Appendix B – Nonattainment Receptors

1 Technical Support Document for EPA’s Proposed Action on the Oregon 2010 Interstate Transport State Impl ementation Plan for the 2006 24-hour Fine Particulate (PM2.5) National Ambient Air Quality Standard



### Appendix B – Nonattainment Receptors

1. EPA Region 9 States – California

1. Southern California –Riverside County

2. Central California – Fresno, Kern, Kings, Ma dera, Merced, San Joaquin, Stanislaus, and

Tulare Counties

2. EPA Region 8 States –Utah

1. Utah – Utah County (Provo-Orem)

2. Utah – Box Elder, Salt Lake, and Webe r Counties (Greater Salt Lake Area)

3. EPA Region 10 States – Idaho

1. Idaho/Utah – Franklin County/Cache County

2. Idaho – Shoshone County (Pinehurst)

3. Idaho – Lemhi County (Salmon)Appendix B – Nonattainment Receptors

2 1.1. Southern California – Riverside County

County Site Name Description

Riverside Mira LomaVan Buren Current monitored values slightly above 35μg/m3. There is a strong

downward trend.

The high 24-hour PM2.5 concentrations in the South Coast Air Basin are mainly due to the secondary formation of smaller particulates resulting from m obile, stationary and area source emissions of precursor gases (i.e., NOx, SOx, NH4, and VOC) that are converted to PM in the atmosphere.

Speciated PM2.5 data at the Central Los Angeles S ite (CELA) and the Rubidoux site (RIVR) indicate that organic carbon, ammonium nitrate, and ammonium sulfate constitute the major components at each site (shown in Figures 1.2.A and 1.2.B, below). 24-hour PM2.5 design value trends show strong

downward trend at all sites in the South Coast Basin (shown in Figure 1.2.C, below). 1

PM2.5 is essentially a combustion gene rated pollutant due to the volume of traffic flow and numbers of sources (both point and area ) located in the region. It is important to note that the areas with the highest concentrations are directly downwi nd of an area with major ammonia sources associated with dairies and poultry farming. 2

The South Coast Air Quality DRAFT 2012 Air Quality Management Plan 3 air quality pr ojections show that the emission control strategy ou tlined in the plan will result in air quality improvement at each of the nonattainment receptors, and that each of these site s will attain the standard in 2014 or sooner (see Figure 1.2.D: Maximum 24-Hour Average PM2.5 Design Concentrations: 2008 Baseline, 2014 and 2014 Controlled).

The spatial distribution of PM2.5 in the South Coast Basin supports the f act that it is largely of local origin. The air quality trends and projections indicate that the emissi on strategy is effective in reducing

24-hour PM2.5 levels. Therefor e, we believe it is reasonable to c onclude that emissions from Oregon do not significantly contribute to nonattainment of the 2006 24-hour PM2.5 NAAQS at the Riverside
receptor.

1 Joe Cassmassi, Scientific, Technical & Modeling Peer Review (STMPR) Advisory Group Meeting, September 22, 2011.

2 Final 2007 Air Quality Management Plan (AQMP), Appendix V – Modeling and Attainment Demonstrations June, V-2-10.

3 http://www.aqmd.gov/aqmp/2012aq mp/draft/Chapters/Ch5.pdfAppendix B – Nonattainment Receptors

3 Figure 1.2.A: Speciated data for Central Los Angeles 4

4 STMPR Item # 5 - 2008 PM2.5 Air Quality Characterization, January 19, 2012. Bong-Mann Kim.Appendix B – Nonattainment Receptors

4 Figure 1.2.B: Speciated PM2.5 data for the Rubidoux site in Riverside County 5

5 STMPR Item # 5 - 2008 PM2.5 Air Quality Characterization, January 19, 2012. Bong-Mann Kim.Appendix B – Nonattainment Receptors

5 Figure 1.2.C: 24-hour PM2.5 Design Value TrendsAppendix B – Nonattainment Receptors

6 Figure 1.2.D: Maximum 24-Hour Average PM2.5 Design Concentrations: 2008 Baseline, 2014 and 2014 Controlled 6

6 http://www.aqmd.gov/aqmp/2012aq mp/draft/Chapters/Ch5.pdfAppendix B – Nonattainment Receptors

7 1.2. Central California – Fresno, Kern, Kings, Madera, Merced, San Joaquin, Stanislaus, and
Tulare Counties

County Site Name

Fresno Fresno-1st Street

Kern Bakersfield-Planz Road Kings Corcoran

Merced Merced-M Street San Joaquin Stockton-Hazelton

Stanislaus Turlock

Tulare Visalia

PM2.5 levels in the San Joaquin Valley are generally highest in the months of January, February, November and December (see Figure 1.3.A, below). PM2.5 builds up in episodes of several days or weeks. These episodes generally occur during pe riods with stagnation, cool temperatures, high humidity, and low mixing depths. 7 The peak day composition of PM2.5 at Bakersfield is primarily ammonia nitrate (67%) a nd organic carbon (16%).

The primary sources of PM2.5 in the region are diesel engines (nitrate), gasoline engines (nitrate), and agricultural activ ities (ammonium) which contribute regiona lly. Wood smoke (organic carbon) and diesel engines (elemental carbon) co ntribute to the elevated 24-hour le vels of PM2.5 in urban areas.

Because PM2.5 builds up in episodes of several days or weeks, during periods with stagnation, and low mixing depths, it is reasonable to co nclude that long range transport doe s not contribute to elevated 24- hour levels of PM2.5 in the San Joaq uin Valley. EPA believes it is reasonab le to conclude that emissions from Oregon do not significantly contribute to nonattainment of the 2006 24-hour PM2.5 NAAQS at these receptors.

7 Nature of PM2.5 in the San Joaquin Valley, Karen Magliano, California Air Resources Board, Technical Symposium April 27, 2012.Appendix B – Nonattainment Receptors

8 Figure 1.3.A: Monthly Average PM2.5 Co ncentration in Bakersfield CaliforniaAppendix B – Nonattainment Receptors

9 Figure 1.3.B: 2008-2010 Peak Day Composition in BakersfieldAppendix B – Nonattainment Receptors

10 2. EPA Region 8 States –Utah 8

2.1. Utah – Utah County (Provo-Orem)

A large portion of Utah County is designated as the Provo 2006 24-hour PM2.5 nonattainment area (NAA).

The Provo NAA is situated in the Utah Valley. Like th e other low-lying valleys ju st west of the Wasatch Front, the topography of the Utah Valley makes it pr one to temperature invers ions. During inversions, the Provo NAA features stagnant air masses and calm to light winds. As the airshed is essentially capped, PM2.5 is formed in-situ (and trapped) via fr esh locally derived emission sources and secondary chemistry. Transport of air masses between the Salt Lake City and Provo NAAs can occur during inversions, as there is a 4.75-mile gap in the mount ains separating these airs heds which is below the approximate average inversion height for these areas.

Speciation data from exceedance days from 2004-2006 showed the average composition of PM2.5 in Provo is 71% ammonium nitrate, wi th 21% carbon and organic compounds, 8% ammonium sulfate, and
2% crustal.

Several factors, including signi ficant mobile, point and area sour ces contribute to primary and secondarily formed PM2.5 that viol ate the 24-hour standard during stable weather events associated with strong inversions.

2.2. Utah – Box Elder, Salt Lake, and We ber Counties (Greater Salt Lake Area)

All of Davis and Salt Lake counties and portions of Box Elder, Tooele and Weber counties are designated as part of the Salt Lake City 2006 24-hour PM2.5 nonattainment area.

The SLC NAA is situated in a valley bordered on the west by the Stansbury Mountains, Promontory Mountains and Great Salt Lake, and on the east by the Wasatch Front. During inversions, the NAA becomes a closed airshed (save for potential tran sport between the Salt La ke City and Provo NAAs) featuring stagnant air masses and light winds which t ypically oscillate back and forth within the airshed. As the airshed is essentially cappe d during inversions, PM2.5 is formed in-situ (and trapped) via fresh locally derived emission sour ces and secondary chemistry.

Speciation data from exceedance days from 2004-2006 showed the average composition of PM2.5 in Salt Lake City is 58% ammonium nitrate, 31% carbon and organic compounds, 8% ammonium sulfate,
and 2% crustal.

Several factors, including signi ficant mobile, point and area sour ces contribute to primary and secondarily formed PM2.5 that viol ate the 24-hour standard during stable weather events associated with strong inversions.

8 For discussion of the Idaho/Utah – Franklin County/C ache County area, see section 3.1 of this Appendix.Appendix B – Nonattainment Receptors

11 Based on the above-described factors, we believe it is reasonable to conclude that emissions from Oregon do not contribute significantly to nonatt ainment of the 2006 24-hour PM2.5 NAAQS at these Utah receptors.

3. EPA Region 10 States – Idaho

3.1. Idaho/Utah – Franklin County/Cache County

Portions of Franklin County, Idaho a nd Cache County, Utah are designated as part of the Cache Valley 2006 24-hour PM2.5, two-state, nonattainment area.

Limited chemical speciation data in the Cach e Valley indicates the 24-hour PM2.5 problem is dominated by ammonium nitrate aerosol similar to nonattainment areas along th e Wasatch front in and near Salt Lake City. The chemical speciation monitor in Bountiful is closest to the Cache Valley and is considered broadly representative of conditions in the Cache Valley.

The ridge dominated synoptic meteorology during PM2.5 cold pool episodes features weak transport winds and near calm surface winds. As a result, tran sport of PM2.5 and precursors from the rural regions at the domain periphery is very small. In addi tion, most of the observed Wasatch Front and Cache Valley PM2.5 is formed in-situ (and trapped) via fr esh locally derived emission sources and secondary chemistry.

Local heating emissions from woodstoves, emissions fr om agricultural activiti es, and mobile emissions contribute to primary and secondarily formed PM2 .5 that violate the 24-hour standard during stable

weather events associated with extremely strong inversions.

These emissions and the related eff ects are limited to the Cache Valley, as they are trapped there due to temperature inversions, low wind, and local topography. The rest of the county is very sparsely populated with no significant sources that can co ntribute to a violati on of the 2006 24-hour PM2.5

standard at the Franklin monitor.

EPA Region 10 Positive Matrix Factor (PMF) recep tor modeling identified 11 factors contributing to

elevated wintertime 24-hour PM2.5 levels at the Bountif ul monitoring site includ ing nitrate rich (56%), ammonium chloride (15%), wood smoke (10%), orga nic pyrolysis rich (6%), sulfate ri ch (5%) and smaller contributions by other identifi ed factors (gasoline vehicles, 2 so il factors, fireworks, iron rich, and urban unidentified).

3.2. Idaho – Shoshone County (Pinehurst)

State information indicates that em issions from woodstoves contribute to primary PM2.5 that violates the 24-hour standard during stable weather events associated with strong inversions. These emissions and the related effects are limited to the city of Pi nehurst airshed, as they are trapped there due to temperature inversions, low wind and local topography.

The rest of the county is very sp arsely populated with no significant sources that can contribute to a

violation of the 2006 24-hour PM2.5 NAA QS at the Pinehurst monitor.

3.3 Idaho – Lemhi County (Salmon)Appendix B – Nonattainment Receptors

12 Information from the State of Idaho indicates th at local emissions, incl uding from woodstoves, contribute to primary PM2.5 that resu lts in elevated daily PM2.5 valu es during stable weather events associated with strong inversions. Ho wever it is important to note that the design values calculated in the table do not take into consideration all flagge d exceptional events due to recent wildfires.

Based on this information, the EPA believes it is reas onable to conclude that emissions from Oregon do not contribute signifi cantly to nonattainment of the 2006 24-hour PM2.5 NAAQS at these Idaho
receptors.