Appendix C – Maintenance Receptors

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### Appendix C – Maintenance Receptors

1. EPA Region 9 States – California and Nevada

1. Eastern California – Inyo County

2. Southern California – Riversid e and San Bernardino Counties

3. Northern California – Butte, Sacr amento, and Sutter Counties

4. California/Mexico Border – Imperial County

5. Nevada – Washoe County

2. EPA Region 8 States – Montana and Utah 1. Montana – Lewis and Clark County (Helena) 2. Montana –Silver Bow County (Butte) 3. Utah – Utah County (Provo-Orem) 4. Utah – Davis, Salt Lake and We ber Counties (Greater Salt Lake Area)

3. EPA Region 10 States –Washington 1. Washington – Pierce County (Tacoma) 2. Washington – Yakima County (Yakima)Appendix C – Maintenance Receptors

2 1.1. Eastern California – Inyo County

County Site Name Description

Inyo Keeler This site is affected primar ily is by local crustal sources.

Massive erosion from Owens dry lake; in Owens Valley.

Elevated levels of PM2.5 in Inyo County are measured at a single monitor, the Keeler monitor, which is located adjacent to the Owens Lake Bed. (See Figur es 1.1.A and 1.1.B, below). The Owens Lake Bed is surrounded by steep terrain. EPA believes that because of the proximity of the monitor to a large local source of particulate matter, and th e steep nearby terrain. It is theref ore reasonable to conclude that emissions from Oregon do not interfere with the ma intenance of the 24-hour PM2.5 standard at this

receptor.

The Owens Valley Planning Area (OVPA) is located in Inyo County in ea stern-central California. It is situated at the south end of the deep, long, narrow Owens Valley with the Sierra Nevada to the west (maximum elevation 14,495 feet), the Inyo Mountains to the east (maximum elevation 14,246 feet), and the Coso Range to the south (maximum elevation 8,160 feet). The predominantly dry, alkaline Owens Lake bed is approximately eight miles south of the community of Lone Pine on U.S. Highway 395, 60 miles north of the city of Ridgecrest, and 35 miles west of Death Valley. The bed of Owens Lake is defined as the area below 3,600 feet above mean sea le vel (all elevations will be given in feet above mean sea level). The lake bed extends about seventeen miles north and south and ten miles east and west and covers an area of approximate ly 110 square miles (70,000 acres).

Table 1: PM2.5 Levels at the Keeler Monitor

Year PM2.5 Level (μg/m3)

2008 -2010 36

2009 -2011 36

2010 -2012 33

Owens Lake is the largest single sour ce of PM-10 in the United States. 1 Water was first diverted from the Owens River to the City of Los Angeles in 1913, and by 1926 Owens Lake was dry. Today, the Owens lakebed produces enormous amounts of windblow n dust in exceedance of federal air pollution standards for particulate matter.

1 http://www.gbuapcd.org/owenslake.htmAppendix C – Maintenance Receptors

3 Monitoring and research conducted for more than 20 years, as well as three previous State Implementation Plans (SIPs), has determined that wi nd-blown dust from the dry bed of Owens Lake is the dominant cause of NAAQS violations for PM10 in the nonattainment area. 2

Figure 1.1.A: Keeler Dunes 3

2 Final 2008 Owens Valley PM10 Planning Area Demonstration of Attainment State Implementation Plan, January 28, 2008. http://www.gbuapcd.org/ovpm10sip.htm

3 http://www.gbuapcd.org/owenslake/dustID/20120516CurrentSites.Appendix C – Maintenance Receptors

4Appendix C – Maintenance Receptors

5 Figure 1.1.B: Owens Lake Dust ID Network MapAppendix C – Maintenance Receptors

6 1.2. Southern California –Riverside, Los Angeles, and San Bernardino Counties

County Site Number 2008-2010 2009-2011 2010-2012

Riverside 060658001 38 35 34

San Bernardino 060710025 37 34 32

San Bernardino 060712002 37 31 32

Los Angeles 060370002 38 36 31

The high PM2.5 concentrations in the South Coast Air Basin are mainly due to the secondary formation of smaller particulates resulting from mobile, stationary and area so urce emissions of precursor gases (i.e., NOx, SOx, NH4, and VOC) that are c onverted 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). 4

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. 5

The South Coast Air Quality DRAFT 2012 Air Quality Management Plan 6 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 receptors (see Figure 1.2.D: Maximum 24-Ho ur Average PM2.5 Design Concentrations: 2008 Baseline, 2014 and 2014 Controlled).

The air quality trends and projections indicate that the emission strategy is effective in reducing PM2.5.

It is therefore reasonable to conc lude that emissions from Oregon do not interfere with the maintenance

of the 24-hour PM2.5 standa rd at these receptors.

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

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

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

7 Figure 1.2.A: Speciated data for Central Los Angeles 7

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

8 Figure 1.2.B: Speciated PM2.5 data for the Rubidoux site in Riverside County 8

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

9 Figure 1.2.C: 24-hour PM2.5 Design Value TrendsAppendix C – Maintenance Receptors

10 Figure 1.2.D: Maximum 24-Hour Average PM2.5 Design Concentrations: 2008 Baseline, 2014 and 2014 Controlled 9

9 http://www.aqmd.gov/aqmp/2012aq mp/draft/Chapters/Ch5.pdfAppendix C – Maintenance Receptors

11 1.3. Northern California – Butte, Sacramento, and Sutter Counties

County Site Name Description

Butte Chico This receptor is in the Chico nonattainment area.

The monitored exceedances likely reflect localized sources occurring during wintertime temperature inversi ons with low winds that persist for several days in an area that tr ap emissions together with complex topography. The speciation data from high concentration days

indicates that as much as 75% of th e concentrations are due to organic carbon, which also indicates that residential wood burning emissions are the dominant source. Also, a bout 70% of the emissions are estimated to be from area sources, of which residential wood burning is the dominant source, contributing 2.65 of the 6.4 tons per day (ARB Almanac website (2006) http://www.arb.ca.gov/ei/maps/statemap/cntymap.htm )

Sacramento SacramentoDel Paso

Manor This receptor is in the Sacr amento Metro nonattainment area.

The monitored exceedances likely reflect localized sources occurring during wintertime temperature inversi ons with low winds that persist for several days. The speciation data on days during cold seasons in 2004-2006 with the highest 5 percentile of PM2.5 concentrations show

that the mass is 47-60% total car bon mass (TCM), which indicates residential wood burning as a sign ificantly contributing source ( http://www.epa.gov/pmdesignations/ 2006standards/final/TSD/tsd_F_li mited_2004-06_speciation_data_report.pdf ).

The largest single source of Sacram ento's wintertime PM2.5 emissions is wood and other solid fuel burning in fireplaces, wood inserts, wood stoves and pellet stoves.

There is a strong downward trend in this area in recent years (http://www.epa.gov/region9/ air/trends/pm25.html).

Sutter Yuba City Yuba City-Marysville

The monitored exceedances likely reflect localized sources occurring during wintertime temperature inversi ons with low winds that persist for several days.

There is a strong downward tre nd and preliminary 2009-2011 data indicates the area may be attaining the standard. (http://www.epa.gov/region9/ air/trends/pm25.html).Appendix C – Maintenance Receptors

12 The Northern Sacramento Valley Air Basin is bo unded on north and west by the Coastal Mountain Range and on the east by the southern portion of th e Cascade Mountain Range and the northern portion of the Sierra Nevada Mountains. These mountain range s reach heights in excess of 6,000 feet with peaks rising much higher. This provides a substantial physical barrier to local ly created pollution.

For the areas under consideration, high PM2.5 concentr ations mostly occur during stagnant conditions during winter, with radiation invers ions. The cooling of the ground, as he at is radiated away, creates an inversion, since air near the ground is cooler than that above. Th is inhibits mixing and confines pollutants to a relatively shallo w layer near the ground. A typical value for maximum mixing height during high PM2.5 conditions is 300 meters (984 f eet) AGL (above ground level). EPA recognizes that an inversion height is not a rigi d boundary extending through a fixed elevation. In reality the inversion would be partly terrain-following, and the degree of stagnation would be subject to additional influences at the foothill edges, such as st rong diurnal slope flows. In any cas e, mixing heights vary by site and date, so any single height can provide only a scale for comparison, not a definitive value. Nevertheless, the inversion height provides an indicator of the area over which inve rsions may be enhancing pollution concentrations, and of the extent of the area that may be contributi ng to NAAQS violations.

Because these areas in Northern California have t opographical features higher than the typical daytime height of the inversion layer, EPA c onsidered the inversion height to esti mate the size of the area likely to have similar pollution conditions and to contribu te to NAAQS violations. For example, the eastern portion of Butte County extends into the foothills of the Sierra Neva da Mountains. For Chico, the 300 meters AGL (984 feet) inversion la yer thickness translates to an el evation contour of 375 meters (1221 feet) MSL (above Mean Sea Level). Much of eastern portion Butte C ounty is above this elevation, as shown in Figure 1.3.B below.

In summary, topography is an importa nt factor in these areas, given th at the inversion layer, which can

lead to winter PM2.5 exceedances in the Sacramento Valley, is blocked by the Sierra foothills.

The steep terrain and speciated PM2.5 data at these No rthern California receptors supports the fact that
the PM2.5 is largely of local origin. It is therefore reasonable to conc lude that emissions from Oregon do

not interfere with maintenance of the 24- hour PM2.5 standard at these receptors.Appendix C – Maintenance Receptors

13 Figure 1.3.A: Average Composition on 14 Exceedance Days - Chico Average Composition on 14 Exceedance Days- Chico

AmmNitrate

16%

AmmSulfate

2%

OC

75% Other

2% Geological

1% Elements

2%

EC

2%

PM2.5 Mass= 52.2 ug/ m3 Sum of Species=51.4 ug/ m3Appendix C – Maintenance Receptors

14 Figure 1.3.B: Map of Butte County PM2.5 Nonattainment AreaAppendix C – Maintenance Receptors

15 1. 4. California/Mexico Border – Imperial County

Levels of PM2.5 in Imperial County that exceed the 2006 24-hour PM2.5 NAAQS are recorded at the
Calexico – Ethel Street monitoring site, which is located near the Me xican Border (see Figure 1 below).
The elevated levels of PM2.5 occur primarily in the wintertime, and seven of the nine values above the
level of 35 μg/m3 in the years 2008-2010 occur in December or January (See table 1, below).

The levels of PM2.5 measured at th e Brawley and El Centro monitoring sites are always lower – usually

much lower – than those measured at the Calexico Ethel Street monitor on days when the PM2.5 levels

at the Calexico Ethel St reet monitor exceed 35 μg/m 3 (see Figure 2, below). Because these nearby

monitors do not show similar increa ses in monitored values, it appears that the cause of elevated PM2.5
appears to be from a local source near the Califor nia/Mexico Border. It is therefore reasonable to

conclude that emissions from Or egon do not interfere with maintena nce of the 24-hour PM2.5 standard
at this receptor.

Figure 1: PM2.5 Monitoring Sites in Imperial County CaliforniaAppendix C – Maintenance Receptors

16 Table 1.1.A: Calexico-Ethel Street: Dates of PM2.5 Values Above 35μg/m 3

for the Years 2006 through 2010

Year Dates 2008 January 4, and December 22, 25 2009 September 4, and December 12, 21, 24
2010 June 28, and December 4

Figure 2: PM2.5 levels (μg/m3) at Imperial PM2.5 Monitoring Sites from 2006 to 2010, for days of elevated PM2.5 0 10 20 30 40 50 60 70 Calexico ‐ Ethel

El Centro

BrawleyAppendix C – Maintenance Receptors

17 1.5 Nevada – Washoe County

Elevated PM2.5 levels at the Reno receptor generall y occur during wintertime st agnation episodes, with lower levels of PM2.5 during the other times of the year (see Fi gures 1.6.A thru 1.6.D: PM2.5 24-hour Averages at the Reno PM2.5 Monitori ng Site.) Low temperatures and st rong inversions are the dominant contributing factors to th e elevated PM2.5 levels:

The year began with several consecutive days of stable atmospheric conditions and strong temperature inversions. The lowest temperatur e of the month (18 degrees) occurred on January 4. The low temperature and the strong inve rsions were contributin g factors to a 24-hour PM2.5 concentration and NAAQS exceedance of 38.8 μg/m3 on January 5, 2010. 10

The levels of PM2.5 measured in March through November in 2008 through 2011 are generally very low. The exception to this is in June and July of 2008 when wildfires had a large impact on PM2.5 concentrations in this area, and the Washoe County Health District has flagged the affected data as exceptional events. 11 An exceptional events request was submitted to EPA Region IX in October 2009. EPA has not yet taken action on the request. 12

The wintertime PM2.5 exceedances o ccur during periods of strong inve rsions and are largely due to

local emissions. . It is therefore r easonable to conclude that emissions from Oregon do not interfere with

maintenance of the 24-hour PM2.5 standard at th is receptor.

10 Washoe County, Nevada Air Quality Trends (2001-2010), May 2011. http://www.co.washoe.nv.us/repository/files/4/ Washoe-County-Air-Quality-Trends-2001-2010.pdf

11 Washoe County, Nevada Air Quality Trends (2002-2011), May 24, 2012. http://www.co.washoe.nv.us/repository/files/4/ Washoe-County-Air-QualityTrends-2002-2011.pdf

12 Id.Appendix C – Maintenance Receptors

18 Figure 1.6.A: PM2.5 24-hour Averages at the Reno PM2.5 Monitoring Site for 2008Appendix C – Maintenance Receptors

19 Figure 1.6.B: PM2.5 24-hour Averages at the Reno PM2.5 Monitoring Site for 2009Appendix C – Maintenance Receptors

20 Figure 1.6.C: PM2.5 24-hour Averages at the Reno PM2.5 Monitoring Site for 2010Appendix C – Maintenance Receptors

21 Figure 1.6.D: PM2.5 24-hour Averages at the Reno PM2.5 Monitoring Site for 2011Appendix C – Maintenance Receptors

22 Figure 1.6.E: Washoe County Ambient Air Monitoring Sites (2002-2011) 13

13 http://www.co.washoe.nv.us/repository/files/4/ Washoe-County-Air-QualityTrends-2002-2011.pdfAppendix C – Maintenance Receptors

23 2. Region 8 States – Montana and Utah

2.1. Montana – Lewis and Clark (Helena)

Elevated levels of PM2.5 in the Helena ar ea occur primarily in the winter months. 14 The Helena Valley is topographically prone to cold pool inve rsion conditions during the winter months. 15 Speciation data

indicates that emissions from wood smoke are th e primary contributor to exceedances of the PM2.5

standard in Helena. 16 In the months when violations of the NAAQS occurred at the Helena receptor, the nearby Gate of the Mountains Wilder ness Area monitor did not exceed 2 μg/m 3

. 17 All of these factors taken together indicate that high levels of PM2.5 in Helena are driven by local emissions, which become trapped and build during wintertime inversions.

2.2. Montana – Silver Bow County (Butte)

Elevated levels of PM2.5 in the Butte ar ea occur primarily in the winter months. 18 The Butte area is topographically prone to wintertime temperature invers ions, as it is situated in a mountain valley. Speciation data indicates that emissions from wood smoke are the primary contributor to exceedances of

the PM2.5 standard in Butte. 19 These factors indicate that high leve ls of PM2.5 in Butte are driven by local emissions, which become trapped a nd build during wintertime inversions.

Based on the above factors, we beli eve it is reasonable to conclude that emissions from Oregon do not

interfere with maintenance of the 2006 24-hour PM2.5 standard at these Montana receptors.

2.3. Utah – Utah County (Provo)

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

14 The maintenance receptor in Helena, MT violated the 2006 PM2.5 NAAQS only in 2010. Each of the exceedances of the

2006 PM2.5 standard at this receptor during 2010 occurred during the winter months, with all but one exceedance
occurring in December or January. Monitor values are accessible on EPA’s AirData website, http://www.epa.gov/airquality/airdata/

. 15 Johnson, J. “Case Study of a Persistent Cold Pool in the Helena Valley.” NOAA. November 21, 2000.

16 Ward, T., Lange, T., “The impact of wood smoke on ambient PM2.5 in northern Rocky Mountain valley communities.”

Environmental Pollution 158 (2010) 723–729.

17 The Gate of the Mountains IMRPOVE monitor is located roughly 17 miles from Helena, MT. The IMPROVE monitor data

can be found in Appendix D to this TSD, in the docket for this action.

18 In 2009 and 2010, the only recent years in which the Butte maintenance receptor violated the 2006 PM2.5 NAAQS, each

exceedance of the NAAQS occurred in either December or January. Monitor values are accessible on EPA’s AirData website, http://www.epa.gov/airquality/airdata/

. 19 Ward, T., Lange, T., “The impact of wood smoke on ambient PM2.5 in northern Rocky Mountain valley communities.”

Environmental Pollution 158 (2010) 723–729.Appendix C – Maintenance Receptors

24 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 airsheds 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 violate the 2006 24- hour PM2.5 standard during stable weather events associated with strong inversions. Based on this in formation, we believe it is reasonable to conclude that emissions from Oregon do not interfere with maintenance of the 2006 24-hour PM2.5 NAAQS at this receptor.

2.4. Utah – Davis, Salt Lake and Web er Counties (Greater Salt Lake Area)

All of Salt Lake and Davis Counties and a portion of Weber County are designate d as part of the Salt Lake City (SLC) 2006 24-hour PM2.5 nonattainment area (NAA).

The SLC NAA is situated in a valley bordered on the west by the Stansbury Mountains, Promontory

Mountains and the 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 violate the 2006 24- hour PM2.5 standard during stable weather events associated with strong inversions.

Based on the above-described factors, we believe it is reasonable to conclude that emissions from Oregon do not interfere with maintenance of the 2006 24-hour PM2.5 NAAQS at these receptors.

3. Region 10 States - Washington

3.1 Washington – Pierce County (Tacoma)

(Site name: Tacoma-South L Street)

A portion of Pierce County (Tacoma) is desi gnated nonattainment for the 2006 24-hour PM2.5 NAAQS.Appendix C – Maintenance Receptors

25 The state analysis indicates that wood smoke associ ated with home heating is the largest source of

PM2.5 in the Tacoma-Pierce C ounty nonattainment area.

The state data asserts that the 24-hour PM2.5 problem is highly localized. Surface measurements at multiple sites suggest that the only design values which violate the 2006 24-hour PM2.5 NAAQS are in the core of the nonattainment area, within about 3 km of the South L Street monitor. Beyond about 3- 5km, the design values drop and are well below the NAAQS.

On-site sonic anemometer and vertical temperature profile measurements revealed that exceedances only occurred: in winter; at night; when there was a surface inversion; below an ambient temperature of about 50F; when wind speeds were less than 1.5 mph.

Within 3km of the South L Street monitor, during the season in whic h the violations occur, wood smoke is the largest source, on-road mobile is second but appears to be significantly smaller, industrial and other sources make up the remainder and are minor.

EPA Region 10 PMF receptor mode ling identified 10 factors contri buting to elevated wintertime 24- hour PM2.5 levels including wood smoke (60%), organi c pyrolysis rich (10%), nitrate rich (7%), iron rich (7%), sulfate rich (5%) and smaller contributions from other identified f actors (gasoline vehicles, sea salt, soil, aged sea salt, and a 2 nd sulfate rich factor).

3.2 Washington – Yakima County (Yakima)

EPA Region 10 PMF receptor modeli ng identified 10 factors contribu ting to elevated wintertime PM2.5 including wood smoke (24%), nitrate rich (24%), gaso line vehicles (16%), orga nic pyrolysis rich (9%), sulfate rich (7%) and smaller contributions from other identified factors (iron ri ch, sea salt, soil, zinc rich, and urban unidentified).

Based on the above-described factors, we believe it is reasonable to conclude that emissions from Oregon do not interfere with maintenance of the 2006 24-hour PM2.5 NAAQS at these Washington

receptors.