indicates
that air pollutants emitted from the construction activities would not add measurably to the air quality
concentrations, haziness, or acid deposition phenomena at more distant higher elevations in the Park, such as
Clingmans Dome.
Projected 2025 traffic volumes for study area roadways and all partial-build and build alternatives are
relatively low. While the increase in traffic from any of these alternatives will result in some additional air
pollution emissions in the Park, over the long term these emission levels are estimated to be negligible,
especially in the regional context. Mareover, the absence of intersections and stoplights in the partial-build
and build alternatives enables traffic to remain free flowing such that hot spots of vehicle exhaust are not
likely to develop. However, as the state of North Carolina and USEPA plan for attainment of the NAAQS
and implement transportation conformity (if necessary), even relatively small increases in e��nissions and
changes in air quality could be important to meeting these CAA requirements. The draft air quality
conformity analysis indicates that the projected future vehicle emissions for the Partial-Build Alternative to
Bushnell and the Northern Shore Corridor (Principal Park Roads) as potential worst-case alternatives are
expected to be lower than 20021evels and, therefore, the partial-build and build alternatives conform to the
regional plan to attain the 8-hour ozone standard (NCDOT 2006). If a partial-build or build altemative were
selected for implementation, a final conformity determination would be completed prior to signing a ROD.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-141
North Shore Road Final Environmental Impact Statement

4.3.4.3 Mitigation
Many of the existing conditions for air quality are regional, resulting from emissions from many different
sources located within several hundred miles of GSMNP. Regulatory requirements recently promulgated by
the USEPA, such as the Regional Haze Rule, Clean Air Interstate Rule, and Heavy-Duty Highway Diesel
Fuel Rule, among others, are expected to have a significantly improve air quality within the region.
Potential impacts to air quality far the proposed partial-build and build alternatives could be minimized by
implementing the following:
■ Minimize earthwork (cut and fill) volumes in the design process;
■ Minimize cut and fill haul distances in the construction planning process;
■ Use new construction equipment with engines that conform to recent low emissions standards;
■ Use dust-suppression techniques during construction;
■ For near-field short-term impacts, limit the amount of construction equipment operating concurrently in
a single construction zone;
■ Implement best construction management practices to minimize impact to air quality. Generally, this
involves maximizing equipment efficiency; minimizing the time that multiple stages of construction
(clearing, grading, and paving) are occurring within the same vicinity; and maximizing the distance
between simultaneous construction operations so that the air quality impacts do not overlap over a
given zone; and
■ For the operating phase, if a Primitive Park Road (gravel) is constructed, minimize road dust by
applying a stabilizer or dust suppressant to the roadway. Effective stabilizers include magnesium
chlaride, calciuin chloride, lignosulfonates, resins, natural clays, liquid asphalts, or soybean oil.
4.3.4.4 Impairment Evaluation
Impairment (as defined by NPS policy) of air quality in GSMNP and the AT would not occur under the No-
Action Alternative, Monetary Settlement Alternative, Laurel Branch Picnic Area, and the Partial-Build
Alternative to Bushnell. The Northern Shore Corridor is not likely to impair air qualiry in GSMNP and the
AT based on the information obtained to date. Due to the magnitude of this alternative, it is likely that
additional NEPA documentation would be required to address sit�specific impacts not currently known, to
determine detailed avoidance, minimization, and mitigation measures as they relate to final design, and to re-
evaluate the impairment determination related to air quality.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-142
North Shore Road Final Environmental Impact Statement