Air Quality Impact and Mitigation Analysis.pdf!1rumEr,r • •
Prepared for:
The City of Edmonds,
Washington
Perteet, Inc.
Everett, Washington
Prepared by:
Michael Minor & Associates
Portland, Oregon
Table of Contents
1. Project Introduction.......................................................................................................... 0
2. Project Description............................................................................................................
1
2.1. Channelization Plan.......................................................................................................
3
2.2. Proposed Right of Way and Public Access....................................................................
3
3. Health Effects of Pollutants..............................................................................................
4
3.1. Particulate Matter...........................................................................................................
4
3.2. Ozone.............................................................................................................................
4
3.3. Carbon Monoxide..........................................................................................................
4
3.4. Mobile Source Air Toxics..............................................................................................
5
3.5. Greenhouse Gases..........................................................................................................
5
4. Ambient Air Quality Standards........................................................................................
6
5. Affected Environment.......................................................................................................
8
5.1. Regional Climate and Meteorology...............................................................................
8
5.2. Major Terrain Features..................................................................................................
8
5.3. Existing Air Quality and Compliance Status with NAAQS..........................................
9
6. Studies and Coordination..................................................................................................
9
6.1. Non -Attainment Areas Affected By This Project........................................................
10
6.2. Project's Relation to Regional and State Transportation Plans ...................................
10
6.3. Methodology and Modeling Assumptions...................................................................
10
6.4. Intersection Selection...................................................................................................
11
7. Impacts............................................................................................................................
12
7.1. Indirect Air Quality Effects.........................................................................................
12
7.2. Cumulative Air Quality Effects...................................................................................
12
8. Mitigation........................................................................................................................12
9. Project Conformity Statement.........................................................................................
12
10. Construction Activity Impacts....................................................................................
13
10.1. Construction Phase Mitigation Measures..................................................................
14
10.2. Construction Mitigation Measures Considered or Available but Not Included ........
15
List of Tables
Table 1: State and Federal Ambient Air Quality Standards..................................................... 7
Table 2. Summary of Data Used to Select Intersections for Modeling .................................. 11
Table 3. PM Peak Carbon Monoxide Levels at 228th St SW-SR99....:......I........................... 12
Table 4. Pollutants Generated by Construction Activities...................................................... 14
List of Figures
Figure1. Project Vicinity.......................................................................................................... 2
Figure2. Proposed Design........................................................................................................ 3
Figure 3. Trends in MSAT Emissions...................................................................................... 5
Figure 4. Sources of Greenhouse Gases in Washington State .................................................. 6
The City of Edmonds wishes to reduce congestion and solve key safety issues for vehicles
accessing SR 99 by extending 2281h Street eastwards from SR 99 to 76th Avenue West,
providing protected left -turn phasing for both approaches to the intersection of SR 99 and
228th Street, and restricting left turns from SR 99 onto 76t" Avenue West. The project will
include two new signals — one at 228th Street Southwest /SR 99 and another at 228th
Street/76th Avenue West. The project will also facilitate better access to the I-5 Mountlake
Terrace Transit Center and to the Interurban Trail located % mile to the east.
Projects located in non -attainment or maintenance areas for a given pollutant must comply
with provisions of the 1990 Clean Air Act Amendments. They must also comply with the
promulgated state and federal rules that require a determination of conformity with the State
Implementation Plan (SIP). The 228th Corridor Improvements Project is located in the
central Puget Sound area, which is an air quality maintenance area for both carbon monoxide
(CO) and ozone. This project is included in the 2010-2013 State Transportation
Improvement Program (identified as EDM -17) and is included as a safety project in the City
of Edmond's 2009 Transportation Plan. The environmental status of the project is identified
as "CE" for categorically exempt. The project is funded by a combination of City and
Federal funds.
The results of this analysis demonstrate that carbon monoxide concentrations resulting from
this project will not create new violations of the National Ambient Air Quality CO Standards
(NAAQS), worsen existing CO exceedances, or delay timely attainment of the CO NAAQS.
Therefore, this project meets the transportation conformity requirements, and no additional
air quality mitigation measures are required.
2. Project Description
The project description that follows was provided to Michael Minor & Associates, Inc.
(MM&A) on January 19, 2012 by Stephanie Hansen, Senior Community Planner at Perteet,
Inc, and updated on May 4, 2012. The project alignment is depicted on aerial photos of the
study area in Figure 1.
The 228th Street SW Corridor Improvements Project will extend a new roadway, including
sidewalks, in the 228th Street SW right-of-way between 76th Avenue W and SR 99. The
project will also include two signals (at 228th Street/SR 99 and at 228th Street/76th Avenue
W), a large underground stormwater vault, and a median along SR 99 at 76th Avenue W.
Existing light poles will need to be relocated, and the project includes removal (and
replacement) of an existing stormwater facility. Lastly, the project will overlay 228th Street
SW with 2" of hot mix asphalt from the intersection of 80th Avenue West to the Andorra
Estates driveway and 76th Ave. W from 228th St. SW to SR 99.
Completion of the project will reduce congestion and solve key safety issues for vehicles
accessing SR 99 by providing protected left -turn phasing for both approaches and restricting
9
left turns from SR 99 onto 76"' Avenue West. Pedestrian safety will also be enhanced by the
new signal at 228th and SR 99. The project will facilitate better access to the I-5 Mountlake
Terrace Transit Center and to the Interurban Trail located''/2 mile to the east. It will also
enhance pedestrian safety by providing a new, signalized pedestrian link that connects the
neighborhoods on either side of SR 99.
SR 99 currently carries high traffic volumes resulting in unsafe turning movements for
vehicles traveling east of 228"' St. Southwest and in unsafe pedestrian crossing conditions.
Current and future volumes and intersection LOS are summarized in Table 2 found in
Intersection Selection Section 5.4.
As described, there are several changes to traffic flow with the proposed project. The new
roadway and lane configurations are shown below in Figure 2.
♦ l f y • �rI M.
The following summarizes the proposed right-of-way and pedestrian access in the project
vicinity:
• 228"' Street Southivest at SR 99 Pedestrians currently have access to all sides of this
intersection. All legs of this intersection are at grade.
41
® 2281h Street Southwest at 76"' West- Pedestrians currently have access to all sides of
this intersection, (currently a "T" configuration). All three legs of this intersection are
at grade.
H190-MUHIMMMA 0411
Of the variety of pollutants emitted by motor vehicles, carbon monoxide, particulate matter,
ozone, mobile source air toxics, and greenhouse gases are of interest for this project. These
pollutants are discussed in more detail below.
3.1. Particulate Matter
Particulate matter consists of particles of wood smoke, diesel smoke, dust, pollen or other
materials. It has traditionally been measured in two forms: PMIo (respirable or fine
particulate matter) and PM2.5, depending upon the diameters of the particles. The former is
defined as all matter smaller than 10 micrometers in diameter; the latter is only that material
smaller than 2.5 microns in diameter. Due to concerns about the effect of very fine
particulate matter such as that found in wood smoke and combustion engine exhaust, the
EPA in 1997 established separate regulations for particulate matter smaller than 2.5 microns
in diameter (PM2.5).
Coarse particles greater than 10 micrometers (such as fugitive dust from earth -moving) settle
out of the air fairly close to where they are produced. PMIo (and to an even greater degree
PM2.5) remains suspended in the air for long periods of time and is readily inhalable deep into
the smaller airways of human lungs. High ambient concentrations of PMIo and PM2.5
contribute to impaired respiratory functioning. Fine particulate matter is primarily
responsible for haze that impairs the visibility of distant objects.
The diesel engines of trucks and heavy equipment are a significant source of particulate
matter. Particulate matter from diesel engines and other sources has come under increasing
scrutiny as a significant source of hazardous air pollutants.
3.2. Ozone
Ozone is a pungent -smelling, colorless gas produced in the atmosphere when nitrogen oxides
and some hydrocarbons chemically react under the effect of strong sunlight. Unlike carbon
monoxide, ozone and the other reaction products do not reach their peak levels closest to the
source of emissions, but rather at downwind locations affected by the urban plume after the
primary pollutants have had time to mix and react under sunlight. It is a pulmonary irritant
that affects lung tissues and respiratory functions. Ozone impairs the normal function of the
lung and, at concentrations between 0.15 and 0.25 ppm, causes lung tightness, coughing and
wheezing.
3.3. Carbon Monoxide
Carbon monoxide is a colorless, odorless, toxic gas commonly formed when carbon -
containing fuel is not burned completely. Motor vehicles are the major source of carbon
121
monoxide in the Pacific Northwest with seasonal contributions from wood burning stoves,
fireplaces and land clearing fires. It chemically combines with the hemoglobin in the red
blood cells to decrease the oxygen -carrying capacity of the blood. Carbon monoxide also
weakens the contractions of the heart, thus reducing the amount of blood pumped throughout
the body. People with heart disease and pregnant women are particularly at risk because of
the effects of carbon monoxide.
Mobile source air toxics (MSATS) consist of a wide variety of pollutants emitted by gasoline
and diesel powered motor vehicles. Six compounds are of particular interest: formaldehyde,
benzene, acrolein, acetaldehyde, 1-3 butadiene and diesel particulate matter. Health effects
include potential cancer risks and pollution of ground water supplies. Useful mitigation
measures have been undertaken on a regional basis, such as the phase-out of lead in gasoline,
the introduction of low -sulfur diesel fuel and the installation of particulate traps on diesel
buses. The particulate matter emissions from diesel engines have been shown to contain
several types of MSATS. Figure 3 shows the trends in MSAT emissions as estimated by the
Federal Highways Administration. Future emissions of the other vehicle -generated
pollutants such as CO, SO2 and NOx are predicted to follow the same downward trends.
®—®®® VMT-Vehicle-Miles Traveled
3.5. Greenhouse Gases
Greenhouse gas is a generic term referring to gases such as carbon dioxide, ozone, methane,
nitrous oxide and hydro fluorocarbons which accumulate in the atmosphere trapping the
sun's energy causing changes in local, regional and world climates. The primary sources of
greenhouse gases are primarily man-made (internal combustion engines, the burning of fossil
fuels and wood and the application of nitrogen fertilizers on agricultural lands), but
61
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2000 2010 2020
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--•---_--
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®—®®® VMT-Vehicle-Miles Traveled
3.5. Greenhouse Gases
Greenhouse gas is a generic term referring to gases such as carbon dioxide, ozone, methane,
nitrous oxide and hydro fluorocarbons which accumulate in the atmosphere trapping the
sun's energy causing changes in local, regional and world climates. The primary sources of
greenhouse gases are primarily man-made (internal combustion engines, the burning of fossil
fuels and wood and the application of nitrogen fertilizers on agricultural lands), but
61
greenhouse gases also come from natural sources (respiration of plants and animals and the
decomposition of organic matter). Figure 4 shows the sources of greenhouse gases in the
nation and Washington State.
RCI Fuel
Washington
us Use
20%
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RCI Fuel
1
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uuui
Transport
Use
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20°i°
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i
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based)
Waste Other
based)
ase
Waste Other
34%
Agric.
2% 8%
Agrlc.
4
0 /o
3%
8%
6%
GIG Emissions by Sector, 2005, US and Washington State
Source: Leading the Tfay: A Comprehensive Approach to Reducing Greenhouse Gases in Rashington State,
Washington.
Climate Advisory Team, 2008, page 33.
Air quality in the study area is regulated by three agencies: the Environmental Protection
Agency (EPA); the Washington State Department of Ecology (DOE); and the Puget Sound
Clean Air Agency (PSCAA). The latter agency and DOE work together to monitor air
quality within the Puget Sound region. The EPA sets national air quality standards and has
oversight authority over PSCAA and DOE.
The EPA has developed National Ambient Air Quality Standards (NAAQS) for six criteria
pollutants to protect the public health and welfare. The NAAQS specify maximum
concentrations for carbon monoxide (CO), particulate matter less than 2.5 microns in
diameter (PM2.5), particulate matter less than 10 microns in diameter (PMto), ozone (03),
sulfur dioxide (SO2), lead, and nitrogen dioxide (NO2). These standards shall not be
exceeded by ambient pollutant concentrations that are averaged over a defined time interval,
ranging from one-hour to three-year averages. DOE and PSCAA have authority to adopt
more stringent standards. Current state and local standards are equivalent to the federal
standards, except for a stricter sulfur dioxide standard. Table 1 provides a listing of
established federal, state and local ambient air quality standards.
0
DOE and PSCAA operate air quality monitoring stations to obtain data on actual ambient air
quality concentrations. hnformation from these stations determines whether the region meets
the NAAQS and assists in providing background level concentrations in the project vicinity.
Areas of the country exceeding the NAAQS for a given pollutant are classified as non -
attainment. In 1991, the western portions of Snohomish, King and Pierce Counties were
designated nonattainment areas for carbon monoxide and nearly all of the three counties were
declared nonattainment for ozone. Portions of the industrial areas of Everett, Seattle, Kent
and Tacoma were declared to be PM10 non -attainment areas. Based upon monitoring results,
which have shown no exceedances for several years, the EPA in 1996 re -designated the
Puget Sound area as a maintenance area for carbon monoxide and ozone. Former non -
attainment areas are required to continue to maintain air quality by adhering to a
"maintenance plan" developed as part of the re -designation process. Transportation projects
must demonstrate "conformity" with the control measures specified in the Washington State
Implementation Plan (SIP). The project site is within these carbon monoxide and ozone
maintenance areas.
Table 1: State and Federal Ambient Air Quality Standards
Pollutant
Federal Standard
State Standard
Puget Sound
Standard
Inhalable Particulate Matter (PM10) (Ag/m3)
Annual (Arithmetic Mean
Gtg/m)
NS
50
NS
24-hour Average ( /m)
150
150
150
Particulate Matter (PM2.5) ( 9/M3)
Annual Average /m3
15
NS
15
24-hour Average ( /m)
35
NS
35
Carbon Monoxide (CO)
8 -hour Average m
9
9 9
1 -hour Average (ppm)
35
35 35
®zone (®3)
8 -hour averse m)
0.075
0.075
0.075
1 -hour (Daily Maximum
NS
0.12
NS
Nitrogen Dioxide (NO2)
Annual Average (ppm)
0.053
0.05
0.053
1 -hour m
0.10
NS
NS
Lead (Pb)
Quarter) Avera e ( /m3 0.15 0.15 0.15
Sulfur Dioxide (S02)
Annual Average pm 0.03 0.03 0.02
24-hour Average ppm 0.14 0.10 0.10
1 -hour Average (ppm) NS 0.40 0.40
Source: PSCAA 2009 Air Quality Data Summary, EPA- wl „vGti.el av/a/air/c_ri;terii a.litin]
WD0E- Nv..A\0 (C} \\ 3. g()Vfl C()f.211Ii1S mllN/711 I:/(. ri�4M iel__Si nds,litnil 2011
NS=No standard established; (µg/m) = micrograms per cubic meter; ppin= parts per million
N
5. Affected Environment
This section provides an understanding of the existing environment as it relates to air quality.
It includes a discussion of the general climate, terrain and existing air quality in the project
area.
5.1. Regional Climate and Meteorology
The project site is subject to the same meteorological conditions that affect Puget Sound.
This region has a marine climate, dominated by cool, moist winds coming off the ocean.
Winter conditions are characterized by marine disturbances originating in the Pacific Ocean.
These storms are the source of the fall rains which usually begin in mid-October and
continue with few interruptions through the spring months. Daytime temperatures are
typically in the 40's and low 50's, with nighttime temperatures in the 30's. The succession
of Pacific disturbances is broken only once or twice each winter by the movement of cold
polar -continental air originating in northern Canada and moving southward over Washington.
Under such conditions, daytime temperatures will drop to around freezing, and nighttime
temperatures can reach 10-20 degrees Fahrenheit. Rainfall averages 4-9 inches per month
from November to February. Snow is frequent at the onset of cold weather, but
accumulations are generally less than two feet at lower elevations, such as the project site.
Winter winds are generally southerly, originating from the southeast to the southwest.
During the spring, the effects of the maritime low-pressure disturbances lessen and the
periods of improving weather, associated with high-pressure systems, lengthen. Daily high
temperatures average 70 to 80 degrees during July, August and September, with nighttime
lows in the 50's and 60's. Rainfall averages about 1 inch per month in July and August, and
about 2 inches per month in May, June and September. Summer winds have a pronounced
northerly component, originating from the north to the northwest.
On a more localized scale, one would expect the concentrations of pollutants in the vicinity
of the project site to be influenced very little by major topographical features, due to its
predominantly flat topography.
Temperature inversions are common throughout the Puget Sound region in fall and winter.
They are characterized by stagnant atmospheric conditions that tend to trap and concentrate
pollutants. In most cases these pollutant -trapping inversions have an upper "lid" at an
altitude between 1000 to 3000 feet and occur during the night, breaking up by early
afternoon. The project lies at less than 1000 feet elevation and thus is within the area subject
to inversions.
5.2. Major Terrain Features
Major terrain features can affect local air quality. To determine if there are any features that
could affect the air quality for this project, the project area was examined using topographical
E
maps and project design drawings. Although there are some slight elevation changes in the
area, the terrain is generally level in the project area, and is not predicted to have a notable
effect on local air quality.
5.3. Existing Air Quality and Compliance Status with NAAQS
The project site is located outside of any PMIo or PM2_5 (termed `fine particulate') non -
attainment areas, which are concentrated in the industrial areas of Everett, Seattle, Kent and
Tacoma. The nearest comparable particulate monitoring station site is operated by PSCAA,
measures PM2.5, and is located approximately 1.5 miles northeast of the project. This station
is located in a residential area experiencing substantial residential wood burning and would
have somewhat higher particulate levels than the project site. In the most recently published
data from 2009, there were no exceedances of the NAAQS, with an annual arithmetic mean
of 8.0ug/m3 and a 24-hour maximum of 25ug/m3.
EPA strengthened its 8 -hour ozone standard from 0.08 parts per million to 0.075 parts per
million in March 2008. Ozone levels at the Enumclaw Mud Mountain Dam monitor violated
the new standard for the period 2006 through 2008. The Puget Sound area is in attainment of
the 0.075ppm standard. PSCAA states that, "The 2009 ozone levels shown in this report just
meet EPA's 2008 standard, and they likely will not meet a further -strengthened standard"
(PSCAA 2009 Air Quality Data Summary). Ozone concentrations in the Puget Sound region
are measured at several locations east and south of the central Puget Sound urban area.
Ozone concentrations have remained relatively steady over the last ten years despite large
increases in regional population, employment and vehicle miles driven. The fact that ozone
concentrations have not increased is due to improvements in automobile engine technology
and the effectiveness of the various state and local programs, such as the Emission Check
program, and permitting requirements for industrial sources of hydrocarbons, one of the
precursors of ozone.
Carbon monoxide is a pollutant that dissipates rapidly with increasing distance from vehicle
traffic. Thus, monitoring results from distant sites will not reflect conditions elsewhere.
Monitoring sites are primarily located in the central business districts and adjacent to urban
arterials. There are no monitors in the immediate project area. Existing locality -wide
concentrations of CO are likely to range from 1.5 to 3.0 ppm. The modeling in this report
uses the EPA suggested value of 3.0 ppm as a one-hour average background CO
concentration. Carbon monoxide concentrations have declined sharply since 1988 at all
monitoring sites despite large increases in number of vehicles and vehicle -miles driven. This
is due to improvements in automobile engine technology and the effectiveness of the State's
Emission Check (I & M) program.
This section provides information on the air related studies required for this project. It
includes the project's status in the regional and state transportation plans, methodology for
the air analysis, and information on intersection performance and selection.
9
6.1. Non -Attainment Areas Affected By This Project
The project is located within the central Puget Sound maintenance area for carbon monoxide
and ozone. No other non -attainment or maintenance areas would be affected.
6.2. Project's Relation to Regional and State Transportation Plans
This project is included in the 2010-2013 State Transportation Improvement Program
(identified as EDM -17) and is included as a safety project in the City of Edmond's 2009
Transportation Plan. Summary of Conformity Guidance
The Transportation Efficiency Act for the 21St Century (TEA -21) and the 1990 Amendments
to the Clean Air Act established what are known as the Conformity Requirements in which
the guidelines for reviewing the air quality impacts of transportation projects were
established. These requirements apply to significant transportation projects, defined as those
being part of the regional transportation network that are located within, or affect, the non -
attainment areas or areas in attainment but subject to maintenance plan requirements. The
228th Street Southwest Corridor Improvement Project will affect motor vehicle traffic on
arterial streets located within the CO and Ozone Maintenance Plan areas. Consequently, a
project -level conformity analysis is required for intersections with LOS of D or worse. This
analysis consists of computer modeling of the project's carbon monoxide concentrations.
Conformity is demonstrated when three conditions are met:
The project does not increase the severity or frequency of existing exceedances of the
NAAQS standards.
The project does not cause new exceedances of the NAAQS standards.
The project does not delay the timely attainment of the NAAQS standards.
6.3. Methodology and Modeling Assumptions
This report presents the results of air quality modeling for carbon monoxide, which is based
upon the use of EPA emissions and dispersion models and Synchro v. 7 Traffic Signal
Coordination, a software implementation of the Highway Capacity Manual. Automobiles
emit other pollutants whose concentrations can be of concern in the Puget Sound region, such
as particulate matter, sulfur dioxide and nitrogen dioxide. However, only carbon monoxide
can be modeled at the microscale level with currently approved EPA models and
methodologies.
The Washington State Intersection Screening Tool (WASIST) was used to estimate current
and future carbon monoxide concentrations during "worst case" meteorological conditions
and heavy traffic flows. The tool uses regional CO emission rates, intersection -specific
traffic volumes, lane configuration and signal timing to determine pollutant concentrations at
specific points or receptors. The WASIST files are included in an Appendix supplied on CD.
Air quality modeling was performed only for the 2035 Build scenario for the 228th Street
Southwest /SR 99 intersection because there are no signals in the No Build scenario and the
2010 Build Synchro models show good LOS.
10
6.4. Intersection Selection
EPA modeling guidance requires that intersections within the project boundaries that have, or
will have, Levels of Service (LOS) of D or worse should be examined and modeled for air
quality impacts. In addition, signalized intersections within 1000 feet of the project
boundaries'that may be affected by the project must also be included in the model. There are
no signalized intersections within 1000 feet of the project boundaries. Table 2 summarizes
the intersection data used to select intersections for air quality modeling. The 228th Street
Southwest project is not expected to cause traffic volumes to increase on any alternate routes.
Table 2. Summary of Data Used to Select Intersections for Modeling
PM Peak
Level of
Included
Intersection and Scenario
Entering
Service'
in WASIST
Notes
Volumes
Model?2
The existing 3 -legged
configuration will be replaced
228' St. SWISR99
by a signalized 4 -legged
intersection.
Base Condition 2008 3010
A
NO
No Signal
2010 No Project 3127
A
NO
No Signal
2010 with Project 3591
C
NO
LOS is good
2035 No Project 5056
A
NO
No Signal
2035 with Project 5682
E
YES
Poor LOS
`
The existing 3 -legged
228" St. SW/76th Ave. W
configuration will be replaced
by a signalized 4 -legged
intersection.
Base Condition 2008 953
A
NO
No Signal
2010 No Project 991
A
NO
No Signal
2010 with Project 1296
B
NO
LOS is good
2035 No Project 1603
F
NO
No signal
2035 with Project 2229
C
NO
I LOS is good
Notes:
1. Level of Service (LOS) definitions for signalized
intersections, (delay in seconds):
A. Delay <= 10 seconds
B. Delay 10 — 20 seconds
C. Delay 20 — 35 seconds
D. Delay 35 — 55 seconds
E. Delay 55 — 80 seconds
F. Delay >= 80 seconds
2. Washington State Intersection Screening
Tool (WASIST) was used to
estimate current and future
carbon monoxide concentrations during "worst case" meteorological conditions and heavy traffic flows
M
The results of the air quality modeling analysis for the single receptor with the highest
pollutant level are shown in Table 3. A complete summary of the modeling results and print-
outs of the modeling inputs and outputs are included in the Appendix (available on CD).
Table 3. PM Peak Carbon Monoxide Levels at 228th St SW-SR99
Scenario
Highest 1 -Hour Concentration
Highest 8 -Hour Concentration
2035 with Project
7.5 ppm NE corner of intersection
16.2 ppm
None of the modeled receptors exceed the 8 -hour CO standards at the current time. None are
expected to exceed the standards in 2035 under the No Build scenario. Likewise, there are
no modeled exceedances due to the project in 2035.
Currently, no EPA -approved method exists for quantitatively predicting ozone or particulate
matter (PM) concentrations at the micro -scale (i.e. intersection) level. The concentrations of
CO emissions are highest in the immediate vicinity of an intersection, while the effects of
pollutants such as ozone and particulate matter are spread out over a larger area. The
complex reactive nature of ozone is such that accurate predictions of micro -scale ambient
concentrations cannot be made using current modeling procedures. Consequently, these
pollutants are regulated using transportation control measures contained in the State
Implementation Plan. Given the small scale of this project, it is assumed that ozone and
particulate matter from this project will have a minimal effect on regional ambient air quality
levels for these pollutants.
7.1. Indirect Air Quality Effects
No indirect air quality effects are expected as a result of this project.
7.2. Cumulative Air Quality Effects
. No cumulative air quality effects are expected as a result of this project.
8. Mitigation
No air quality impacts were identified and therefore no air quality mitigation measures are
required for this project. However, some of the usual mitigation measures that are normally
considered for the operational impacts of a highway project have been incorporated into the
project design. For example, one of the most effective mitigation measures available for
intersection design is partly incorporated into the design: the use of fully actuated signals
coordinated along the length of SR 99 in the vicinity of 228th Street SW.
This analysis is based upon the latest planning assumptions, uses the latest emissions and
dispersion models and follows the procedures setout in the Conformity Rule. The results of
WA
this analysis demonstrate that CO concentrations resulting from the project will not create
new violations of the CO NAAQS, worsen existing exceedances or delay the timely
attainment of the NAAQS. Therefore, this project meets the project -level transportation
conformity requirements.
Currently, no EPA -approved method exists for quantitatively predicting ozone or particulate
matter concentrations at a given intersection. The effects of CO emissions impact the
immediate area of emission, while the effects of pollutants such as ozone and particulate
matter are larger scale. The chemistry of ozone formation is complex, and accurate
predictions of microscale ambient concentrations cannot be made using current modeling
procedures. Typically these pollutants are monitored and modeled on a regional scale. It is
assumed that ozone and particulate matter from this project will have a minimal effect on
regional ambient air quality levels for these pollutants.
Local emissions of MSATS are expected to follow the same downward trend as the national
emissions shown in Figure 2. Greenhouse gas emissions will increase as vehicle volumes
rise and decline as the fuel mileage of the regional fleet improves.
10. Construction Activity Impacts
This project will involve several types of construction activities, including the following:
® Grading for the new road, buffer median and bike lanes
® Removing some portions of existing sidewalks, parking lots and road
pavement in the right-of-way
® Relocating underground utilities, light poles and signs
® Repaving and re -striping
® Installing new traffic signals
Typical emissions from these activities may include some combination of the six criteria
pollutants, in addition to fugitive dust and in some cases, MSATS. Table 4 provides a
summary of the different construction activities that are expected to occur and the typical
pollutants generated.
13
Table 4. Pollutants Generated by Construction Activities
Construction Task
Source of Emissions
Emissions
Removing existing buildings and/or
Track /wheel loaders,
CO, PM10, PM2.5, NOx,
concrete & paved surfaces
bulldozer, haul trucks,
SO2, fugitive dust, MSATS
tractor -mounted jack
hammers
Removing of concrete debris
Haul trucks, primary
Same as above
crusher, aggregate screens
Re -grading of roadbed, laying the
Track /wheel loaders,
Same as above
aggregate base
bulldozer, grader
Trenching for new utilities
Backhoe, gravel trucks
Same as above
Paving roads
Concrete trucks, asphalt
CO, PM10, PM2.5, NOx,
trucks, asphalt rollers
S02i MSATS
Painting lane markers
Paint spray equipment
Odorous compounds,
MSATS
10.1. Construction Phase Mitigation Measures
The Puget Sound Clean Air Agency (PSCAA) is responsible for enforcing air quality
regulations in the Puget Sound region of Washington, and they have developed fugitive dust
regulations contained in Section 9.15 of Regulation 1. The project shall utilize best available
control measures, including some of the following:
® Suppress dust on the construction site with water sprays.
® Construct pavement or riprap exit aprons.
® Prevent dust emissions during transport of fill material or topsoil by covering
load, by wetting down or by ensuring adequate freeboard on trucks.
® Prompt cleanup of spills from transported material on public roads by frequent
use of a street sweeper machine.
® Schedule work tasks to minimize disruption of the existing vehicle traffic on
streets in the vicinity of the proposed project.
® Maintain all construction machinery engines in good mechanical condition to
minimize exhaust emissions.
® All vegetation removed from the site will be trucked offsite for chipping and
reuse as mulch or composted.
The air quality impacts of the construction phase are not expected to present serious health
hazards. The contractors should minimize the idling of diesel engines and ensure that the
heavy equipment and trucks used in this project are in good repair. Some work may be
scheduled for hours of the day or night when there are fewer pedestrians and less traffic.
10.2. Construction Mitigation Measures Considered or Available but Not
Included
Some of the usual mitigation measures that are normally considered for the construction
impacts of a highway project, such as wheel washers for trucks exiting the construction site,
were examined and found to be not applicable for this project due to the relatively small
amount of earth -moving involved.
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U.S. Department of Transportation- Federal Highway Administration, March 31, 1989.
Memorandum: Revised Guidelines for the Control of Carbon Monoxide (CO) Levels in
Tunnels.
U.S. Environmental Protection Agency, November 1992a. Guideline for Modeling Carbon
Monoxide from Roadway Intersections. Report Number EPA -454/R-92-05. Research
Triangle Park, N.C.
U.S. Environmental Protection Agency, November 1992b. User's Guide to CAL3QHC
Version 2.0: A Modeling Methodology for Predicting Pollutant Concentrations near Roadway
Intersections. Report Number EPA -454/R-92-006. Research Triangle Park, N.C.
U.S. Environmental Protection Agency, October 2002. User's Guide to Mobile 6.1 and
Mobile 6.2: Mobile Source Emission Factor Model. Report Number EPA -420-R-02-028.
Research Triangle Park, N.C.
Washington State Department of Transportation, Section 425 Environmental Procedures
Manual — M31-11 September 2009.
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