# Appendix N

Contingency Measures Documentation

### Contingency Measures Documentation i The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

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### Contingency Measures Documentation ii The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

# TABLE OF CONTENTS

1 Introduction ................................................................................................................ .................. 1

2 Region for Contingency Measures ............................................................................................. .. 2

3 2002 Baseline SO 2 

## Emissions ...................................................................................................... 3

4 Contingency Measures ........................................................................................................ ......... 5

4.1 Hickory Area Contingency Measure Reductions .............................................................. 10

4.2 Triad Area Contingency Measure Reductions ................................................................... 10

5 Conclusions ................................................................................................................. ............... 11



# LIST OF TABLES

Table 3-1 2002 Baseline SO2 Emissions For Hickory Region of Influence ................................. 4

Table 3-2 2002 Baseline SO2 Emissions For Triad Region of Influence...................................... 4

Table 4-1 Comparison of Modeled 2009 Emissions to Expected 2009 Emissions ........................ 7

Table 4-2 Estimated Emission Reductions E xpected from Clean Smokestacks Act ...................... 8



# LIST OF FIGURES

Figure 2-1. The shaded countie s represent the region where SO 2 

## contingency measures were considered for the Hickory nonattainment area. ..................................................................... 2

Figure 2-2. The shaded countie s represent the region where SO 2 

## contingency measures were

considered for the Triad nonattainment area........................................................................... 3

Figure 4-1. Location of the Uti lities Subject to the CSA. .............................................................. 9

Figure 4-2. Back Trajectory Analysis for Hickory PM 2.5 

## Monitor. ............................................... 9

Figure 4-3. Back Trajectory Analysis for Lexington PM 2.5 

## Monitor........................................... 10

### Contingency Measures Documentation iii The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

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### Contingency Measures Documentation 1 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

# 1 Introduction

Section 172(c)(9) requires that the nonattainment State Impl ementation Plan (SIP) contain specific measures that would take effect upon a Stat e’s failure to attain th e fine particulate matter (PM 2.5 

## ) standard in a given area. These contingenc y measures must be fully adopted rules or control measures that are ready to be implemen ted quickly upon failure to meet the standard by the attainment date. Additionally, the contin gency measures must be beyond the modeled

controls needed to demonstrate attainment of the standard. Finally, the SIP should contain trigger mechanisms for the contingency measures, specify a schedule for implementation, and

indicate that the measures w ill be implemented without furthe r action by the State or by the United States Environmental Protection Agency (USEPA).

In the April 25, 2007, Clean Air Fine Particle Implementation Rule (72 FR 20586), the USEPA stated that the measures should provide for emis sion reductions equivalent to about one year of reductions needed for Reasonable Further Progre ss (RFP). However, since North Carolina is

able to model attainment of the PM 2.5 

## National Ambient Air Quality Standard (NAAQS) within five years of designation, RFP is not required. The USEPA’s guidance to the North Carolina Division of Air Quality (NCDAQ) was to have contingency measures that amounted to oneseventh of the emission reductions that occurred between the base year 2002 and the attainment year 2009, or approximately one year’s worth of emission reductions.

The NCDAQ modeled the emission reductions that occurred as a result of the North Carolina Clean Smokestacks Act (CSA) legislation, which requires coal-fired power plants in North

Carolina to reduce annua l sulfur dioxide (SO 2 

## ) emissions by 49% by 2009 and by 74% by 2013

and to reduce the annua l nitrogen oxides (NO

x 

## ) emissions by 78% by 2009. These emission reductions went well beyond what was needed to attain the annual PM 2.5 

## NAAQS of 15.0 microgram per cubic meter ( μ g/m 3 

## ), evident by the predicted future design values being over

1.5 μ g/m 3 

## below the PM 2.5 

## NAAQS. Therefore, the NCDAQ thought it was unreasonable to require contingency measures of such a large quantity when the Stat e had already reduced a significant amount of the precursor pollutants throughout the State.

Another suggestion by the USEPA was to do sens itivity modeling to determine approximately

the level of emission reductions needed to model 15.0 μ g/m 3 

## and use one-seventh of this

emission reduction level to determine the am ount of contingency measures needed. The NCDAQ did not believe it was a wise use of Stat e resources to perform further modeling when

both nonattainment areas have al ready attained the annual PM 2.5 

## NAAQS.

Therefore, the NCDAQ has documented the expect ed 2009 utility emissions, based on the latest CSA compliance plans, which go beyond what was m odeled in the attainment demonstration, as well as the estimated emission reductions expect ed in 2010. All of these emission reductions will take place without further action from the State. Since the purpose of the contingency measures is to provide for the implementation of measures in the event an area fails to attain the NAAQS, the NCDAQ believes it has met the spirit of this requirement.

### Contingency Measures Documentation 2 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

# 2 Region for Contingency Measures

Since the most significant man-ma de emissions contributor to PM 2.5 

## formation in North Carolina is the precursor pollutant SO 2 

## , the NCDAQ has elected to have only SO 2 

## contingency measures. Under the section for RFP in the Implementation Rule, geographic coverage of emission sources is discussed (72 FR 20636). Due to the regional nature of PM 2.5 

## , it makes senses that sources of

SO 2 

## outside of the nonattainment area may be impacting the PM 2.5 

## concentrations in the nonattainment area. Therefore, the USEPA is a llowing states to consid er emission reductions from emission sources up to 200 kilometer (km) beyond the nonattainment area for contingency measures. The NCDAQ has elected to go beyond the nonattainment areas for its contingency measure plan.

For the Hickory nonattainment area’s contingenc y measures, the NCDAQ has elected to include all counties that are within, or bisected by, a 75 km circle from the nonattainment area boundary. Figure 2-1 displays the region th at contingency measures are be ing considered for the Hickory nonattainment area. The yellow and blue line s represents a 75 km and 200 km radius, respectively, from the nonattain ment area boundary. The emissions from all counties that are shaded are considered in the analysis. For simp licity, these counties will be referred to as the region of influence for the Hickory nonattainment area.

Figure 2-1. The shaded counties represent the region where SO 2 

## contingency measures were considered for the Hickory nonattainment area.

### Contingency Measures Documentation 3 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## Similarly, for the Greensboro/Winston-Salem/High Point nonattainment area (referred to as the Triad area), all counties within, or bisected by, a 75 km circle from the nonattainment area boundary are considered for contingency measur es. Figure 2-2 displays the region that contingency measures are being considered for the Triad nonattainment area. Again, the yellow and blue lines represents a 75 km and 200 km ra dius, respectively, from the nonattainment area boundary. The emissions from all counties that are shaded are considered in the analysis. For simplicity, these counties will be referred to as the region of influence for the Triad

nonattainment area.

Figure 2-2. The shaded counties represent the region where SO 2 

## contingency measures

were considered for the Triad nonattainment area.



# 3 2002 Baseline SO 2 

# Emissions

Table 3-1 displays the 2002 baseline SO 2 

## emissions, by source sector, for the counties located within the region of influence for the Hickory nonattainment area. The total 2002 baseline SO 2 

## emissions for the region of influence is 215,080 tons per year. Table 3-2 displays the 2002

baseline SO 2 

## emissions, by source sector, for the countie s located within the region of influence

for the Triad nonattainment area. The total 2002 baseline SO 2 

## emissions for the region of influence is 401,290 tons per year.

### Contingency Measures Documentation 4 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## Table 3-1 2002 Baseline SO2 Emissions For Hickory Region of Influence

County Point Non-road

Mobile Area Highway

Mobile

Alexande r 4.0 17.4 23.5 28.2

Alle g han y 0.3 8.8 13.0 10.7

Ashe 22.0 16.8 31.1 29.2

Aver y 12.2 15.7 43.7 24.3

Buncombe 17

, 031.5 137.5 235.0 278.4

Burke 242.3 36.9 70.5 166.6

Cabarrus 2

, 081.4 126.9 57.0 233.2

Caldwell 37.8 34.3 56.9 101.5

Catawba 82

, 371.7 99.7 91.5 259.8

Clevelan d 172.4 54.6 88.9 119.8

Davidson 408.0 101.7 97.5 229.9

Davie 16.0 24.3 24.7 75.4

Fors y th 3

, 784.3 157.6 244.0 455.3

Gaston 54

, 597.3 106.2 90.8 296.1

Henderso n 1.7 58.2 62.2 105.4

Iredell 539.6 102.4 108.2 323.6

Lincol n 17.8 42.5 68.5 90.4

Mc Dowell 50.7 55.5 32.2 88.9

Mecklenbur g 867.7 836.8 356.5 1

, 122.0

Mitchell 23.6 42.9 21.1 16.2

Pol k 1.2 11.1 28.2 41.7

Rowan 10

, 600.6 86.6 116.1 229.0

Rutherfor d 29

, 902.4 45.0 47.3 71.8

Stanl y 1

, 654.0 39.2 40.9 92.0

Surr y 320.5 36.2 55.2 125.5

Union 169.1 187.0 62.5 170.7

Watau g a 40.1 46.3 85.0 47.6

Wilkes 95.1 26.6 83.8 82.6

Yadkin 7.0 21.3 28.2 72.0

Yance y 5.3 26.6 29.5 18.9

Total 205,077.6 2,602.6 2,393.5 5,006.7

Table 3-2 2002 Baseline SO2 Emissions For Triad Region of Influence

County Point Non-road

Mobile Area Highway

Mobile

Alamance 23.9 77.2 75.6 210.8

Alexander 4.0 17.4 23.5 28.2 Alleghany 0.3 8.8 13.0 10.7

Anson 172.1 36.8 20.3 39.4

### Contingency Measures Documentation 5 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## Table 3-2 2002 Baseline SO2 Emissions For Triad Region of Influence

County Point Non-road

Mobile Area Highway

Mobile

Cabarrus 2,081.4 126.9 57.0 233.2

Caswell 0.0 17.4 18.9 27.1

Catawba 82,371.7 99.7 91.5 259.8

Chatham 11,871.7 55.2 42.3 99.9

Davidson 408.0 101.7 97.5 229.9

Davie 16.0 24.3 24.7 75.4

Durham 593.3 215.6 117.3 337.8 Forsyth 3,784.3 157.6 244.0 455.3

Gaston 54,597.3 106.2 90.8 296.1

Granville 1.5 49.6 33.6 117.6

Guilford 282.2 376.3 231.8 675.2

Harnett 0.0 72.4 62.1 107.0

Iredell 539.6 102.4 108.2 323.6

Lee 90.7 45.3 31.1 64.8

Lincoln 17.8 42.5 68.5 90.4 Mecklenburg 867.7 836.8 356.5 1,122.0
Montgomery 54.2 18.8 31.8 46.8

Moore 14.7 48.9 54.3 87.1
Orange 148.6 96.0 122.9 247.7

Person 126,780.3 23.2 40.8 33.8 Randolph 3.0 66.4 88.1 218.2

Richmond 64.8 47.4 37.9 65.5 Rockingham 5,290.8 56.4 66.6 109.3

Rowan 10,600.6 86.6 116.1 229.0

Scotland 252.1 31.9 46.1 48.0 Stanly 1,654.0 39.2 40.9 92.0

Stokes 83,483.9 24.7 45.8 43.9
Surry 320.5 36.2 55.2 125.5

Union 169.1 187.0 62.5 170.7

Wake 76.4 657.4 346.1 961.5

Wilkes 95.1 26.6 83.8 82.6

Yadkin 7.0 21.3 28.2 72.0
Total 386,738.6 4,038.1 3,075.3 7,437.8



# 4 Contingency Measures

As stated above, the NCDAQ ha s elected to have only SO 2 

## contingency measures. As can be seen in Tables 3-1 and 3-2, the vast majority of the SO 2 

## emissions come from point sources

### Contingency Measures Documentation 6 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## (approximately 96%). Therefore, the NCDAQ on ly looked at the point source sector for emissions reductions, and specifi cally the coal-fired power pl ants since they make up the majority of the point source SO 2 

## emissions.

In June 2002, the North Carolina General Assembly enacted the CSA, requiring coal-fired power plants to reduce annual SO 2 

## emissions by 49% by 2009 and 74% by 2013. Additionally, this legislation required reductions in annual nitrogen oxide emissions. One of the first state laws of its kind in the nation, this legislation provides a model for other states in controlling multiple air pollutants from older coal-fired power plants. The reduction in emissions achieved through the

CSA are not allowed to be traded in the Nationa l emissions trading program, but rather are held in trust by the citizens of North Carolina.

Since the first phase-in year is 2009, which coin cides with the attainment year for the PM 2.5 

## nonattainment areas, some of the SO 2 

## reductions expected from the CSA were modeled as part of the attainment demonstration. However, not a ll of the units expecti ng to have controls operational in 2009 were modeled at full compliance. Additionally, one facility’s controls will be fully implemented during the middle of 2010. Since these additional emission reductions were not modeled as part of the attainment de monstrations and will ta ke place in 2010 without further action from the State or the USEPA, they can be considered as contingency measures. Additionally, when the attainment demonstration modeling project started, the latest compliance plan for CSA was the 2006 plan. The utility comp anies now have a better understanding of what

the SO 2 

## emissions will be in 2009 and are reflect ed in the 2009 CSA compliance plan. The

difference between the emissions modeled and th e current expectations for the 2009 emissions

are further emission reductions that are expected to occur that we re not modeled as part of the

attainment demonstration.

All the Duke Energy and Progress Energy units th at are in the area of influence for both

nonattainment areas were reviewed to determin e the difference in the 2009 emissions modeled and the current expectation based on the latest CSA compliance plan. The units that were considered for the analysis of emissi on reductions to occur in 2010 include:

• Duke Energy Allen Steam Station, units 1 through 5, located in Gaston County;

• Duke Energy Cliffside, unit 5, locat ed in Rutherford County; and

• Progress Energy Mayo, unit 1, locat ed in Person County.

The table below shows the 2009 emissions modeled based on the 2006 CSA compliance plan, the expected 2009 emissions based on the late st CSA compliance plan and the difference between them. The 2006 CSA compliance plan is attached to this appendix and the 2009 CSA compliance plan can be found in Appendix M.

### Contingency Measures Documentation 7 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## Table 4-1 Comparison of Modeled 2009 Emissions to Expected 2009 Emissions

Unit Area of Influence 2009 Modeled

Emissions Expected 2009

Emissions Difference

Duke Energy Facilities

Allen Unit 1

Both Areas 2,659 1,336 -1,323 Allen Unit 2 2,488 1,842 -646 Allen Unit 3 9,864 5,694 -4,170 Allen Unit 4 10,746 6,556 -4,190 Allen Unit 5 4,215 4,333 118

Belews Unit 1 Triad Area 5,927 5,476 -451 Belews Unit 2 4,579 4,535 -44

Buck Unit 3 Both Areas 1,542 1,017 -525

Buck Unit 4 983 642 -341

Buck Unit 5 Both Areas 4,412 4,472 60 Buck Unit 6 4,410 4,784 374

Dan River Unit 1

Triad Area 2,184 1,919 -265 Dan River Unit 2 2,336 2,081 -255 Dan River Unit 3 5,202 5,062 -140

Cliffside Unit 1

Hickory Area 1,170 488 -682 Cliffside Unit 2 1,198 469 -729 Cliffside Unit 3 2,243 1,385 -858 Cliffside Unit 4 2,213 1,414 -799 Cliffside Unit 5 31,193 28,476 -2717

Marshall Unit 1

Both Areas 1,952 1,742 -210 Marshall Unit 2 1,940 1,742 -198 Marshall Unit 3 3,539 3,439 -100 Marshall Unit 4 3,333 3,354 21

Riverbend Unit 4

Both Areas 3,635 3,344 -291 Riverbend Unit 5 3,641 3,219 -422 Riverbend Unit 6 5,799 5,320 -479 Riverbend Unit 7 5,942 5,260 -682

Progress Energy Facilities

Asheville Unit 1 Hickory Area 864 1,003 139

Asheville Unit 2 886 770 -116 Cape Fear Unit 5 Triad Area 6,249 4,829 -1,420 Cape Fear Unit 6 7,725 6,705 -1,020 Mayo Unit 1 Triad Area 14,361 5,232 -9,129

Roxboro Unit 1

Triad Area 1,741 1,341 -400 Roxboro Unit 2 2,853 2,687 -166 Roxboro Unit 3 2,928 2,716 -212 Roxboro Unit 4 2,363 3,120 757
Total Emissions 169,315 137,804 -31511

### Contingency Measures Documentation 8 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## This difference of 31,511 tons per year of SO 2 

## emissions represents emissions that were not modeled but are expected to occu r in 2009 within the ar ea of influences of the two nonattainment areas combined. The expected versus modeled SO 2 

## emissions will be 25,749 tons per year lower

within the Triad’s area of influe nce and 18,766 tons per year lower within the Hickory’s area of

influence.

To estimate the additional amount of SO 2 

## emissions that will be reduced in 2010, the 2009

annual SO 2 

## emissions that were listed in the 2009 CSA compliance pl an were subtracted from

the 2013 annual emissions. For the unit that the c ontrol equipment is exp ected to come on-line in the middle of 2010, only a half-year compliance wa s considered, i.e., half of the controlled emissions plus half of the uncontrolled emi ssions. The 2013 annual emissions represent full implementation of the control measures and is a conservative surroga te for estimating 2010 SO 2 

## emissions since 2013 energy demands will be higher than 2010 and therefore the expected emissions for 2013 will be slightly higher than 2010. Table 4-2 displays the expected compliance period, the expected 2009 emissions , the estimated 2010 emissions, area impacted

and the estimated emission reductions for the un its considered for the contingency measures.

Table 4-2 Estimated Emission Reductions Expected from Clean Smokestacks Act

Unit Compliance

Period Area of

Influence 2009 SO2 (tons/year) 2010 SO2 (tons/year) Reductions (tons/year)
Allen –1 Early 2009

Both areas 1,336 660 - 676 Allen – 2 Early 2009 1,842 644 -1,198 Allen – 3 Late 2009 5,694 1,239 -4,455 Allen – 4 Late 2009 6,556 1,321 -5,235 Allen – 5 Mid 2009 4,333 1,134 -3,199 Cliffside – 5 Mid 2010 Hickory 28,476 15,667 -12,809 Mayo – 1 Late 2009 Triad 5,232 1,969 -3,263

To demonstrate that the expected emission re ductions have an impact on the nonattainment areas, the NCDAQ relied on the back traject ory analysis that was done for the PM 2.5 

## nonattainment boundary recommendation package. For the details of how these trajectory analyses were created, please refer to the documentation used for the boundary recommendation package attached to this appendix.

Figure 4-1 displays the location of the utilities subject to the CSA. Figures 4-2 and 4-3 displays the back trajectory analysis for the Hickory and Lexington PM 2.5 

## monitors, respectively. The back trajectories were overlaid on a map with the utility locations displayed with red dots. It is clear from these figures that the air masses pass over or near large utility plants on days when high PM 2.5 

## levels were observed at the monitors.

### Contingency Measures Documentation 9 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## Figure 4-1. Location of the Utilities Subject to the CSA.

Figure 4-2. Back Trajectory Analysis for Hickory PM 2.5 

## Monitor.

### Contingency Measures Documentation 10 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## Figure 4-3. Back Trajectory Analysis for Lexington PM 2.5 

## Monitor.

4.1 Hickory Area Contingency Measure Reductions

In order to estimate the total emission reducti ons from point sources in 2010, the other point

sources located within the region of influence had to be grown from 2009 to 2010. The NCDAQ estimated that the other point s ources within the region of infl uence would grow approximately

50 tons.

The total reduction that is expected beyond the em issions that were modeled in the attainment demonstration is 18,766 tons in 2009 emissions and approximately 27,500 tons per year that are expected to occur between 2009 and 2010, for a total of over 46,000 tons per year of SO 2 

## emissions reduced. This is a pproximately a twenty-two percen t reduction from the 2002 baseline

SO 2 

## emissions for the Hickory region of influence, which is a significant reduction of emissions. This reduction in emissions beyond what was mode led should satisfy the contingency measure requirement for this nonattainment area.

4.2 Triad Area Contingency Measure Reductions

Again, in order to estimate the to tal emission reductions from point sources in 2010 for the Triad region of influence, the other po int sources located within the re gion of influences had to be grown from 2009 to 2010. The NCDAQ estimated that the other point sour ces within the region of influence would grow approximately 85 tons.

### Contingency Measures Documentation 11 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

## The total reduction that is expected beyond the em issions that were modeled in the attainment demonstration is 25,749 tons in 2009 emissions and approximately 18,000 tons per year that are expected to occur between 2009 and 2010, for a total of over 43,000 tons per year of SO 2 

## emissions reduced. This is a pproximately an eleven percent reduction from the 2002 baseline

SO 2 

## emissions for the Triad area of influence, which again is a significant reduction of emissions. This reduction in emissions beyond what was modeled should satisfy the contingency measure requirement for this nonattainment area.



# 5 Conclusions

The NCDAQ believes that existing control me asures required by the North Carolina Clean

Smokestacks Act results in a sufficient amount of SO 2 

## emission reductions to adequately meet the contingency measure requirements of Section 172(c)(9). The Hickory area is expected to achieve over 46,000 tons per year of SO 2 

## reduction and the Triad area is expected to achieve over 43,000 tons per year SO2 reductions. Consider ing the purpose of contingency measures is to require further emission reduc tions in case a nonattainment area does not attain the NAAQS by the prescribed attainment date and both nonatt ainment areas in have already attained the

PM 2.5 

## NAAQS, the NCDAQ firmly believes that North Carolina has more than fulfilled the contingency measure requirement.

### Contingency Measures Documentation 12 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

# Attachment 1

2006 Clean Smokestacks Act Compliance Plan

### Contingency Measures Documentation 13 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

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### Contingency Measures Documentation 51 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

# Attachment 2

Catawba and Davidson Counties Trajectory Analysis

### Contingency Measures Documentation 52 The Hickory And Greensboro/Winston-Salem/High Point, NC PM2.5 Appendix N North Carolina Attainment Demonstration August 21, 2009 

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# Catawba and Davidson Counties HY SPLIT Back-Trajectory Analysis

to Determine PM 2.5 

# Source Regions

Michael A. Abraczinskas, K. Wyat Appel, George M. Bridgers, Scott A. Jackson North Carolina Division of Air Quality Raleigh, NC

March 8, 2004

1. Introduction

The purpose of this analysis is to access the source regions, in particular according to state boundaries, which contribute significantly to elevated daily Fine Particulate Matter (PM 2.5 

## ) levels in North Carolina. The North Carolina Division of Air Quality (NC DAQ) has identified a specific need to know th e regions, specifically according to state boundaries, which contribute significan tly to primary and secondary PM 2.5 

## in North Carolina. The Environmental Protection Ag ency (EPA) has established standards for

PM 2.5 

## at 15 μ g/m 3 

## for the annual standard and 65 μ g/m 3 

## for the 24-hour standard.

2. Methodology

An analysis of the National Oceanic and Atmospheric Administration Air Resource Laboratory (NOAA ARL) HYbrid Single-Partic le Lagrangian Integrated Trajectory (HYSPLIT; Draxler and Rolph, 2003) model back trajectories was performed in order to

access the sources that contribute to elevated PM 2.5 

## levels in North Carolina. An analysis of observed 24-hour average PM 2.5 

## values throughout from North Carolina’s PM 2.5 

## monitor network determined that the tw o monitors with the highest annual PM 2.5 

## values

in North Carolina are located in Catawba a nd Davidson Counties. The monitors located

in these counties are Federal Referen ce Method (FRM) monitors and sample PM 2.5 

## every three days. Because these monitors had the two highest annual-average PM 2.5 

## values, the

monitors located in these two counties were chosen as the endpoints for the HYSPLIT back trajectories. The specific location of Catawba County monitor is 35.73 ° N,

81.36 ° W, while the Davidson County monitor is located at 35.81 ° N, 80.26 ° W.

PM 2.5 

## data from January 1, 1999 through June 30, 2002 was analyzed to identify days when the 24-hour average PM 2.5 

## value was greater than or equal to 27.9 μ g/m 3 

## . This concentration was chosen since it represen ts the midpoint of the yellow AQI range
(15.5 μ g/m 3 

## – 40.4 μ g/m 3 

## ) for PM 2.5 

## , and conversations with EPA representatives have indicated that values above this point could pose a significant health risk. From the three and half years of available PM 2.5 

## data from those two monitors, there were a total of 41 days from the Catawba County monitor and 32 days from the Davidson County monitor where the 24-hour average PM 2.5 

## value was greater than or equal to 27.9 μ g/m 3 

## . The dates and observed 24-hour average PM 2.5 

## of these days are shown in Table 1.

For the days indicated above, HYSPLIT back tr ajectories were run. Thirty-six hour back trajectories ending at 17UTC, noon Eastern Day light Time, were run separately for each

1

## monitor using the model vertical velocity option. The trajectories were run at three separate heights, specifically 10, 300 and 1000 meters above ground level (AGL). The 10 and 300-meter trajectory levels are heights of lower level circulations, while the 1000- meter trajectory level represents the top of the mixed layer and is generally a transport

level. The choice of these levels is base d on the experience of NC DAQ meteorologists, who use the HYSPLIT model trajectories as a routine part of their ozone and PM 2.5 

## forecast process. 17UTC (Noon EDT) was chosen as the ending time of the trajectories because it represents a time when significant mixing of the boundary and residual layers has occurred, but significant contributions from local-secondary production has not

occurred.

3. Results

Table 1 shows the results of the analysis of the back trajectories. Columns 4 and 5 in Table 1 identify the primary and secondary source regions. The primary source region identifies the most significant region(s) contributing to the PM 2.5 

## in that county on that day, as determined by the meteorologists. The secondary source region identifies a region(s) that, while is not a primary c ontributor, does appear to contribute to a significant portion of the PM 2.5 

## on that day. Note that while there is always a primary source identified for a given day, there may not be secondary source identified.

Figures 1-4 show composites of the back trajectories originating from the Catawba County site at 10, 300, and 1000 meters AGL for those days when PM 2.5 

## concentrations were high. Note that the trajectories are re latively short, indicating regional stagnation and recirculation. Figures 5-8 show similar composites for the Davidson County site.

Analysis of the HYSPLIT back trajectories s howed that on the majority of the days the primary source region of the back trajector y was North Carolina. Table 2 shows the distribution of both primary and secondary source regions for the trajectories for both Catawba and Davidson counties. Of the 41 days for which back trajectories were run for the Catawba County monitor, 31 (76%) of them were considered to have North Carolina as the primary source region (Figure 9). Tenne ssee and Virginia were considered to be primary sources on 9 (22%) and 6 (15%) da ys, respectively. Significant secondary sources were South Carolina, Tennessee, and Georgia, which contributed on 9 (22%), 8 (20%), and 7 (17%) days respectively (Figur e 10). Figure 11 shows the percent of the days in which each region was identified as either a primary or secondary source, or both.

There were 27 (66%) days when North Caro lina was identified to be the only primary source region, while there were 4 (10 %) days when North Carolina and another state(s) was identified to be the source region, and 10 (24%) days when North Carolina was not identified as part of the source region. This result is significant, since it indicates that nearly 35 percent of the days when PM 2.5 

## was greater than or equal to 27.9 μ g/m 3 

## , backtrajectory analysis indicates transport from neighboring states, in particular Tennessee, Virginia, Georgia and South Carolina.

2

## For the Davidson county monitor, 26 (81%) of the 31 days for which the trajectories were run indicated North Carolina as the primary source (Table 2, Figure 12). Note that there was one day for which a trajectory could not be run due to missing data. Other significant primary sources were Virginia, with 7 (23%) days, and South Carolina and Tennessee, each with 4 (13%) days. Significan t secondary sources were South Carolina, Tennessee, and Virginia, each with 5 (16%) days, and Ohio with 4 (13%) days (Figure 13). Of the 31 days for which the back traj ectories were run, 17 (55%) of them indicated North Carolina as the only primary source re gion, while on 14 (45%) days trajectories indicated another state as the primary s ource region. As with the Catawba County analysis, there were a significant percentage of days when trajectory analysis indicates transport from neighboring states on days when PM 2.5 

## was greater than or equal to 27.9

μ g/m 3 

## . The percent of days in which each regi on contributed as a primary or secondary source (or both), is shown in Figure 14.

Another interesting analysis is examining the 24-hour average PM 2.5 

## value and the associated primary source region. The trajector ies run for each monitor were divided into an upper third, a middle third, and a lower third based on the observed PM 2.5 

## concentration. For the Catawba County m onitor the upper third consists of a PM 2.5 

## range
between 32.8 and 54.7 μ g/m 3 

## , the middle third from 30.0 and 32.7 μ g/m 3 

## , and the lower

third from 28.1 to 29.6 μ g/m 3 

## . Note that there are 14 days included in the upper and middle thirds, and only 13 days included in the bottom third (Tables 3-5).

For the upper third of the days for the Cata wba County monitor site, North Carolina was the primary source on 10 days, followed by Te nnessee and Virginia with 2 days each. South Carolina, Tennessee, Virginia and Georgia are common secondary source regions. For total days (primary and secondary co mbined), North Carolina was identified on 10 days, followed by Tennessee on 5 days and S outh Carolina, Virginia, and Georgia each on 3 days. The results for the middle and lower third of the days are similar to those for the upper third. The same analysis for the Davidson County monitor site yields similar results. Note also that 11 days are included in the upper and middle thirds, while only 10 days are included in the bottom third.

Another analysis that was performed using the back trajectories was to quantify the residence time that the trajectories spent in each state, other than North Carolina. This was accomplished by analyzing each trajectory individually and recording the amount of time the trajectory spent in each individual stat e. Since trajectories were run at multiple heights, to avoid double counting, only the maximum time that all trajectory heights spent in any one state are reported. Obviousl y, since the end points of the trajectories are within North Carolina, some time for each traj ectory must be spent in North Carolina. The results of the analysis for Davidson and Catawba counties are shown in Tables 6 and 7 respectively. Note that this analysis contains seven events in 2002 for Catawba County and four events in 2002 for Davidson County that are not included in the previous analysis of the trajectories.

For Catawba County, the maximum number of hours the trajectories spent in another state for all events was 258 in Tennessee (reca ll that an event is a day where the PM2.5

3

## concentration exceeded 27.9 μ g/m 3 

## at the monitor in that county). This represents 15.6 percent of the total trajectory time (36 hours/ event * 46 events = 1656), with an average of 18.4 hours per event. The average represen ts the average hours the trajectory spent in each state for only those events where the traj ectory spent at least some amount of time in the state (zero hour events are not included in the average). Other results include 207 hours (12.5% of total) for South Carolina, w ith an average of 18.8 hours per event, and 201 hours (12.1% of total) for Kentucky, with an average of 14.4 hours per event.

For Davidson County, the maximum number of hours the trajectories spent in another state for all events was 278 in South Carolina. This was 22.7 percent of the total trajectory time (36 hours/event * 34 days), with an average of 19.9 hours spent in South Carolina for each event. Virginia had a to tal of 275 hours (22.5% of total) with an average of 14.5 hours per event. Tennessee had a total of 166 hours (13.6 % of total) with an average of 15.1 hours per event.

4. Discussion

Analysis of HYSPLIT back trajectories from two PM 2.5 

## monitor locations in North Carolina on days when 24-hour average PM 2.5 

## levels were 27.9 μ g/m 3 

## or greater indicates that while North Carolina is the primary s ource region for the majority of those days, states neighboring and near North Carolin a (including Kentucky, West Virginia, and Ohio) were shown through the trajectory analys is to be potential sources of transported pollution. Back trajectories run from points in Catawba and Davidson Counties in North Carolina show a significant percentage of da ys for which neighboring states could be considered primary sources for transported pollution. Significant secondary states include South Carolina, Tennessee, and Virginia. Othe r states with slightly fewer days when back trajectories indicated potential transpor t include Georgia, Kentucky, and the Ohio Valley.

REFERENCES

Draxler, R.R. and Rolph, G.D., 2003. HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY Website (http://www.arl.noaa.gov/ready/hysplit4.html). NOAA Air Resources Laboratory, Silver Spring, MD.

4CountyDatePM 2.5PrimarySecondaryNotesDavidson1/1/200046.8NC (Millenium Celebration)Low: NC (calm conditions) and CLT;Mid and Upper: Upstate SC and GADavidson8/13/199944.8NC / SCLow: NC and Eastern SC;Mid:SC and NC;Upper: NC and Upstate SCDavidson6/21/200141.6NCCentral SCLow and Mid: NC and Central SC;Upper:NC, Northeast TN and SW Virginia (minor)Davidson7/23/199940.5E. KY, SW. VAOhio ValleyLow and Mid:SW Virginia and E. KY;Upper:long transport from Ohio ValleyDavidson1/5/200239.2NC / TNLow: NC and NE TN;Mid: NC and Eastern TN;Upper:TNDavidson7/17/199938.9NCCentral SCLow: NC (CLT);Mid: NC and SC;Upper: NC and SW VirginiaDavidson12/11/200038.7Missing DataDavidson10/21/200037.7SW. VA / E. TNNCLow: NC and Upstate SC;Mid: Eastern TN:Upper: SW VA and Eastern TNDavidson7/18/200137.7NC / SCSE. TN / N. GALow: SC and some NC;Mid: NC and Northern GA;Upper: NC, Eastern TN, N. GADavidson7/5/199936.6NCEastern TN (significant)Low: All in NC;Mid: Origin in NE TN;Upper: Crosses KY, WV, VADavidson6/2/200034.9NCEastern TNMissing DataDavidson6/29/200034.1NC / N. GA / N. SCAloft from Ohio ValleyLow: NC, SC, and GA;Mid: NC and GA (ATL);Upper: Ohio ValleyDavidson8/7/199933.8NCSW. VALow: NC;Mid: NC and SW VA;Upper: NC (CLT)Davidson7/2/200032.7NC (CLT)North Central SCLow: Completely in NC;Mid: NC and Upstate SC;Upper: NC and Upstate SCDavidson8/28/199932.1NCSW. VA (less sig)Low: NC;Mid: NC and SW VA;UpperNC and SW VADavidson11/11/199931.8TNLow, Mid, and Upper: Long transport from TennesseeDavidson8/16/200031.2NC / VAOhio ValleyMissing DataDavidson8/19/199931.1NC / VAOhio ValleyLow: NC, VA, and WV;Mid: Eastern VA;Upper: NC, SW VA, and Ohio ValleyDavidson10/27/200031.1VALow, Mid, and Upper: VirginiaDavidson1/21/199931.0NC (CLT, I-85)Upstate SCLow: All in NC;Mid and Upper: long transport from the westDavidson11/8/200030.7NCLow:Short over NC;Mid and Upper: Long transport from the south (SC, GA, FL)Davidson7/20/199930.6NE. TN, SW. VA, NCLow: NC and Upstate SC;Mid: E. TN and NCUpper: VA, KY, and TNDavidson8/16/199930.1NCLow, Mid, and Upper: All completely in NC (short trajectories)Davidson6/11/199929.8NC (PP, I-40)Tidewater of VA (minimal)Low, Mid, and Upperall over NC and originate in the AtlanticDavidson2/9/200029.4NCI-95 VirginiaLow: NC and VA;Mid: NC and VA;Upper: NC (over the mountains)Davidson5/30/199929.1NC (CLT)NCLow, Mid, and Upperall in NC and very northern SCDavidson8/8/200129.0Ohio ValleyWV / VA / NCLow: NC and SW VA;Mid: VA and WV;Upper:VA, WV and Ohio ValleyDavidson10/30/199928.5NCMissing DataDavidson8/17/200128.5NC / SCGA (ATL)Low: NC (CLT) and SC;Mid: Mostly SC, some NC;Upper: NC and GA (ATL)Davidson7/8/199928.4NCUpstate SC, Eastern TN (3rd)Low: NC;Mid: Upstate SC;Upper: NE TennesseeDavidson10/18/200028.0NCEastern TNLow: Completely in NC;Mid: Completely in NC;Upper: long transport from TNDavidson8/14/200127.9NC / VAWVLow: NC and SW VA;Mid: NC, Central VA, and WV;Upper: VA, WV, and Ohio ValleyTable 1. Days when observed PM2.5values in Catawba and Davidson Counties was above 27.8 ug/m3. Indicated in the table is the county, date, PM2.5observed value, the primary and secondary sources as determinedby the NC DAQ meteorologists, and any notes made by the meteorologists concerning that days trajectories. Purple shading indicates observed values greater than 39.9 ug/m3, red shading between 35.0 ug/m3and 39.9ug/m3, orange shading between 30.0 ug/m3to 34.9 ug/m3, yellow shading between 27.9 ug/m3and 29.9 ug/m3. Blue shading indicates known fire events in North Carolina. On days with missing EDAS data, surfacemaps were used to determine the source region(s).CountyDatePM 2.5PrimarySecondaryNotesCatawba11/2/200054.7NC (Fire Event)Ohio ValleyLow and Mid: Completely in NC;Upper: Long transport from the Ohio ValleyCatawba11/8/200050.1NC (Fire Event)SC / E. GA / FL (minor)Low, Mid, and Upper: Short trajectories in NC, then long transport from the southCatawba1/21/199941.0NCUpstate, North Central GALow: all in NC;Mid: NC, Upstate SC, and N. GA;Upper: long transport from the southwestCatawba6/21/200140.0NCSC (minor)Low: NC and Upstate SC;Mid: Completely NC;Upper: All NC except for couple hours in TNCatawba10/21/200038.0NCN. SC and E. TNLow: NC and Upstate SC;Mid: Eastern TN and N. GA;Upper: Central TN and Northern MSCatawba10/27/200036.7SW. VA / WVSouthern Ohio ValleyLow: SW VA and Eastern KY;Mid and Upper: SW VA, Western WV, Southern Ohio ValleyCatawba7/23/199936.1NE. TN / OV / SW. VALow and Mid: Northern TN;Upper: long transport from the northwestCatawba8/7/200034.2NCEastern TN, GA (ATL)Low and Mid: NC and Northern GA;Upper: Eastern TN and Northern GACatawba3/31/199930.0NCNorthern SCLow: NC;Mid: NC, minor SC and VA;Upper; Upstate SCCatawba2/9/200033.5NCEastern TN, Northern GALow: NC and very minor VA;Mid: NC and very minor SC;Upper: NC, E. TN, and N. GACatawba6/5/199933.2NCLow, Mid, and Upper: NC (CLT and Triad)Catawba8/7/199933.1NCSW. VALow and Mid: Mostly NC, few hours in SW VA;Upper: Mostly in NC, few hours in NE TNCatawba1/1/200033.0MilleniumLow, Mid, and Upper: NC and transport from the westCatawba2/21/200132.8Eastern TNNorthern GALow: Eastern TN and Northern GA;Mid: NE TN, SW VA (minor), and TN;Upper: TN and KYCatawba7/8/200032.7NCLow and Mid: Completely in NC;Upper: NC and Upstate SC (minor, mostly NC)Catawba7/17/199932.3NCUpstate SCLow and Mid: NC and Upstate SC;Upper: All in NCCatawba8/2/200132.0NCLow, Mid, and Upper: Trajectories completely in NCCatawba6/8/199931.7NE. TN / SW. VA / KYLow: NE TN and SW VA;Mid and Upper: NE TN, SW VA, KY;Catawba8/16/199931.1NCLow and Mid: Completely in NC;Upper: NC and Upstate SC (CLT area)Catawba8/13/199931.0NCSCLow: Completely in NC;Mid: NC and Upstate SC (CLT);Upper: NCCatawba6/2/200031.0Eastern TNN. GA and NCmissing dataCatawba7/20/199930.9NC / E. TNLow: Completely in NC;Mid and Upper: Eastern TNCatawba5/3/200030.8NCVA and SCLow: majority NC and VA;Mid: NC (half), VA (half);Upper: mostly NC, minor SCCatawba7/23/200030.6NCLow, Mid, and Upper: Completely in NCCatawba9/7/200130.4NCNE. TNLow and Mid: Completely in NC;Upper: NC and NE TennesseeCatawba8/26/200130.2NCEastern TN and SC (minor)Low: Completely in NC;Mid: Mostly in NC, few hours in Upstate SC;Upper: Eastern TNCatawba1/30/199930.0NCLow, Mid, and Upper: NC and VA (few hours);Catawba2/17/199930.0NC / N. GA / Upstate SCmissing dataCatawba8/19/199929.6Ohio Valley / SW. VALow: NC, SW VA, and WV;Mid: NC, VA, and WV;Upper: NC, NE TN, SW VA, and E. KYCatawba7/2/200029.4NCSCLow: NC (CLT);Mid: NC and Upstate SC;Upper: NC and Central SCCatawba7/18/200129.3NCSE. TN and N. GALow: NC and Northern GA;Mid and Upper: Southeast TN and Northest MSCatawba7/5/200029.1Eastern and Central TNLow, Mid, and Upper: Transport from Central and Eastern TennesseeCatawba11/18/200129.0NCVA / Ohio Valley (upper)Low and Mid: NC and VA;Upper: SW VA, KY, and Southern Ohio ValleyCatawba8/10/199928.4NCE. TNLow and Mid: All in NC;Upper: transport from KY and TNCatawba6/4/200228.4SCNCLow: Upstate SC and NC;Mid: SC and NC;Upper: SC and NCCatawba7/5/199928.2NE. TNSW. VA / KYLow: NE TN;Mid: NE TN and SW VA;Upper: SW VA and KYCatawba6/11/200028.2NC / NE. TN / SCLow and Mid: Majority Upstate SC, some NC;Upper: NC and some NE TN and Upstate SCCatawba8/16/200028.2NE. TN / SW. VAKYmissing dataCatawba10/18/200028.2NCNE and Central TNLow: Completely in NC;Mid and Upper: Eastern and Central TNCatawba8/4/199928.1NC / VALow, Mid, and Upper: NC and SW VACatawba9/31/0128.1NCSW. VA and E. KYLow and Mid: Completely in NC;Upper: SW VA and SE KYTable 1 Continued

### Table 2. Number of days that the HYSPLIT back trajectories indicated a region as a primary or secondary

source for locations in Catawba and Davidson Counties in North Carolina.



## Catawba County Davidson County

State/Area Primary (days) Secondary (days) Total (days) State/Area Primary (days) Secondary (days) Total (days)

North

Carolina 

## 31 2 33 North

Carolina 

## 26 2 28

South

Carolina 

## 3 9 12 South

Carolina 

## 4 5 9

Tennessee 

## 9 8 17 Tennessee 

## 4 5 9

Virginia 

## 6 5 11 Virginia 

## 7 5 12

Georgia 

## 1 7 8 Georgia 

## 1 2 3

Kentucky 

## 1 3 4 Kentucky 

## 1 0 1

Ohio Valley 

## 2 3 5 Ohio Valley 

## 1 4 5

NC Only 

## 27 NC Only 

## 17

NC + Other 

## 4 NC + Other 

## 9

No NC 

## 10 No NC 

## 5

Table 3. Number of days in the highest one-third of 24-hour average PM 2.5 

### values for all days for which HYSPLIT trajectories were run. Specific PM 2.5 

### values were 32.8 – 54.7 μ g/m 3 

### for Catawba County and

34.9 – 46.8 μ g/m 3 

### for Davidson County.



## Catawba County – Upper Third Davidson County – Upper Third

State/Area Primary (days) Secondary (days) Total (days) State/Area Primary (days) Secondary (days) Total (days)

North

Carolina 

## 10 0 10 North

Carolina 

## 8 1 9

South

Carolina 

## 0 3 3 South

Carolina 

## 2 2 4

Tennessee 

## 2 3 5 Tennessee 

## 2 3 5

Virginia 

## 2 1 3 Virginia 

## 2 0 2

Georgia 

## 0 3 3 Georgia 

## 0 1 1

Kentucky 

## 0 0 0 Kentucky 

## 1 0 1

Ohio Valley 

## 1 1 2 Ohio Valley 

## 0 1 1

### Table 4. Number of days in the middle one-third of 24-hour average PM 2.5 

### values for all days for which HYSPLIT trajectories were run. Specific PM 2.5 

### values were 30.0 – 32.8 μ g/m 3 

### for Catawba County and

30.6 – 34.1 μ g/m 3 

### for Davidson County.



## Catawba County – Middle Third Davidson County – Middle Third

State/Area Primary (days) Secondary (days) Total (days) State/Area Primary (days) Secondary (days) Total (days)

North

Carolina 

## 10 0 10 North

Carolina 

## 9 0 9

South

Carolina 

## 1 4 5 South

Carolina 

## 1 2 3

Tennessee 

## 3 2 5 Tennessee 

## 2 0 2

Virginia 

## 2 1 3 Virginia 

## 4 2 6

Georgia 

## 1 0 1 Georgia 

## 1 0 1

Kentucky 

## 1 0 1 Kentucky 

## 0 0 0

Ohio Valley 

## 1 0 1 Ohio Valley 

## 0 3 3

Table 5. Number of days in the lowest one-third of 24-hour average PM 2.5 

### values for all days for which HYSPLIT trajectories were run. Specific PM 2.5 

### values were 28.1 – 29.6 μ g/m 3 

### for Catawba County and

27.9 – 30.1 μ g/m 3 

### for Davidson County.



## Catawba County – Lower Third Davidson County – Lower Third

State/Area Primary (days) Secondary (days) Total (days) State/Area Primary (days) Secondary (days) Total (days)

North

Carolina 

## 8 1 9 North

Carolina 

## 9 2 11

South

Carolina 

## 2 1 3 South

Carolina 

## 1 1 2

Tennessee 

## 4 3 7 Tennessee 

## 0 1 1

Virginia 

## 3 3 6 Virginia 

## 1 3 4

Georgia 

## 0 1 1 Georgia 

## 0 1 1

Kentucky 

## 0 2 2 Kentucky 

## 0 0 0

Ohio Valley 

## 1 1 2 Ohio Valley 

## 1 0 1

### Table 6. Total number of hours back trajectories spent in states other than North Carolina for all events for the Davidson County PM 2.5 

### monitor. Hours are based on the maximum of all trajectory heights, and therefore do not double count. Percent of total hours based on maximum hours of all events (1224 hours). Average hours based on average of each event, excluding zero hour events.

Davidson County

Date PM2.5 SC (hrs) GA (hrs) TN (hrs) V A (hrs) KT (hrs) WV (hrs) OH (hrs) MAX

1/21/1999 31.0 12 8 36

5/30/1999 29.1 20 36

6/11/1999 29.8 36

7/5/1999 36.6 6 16 12 36

7/8/1999 28.4 23 10 20 36

7/17/1999 38.9 22 22 36

7/20/1999 30.6 22 12 11 36

7/23/1999 40.5 18 13 7 4 36

8/7/1999 33.8 7 36

8/13/1999 44.8 23 36

8/16/1999 30.1 36

8/19/1999 31.1 28 13 8 36

8/28/1999 32.1 25 36

11/11/1999 31.8 15 9 36

1/17/2000 N/A 36

2/9/2000 29.4 13 36

6/2/2000 34.9 36

6/29/2000 34.1 10 16 6 18 6 36

7/2/2000 32.7 21 36

10/18/2000 28.0 25 36

10/21/2000 37.7 16 9 10 6 6 36

10/27/2000 31.1 34 36

11/8/2000 30.7 14 9 36

12/11/2000 38.7 12 36

6/21/2001 41.6 28 10 3 3 36

7/18/2001 37.7 29 11 14 36

8/8/2001 29.0 20 14 18 36

8/14/2001 27.9 20 11 36

8/17/2001 28.5 17 16 36

1/5/2002 39.2 20 4 36

7/1/2002 31.1 23 18 36

7/16/2002 33.1 6 12 12 36

8/12/2002 36.9 20 12 19 36

12/7/2002 43.7 6 5 9 36

Total Hours 278 94 166 275 81 73 30 1224

% of Total 22.7 7.7 13.6 22. 5 6.6 6.0 2.5

Avg. Hours 19.9 11.8 15.1 14. 5 10.1 12.2 7.5

### Table 7. As in Table 6, except for Catawba County.

Catawba County

Date PM2.5 SC (hrs) GA (hrs) TN (hrs) VA (hrs) KT (hrs) WV (hrs) OH (hrs) MAX

1/21/1999 31.0 12 10 36

1/30/1999 30.0 10 3 36

3/31/1999 30.0 9 6 36

5/30/1999 29.1 36

6/8/1999 31.7 7 25 36

7/5/1999 28.2 25 15 21 36

7/17/1999 32.3 20 36

7/20/1999 30.9 28 36

7/23/1999 36.1 30 12 36

8/4/1999 28.1 17 2 36

8/7/1999 33.1 36

8/10/1999 28.4 10 26 36

8/13/1999 31.0 31 36

8/16/1999 31.1 36

8/19/1999 29.0 6 12 16 36

1/1/2000 33.0 36

2/9/2000 33.5 6 15 12 4 36

5/3/2000 30.8 4 21 7 36

6/2/2000 31.0 36

6/11/2000 28.2 25 36

7/2/2000 29.4 24 36

7/5/2000 29.1 34 36

7/8/2000 32.7 36

7/23/2000 30.6 36

8/7/2000 34.2 26 6 36

8/16/2000 28.2 36

10/18/2000 28.2 31 6 36

10/21/2000 38.0 19 13 3 6 36

10/27/2000 36.7 13 13 10 12 36

11/2/2000 54.7 36

11/8/2000 50.1 36

2/21/2001 32.8 6 9 13 36

6/21/2001 40.0 20 36

7/18/2001 29.3 16 10 36

8/2/2001 32.0 36

8/26/2001 30.2 34 36

9/7/2001 30.4 10 36

9/13/2001 28.1 6 26 36

11/18/2001 29.0 12 15 5 36

6/4/2002 28.4 31 36

7/1/2002 33.5 25 9 16 36

7/7/2002 28.3 8 36

7/16/2002 33.5 11 15 15 36

8/3/2002 30.0 36

8/12/2002 40.7 20 8 36

12/7/2002 29.2 6 10 36

12/31/2002 28.9 12 19 36

Total Hours 207 92 258 168 201 61 32 1656

% of Total 12.5 5.6 15.6 10.1 12.1 3.7 1.9

Avg. Hours 18.8 15.3 18.4 10.5 14.4 10.2 10.7FIG1. 36-hour back trajectories at 10 meters (red), 300 meters(blue) and 1000 meters (green) from the Catawba County site fordays when the PM2.5concentration was high.FIG2. 36-hour back trajectories at 10 meters from the Catawba County site for days when the PM2.5concentration was high.FIG3. 36-hour back trajectories at 300 meters from the Catawba County site for days when the PM2.5concentration was high.FIG4. 36-hour back trajectories at 1000 meters from the Catawba County site for days when the PM2.5concentration was high.FIG5. As in Figure 1, except for Davidson County.FIG6. As in Figure 2, except for Davidson County.FIG7. As in Figure 3, except for Davidson County.FIG8. As in Figure 4, except for Davidson County.Catawba County - Primary PM2.5Sources58%6%17%11%2%2%4%North CarolinaSouth CarolinaTennesseeVirginiaGeorgiaKentuckyOhio ValleyFIG9. Percent of the days for which HYSPLIT back trajectories were run for the Catawba County PM2.5monitor for which eachregion was determined to be a primary source. Dark Blue: North Carolina; Burgundy: South Carolina; Yellow: Tennessee; LightBlue: Virginia; Orange: Georgia; Pink: Kentucky; Green: Ohio Valley.FIG10. Percent of the days for which HYSPLIT backtrajectories were run for the Catawba County PM2.5monitor for whicheach region was determined to be a secondary source. Dark Blue: North Carolina; Burgundy: South Carolina; Yellow:Tennessee; Light Blue: Virginia; Orange: Georgia; Pink: Kentucky; Green: Ohio Valley.Catawba County - Secondary PM2.5Sources5%24%22%14%19%8%8%North CarolinaSouth CarolinaTennesseeVirginiaGeorgiaKentuckyOhio ValleyFIG11. Percent of the days for which HYSPLIT backtrajectories were run for the Catawba County PM2.5monitor for whicheach region was determined to be a primary source, secondary source, or both. Dark Blue: North Carolina; Burgundy: SouthCarolina; Yellow: Tennessee; Light Blue: Virginia; Orange: Georgia; Pink: Kentucky; Green: Ohio Valley.Catawba County - Total Sources (Primary and Secondary PM2.5)37%13%19%12%9%4%6%North CarolinaSouth CarolinaTennesseeVirginiaGeorgiaKentuckyOhio ValleyDavidson County - Primary PM2.5Sources60%9%9%16%2%2%2%North CarolinaSouth CarolinaTennesseeVirginiaGeorgiaKentuckyOhio ValleyFIG12. Percent of the days for which HYSPLIT back trajectories wererun for the Davidson County PM2.5monitor for whicheach region was determined to be a primary source. Dark Blue: North Carolina; Burgundy: South Carolina; Yellow: Tennessee;Light Blue: Virginia; Orange: Georgia; Pink: Kentucky; Green: Ohio Valley.FIG13. Percent of the days for which HYSPLIT back trajectories wererun for the Davidson County PM2.5monitor for whicheach region was determined to be a secondary source. Dark Blue: North Carolina; Burgundy: South Carolina; Yellow:Tennessee; Light Blue: Virginia; Orange: Georgia; Pink: Kentucky; Green: Ohio Valley.Davidson County - Secondary PM2.5Sources9%21%22%22%9%0%17%North CarolinaSouth CarolinaTennesseeVirginiaGeorgiaKentuckyOhio ValleyFIG14. Percent of the days for which HYSPLIT back trajectories wererun for the Davidson County PM2.5monitor for whicheach region was determined to be a primary source, secondary source, or both. Dark Blue: North Carolina; Burgundy: SouthCarolina; Yellow: Tennessee; Light Blue: Virginia; Orange: Georgia; Pink: Kentucky; Green: Ohio Valley.Davidson County - Total Sources (Primary and Secondary PM2.5)43%13%13%19%4%1%7%North CarolinaSouth CarolinaTennesseeVirginiaGeorgiaKentuckyOhio Valley