1 4.0 Analyses of Individual Nonattainment Area

4.10 Region 10 Nonattainment Areas

4.10.4 Washington

State of Washington Area Designations For the 24-Hour Fine Particle National Ambient Air Quality Standard

The table below identifies the counties in Washington State that EPA has designated as not attaining the 2006 24-hour fine particle (PM2.5) standard. 1 A county (or part thereof) is designated as nonattainment if it has an air quality monitor that is violating the standard or if the county is determined to be contributing to the violation of the standard.

Area WA Recommended

Nonattainment Counties EPA’s Designated

Nonattainment Counties Wapato Hills-Puyallup River Valley (Tacoma) Pierce (partial) Pierce (partial)

EPA has designated the remaining counties in the state as “attainment/unclassifiable.”

EPA Technical Analysis for the Wapato Hills-Puyallup River Valley nonattainment area in Washington State

Introduction

Pursuant to section 107(d) of the Clean Air Ac t, EPA must designate as nonattainment those areas that violate the NAAQS and those nearby areas that contribute to violations. This technical analysis for the Wapato Hills-Puyallup River Valley nonattainment area identifies the single county in Washington State with a monitor that violates the 24-hour PM2.5 standard (Pierce County) and evaluates nearby counties in the Seattle-Tacoma-Olympia area for contributions to fine particle concentrations in the area. EPA has evaluated these counties based on the weight of evidence of the following nine factors recommended in EPA guidance and any other relevant

information:

- pollutant emissions - air quality data - population density and degree of urbanization

1 EPA designated nonattainment areas for the 1997 fine particle standards in 2005. In 2006, the

24-hour PM 2.5 standard was revised from 65 micrograms per cubic meter (average of 98 th
percentile values for 3 consecutive years) to 35 micrograms per cubic meter; the level of the

annual standard for PM 2.5 remained unchanged at 15 micrograms per cubic meter (average of annual averages for 3 consecutive years).2 - traffic and commuting patterns - growth - meteorology - geography and topography - jurisdictional boundaries

- level of control of emissions sources

We also used analytical tools and data such as pollution roses, fine particle composition monitoring data, back trajectory analyses, and the contributing emission score (CES) to evaluate these areas. (See additional discussion of the CES under factor 1 below.)

Figure 1 is a map of the counties in the Seattle-Tacoma-Olympia area and other relevant information such as the locations and design values of air quality monitors, and the metropolitan area boundary.

Figure 1. Wapato Hills-Puyallup River Valley (partial Pierce County) nonattainment area and surrounding counties in Seattle Tacoma area3 The violating monitor in the Pierce County area is located at 7802 South L Street (South L Street monitor) in a suburban area of the City of Tacoma. The nonattainment area is referred to as the Wapato Hills-Puyallup River Valley (WHPRV) area. The City of Tacoma is a major urban center in the Southern Puget Sound Region. Situated on Commencement Bay, an inlet of Puget Sound, Tacoma lies at the foot of Mt. Rainier in the Puyallup River valley, bordered by mountains. Commencement Bay serves the Port of Tacoma, a major center of international trade. The Port handled more than $36.33 billion in annual trade and nearly 2 million TEUs(Twenty-foot Equivalent container Units) in 2007. Tacoma is situated in the Seattle-TacomaOlympia Consolidated Statistical Area, a highly urbanized area along the Interstate 5 corridor. To the east of Interstate 5, along the eastern portion of Pierce, King, Snohomish, and Thurston Counties the Cascade mountains rise to over 14,000 feet in elevation at Mt Rainier in Pierce County. Tacoma is about 36 miles south from the city of Seattle, the largest city in Washington State and 30 miles north of the City of Olympia, the Capitol of Washington State. See Figure 2. The Puyallup Indian Reservation is located in the Tacoma Area, about five miles northeast of the violating monitor and is located within in the Wapato Hills-Puyallup River Valley partial county nonattainment area boundary. See Figure 3. The nonattainment area boundary is the pink line and the Puyallup Indian Reservation is shown in cross hatch.

Figure 2. Southern Puget Sound area topography4 Figure 3. Wapato Hills-Puyallup River Valley Nonattainment Area

The boundary of the Wapato Hills-Puyallup River Valley nonattainment area is described as

follows:

• Starting from where an extension of Kennedy Road Northeast would intersect Commencement Bay, proceed north to the intersection of Marine View Drive (State Route 509) and Kennedy Road Northeast.

• Proceed south on Marine View Drive to Hylebos Creek.

• Proceed south along Hylebos Creek to 12th Street East.

• Proceed east on 12th Street East to 70th Avenue East.

• Proceed south on 70th Avenue East to State Route 99 (S.R. 99).

• Proceed north on S.R. 99 0.1 mile north of Birch Street to a driveway to the east.

• Proceed east along the driveway and continue east along the same alignment to the Pierce County Line/Comprehensive Urban Growth Area (CUGA) boundary.

• Proceed east along the Pierce County Line /CUGA boundary to the eastern boundary of Edgewood.

• Proceed south along the eastern boundary of Edgewood to eastern boundary of the

Sumner Urban Service Area.

• Proceed south along eastern boundary of the Sumner Urban Service Area to the eastern boundary of the Puyallup Urban Service Area.5 • Proceed south along the eastern boundary of the Puyallup Urban Service Area to the eastern boundary of Puyallup/CUGA boundary.

• Proceed south and then west along the CUGA boundary to the eastern boundary of

McChord Air Force Base.

• Proceed north along the eastern boundary of McChord Air Force Base to the northernmost point on the eastern boundary.

• Proceed from the northernmost point on the eastern boundary of McChord Air Force Base to the south right-of-way of S.R. 512.

• Proceed west along the south right-of-way of S.R. 512 to the south right-of-way of I-5.

• Proceed south along the south right-of-way to I-5 to the point opposite the boundary between Lakewood and Camp Murray.

• Proceed north across I-5 to the boundary between Lakewood and Camp Murray.

• Proceed north along the western boundary of Lakewood to the point where the western boundary coincides with the CUGA boundary.

• Proceed north along the CUGA boundary to the southern boundary of Point Defiance

Park.

• Proceed east along the southern boundary of Point Defiance Park to Commencement Bay/CUGA boundary.

• Proceed southeast, then northeast, and finally northwest along the CUGA boundary to the starting point.6 In December 2007, the State of Washington reco mmended that a portion of Pierce County (the Wapato Hills-Puyallup River Valley area) be designated as “nonattainment” for the 2006 24-

hour PM 2.5 standard based on air quality data from 2004-2006. These data are from Federal Reference Method (FRM) monitors located in the State. See December 18, 2007 letter from Jay Manning, Director of the Washington Departme nt of Ecology to Elin Miller, Regional Administrator EPA Region 10. On March 13, 2008, the State submitted to EPA the partial county boundary shown in Figure 27. The State also submitted the following information to supplement their recommendation in a letter to EPA on July 25, 2008 2 :

• An analysis of speciation data for the South L Street monitor and monitors in the

Duwamish area and Lake Forest Park area

• An analysis of meteorological data from meteorological instrumentation colocated with the South L Street monitor

• An analysis of continuous monitoring data including diurnal air quality trends for monitors in King and Pierce Counties

Based on EPA's technical analysis and review of information provided by the State as described below, EPA has designated the Wapato Hills-Puyallup River Valley area (a portion of Pierce County) in State of Washington as nonattainment for the 24-hour PM 2.5 air-quality standard, based upon currently available information (see table below).

Wapato Hills-Puyallup River Valley nonattainment

area WA Recommended

Nonattainment Counties EPA’s-Final Designated

Nonattainment Counties

Washington State Pierce (partial) Pierce (partial)

The following is a technical analysis for the Wapato Hills-Puyallup River Valley nonattainment area (a portion of Pierce County) in State of Washington.

Factor 1: Emissions data

For this factor, EPA evaluated county level emission data for the following PM 2.5 components and precursor pollutants: “PM 2.5 emissions total,” “PM 2.5 emissions carbon,” “PM 2.5 emissions other,” “SO 2 ,” “NO

x ,” “VOCs,” and “NH 3. ” “PM 2.5 emissions total” represents direct emissions

of PM 2.5 and includes: “PM 2.5 emissions carbon,” “PM 2.5 emissions other”, primary sulfate (SO 4 ), and primary nitrate. (Although primary sulfate and primary nitrate, which are emitted directly from stacks rather than forming in atmospheric reactions with SO 2 and NO

x , are part of

“PM 2.5 emissions total,” they are not shown in Table 1 as separate items). “PM 2.5 emissions

2 See the following docket materials:

• July 25 WA State letter attachment PS Diurnals_2005-2007 data.png

• July 25 WA State letter attachment Presentation to OAQPS_as of25-Jul-08.pdf

• July 25 WA State letter attachment Tacoma L Street characteristics.pdf

• July 25 WA State letter attachment Tacoma L Street Speciation.pdf

• July 25 WA State letter attachment Tacoma_PM2.5 episode_12-16-Jan-07.png

• July 25 WA State letter attachment Duwamish_SO4_NO3_OC_ECvs_PM2.5_with_FRM.png

• July 25 WA State letter attachment Lake Forest_Park_SO4_NO3_OC_ECvs_PM2.5_with_FRM.png7 carbon” represents the sum of organic carbon (OC) and elemental carbon (EC) emissions, and

“PM 2.5 emissions other” represents other inorganic particles (crustal). Emissions of SO 2 and

NO

x , which are precursors of the secondary PM 2.5 components sulfate and nitrate, are also considered. VOCs (volatile organic compounds) and NH 3 (ammonia) are also potential PM 2.5 precursors and are included for consideration.

Emissions data were derived from the 2005 Nationa l Emissions Inventory (NEI), version 1. See http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html.

EPA also considered the Contributing Emissions Score (CES) for each county. The CES is a metric that takes into consideration emissions data, meteorological data, and air quality monitoring information to provide a relative ranking of counties in and near an area. Note that this metric is not the exclusive manner for considering data for these factors. A summary of the CES is included in attachment 2, and a more detailed description can be found at http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html#C.

Table 1 shows emissions of PM 2.5 and precursor pollutants components (given in tons per year) and the CES for violating and potentially contributing counties in the Seattle-Tacoma-Olympia area. Counties are listed in descending order by CES.

Table 1. PM 2.5 Related Emissions and Contributing Emissions Score

County State

Recommended

Nonattainment? CES

Score (Rank) PM2.5

emissions

- total (tpy) PM2.5

emissions - carbon (tpy) PM2.5

emissions - other (tpy) SO2

emissions (tpy) NOx

emissions (tpy) VOC

emissions (tpy) NH3

emissions (tpy)

King No 100 (1) 6,362 4,168 2,194 7,361 75,825 89,446 2,564 Pierce Yes (partial) 60 (2) 3,766 2,255 1,511 3,200 31,905 32,097 1,410

Thurston No 17 (3) 2,221 1,348 873 478 8,389 14,985 1,620

Kitsap No 14 (4) 2,204 1,201 1,004 442 6,199 9,588 274

Snohomish No 13 (5) 3,714 2,223 1,492 2,256 22,687 28,861 1,932

Skagit No 11 1,605 819 786 10,345 12,417 11,173 1,809

Island No 4 841 453 388 485 4,463 4,128 358

Mason No 3 767 439 328 100 1,623 3,846 90

Total PM 2.5 emissions in King County as well as individual chemical precursor components of

PM 2.5 are generally two times the emissions in Pierce County, the county which contains the violating monitor. In addition, the CES score of 100 indicates potential contributing emissions from King County. The next highest CES score of 17 was for Thurston County, which contains the City of Olympia located 36 miles to the south of the violating monitor. Given the low CES scores and relatively low emissions in Thurston, Kitsap, Snohomish, Skagit, Island and Mason Counties these Counties are less likely to contribute to the exceedences at the South L Street monitor than King County and Pierce County which have higher emissions and CES scores. We note that in counties with large land areas and complex terrain such as King and Pierce Counties, the CES does not account for diurnal variation in hourly PM 2.5 and sharp spatial gradients in8 emissions. 3 Those factors were separately considered and used in developing our designation

rationale.

The State of Washington submitted seasonal emissions inventory data as part of its nine factors analysis attachment to its letter to EPA dated December 18, 2007. Figure 4 and Table 2 display seasonal emissions in Pierce County, Washington for 2005 from the State’s submittal. As discussed below in factor 2 (air quality data), PM 2.5 exceedences at the violating monitor in Pierce County have occurred in the months of November, December, January and February during the years 2004-2007.

Winter season (December through February) air emissions of PM 2.5 in Pierce County are balanced among:

(1) outdoor open burning (202 tons per season, 24%),

(2) mobile sources (230 tons per season, 27%),

(3) fireplaces and woodstoves (326 tons per season, 39%), and

(4) other sources (84 tons per season, 10%)

Washington noted that these are estimates for a countywide emission inventory, and that outdoor open burning (with an estimated 24% contribution) is likely not occurring in the urban portion of the county near the violating monitor. Open burning is prohibited in these areas.

Figure 4.

3 See supporting documentation section on limitations of the CES. Because of differences in county size, and topography across the country, the score may require careful interpretation for some areas, particularly in the

western United States. 

### Pierce County Winter PM2.5 Emissions in 2005

Mobile

Sources

27% Fireplaces

and

Woodstoves

39% Other

Source
Categories

10% Outdoor
Open
Burning

24%9 Table 2. Pierce County Seasonal PM 2.5 Emission Sources in 2005

tp y tp y Annual Summer Fall Winter Spring A nnual Summer Fall Winter Spring

1,258 377 377 202 302 Outdoor Open Burning Land clearing burning 941 282 282 151 226 Yard waste burning 185 56 56 30 44 Forest wildfires and managed burns 117 35 35 19 28

Structural fires 11 3 3 3 3 Agricultural waste burning 4 1 1 1 1 1,036 284 259 230 263 Mobile Sources On-road gasoline vehicles 296 77 74 71 74 Non-road diesel engines 280 78 67 62 73

On-road diesel vehicles 201 52 50 48 50 Non-road gasoline engines 80 22 19 18 21 Ocean-going vessels 54 14 14 14 14

Harbor vessels 35 9 9 9 9 Railroad diesel engines 27 7 7 7 7 On-road CNG and LPG engines 4 1 1 1 1 Aircraft ground support engines 3 1 1 1 1

Aircraft 2 1 1 1 1 Non-road LPG engines 2 1 1 1 1

Recreational boats 52 22 17 0 13 679 34 95 326 224 Fireplaces and Woodstoves Wood stove wood burning 430 22 60 206 142 Fireplace wood burning 165 8 23 79 54 Fireplace and wood stove firelog burning 78 4 11 37 26 Pellet stove wood burning 6 0 1 3 2 261 49 56 84 72 Other Source Categories Industrial point sources 181 45 45 45 45 Natural gas burning 67 3 9 32 22 Boiler and furnace distillate oil burning 11 1 2 5 4 Propane furnaces and boilers 2 0 0 1 1 3,234 744 787 842 860 Totals 3,234 744 787 842 860 PM2.5 Emission Source Categories and Subcategories 2005 Category PM2.5 Emissions

tons/season 2005 Subcategory PM2.5 Emissions

tons/season

Fireplaces and woodstoves are the largest source of emissions in Pierce County (39%). The State conducted additional analyses to determine the spatial variation in wood burning activities. Figure 5 displays the number of people using wood as a primary source of heat in the immediate area of the South L monitor, per square mile. The information source is the 2000 census, and is presented at a block group level 4 . This information does not capture those who use wood as a secondary heat source, or those who use fireplaces for ambiance. The highest density of woodstove/fireplace use occurs within the Tacoma urban growth boundary and in census blocks north of SR 512 in the vicinity of the monitor. See Figures 5 and 6.

Based on annual emissions inventory data for Pierce, King and surrounding counties, VOC and NOx emissions comprise the largest portion of total PM 2.5 emissions. However, this

data is annual data and exceedences of the 24-hour PM 2.5 standard at the South L Street monitor occur exclusively in the late fall-winter seasons. Seasonal emissions inventory data submitted by

the State indicates that emissions from woods toves and fireplaces account for over 40% of the

4 US Census Bureau. http://factfinder.census.gov/home/saff/main.html10 total emissions in Pierce County, while mobile sources account for 27% of total emissions in Pierce County during the winter season when exceedences of the 24-hour PM 2.5 standard occur.

Based on emission levels and CES values, EPA considered King and Pierce Counties

candidates for a 24-hour PM 2.5 nonattainment designation for violations at the South L Street monitor in Pierce County. However, we have further evaluated potential contributions fromsurrounding counties in the Seattle-Tacoma-Olympia area in our analysis of the remaining ninefactors.11 Figure 5.12 Figure 6.13 Factor 2: Air quality data

This factor considers the 24-hour PM 2.5 design values (in μg/m 3 ) for air quality monitors in counties in the Seattle-Tacoma-Olympia based on data for the 2005-2007 period. A monitor’s design value indicates whether that monitor attains a specified air quality standard. The 24-hour

PM 2.5 standards are met when the 3-year average of a monitor’s 98 th percentile values is 35 μg/m 3 or less. A design value is only valid if minimum data completeness criteria are met.

. The 24-hour PM 2.5 design values for counties in the Seattle-Tacoma-Olympia area are shown in

Table 3.

Table 3. Air Quality Data for Seattle-Tacoma-Olympia Area

County State

Recommended

Nonattainment? Design Values

2004-06 (μg/m 3 ) Design Values

2005-07 (μg/m 3 )

Pierce, WA Yes 42 43 King, WA No 29 31
Snohomish, WA No 33 35
Thurston, WA No N/A N/A
Island, WA No N/A N/A Kitsap, WA No N/A N/A
Mason, WA No N/A N/A

In Washington State, the monitor at 7802 South L Street in Tacoma (Pierce County) is the only

monitor that violates the 24-hour PM 2.5 standard based on 2005-2007 data. King and Snohomish County do not violate based on 2004-2006 or 2005- 2007 data. The remaining counties do not have Federal Reference Method monitor, therefore Federal Reference Method 5 data is not

available for these counties.

Although the surrounding counties of King a nd Snohomish do not violate the standard, this alone was not sufficient information for EPA to eliminate King County or Snohomish County as candidates for inclusion in the nonattainment area. Nearby counties could be contributing to the violations at the South L Street monitor even though there are no violating

monitors in those counties.

EPA analyzed data submitted by the State of Washington collected from monitoring several sites in addition to the Pierce County Tacoma South L Street Site to better characterize

PM 2.5 in Tacoma and in the surrounding counties. Since the high CES score for King County indicates a potential contribution to the exceedences at the South L Street monitor from King County, and since western King County is a highly urbanized area, this analysis focused in particular on examining additional air quality data for King County.

5 Design values are based on data collected at FRM or FEM mon itors. The State operates other monitors in these counties but they are not FRM or FEM monitors.14 Figure 7 shows the location of several monitors in the Puget Sound area. The following pages discuss air quality data from these sites locat ed along the Interstate 5 corridor in Pierce and King Counties. These areas include Marysville, Lynnwood, Lake Forest Park and Tacoma, which are largely urban-suburban residential ar eas, and the Duwamish, Puyallup South and Kent Valley areas, which are more industrialized areas.

Table 4 displays the top 5% of concentra tions at the South L Street Monitor from 2004- 2007 from EPA’s Air Quality System (AQS) repository of ambient air quality data. All of these concentrations occurred during the months of November, December, January or February with the exception of one which occurred in late October, 2007. The exceedences at the South L Street monitor occur during the winter as the State suggests in its nine factor analysis.

Table 4. Top 5% values at Tacoma L Street Monitor from 2004-200715 Figure 7. Puget Sound Area monitor locations

Lake Forest Mar y swville

Lake Forest Par k

Mountlake Terrace

Queen Anne Hill

Duwamish

Kent

South L Street Monito r Pu y allu p South16 Speciation Profiles

The State submitted chemical speciation monitoring data collected at the Tacoma South L Street monitoring site in the year 2006. Fifty nine (59) samples were collected (one sample every six days). Out of these 59 samples, four samples were for days above 30 μg/m 3 , and 55 samples were for days that were below 20 μg/m 3 . Figure 8 displays percentage of the speciated components of total PM 2.5 for the two highest days in 2006 for which the speciation data was

collected. On December 19 th , 21.57 μg/m 3 (74%) of the total PM 2.5 was organic and elemental carbon. Sulfate and nitrate were .87 μg/m 3 (3%) and 1.86 (6%) respectively of the total PM 2.5

. On December 31, 37.67 μg/m 3 of PM 2.5 (69%) was organic carbon, 2.86 μg/m 3 was elemental carbon (5%), 1.94 (4%) was sulfate and 1.54 μg/m 3 (3%) was nitrate.

Figure 8. Speciated components of Total PM 2.5 from the Tacoma South L Street Monitor on high days in 2006

Figure 9 is a plot of PM 2.5 fraction components by season against PM 2.5 concentration. The highest concentrations of PM 2.5 occur at the L Street monitor in November and December. During the first (Jan- March) and fourth (Oct -Dec) quarters when the exceedences occur, the

ratios of sulfate and nitrate with total PM 2.5 are generally less than 0.2. The highest ratios of

sulfate and nitrate to total PM 2.5 (above 0.2) occur in the second (April-June) and third (JuneAugust) quarters when PM 2.5 concentrations are less than 15 μg/m 3 . The organic carbon fraction

to total PM 2.5 ratio is highest of any component at all times during the year ranging from 0.2- 0.5). In the fourth quarter, the OC/total PM reaches its highest levels when PM 2.5 concentrations are greater than 30 μg/m 3

.17 Figure 9. Seasonal PM2.5 components collected at the South L Street monitor in 2006.18 Positive Matrix Factorization analysis of chemical components on Pierce County filter

Since an analysis of chemical speciation data for high PM2.5 days at the South L Street monitor in 2006 was an important part of the State’s submittal, EPA evaluated the State's submittal of speciation data for the South L Street site using the Positive Matrix Factorization (PMF) tool. PMF is one of the receptor models that EPA’s Office of Research and Development has developed to provide scientific support for current ambient air quality standards and for implementation of those standards by identifying and quantifying contributions for source apportionment. This model draws from ambient air quality data sets and receptor model algorithms to compute profiles and relative contri butions from different source categories. See http://www.epa.gov/heasd/products/pmf/pmf.htm. 6 This evaluation using the PMF tool also supplements the speciation data and other information provided by the State on source

contributions to the violations at the Sout h L Street monitor by providing information on categories of sources and relative contributions from these sources to the violations at the South L Street Federal Reference Monitor. This analysis was particularly informative in our evaluation of the unique Tacoma area PM 2.5 pollution problem where the State's submittal suggests

localized sources cause and contribute to the viola tions at the South L Street monitor and where, as explained above, and distinct from most other areas in the country we have evaluated, the CES tool had limitations for the area. Additionally, and as explained above, our final boundary determination for this area is based on a myriad of factors and various analyses, only one of which is a PMF analysis. Taken together with other data and facts analyzed and explained in detail elsewhere in this document, it helps us to better understand the types of source categories which cause or contribute to the PM2.5 pollution in the Tacoma area.

The 2006-07 PMF data set included 111 data points (a sample every 6th day), most of which was the same period that the State used in their speciation monitoring study of the area. EPA's evaluation of this dataset using PMF indicates relative source contributions that support the State’s analysis of the chemical speciation and other air quality data which indicates that smoke from woodstoves and fireplaces is the major c ontributor to PM2.5 on high days at the South L

Street monitor. PMF results indicate that w ood smoke contributed 60-90% of the mass on 6 out of 7 days when total PM2.5 mass exceeded 30 μg/m3

. See Table 5. More detailed information on the PMF analysis for the South L Street monitor is included in the docket for this action.

6 Positive matrix factorization (PMF) (Footnoted: A. Reff et al, “Receptor Modeling of Ambient Particulate Matter Data Using Positive Matrix Factorizati on: Review of Existing Me thods,” Journal of the Ai r and Waste Management

Association , 57:146-154, February 2007.) is a recent development in the class of data analysis techniques called factor analysis, in which the fundamental problem is to resolve the identities and contri butions of components in an unknown mixture. PMF has been used extensively for source apportionment of ambient particulate matter (PM), to resolve the mixture of sources that contributes to PM samples. PMF is especially applicable to working with environmental data because it incorpor ates the variable uncertainties often associated with measurements of environmental samples, and forces all of the values in the solution profiles and contributions to be nonnegative, which is more realistic than solutions from previously used methods like principal components analysis

.19 Table 5. Positive Matrix Factorization Results for L Street monitor for days over 30 in 2006 and

2007

Comparison with monitoring data from other sites in King County

Figure 10 contains seasonal PM 2.5 components from two monitors, one in an industrialized area the southern portion of King County (Duwamish) and the other in northern King County in a residential area, Lake Forest Park. The Lake Forest Park monitor is a neighborhood scale site and is representative of the Lake Forest Park general area. 7 Figure 11 shows the location of these

monitors in relation to the South L Street Monitor in Tacoma. The Duwamish monitor is about

30 miles north of the South L Street Monitor and the Lake Forest Park Monitor is about 50 miles

north of the South L Street Monitor.

The Lake Forest Park monitor generally shows the same pattern observed at the South L Street monitor. Organic carbon dominates all fractions but the highest (>20 ug/m3 occur) fraction occurs in the first and fourth quarters. The highest fractions of sulfate and nitrate occur in the second and third quarters of the year when PM 2.5 concentrations are lowest (generally below 10). The Duwamish monitor shows a shift upward of sulfate/ PM 2.5 ratio for all quarters.

Ratios of sulfate to total PM 2.5 are more consistent throughout the year at the Duwamish monitor and generally range between .1-.3. The data points at this monitor are more tightly clustered showing less seasonal variation then at the Lake Forest Park and Tacoma monitor.

7 Washington State Department of Ecology 2008 Ambient Air Monitoring Network Report20 Figure 10. Seasonal PM 2.5 components at Lake Forest Park and Duwamish since 200521 Figure 11. Location of monitors in the Southern Puget Sound Area

Figure 9 Seasonal PM2.5 components at Duwamish since 2005 Lake Forest Park

Duwamish

Tacoma S L. Kent Valley Queen Anne Hill Mountlake Terrace Marysville

Puyallup South22 Diurnal Profiles

Figures 12-14 display diurnal PM 2.5 concentrations at continuous monitors throughout the Puget Sound Area. Figure 12 shows diurnal PM 2.5 concentrations at the South L Street monitor for the period 2001-2007. PM concentrations at the South L Street monitor rise sharply beginning in the late afternoon and then peak around midnight then tail off around mid day. Survey data from Washington State indicate that this profile is related to woodstove use 8 . Surveys indicate that individuals ignite or add fresh fuel in the la te afternoon or early evening and often add fuel before bedtime resulting in peak concentrations at night and lowest concen trations during the day while individuals are away from home. The diurnal profile for the Lake Forest Park monitor (Figure 13) shows a similar “V” shaped profile to the profile observed at the L Street monitor while the profile while the profile for the Duwamish monitor (Figure 14) is relatively flat. Figure 15 is a map of the monitors throughout the Puget Sound area with diurnal profiles. The “V” shaped profile is observed at monitors in the communities in Snohomish County to the North (Lynnwood, Lake Forest Park and Marysville). A flatter profile is observed at the monitors in central and southern King County; the Queen Anne monitor, the Seattle Duwamish Valley monitor and the Kent Valley monitor.

Figure 12.

Figure 13.

8 Puget Sound Clean Air Agency 2007 woodstove use survey23 Figure 14.

Figure 15. Diurnal profiles at monitoring sites in Pierce, King and Snohomish Counties24 Figure 16 plots one hour averages from a co-located nephelometer at the Tacoma L Street monitor during an episode. On January 12, 2007 the 24-hour design value at the L Street monitor was 44.7 μg/m 3 and on January 15, 2007, the 24-hour design value at the L Street monitor was 58.6 μg/m 3 . The red line indicates the 24-hour standard, 35 μg/m 3 . Peak PM 2.5 during this episode occurred around midnight on January 13 and January 15. During the day of

the 12 th and the 13 th PM 2.5 levels dropped to less than 10 μg/m 3 . The pattern repeats with nighttime highs climbing well above the standard and daytime lows.

When this pattern is observed at Tacoma, an identical pattern is noted at the other monitors throughout the Region with the V shaped profile. In between events, PM 2.5 levels generally drop to very low levels (<10 μg/m 3 ) indicating that there is not significant transport of PM precursors from other areas (Figure 18). Days that do not drop to very low levels are days where inversions have not broken down completely.

Figure 16. PM 2.5 Tacoma L Street January 11-16 200725 Figure 17. Simultaneous PM 2.5 peaks at Southern Puget Sound monitors

Air Quality Data Discussion/Conclusions

Concentrations of PM 2.5 throughout the Southern Puget Sound area peak at night and in the winter. The diurnal patterns are observed at neighborhood scale monitors in Pierce and King County and show peaks consistent with use of woodstoves collected through woodstove surveys. Monitors in the more industrial areas in southern King County (Kent and Duwamish) between the neighborhood scale monitors to the north and the South L Street monitor to the south do not exhibit strong diurnal patterns consistent with w oodstove use surveys. Seasonality of sulfate and nitrate concentrations at these monitors is also less variable than the seasonality of sulfate, nitrate and organic carbon observed at the South L St reet monitor and other neighborhood monitors (Lake Forest Park). The diurnal profiles and seasonality of organic carbon (components that are associated with burning of wood) indicate th at emissions from woodstoves and fireplaces

contribute to elevated wintertime concentrations in residential areas such as the South L Street

and Lake Forest Park areas.

Based on EPA’s PMF analysis, organic carbon/woodstoves contribute 60-90% of PM 2.5 to the exceedences at the South L Street Monitor. Contributions of regional PM 2.5 precursors (SOx and NOx) that dominate the King County em issions inventory contribute less than 20-30%

of total PM 2.5 to the Tacoma monitor. Based on speciation monitoring at the South L Street monitoring site, organic carbon and elemental carbon contribute over 70% of the PM 2.5 concentration on the highest days in 2006 and sulfate and nitrate contribute less than 10%

combined of the total PM 2.5 concentration on these days. Based on speciation monitoring, emissions from King County (over 75,000 tpy NOx and 7500 tpy SOx) as well as emissions from the other counties in the CMSA potentially contribute less than 10 % of total PM 2.5 concentrations on high days at the South L Street Monitor.

Based on the foregoing analyses, EPA conclude s that sources contributing the violations

of the PM 2.5 exceedences at the South L Street monitor are predominantly local sources dominated by woodstove and fireplace emissions in the Tacoma area and not transport from King County or other counties in the Seattle-Tacoma-Olympia area.

This information along with the information discussed in the other factors, particularly factors 6 and 7 (meteorology and topography) was used to determine that the partial Pierce County boundary submitted by the State on March 13, 2008 is sufficiently large enough to contains sources contributing to the 24-hour PM 2.5 violations at the South L Street monitor.26 Factor 3: Population density and degree of urbanization (including commercial development)

Table 6 shows the 2005 population for each county in the Seattle-Tacoma-Olympia area being evaluated, as well as the population density for each County in that area. Population data give an indication of whether it is likely that population- based emissions might contribute to violations

of the 24-hour PM 2.5 standards. King County, Pierce County and Snohomish County contain large cities with large populations. Most of the areas in between are urban or suburban. The City of Everett is the largest city in Snohomish County. King County has the highest population (1.79 million) and the highest population density with 824 people/square mile. Pierce County has the next highest population at 753,209 with the third highest population density in the Seattle-Tacoma-Olympia area. Snohomish County has the third highest population in the area. King County and Pierce Counties have the highest CES scores at 100 and 60 respectively. The CES Score for Snohomish County is much lower at 13.

Table 6. Population in the Puget Sound area

County State

Recommended

Nonattainment? 2005 Population 2005 Population Density (people/sq mi) Percent Population Change (2000-05)

King No 1,799,119 824 3
Pierce Yes 753,209 445 7
Thurston No 228,881 305 10 Kitsap No 241,525 583 4
Snohomish No 655,564 312 8 Skagit No 113,181 65 9
Island No 79,983 377 11
Mason No 54,169 54 9

The State addressed population density in its ni ne factor analysis. Figure 18 shows population density for the city of Tacoma and surrounding Pierce County areas, at the 2000 census block group level. In Pierce County, the highest population density occurs inside of the Comprehensive Urban Growth Area (CUGA) in the vicinity of the L Street monitor, and along the eastern shore of the Puget Sound to the north of the Port of Tacoma. 9 Population density generally decreases to the south and the east of the Port of Tacoma and the CUGA. Figure 19 shows the population of the recommended nonattainment area and the surrounding portions of Pierce County.

Based on the air quality data we reviewed above and the additional factors that we review below

which indicate that local sources cause the violati ons at the South L Street monitor, and based on population data which indicate that the highest population density in the Pierce County area is within the Tacoma CUGA, EPA concludes that a boundary that includes populations/potential sources in the Tacoma CUGA is appropriately large enough to include populations and sources contributing to the violations at the South L Street monitor.

9 See Chapter 36.70A RCW for more on the Washington State Growth Management Act which defines an urban growth area or areas within which urban growth shall be encouraged and outside of which growth can occur only if

it is not urban in nature.27 Figure 18.28 Figure 19. Pierce County Population Density with recommended nonattainment area boundary

Factor 4: Traffic and commuting patterns

This factor considers the number of commuters in each county who drive to another county within the Seattle-Tacoma-Olympia area, the pe rcent of total commuters in each county who

commute to other counties within the Seattle-Taco ma-Olympia area, as well as the total Vehicle Miles Traveled (VMT) for each county in millions of miles (see Table 7). A county with numerous commuters is generally an integral part of an urban area and could be an appropriate29 county for implementing mobile-source emission control strategies, thus warranting inclusion in

the nonattainment area. 10

Table 7. Traffic and commuting patterns in the Puget Sound area

County State

recommend

ed

Nonattainm

ent? Vehicle

Miles

Traveled in

2005 (millions annually) Percent

VMT

Growth (1996- 2005) Number commuting into any violating

counties Percent commuting into any violating

counties Number commuting into

and w/in the

statistical area Percent commuting

into and w/in

the statistical

area

King No 16,806 10 18,560 2 903,520 99

Pierce Yes (P) 6,247 13 228,280 70 319,830 99

Thurston No 2,146 7 14,350 14 96,030 95

Kitsap No 1,633 (10) 5,120 5 104,640 98

Snohomish No 5,225 9 1,240 0 296,750 99

Skagit No 1,185 35 140 0 42,950 95

Island No 397 (5) 50 0 31,510 97

Mason No 438 13 860 5 18,310 97

The listing of Counties on Table 7 reflects a ranking based on the number of people commuting to other counties. King County VMT in 2005 was the highest in the area with historic VMT growth of 10%. Two percent of commuters from King County commute into Pierce County, the County with the violating monitor. Seventy percent of commuters in Pierce County remain within Pierce County. VMT growth in Pier ce County between 1996-2005 was 13%. Both King County and Pierce County contain major ports (the Port of Tacoma and the Port of Seattle), so there are increased levels of diesel traffic to move goods at the Ports

. Interstate 5 is a major N-S corridor along the West Coast of the United Stat es with significant diesel truck traffic.

Washington looked at Pierce County VMT grow th in its nine factors analysis. Washington obtained information from the Puget Sound Regional Council’s recently released draft Vision 2040 transportation plan for the re gion, incorporating known travel improvements and the preferred growth options emphasizing core centers for development. The output from PSRC's transportation demand model provides some travel growth estimates for the Pierce County area and is shown in Table 8. 11

10 Note: The 2005 VMT data used for table 5 and 6 of the 9-factor analysis has been derived using methodology similar to that

described in “Documentation for the final 2002 Mobile National Emissions Inventory, Version 3, September 2007, prepared for the Emission Inventory Group, U.S. EPA. This document may be found at: at ftp://ftp.epa.gov/EmisInventory/2002finalnei/docum entation/mobile/2002_mobile _nei_version_3_report_092807.pdf

The 2005 VMT data were taken from documentation which is still draft, but which should be released in 2008.

11 Puget Sound Regional Council. Draft Vision 2040 Supplemental Draf t Environmental Impact Statem ent (SDEIS). July 2007.
http://www.psrc.org/projects/ vision/pubs/sdeis/index.htm and http://www.psrc.org/tpbgrowthandtrans2.pdf

. Puget Sound Regional Council. Vision 2020 Update DEIS. Tr ansportation Demand Model Out put Data. Appendix D-5, pages D-18 to D-29. http://www.psrc.org/proj ects/vision/deis/appd.pdf

.30 Table 8. Pierce County Daily Travel Measures by Category in 2000 and 2040 Daily Category of Travel 2000 Reference Data 2040 Units Work Person Trips 293,886 535,330 Trips Non-work Person Trips 1,757,784 3,183,447 Trips Freeways Vehicle Miles Traveled 6,288,090 8,870,622 VMT
Arterials/Local Streets VMT 10,650,108 16,299,840 VMT Freeways Vehicle Hours Traveled 129,929 191,106 VHT
Arterials/Local Streets VHT 363,175 617,769 VHT

Even with planned road and transit improvements, work and non-work person trips are estimated to increase by over 80%, while vehicle miles traveled and vehicle hours traveled are estimated to increase by 40% and 60%, respectively, from 2000 to 2040. Based on EPA’s PMF analysis of air quality data, mobile emissions likely do not contribute more than 5-10% of total PM 2.5 at the L Street monitor on high days. The State’s boundary includes potential mobile source related contributions in the Tacoma area including the Port of Tacoma as well as sections of Interstate 5 and State Highway 99 and EPA has concluded that the inclusion of these areas is sufficient to capture potential contributions from these sources.

Note: The 2005 VMT data used for table 5 and 6 of the 9-factor analysis have been derived using methodology such as that described in "Documentation for the 2005 Mobile National Emissions Inventory, Version 2," December 2008, prepared for the Emission Inventory Group, U.S. EPA. This document may be found at: ftp://ftp.epa.gov/EmisInventory/2005_nei/mobile _sector/documentation/2005_mobile_nei_versi on_2_report.pdf

Factor 5: Growth rates and patterns

This factor looks at expected population and VMT for Counties in the Seattle-Tacoma-Olympia area from 2000 to 2005, as well as patterns of popul ation and VMT growth. A county with rapid population or VMT growth is generally an inte gral part of an urban area and could be contributing to fine particle concentrations in the area.

Table 9 below shows population, population gr owth, VMT and VMT growth for counties that are included in the Seattle-Tacoma-Olympia area. Counties are listed in descending order based on VMT growth between 1996 and 2005.31 Table 9. Population and VMT Growth and Percent Change

County 2005 Population Percent Population Change (2000-05) Vehicle Miles Traveled in 2005 (millions annually) Percent VMT Growth (1996-2005)

King, WA 1,799,119 3 16,806 10

Pierce, WA 753,209 7 6,247 13

Thurston, WA 228,881 10 2,146 7
Kitsap, WA 241,525 4 1,633 (10)

Snohomish, WA 655,564 8 5,225 9
Skagit, WA 113,181 9 1,185 35

Island, WA 79,983 11 397 (5)

Mason,WA 54,169 9 438 13

King County has the highest population but had the lowest population growth rate from 2000- 2005 (3%). Pierce County population growth was double that of King County for the same time period. Thurston County and Island Counties experi enced the highest growth in population from 2000-2005 at 10% and 11% respectively. However, the population of both of these areas is 1-2 orders of magnitude lower than that of King County and 3-8 times lower than that of Pierce County. As stated above, based on air quality data, mobile emissions likely do not contribute

more than 5-10% of total PM 2.5 to L Street monitor PM 2.5 concentrations on high days. EPA’s final boundary includes most of the Pierce County Growth area including the Port of Tacoma.

Factor 6: Meteorology (weather/transport patterns)

For this factor, EPA considered data from National Weather Service instruments in the area. Wind direction and wind speed data for 2005-2007 were analyzed, with an emphasis on “high

PM 2.5 days” for each of two seasons (an October-April “cold” season and a May-September “warm” season). These high days are defined as days where any FRM or FEM air quality

monitors had 24-hour PM 2.5 concentrations above 95% on a frequency distribution curve of

PM 2.5 24-hour values.

For each air quality monitoring site, EPA developed a “pollution rose” to understand the prevailing wind direction and wind speed on the days with highest fine particle concentrations. The figure identifies 24-hour PM2.5 values by color; days exceeding 35 ug/m3 are denoted with a red or black icon. A dot indicates the day occurred in the warm season; a triangle indicates the day occurred in the cool season. The center of the figure indicates the location of the air quality monitoring site, and the location of the icon in relation to the center indicates the direction from which the wind was blowing on that day. An icon that is close to the center indicates a low average wind speed on that day. Higher wind speeds are indicated when the icon is further away

from the center.

Figure 20 is a pollution rose from instrume ntation at Boeing Field, a King County airport which is located about 24 miles north of the violating monitor. Based on this pollution rose, the prevailing surface wind directions for the highest PM 2.5 days in King County are from the southeast of the Lake Forest Park monitoring site in King County.32 Given terrain influence and complex meteorology in King County and Pierce County, it was important to look at data from a meteorol ogical station located closer to the violating monitor. As mentioned above, the Boeing Field monitor is located 24 miles away from the South L Street monitor. EPA, therefore, also created a pollution rose using data from the McChord Air Force Base which is located about 3 miles southwest of the violating monitor. Figure 21 is the pollution rose created with the McChord data. Based on this pollution rose, during high days at the Tacoma L Street monitor, wind speeds are less than 2 miles per hour. Because of these low wind speeds we could not draw a conclusion on an average prevailing surface wind direction for high PM 2.5 days (exceeding 30 ug/m3). For days below 30 ug/m3 average prevailing winds are from the southwest. The low wind speeds as well as the direction of the average prevailing winds at the McChor d indicate that emissions from King County are not likely contributing to the violations at the South L Street monitor.

Figure 20. Pollution Rose for King County WA (Source: Boeing Field)33 Figure 21. Pollution rose for Pierce County WA (Source: McChord AFB)34 We note that the meteorology factor is also c onsidered in each county’s Contributing Emissions Score because the method for deriving this metric included an analysis of trajectories of air masses for high PM 2.5 days. The data used to create the CES for the Tacoma monitor was from the Seattle –Tacoma International Airport which is located 6 miles south of Boeing Field. Given the complex meteorology and topography of the area, and given that EPA’s pollution roses for the McChord Air Force Base meteorological s ite and the King County Boeing Field Airport show very different wind patterns, EPA consider ed the data from the McChord Air Force Base meteorological site in lieu of the CES for the meteorological factor analysis for the Wapato Hills-Puyallup River Valley area

.

The wind rose from the McChord Air Force ba se demonstrates meteorological conditions in the Wapato Hills-Puyallup River Valley area during the fall and winter seasons when the exceedences occur at the South L Street monitor. During this time, regional air stagnations interrupt westerly wind flows and strong subsiden ce temperature inversions trap pollution levels and colder mean temperatures stimulate the use of residential heating devices.

Temperature inversions vary in intensity and can persist over a period of days. These inversions change the mixing layer depth dramatically but generally lower the layer to less than 800m. During persistent winter stagnations, mixing heights less than 300m are frequently observed typically these conditions occur when the duration of stable conditions extends beyond three days. 12 This occurs approximately 3-4 times during the fall and winter seasons.

Puget Sound Clean Air Agency, in coordination with the National Weather Service office in Seattle operates a radar wind profiler at the Sand Point Laboratory of the NOAA. Figure 22 displays the mixing height during the typical st agnation event in the Puget Sound area. Mixing heights at 600 meters or less are observed during the typical PM 2.5 event.

12 A Presentation to Northwest AirQuest on Analysis of Sand Point Wind Profiler and RASS system, included in the

docket for this action.35 Figure 22. Typical inversion profile for the Southern Puget Sound Region stagnation

Air movement in the area surrounding the South L Street monitoring station is influenced by these meteorological conditions. Figure 26 plots wind direction against hourly concentrations, wind direction against wind speed, wind speed ag ainst hourly concentrations and temperature against hourly concentration data gathered from a 2001-2008 Washington State temporary monitoring study 13 . This data indicates that meteorological conditions that are present at the L Street Monitoring site are typical of those obser ved in the area's fall and winter seasons including periods influenced by moderate temperatures, str ong Pacific storms, and air stagnations. Highest hourly concentrations occur at temperatures below freezing, highest concentrations are associated with winds below 5 mph and often times less than 1 mph, and the highest winds from

13 Study results are included in the State of Washington’s Nine Factors Analysis36 the south and the southwest quadrant correspond to lowest PM 2.5 concentrations and the lowest winds from the east to southeast correspond to highest PM 2.5 concentrations.

EPA determined from this meterological data that transport from King County and other areas is not occurring during the periods of the hi ghest concentrations and that a partial county boundary surrounding the South L Street monitor and capturing the sources in the Tacoma area within the CUGA is sufficiently large enough to sources of emissions that contribute to the

violations at the South L Street monitor.

Figure 23. Hourly concentrations and wind sp eed at Tacoma L Street Monitor from 2001-2008

2004

Factor 7: Geography/topography (mountain ranges or other air basin boundaries)

The geography/topography analysis evaluates the physi cal features of the la nd that might have an

effect on the air shed and therefore on the distribution of PM 2.5 over the Wapato Hills-Puyallup River Valley/Tacoma area. Tacoma lies east of the Cascade Mountains, which act as a topographical barrier to pollution flow from east to west. The Olympic Mountains to the west result also influence pollution flow. Air flow fr om the west typically flows around the Olympics and converges in the Seattle Tacoma area. See Figure 24. This flow is interrupted during periods of stagnation during which low lying t opographic features can influence the flow of pollution.37 Local topography in the Tacoma area has an influence on pollutant transport. Figure 25 displays topography in the Tacoma area. The Port area of Tacoma is surrounded by bowl like topography. Beyond the Port to the north, hills ri se to 400 ft creating a topographical barrier between the north and the south. The northernmost boundary occurs at the foot of this bluff along SR 509. Based on our review of topographical information, as well as air quality data

which shows that local sources contribute to the violations at the South L Street monitor and meteorology data which indicates that wind speeds are less than 5 mph during exceedences, EPA’s boundary follows the topographical bluff along SR 509 is sufficiently large enough to capture the sources in the area contributing to the violations at the South L Street monitor.

Figure 24. Seattle-Tacoma-Olympia area topography

Marysvill

Lake Forest

Duwamish

Tacoma L Lynnwoo

Queen

Kent

Puyallup South38 Figure 25. Tacoma area topography

Factor 8: Jurisdictional boundaries (e.g., existing PM2.5 areas)

In evaluating the jurisdictional boundary factor, EPA gave special consideration to areas that were already designated nonattainment in 2005 for violating the 1997 fine particle standards. Analysis of chemical composition data in these areas indicates that the same components that make up most of the PM2.5 mass in the area on an annual average basis (such as sulfate and direct PM2.5 carbon in many eastern areas) also are key contributors to the PM2.5 mass on days exceeding the 24-hour PM2.5 standard. These data indicate that in many cities, the same source categories that contribute to violations of the a nnual standard also contribute to exceedances of

the 24-hour standard.

Most areas that were originally designated nonattainment for the PM2.5 standards still have not attained the standards. Thus, EPA has generally concluded that counties that were designated as having emissions sources contributing to fine par ticle concentrations which continue to exceed the 1997 standards (all areas violated the annual st andard, two also violated the previous 24-hour standard) also contribute to fine particle concentrations on the highest days. For this reason,39 EPA believes that for most existing nonattainment areas, the nonattainment area for the 2006 24-

hour standard should be the same. Considerati on also should be given to existing boundaries and organizations as they may facilitate air quality planning and the implementation of control measures to attain the standard. Areas already designated as nonattainment represent important boundaries for state air quality planning.

Given that no areas in Washington State violated the 1997 PM 2.5 standards, our analysis ofjurisdictional boundaries considered the planning and organizational structure of the SeattleTacoma-Olympia area to determine if the implementation of controls in a potential nonattainment area can be carried out in a cohesive manner. The boundary of King and Pierce County is less than 5 miles north of the Port of Tacoma and runs east-west along the top of the

bluff north of the Port of Tacoma.

Puyallup Tribal trust land parcels are located within 5-10 miles to the north and northwest of the L Street monitor and are contained within the boundary of the nonattainment area recommended by the State. To the south of the L Street m onitor, Fort Lewis and the McChord Airforce base form a jurisdictional boundary (federal/state) land. (Figure 26).

Figure 26. Wapato Hills-Puyallup River Valley nonattainment area and jurisdictional boundaries of surrounding areas

EPA examined emissions from the two military jurisdictions to determine if sources in these areas are contributing to the violations at the South L Street Monitor. Emissions from the40 McChord Airforce base are less than 1.5 tons per year in 2006. On-base housing units include only 11 wood burning fireplaces and no woodstoves. Additionally, emissions at Fort Lewis are 5 tons per year or less than 0.2% of the total PM 2.5 for the PM2.5 inventory for Pierce County. Accordingly, EPA is excluding these military areas from the nonattainment area boundary.

The Wapato Hills-Puyallup River Valley nonattainment area contains the Puyallup Indian Reservation. Congress explicitly authorized the State of Washington and local agencies to administer environmental laws regulating activities on non-trust lands within the Puyallup Indian Reservation under the Puyallup Tribe of Indians Land Claims Settlement Act of 1989, 25 U.S.C. 1773. Activities on trust and restricted lands within the boundary of the Puyallup Reservation are the responsibility of EPA and the Tribe. Given these separate jurisdictions, the Wapato Hills- Puyallup River Valley nonattainment area will be managed as a multi-jurisdictional nonattainment area with the EPA and the Puyallup Tribe responsible for nonattainment area air quality planning activities on trust and restricted lands within the Puyallup Reservation and the State responsible for nonattainment area air quality planning activities on all other portions of the nonattainment area including non-trust lands within the boundary of the Puyallup Reservation.

Given low potential contributions of the McChord Air Force Base, the Fort Lewis Military Base, and King County to the north (based on the air quality, topography and meteorology data discussed above), as well as lo w potential contributions from areas outside of the Tacoma CUGA, EPA’s boundary follows the Pierce-King County line, excluding King County to the north and along the boundaries of the military bases, to the south, excluding those boundaries as well as excluding areas to the east of the easternmost boundary of the Tacoma

CUGA.

Factor 9: Level of control of emission sources

Under this factor, the existing level of control of emission sources is taken into consideration. The emissions data used by EPA in this technical analysis and provided in Table 1 (under Factor 1) represent emissions levels taking into account any control strategies implemented in the Seattle-Tacoma-Olympia area before 2005 on stationary, mobile, and area sources. Data are presented for PM 2.5 components that are directly emitted (carbonaceous PM 2.5 and crustal PM

2.5 ) and for pollutants which react in the atmosphere to form fine particles (e.g. SO 2 , NOx, VOC, and ammonia).

The State addressed the level of control of emission sources in the Seattle-TacomaOlympia area in their nine factors analysis noting a number of regulatory and non-regulatory programs in the area.

However, given that EPA’s analysis of the ot her eight factors has shown that the State’s boundary is sufficient to capture sources contributing to the violations at the South L Street monitor, this information was not an important consideration in our decision on our intended boundary.41 The following is a summary of the State’s submittal followed by a summary of EPA’s nine factor analysis.

Summary of the State’s submittals

The State submitted to EPA the partial county boundary shown in Figure 27 to EPA on March 13, 2008. In its nine factors analysis included with this and its December 18, 2007 submittal, the State focused on local sources potentially contributi ng to the violating monitor at South L Street. The State explained that air quality data indicates that exceedences occur during the winter months (November-February), when meteorology is conducive to inversions that trap pollutants and people use wood to heat their homes. Conti nuous air quality monitors and woodstove survey data indicate that concentrations are highest during evening hours, and this corresponds to times when people burn in woodstoves and fireplaces. The State also reviewed PM 2.5 speciation data from the South L Street monitor for the highest day in 2006 that indicates that carbonaceous

PM 2.5, which is an indicator of emissions from bur ning of wood, accounts for 74% or more of the

total PM 2.5 observed at the South L Street monitor.

The State’s conclusion from this air quality data as well as the other data it analyzed in its nine factors analysis is that elevated concentrati ons at the South L Street monitor are due to local emissions (dominated by woodstove and fire place emissions) occurring under meteorological conditions conducive to trapping those emissions locally. Accordingly, the State used the comprehensive urban growth area (CUGA) as a starting point for defining the nonattainment area because it encompasses woodstoves and other sources in Tacoma, its suburbs and the Urban Growth Area. They further excluded areas in the CUGA from inclusion in the boundary based on lack of population or sources of emissions. Thes e areas include Port Defiance Park, Fort Lewis

Base and McChord Air Force Base to the south and a topographic bluff to the northernmost edge of the (CUGA). See Figure 27. The State’s basis for excluding these areas is:

1) The Fort Lewis and McChord Air Force Bases have minimal PM 2.5 emissions, population density and forecasted growth. The State also argued that these areas are not upwind of the violating monitor when it experiences elevated PM 2.5 concentrations. 2) Throughout the area near the Pierce-King County line, sites are either on highlands or in valleys with little in between. The State’s analysis found that the highlands along the northern county line are in a different air shed from the land to the south and that the bluffs bordering Commencement Bay and the river valley to the south help trap fine particulates and increase pollutant concentrations during inversions that occur in the

winter months. The State drew the northwe stern boundary of the proposed nonattainment area to exclude these bluffs. They used surrogates of a road (S.R 509) and a stream to draw the boundary. This use of surrogates does not exclude any major sources from the

nonattainment area. 3) The State excluded Point Defiance Park from the proposed nonattainment area because the area does not contribute to nonattainment. Only 105 of the Park’s 702 acres are

maintained.

In focusing its initial analysis on the CUGA and local sources, the State did not directly address

whether or not contributions from areas outside of the CUGA contribute to the violations at the L42 Street monitor. After EPA shared information w ith the states from contributing emissions score (CES) modeling which indicated a potential contri bution from regional sources to the north, the State submitted additional analyses and data that focused on assessing regional contributions to the Tacoma L Street Monitor. This information included the following:

1) Hourly monitoring data over 24-hour periods for the South L Street site and other sites in Puget Sound that show 24-hour patterns in PM 2.5 levels at sites in the southern King County industrial areas (Duwamish and Kent), differ from those observed at monitors in N. King County (Lake Forest Park) and in Tacoma. In N. King County and in Tacoma, “v” shaped diurnal patterns are observed. These patterns indicate that peak PM 2.5 concentrations occur at night and concentrations decrease during the day. These patterns generally correspond with periods of increased woodstove use in the evening hours noted on surveys conducted by the Puget Sound Clean Air Agency.

2) Speciated PM 2.5 data for the South L Street monitor compared with data for other sites indicating that carbonaceous PM impacts the Tacoma monitor predominantly in the winter when fractions of sulfate and nitrate compared with total PM 2.5 are low. The Duwamish monitor shows ratios of sulfate/total PM that are more consistent throughout the year.

3) Additional meteorological data for the L Street Monitor showing that exceedences occur in the winter during very low wind speeds (less than 5 mph) indicating stagnant

conditions.

The State concluded from this additional analysis that high Tacoma concentrations are due to local emissions dominated by emissions of carbonaceous PM 2.5 occurring under conditions conducive to high concentrations (meteorology) and not transport.

Conclusion: EPA’s review of the State’s submittal and summary of final decision

Based on monitoring data for the years 2005-2007, EPA’s nine factors analysis for the SeattleTacoma-Olympia area and other relevant factual and technical information as discussed above, EPA is designating the Wapato Hills-Puyallup Rive r Valley (a portion of Pierce County) area in the State of Washington as “nonattainment” for the 24-Hour PM 2.5 standard. See Figure 27.

EPA’s final designations for the State of Washington also included a review of information submitted by the State of Washington in determining the attainment status for the

24-Hour PM 2.5 standard areas in the State of Washington as well as the boundary for the Wapato Hills-Puyallup River Valley Nonattainment area 14

.

14 On March 13, 2008, the State submitted a supplement to their initial designation r ecommendation letter and nine factors analysis dated December 18 th letter and included a boundary recommendation for the area surrounding the

monitor at 7802 South L Street (South L Street monitor). In addition to the March 13 th letter, the State submitted a letter dated July 28, 2008 containi ng addition technical in formation for EPA’s consideration.43We note that The Wapato Hills-Puyallup River Valley nonattainment area is a multijurisdictional nonattainment area, with the EPA and the Puyallup Tribe responsible for nonattainment area air quality planning activities on Puyallup tribal trust and restricted lands and the State responsible for nonattainment area air quality planning activities on all other portions of the nonattainment area including non-trust lands within the boundary of the Puyallup

Reservation. 15

.

EPA conducted a nine factors analysis of data for the Wapato Hills-Puyallup River Valley area and surrounding areas (counties in the Seattle-Tacoma-Olympia CMSA) and reviewed information that Washington State submitted on March 13, 2008 focused on the Tacoma CUGA as well as the information it later submitted on July 25, 2008. EPA’s nine factors analysis and review of the State’s submittals supports using the partial county boundary that the State of Washington submitted to EPA because:

• Chemical speciation data indicates that th ere is a 74% or more contribution from

carbonaceous PM 2.5 PM which is associated with burning in woodstoves and fireplaces, and 10% or less contribution from PM 2.5 components that are typically regional such as sulfate and nitrate.

• EPA’s analysis of positive matrix factorization data indicates that 60-90% of total

PM 2.5 on exceeding days at the South L Street monitor is from wood smoke. There are no other sources of smoke during the winter season in the CUGA. By law outdoor burning is prohibited in this area.

• Hourly PM 2.5 levels at the South L Street monitor peak in the evenings and decrease dramatically during the day. These patterns are consistent with woodstove surveys conducted in Tacoma which show that on high PM 2.5 days,

woodstove use PM 2.5 peaks in the late evening and is lowest around noon.

• Meteorological data shows very low mi xing heights during stagnation events when the exceedences are occurring, and low wind speeds (typically less than 5 mph). Local topographical features in the area restrict pollution flow in the Tacoma area during stagnation events.

• Population density in Pierce County is concentrated within the CUGA. The Fort Lewis and McChord Air Force Base military installations to the south are not

included in the nonattainment area because emissions from the bases contribute less than 0.2% to the total inventory of PM 2.5 emissions in the area.

• The nonattainment area includes the Port of Tacoma because it has substantialPM2.5 emissions (estimated at 90 tons per year). This does not include offterminal emissions, which contribute additional PM 2.5 . The Port projects a

15 Congress explicitly authorized state and local agencies to adminster activ ities only on non-trust lands within the Puyallup Indian Reservation under the Puyallup Tribe of Indians Land Claims Settlement Act of 1989, 25 U.S.C.

1773. Activities on trust land restricted ands within the boundary of the Puyallup Reserv ation are the responsibility of EPA and the PuyallupTribe.44 dramatic increase of its cargo handling capacity in the next two decades, with an estimated cargo growth factor of 4.8 from 1999 to 2015.

• Analyses of speciated PM 2.5 data, diurnal patterns of PM 2.5 concentrations, and meteorological information from the Puget Sound region indicate that sources contributing the violations of the 24-hour PM 2.5 standard at the South L Street monitor are predominantly local sources dominated by woodstove and fireplace emissions in the Tacoma area and not transport from King County or other counties in the Seattle-Tacoma-Olympia area.

EPA has determined the boundary submitted by the State of Washington in March 2008 is appropriately sized to contain the sources that c ontribute to the violations at the South L Street monitor including populated areas in the Tacoma area where households operate woodstoves and fireplaces in the winter, and mobile sources and diesel traffic associated with good movements at the Port of Tacoma and sections of Interstate 5 and State Highway 99. The final boundary includes all land within the boundary of the Puyallup Indian Reservation.

Additional information regarding responses to specific State comments can be found in EPA's Response to Comments document at http://www.epa.gov/pmdesignations/2006standards/tech.htm

.45 Figure 27. Wapato Hills-Puyallup River Valley nonattainment area46 Attachment 2 Description of the Contributing Emissions Score

The CES is a metric that takes into consideration emissions data, meteorological data, and air quality monitoring information to provide a relative ranking of counties in and near an area. Using this methodology, scores were developed fo r each county in and around the relevant metro area. The county with the highest contributi on potential was assigned a score of 100, and other county scores were adjusted in relation to the highest county. The CES represents the relative

maximum influence that emissions in that count y have on a violating county. The CES, which reflects consideration of multiple factors, shoul d be considered in evaluating the weight of evidence supporting designation decisions for each area.

The CES for each county was derived by incorpor ating the following significant information and variables that impact PM 2.5 transport:

• Major PM 2.5 components: total carbon (organic carbon (OC) and elemental carbon (EC)), SO 2 , NO

x , and inorganic particles (crustal).

• PM 2.5 emissions for the highest (generally top 5%) PM 2.5 emission days (herein called “high days”) for each of two seasons, cold (Oct-Apr) and warm (May-Sept)

• Meteorology on high days using the NOAA HYSPLIT model for determining trajectories of air masses for specified days

• The “urban increment” of a violating monitor, which is the urban PM 2.5 concentration that is in addition to a regional background PM 2.5 concentration, determined for each

PM 2.5 component

• Distance from each potentially contributing county to a violating county or counties

[A more detailed description of the CES can be found at http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html#C.]