&EPA
United States
Environmental
Protection Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 2771 1
EPA-452/R-01-008
November 2001
Air
Visibility In Mandatory
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ral Class I
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(1994-1998)
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EPA-452/R-01-008
November 2001
Visibility in Mandatory
Federal Class I Areas
(1994-1998)
A Report to Congress
Prepared by:
Science Applications International Corporation
615 Oberlin Road, Suite TOO
Raleigh, NC 27605
Prepared for:
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711 -
Contract Number: 68-D-98-113 .
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Table of Contents
Table of Contents
Abbreviations and Acronyms
Glossary of Terms
Executive Summary
Chapter 1 . Introduction to Visibility Issues
A. Description of Visibility Impairment
B. Relevant Pollutants and Their Sources
C. Visibility Measurements
D. National Programs to Improve Visibility
E. IMPROVE Monitoring Systems in and near the Mandatory Federal Class I Areas
Chapter 2. Visibility in Individual Mandatory Federal Class 1 Areas
A. Introduction
B. Methodology
C. General Findings
D. Visibility Discussions by State
1 . Alabama
2, Alaska
3. - Arizona
4. Arkansas
• 5. California
6. Colorado
7. Florida
8. Georgia
9. Kentucky .
10. Maine
1 1 . Minnesota
12. Montana
13. Nevada
14. New Jersey
15. New Mexico
16. Oregon
•
I
• •
ll
ES-1
1-1
1-1
1-3
1-5
1-7
1-8
2-1
2-1
7 1
Z< JL
2-3
2-5
' 2-5
2-^9
2-13
2-32
2-36
2-60
2-76
2-80
2-84
2-88
2-92
2-96
2-100
2-104
2-108
2-112
November 2001
TOC-1
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
17. South Dakota " 2-120
18. Tennessee . 2-124
19. Texas 2-128
20. Utah ; . - 2-136
21. Vermont , • ' - 2-144
22. Virginia - 2-148
23. Washington 2-152
24. West Virginia . 2-160
25. Wyoming - 2-164
Chapter 3. National and Regional Discussions of Visibility 3-1
A. Introduction 3-1
B. National Visibility . 3-2
Trends for Least-Impaired Days 3-2
Trends for Mid-Range Days 3-4
Trends for Most-Impaired Days - " 3-6
C. Contributors to Visibility Impairment - - 3-8
D. Regional Pollutants ~ - ' _ " 3-30
Chapter 4. References , 4-1
Appendix A. List of 156 Mandatory Federal Class I Areas Where
Visibility is an Important Value A-l
Appendix B. Explanation of Method for Creating Summary
Data from Raw IMPROVE Data B-1
Appendix C. Methodology for Calculating Light Extinction from
Monitored Aerosol Mass Data - C-l
Appendix D. Theil Method to Determine Statistically Significant Trends D-l
TOC-2
November 2001
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Tabte of Confenfs
LIST OF TABLES
Table ES-l. Annual Average Light Extinction (1994-1998). ES-2
Table ES-2. Visibility Trends at IMPROVE Monitoring Locations • ES-5
Table 1-1. Atmospheric Fine Particles (< 2.5um) and Their Major Emission Sources 1-4
Table 1-2. IMPROVE andTMPROVE Protocol Sites Collecting Data from 1994 through 1998 1-9
Table AZ-1. Arizona Calculated Total Extinction Coefficients from 1994-1998 2-31
Table CA-1. California Calculated Total Extinction Coefficients from 1994-1998 2-59
Table CO-1. Colorado Calculated Total Extinction Coefficients from 1994-1998 2-75
Table OR-1. Oregon Calculated Total Extinction Coefficients from 1994-1998 2-119
Table TX-1. Texas Calculated Total Extinction Coefficients from 1994-1998 2-135
Table UT-1. Utah Calculated Total Extinction Coefficients from 1994-1998 2-143
Table WA-1. Washington Calculated Total Extinction Coefficients from 1994-1998 2-159
Table WY-1. Wyoming Calculated Total Extinction Coefficients from 1994-1998 2-171
Table 3-1. Average Calculated Total Light Extinction Coefficients from 1994-1998 3-31
November 2001
TOC-3
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Visibility in Mandatory Federal Class I Areas (1994-1998): 'A Report to Congress
LIST OF FIGURES
ES-l. Locations of IMPROVE Particulate Matter Samplers Operating Continuously from ES-2
1994-1998
ES-2. Relationship Between the Light Extinction, Deciview, and Visual Range Scales ES-4
1—1. Visibility Impairment (Haze) in Glacier National Park, Montana ' 1-2
1-2. Visibility Impairment (Haze) in Shenandoah National Park, Virginia 1-2
1-3. Relationship Between the Light Extinction, Deciview, and Visual Range Scales 1-6
1-4. Locations of IMPROVE Particulate Matter Samplers Operating Continuously from 1994-1998 1-8
AL-1. Mandatory Federal Class I Area and IMPROVE Monitoring Site in Alabama 2-5
AL-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days , 2-6
from 1992-1998 for the Sipsey IMPROVE Particulate Sampler
AL-3. Seasonal Deciview Averages from 1992-1998 for the Sipsey IMPROVE 2-6
Particulate Sampler
AL-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 . 2-7
for the Sipsey IMPROVE Particulate" Sampler
AL-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-7
for the Sipsey IMPROVE Particulate Sampler
AL-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998 2-8
for the Sipsey IMPROVE Particulate Sampler
AK-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Alaska 2-9
AK-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least- - 2-10
Impaired Days'from 1988-1998 for the Denali IMPROVE Particulate Sampler
AK-3. Seasonal Deciview Averages from 1988-1998 for the Denali IMPROVE 2-10
Particulate Sampler
AK-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-11
for the Denali IMPROVE Particulate Sampler
AK-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-11
for the Denali IMPROVE Particulate Sampler
AK-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-12
for the Denali IMPROVE Particulate Sampler-
AZ-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Arizona 2--13
AZ-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-14
from 1988-1998 for the Chiricahua IMPROVE Particulate Sampler
AZ-3. Seasonal Deciview Averages from 1988-1998 for the Chiricahua IMPROVE , 2-15
Particulate Sampler
AZ-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-15.
for the Chiricahua IMPROVE Particulate Sampler
TOC-4
November 2001
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AZ-5.
AZ-6.
AZ-7. "
AZ-8.
AZ-9.
AZ-10.
AZ-11.
AZ-12.
AZ-13.
AZ-14.
AZ-15.
AZ-16.
AZ-17.
AZ-18.
AZ-19.
AZ-20.
AZ-21.
AZ-22,
AZ-23.
AZ-24.
Table of
Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998
for the Chiricahua IMPROVE Particulate Sampler
Contributions to Calculated Annual Aerosol Light Extinction from 1994-1998
for the Chiricahua IMPROVE Particulate Sampler
Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days
from 1989-1997 for the Grand Canyon IMPROVE Particulate Sampler "
Seasonal Deciview Averages from 1989-1998 for the Grand Canyon IMPROVE
Particulate Sampler
Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 .
for the Grand Canyon IMPROVE Particulate Sampler
Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998
for the Grand Canyon IMPROVE Particulate Sampler
Contributions to Calculated Annual Aerosol Light Extinction from 1989-1997
for the Grand Canyon IMPROVE Particulate Sampler
Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days
from 1990-1998 for the Indian Garden IMPROVE Particulate Sampler
Seasonal Deciview Averages from 1990-1998 for the Indian Garden IMPROVE
Particulate Sampler
Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998
for the Indian Garden IMPROVE Particulate Sampler
Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998
for the Indian Garden IMPROVE Particulate- Sampler -
Contributions to Calculated Annual Aerosol Light Extinction from 1990-1998
for the Indian Garden IMPROVE Particulate Sampler
Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days
from 1988-1998 for the Petrified Forest IMPROVE Particulate Sampler
Seasonal Deciview Averages from 1988-1998 for the Petrified Forest IMPROVE
Particulate Sampler
Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998
for the Petrified Forest IMPROVE Particulate Sampler
Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998
for the Petrified Forest IMPROVE Particulate Sampler
Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998
for Petrified Forest IMPROVE Particulate Sampler
Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days
from 1988-1998 for the Tonto IMPROVE Particulate Sampler
Seasonal Deciview Averages fromfl 988-1 998 for the Tonto IMPROVE
Particulate Sampler - -
Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998
for the Tonto IMPROVE Particulate Sampler
November 2001 ' '
Contents
2-16
2-17
2-18
2-19
2-19
2-20
2-21
2-22
2-22
2-23
2-23
2-24
2-25
2-25
2-26
2-26
2-27
2-28
2-29
- 2-29
TOC-5
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
AZ-25." Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-30
for the Tonto IMPROVE Particulate Sampler
AZ-26. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-31
for the Tonto IMPROVE Particulate Sampler
AR-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Arkansas 2-32
AR-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-33
from 1992-1998 for the Upper Buffalo IMPROVE Particulate Sampler
AR-3. Seasonal Deciview Averages from 1992-1998 for the Upper Buffalo IMPROVE 2-33
.Particulate Sampler
AR-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-34
for the Upper Buffalo IMPROVE Particulate Sampler
AR-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-34
for the Upper Buffalo IMPROVE Particulate Sampler
AR-6. Contribution to Calculated Annual Aerosol Light Extinction from 1992-1998 2-35
for the Upper Buffalo IMPROVE Particulate Sampler
CA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in California 2-37
CA-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-38.
from 1988-1998 for the Lassen Volcanic IMPROVE Particulate Sampler ',
CA-3. Seasonal Deciview Averages from 1988-1998 for the Lassen Volcanic IMPROVE 2-39
Particulate Sampler
CA-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 - 2-39
for the Lassen Volcanic IMPROVE Particulate Sampler
CA-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-40
for the Lassen Volcanic IMPROVE Particulate Sampler
CA-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-41
for the Lassen Volcanic IMPROVE Particulate Sampler
CA-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-42
from 1988-1998 for the Pinnacles IMPROVE Particulate Sampler
CA-8. Seasonal Deciview Averages from 1988-1998 for the Pinnacles IMPROVE 2-42
Particulate Sampler.
CA-9. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-43
for the Pinnacles IMPROVE Particulate Sampler
CA-10. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-43
for the Pinnacles IMPROVE Particulate Sampler
CA-11. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-44
for the Pinnacles IMPROVE Particulate Sampler J
CA-12. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-45
from 1988-1998 for the Point Reyes IMPROVE Particulate Sampler
CA-13. Seasonal Deciview Averages from 1988-1998 for the Point Reyes IMPROVE 2-46
Particulate Sampler
TOC-6
November 2001
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Tabfe of Contents
CA-14. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-46
for the Point Reyes IMPROVE Particulate Sampler
CA-15. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-47
for the Point Reyes IMPROVE Particulate Sampler
CA-16. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-48
for the Point Reyes IMPROVE Particulate Sampler
CA-17. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-49
from 1988-1998 for the Redwood IMPROVE Particulate Sampler
CA-18. Seasonal Deciview Averages from 1988-1998 for the Redwood IMPROVE 2-49
Particulate Sampler
CA-19. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-50
for the Redwood IMPROVE Particulate Sampler
CA-20. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-50
for the Redwood IMPROVE Particulate Sampler
CA-21. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-51
for the Redwood IMPROVE Particulate Sampler
CA-22. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-52
from 1988-1998 for the San Gorgonio IMPROVE Particulate Sampler
CA-23. Seasonal Deciview Averages from 1988-1998 for the San Gorgonio IMPROVE 2-53
Particulate Sampler
CA-24. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-53
for the San Gorgonio IMPROVE Particulate Sampler
CA-25. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-54
for the San Gorgonio IMPROVE Particulate Sampler
CA-26. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-55
for the San Gorgonio IMPROVE Particulate Sampler
CA-27. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2—56
from 1988-1998 for the Yosemite IMPROVE Particulate Sampler
CA-28. Seasonal Deciview Averages from 1988-1998 for the Yosemite IMPROVE 2-56
Particulate Sampler
CA-29. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-57
for the Yosemite IMPROVE Particulate Sampler
CA-30. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-57
for the Yosemite IMPROVE Particulate Sampler
CA-31. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-58
for the Yosemite IMPROVE Particulate Sampler
CO-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Colorado 2-60
CO-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-61
from 1988-1998 for the Great Sand Dunes IMPROVE Particulate Sampler
November 2001
TOC-7
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
CO-3. Seasonal Deciview Averages from 1988-1998 for the Great Sand Dunes IMPROVE 2-62
Particulate Sampler
CO-4. Contribution to Calculated Annual-Aerosol Light Extinction from 1994-1998 2-62
for the Great Sand Dunes IMPROVE Particulate Sampler
CO-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-63
for the Great Sand Dunes IMPROVE Particulate Sampler
CO-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-64
for the Great Sand Dunes IMPROVE Particulate Sampler
CO-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-65
from 1988-1998 for the Mesa Verde IMPROVE Particulate Sampler
CO-8. Seasonal Deciview Averages from 1988-1998 for the Mesa Verde IMPROVE 2-65
Particulate Sampler
CO-9. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-66
for the Mesa Verde IMPROVE Particulate Sampler
CO-10. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-66
for the Mesa Verde IMPROVE Particulate Sampler
CO-11. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-67
for the Mesa Verde IMPROVE Particulate Sampler
CO-12. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-68
from 1988-1998 for the Rocky Mountain IMPROVE Particulate Sampler
CO-13. Seasonal Deciview Averages from 1988-1998 for the Rocky Mountain 2-69
IMPROVE Particulate Sampler
CO-14. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-69
for the Rocky Mountain IMPROVE Particulate Sampler
CO-15. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-70
for the Rocky Mountain IMPROVE Particulate Sampler
CO-16. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-71
for the Rocky Mountain IMPROVE Particulate Sampler
CO—17. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-72
from 1988-1998 for the Weminuche IMPROVE Particulate Sampler
CO-18. Seasonal Deciview Averages from 1988-1998 for the Weminuche IMPROVE - 2-72
Particulate Sampler
CO-19. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-73
for the Weminuche IMPROVE Particulate Sampler
CO-20. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-73
for the Weminuche IMPROVE Particulate Sampler
CO-21. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-74
for the Weminuche IMPROVE Particulate Sampler
FL-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Florida 2-76
TOC-8
November 2001
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Table of Contents
FL-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-77
from 1993-1998 for the Chassahowitzka IMPROVE Particulate Sampler
FL-3. Seasonal Deciview Averages from 1993-1998 for the Chassahowitzka IMPROVE 2-77
Particulate Sampler
FL-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-78
for the Chassahowitzka IMPROVE Particulate Sampler
FL-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-78
for the Chassahowitzka IMPROVE Particulate Sampler
FL-6. Contributions to Calculated Annual Aerosol Light Extinction from 1993-1998 2-79
for the Chassahowitzka IMPROVE Particulate Sampler
GA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Georgia 2-80
GA—2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-81
from 1992-1998 for the Okefenokee IMPROVE Particulate Sampler
GA-3. Seasonal Deciview Averages from 1992-1998 for the Okefenokee IMPROVE 2-81
Particulate Sampler
GA-A Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-82
for the Okefenokee IMPROVE Particulate Sampler
GA-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-82
for the Okefenokee IMPROVE Particulate Sampler
GA-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998 2-83
for the Okefenokee IMPROVE Particulate Sampler
KY-1. Mandatory Federal Class I Area and IMPROVE Monitoring Site in Kentucky 2-84
KY-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-85
from 1992-1998 for the Mammoth Cave IMPROVE Particulate Sampler
KY-3. Seasonal Deciview Averages from 1992-1998 for the Mammoth Cave IMPROVE 2-85
Particulate Sampler
KY-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-86
for the Mammoth Cave IMPROVE Particulate Sampler
KY-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-86
for the Mammoth Cave IMPROVE Particulate Sampler
KY-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998 2-87
for the Mammoth Cave IMPROVE Particulate Sampler
ME-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Maine 2-88
ME—2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-89
from 1988-1998 for the Acadia IMPROVE Particulate Sampler
ME-3. Seasonal Deciview Averages from 1988-1998 for the Acadia IMPROVE 2-89
Particulate Sampler
ME-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-90
for the Acadia IMPROVE Particulate Sampler
November 2001 TOC-9
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
ME-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-90
for the Acadia IMPROVE Particulate Sampler
ME-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-91
for the Acadia IMPROVE Particulate Sampler
MN-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Minnesota 2-92
MN-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-93
from 1992-1998 for the Boundary Waters IMPROVE Particulate Sampler
MN-3. Seasonal Deciview Averages from 1992-1998 for the Boundary Waters IMPROVE 2-93
Particulate Sampler
MN-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-94
for the Boundary Waters IMPROVE Particulate Sampler
MN-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-94
for the Boundary Waters IMPROVE Particulate Sampler
MN-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998 2-95
for the Boundary Waters IMPROVE Particulate Sampler
MT-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Montana 2-96
MT-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-97
from 1988-1998 for the Glacier IMPROVE Particulate Sampler
MT-3. Seasonal Deciview Averages from 1988-1998 for the Glacier IMPROVE 2-97
Particulate Sampler
MT-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-98
for the Glacier IMPROVE Particulate Sampler
MT-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-98
for the Glacier IMPROVE Particulate Sampler
MT-6. Contributions to Calculated Annual Aerosol Light Extinction From 1988-1998 2-99
for Glacier IMPROVE Particulate Sampler
NV-1. Mandatory Federal Class I Area and IMPROVE Monitoring Sites in Nevada 2-100
NV—2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2—101
from 1988-1998 for the Jarbidge IMPROVE Particulate Sampler
NV-3. Seasonal Decivew Averages from 1988-1998 for the Jarbidge IMPROVE 2-101
Particulate Sampler
NV-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-102
for the Jarbidge IMPROVE Particulate Sampler
NV-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-102
for the Jarbidge IMPROVE Particulate Sampler
NV-6. Contributions to Calculated Annual"Aerosol Light Extinction from 1988-1998 2-103
for the Jarbidge IMPROVE Particulate Sampler
NJ-1. Mandatory Federal Class I Area and IMPROVE Monitoring Site in New Jersey 2-104
TOC-10
November 2001
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Table of Confenfs
NJ-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-105
from 1992-1998 for the Brigantine IMPROVE Particulate Sampler
NJ-3. Seasonal Deciview Averages from 1992-1998 for the Brigantine IMPROVE , 2-105
Particulate Sampler
NJ-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-106
for the the Brigantine IMPROVE Particulate Sampler
NJ-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-106
for the Brigantine IMPROVE Particulate Sampler
NJ-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998 * 2-107
" for the Brigantine IMPROVE Particulate Sampler
NM-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in New Mexico 2-108
NM-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-109
from 1988-1998 for the Bandelier IMPROVE Particulate Sampler
NM-3. Seasonal Deciview Averages from 1988-1998 for the Bandelier IMPROVE 2-109
Particulate Sampler
NM-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-110
for the Bandelier IMPROVE Particulate Sampler
NM-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-110
for the Bandelier IMPROVE Particulate Sampler
NM-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-111
for the Bandelier IMPROVE Particulate Sampler
OR-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Oregon 2-112
OR—2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-113
from 1988-1998 for the Crater Lake IMPROVE Particulate Sampler
OR-3. Seasonal Deciview Averages from 1988-1998 for the Crater Lake IMPROVE 2-113
Particulate Sampler
OR-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-114
for the Crater Lake IMPROVE Particulate Sampler
OR-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-114
for the .Crater Lake IMPROVE Particulate Sampler
OR-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-115
for the Crater Lake IMPROVE Particulate Sampler
OR-7, Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-116
from 1994-1998 for the Three Sisters IMPROVE Particulate Sampler
OR-8. Seasonal Deciview Averages from 1994-1998 for the Three Sisters IMPROVE 2-116
Particulate Sampler
OR-9. Contribution to Calculated Annual Light Extinction from 1994-1998 2-117
for the Three Sisters IMPROVE Particulate Sampler
OR-10. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 « 2-117
for the Three Sisters IMPROVE Particulate Sampler
November 2001 ' • TOC-1 1
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
OR-11. Contributions to Calculated Annual Aerosol Light Extinction from 1994-1998 2-118
for the Three Sisters IMPROVE Particulate Sampler
SD-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in South Dakota 2-120
SD-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-121
from 1988-1998 for the Badlands IMPROVE Particulate Sampler
SD-3. Seasonal Deciview Averages from 1988-1998 for the Badlands IMPROVE 2-121
Particulate Sampler
SD-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-122
for the Badlands IMPROVE Particulate Sampler
SD-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-122
for the Badlands IMPROVE Particulate Sampler
SD-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-123
for the Badlands IMPROVE Particulate Sampler
TN-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Tennessee 2-124
TN-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-125
from 1988-1998 for the Great Smoky Mountains IMPROVE Particulate Sampler
TN-3. Seasonal Deciview Averages from 1988-1998 for the Great Smoky Mountains 2-125
IMPROVE Particulate Sampler
TN-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-126
for the Great Smoky Mountains IMPROVE Particulate Sampler
TN-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-126
for the Great Smoky Mountains IMPROVE Particulate Sampler
TN-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-127
for the Great Smoky Mountains IMPROVE Particulate Sampler
TX-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Texas 2-128
TX—2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-129
from 1988-1998 for the Big Bend IMPROVE Particulate Sampler
TX-3. Seasonal Deciview Averages from 1988-1998 for the Big Bend IMPROVE 2-129
Particulate Sampler
TX-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-130
for the Big Bend IMPROVE Particulate Sampler
TX-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-130
for the Big Bend IMPROVE Particulate Sampler
TX-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-131
for the Big Bend IMPROVE Particulate Sampler
TX-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-132
from 1988-1998 for the Guadalupe Mountains IMPROVE Particulate Sampler
TX-8. Seasonal Deciview Averages from 1988-1998 for the Guadalupe Mountains 2-132
IMPROVE Particulate Sampler
TOC-12
November 2001
-------
Table of Confenfs
TX-9. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-133
for the Guadalupe Mountains IMPROVE Particulate Sampler
TX-10. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-133
for the Guadalupe Mountains IMPROVE Particulate Sampler
TX-11. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-134
for the Guadalupe Mountains IMPROVE Particulate Sampler
UT-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Utah 2-136
UT-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-137
from 1988-1998 for the Bryce Canyon IMPROVE Particulate Sampler
UT-3. Seasonal' Deciview Averages from 1988-1998 for the Bryce Canyon IMPROVE 2-137
Particulate Sampler
UT-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-138
for the Bryce Canyon IMPROVE Particulate Sampler
UT-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-138
for the Bryce Canyon IMPROVE Particulate Sampler
UT-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-139
for the Bryce Canyon IMPROVE Particulate Sampler
UT-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-140
from 1988-1998 for the Canyonlands IMPROVE Particulate Sampler
UT-8. Seasonal Deciview Averages from 1988-1998 for the Canyonlands IMPROVE 2-141
Particulate Sampler
UT-9. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-141
for the Canyonlands IMPROVE Particulate Sampler
UT-10. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-142
for the Canyonlands IMPROVE Particulate Sampler
UT-11. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-143
for the Canyonlands IMPROVE Particulate Sampler
VT-1. Mandatory Federal Class I Area and IMPROVE Monitoring Site in Vermont 2-144
VT-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-145
from 1992-1998 for the Lye Brook IMPROVE Particulate Sampler
VT-3. Seasonal Deciview Averages from 1992-1998 for the Lye Brook IMPROVE 2-145
Particulate Sampler
VT-4. . Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-146
for the Lye Brook IMPROVE Particulate Sampler
VT-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-146
for the Lye Brook IMPROVE Particulate Sampler
VT-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998 2-147
for the Lye Brook IMPROVE Particulate Sampler
VA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Virginia 2-148
November 2001 TOC-13
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
VA-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-149
from 1988-1998 for the Shenandoah IMPROVE Particulate Sampler
VA-3. Seasonal Deciview Averages from 1988-1998 for the Shenandoah IMPROVE 2-149
Particulate Sampler
VA-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-150
for the Shenandoah IMPROVE Particulate Sampler
VA-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-150
for the Shenandoah IMPROVE Particulate Sampler
VA-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-151
for the Shenandoah IMPROVE Particulate Sampler
WA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Washington 2-152
WA-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-153
from 1988-1998 for the Mount Rainier IMPROVE Particulate Sampler
WA-3. Seasonal Deciview Averages from 1988-1998 for the Mount Rainier IMPROVE 2-153
Particulate Sampler
WA-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-154
for the Mount Rainier IMPROVE Particulate Sampler
WA-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-154
for the Mount Rainier IMPROVE Particulate Sampler
WA-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-155
for the Mount Rainier IMPROVE Particulate Sampler
WA—7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2—156
from 1994-1998 for the Snoqualmie Pass IMPROVE Particulate Sampler
WA-8. Seasonal Deciview Averages from 1994-1998 for the Snoqualmie Pass 2-156
IMPROVE Particulate Sampler
WA-9. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-157
for the Snoqualmie Pass IMPROVE Particulate Sampler
WA-10. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-157
for the Snoqualmie Pass IMPROVE Particulate Sampler
WA-11. Contributions to Calculated Annual Aerosol Light Extinction from 1994-1998 2-158
for the Snoqualmie Pass IMPROVE Particulate Sampler
WV-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in West Virginia 2-160
WV—2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2—161
from 1992-1998 for the Dolly Sods IMPROVE Particulate Sampler
WV-3. Seasonal Deciview Averages from 1992-1998 for the Dolly Sods IMPROVE 2-161
Particulate Sampler
W V-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-162
for the Dolly Sods IMPROVE Particulate Sampler
TOC-14
November 2001
-------
Table of Contents
WV-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-162
for the Dolly Sods IMPROVE Particulate Sampler
WV-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998 2-163
for the Dolly Sods IMPROVE Particulate Sampler
WY-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Wyoming 2-164
WY-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2—165
from 1988-1998 for the Bridger IMPROVE Particulate Sampler
WY-3. Seasonal Deciview Averages from 1988-1998 for the Bridger IMPROVE 2-165
Particulate Sampler
WY-4. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-166
for the Bridger IMPROVE Particulate Sampler
WY-5. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-166
for the Bridger IMPROVE Particulate Sampler
WY-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-167
for the Bridger IMPROVE Particulate Sampler
WY-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired Days 2-168
from 1988-1998 for the Yellowstone IMPROVE Particulate Sampler
WY-8. Seasonal Deciview Averages from 1988-1998 for the Yellowstone IMPROVE 2-168
Particulate Sampler
WY-9. Contribution to Calculated Annual Aerosol Light Extinction from 1994-1998 2-169
for the Yellowstone IMPROVE Particulate Sampler
WY-10. Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998 2-169
for the Yellowstone IMPROVE Particulate Sampler
WY-11. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998 2-170
for the Yellowstone IMPROVE Particulate Sampler
3—1. Annual Average Visibility Indices for Least-Impaired Days from 1994-1998 . 3-2
3-2. IMPROVE Sites Showing Statistically Significant Trends in Visibility on 3-3
Least-Impaired Days
3-3. Annual Average Visibility Indices for Mid-Range Days from 1994—1998 3-4
3-4. IMPROVE Sites Showing Statistically Significant Trends in Visibility on 3-5
Mid-Range Days
3-5. Annual Average Visibility Indices for Most-Impaired Days from 1994—1998 3-6
3-6. IMPROVE Sites Showing Statistically Significant Trends in Visibility on 3-7
Most-Impaired Days
3-7. Average Annual Sulfate PM Concentrations at IMPROVE Monitoring 3-8
from 1994-1998
3-8. Average Annual Contributions of Sulfate PM to Total PM2.5 Levels at IMPROVE 3-9
Monitoring Sites from 1994-1998
November 2001
TOC-15
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
3-9.
3-10.
3-11.
3-12.
3-13.
3-14.
3-15.
3-16.
3-17.
3-18.
3-19.
3-20.
3-21.
3-22.
3-23.
3-24.
3-25.
3-26.
3-27.
3-28.
Average Annual Sulfate Extinction Coefficients at IMPROVE Monitoring Sites
from 1994-1998
Average Annual Contributions of Sulfate PM to Calculated Aerosol Light Extinction
at IMPROVE Monitoring Sites from 1994-1998
Average Annual Nitrate PM Concentrations at IMPROVE Monitoring Sites
from 1994-1998 .
Average Annual Contributions of Nitrate PM to Total PM2.5 Levels at IMPROVE
Monitoring Sites from 1994-1998
Average Annual Nitrate Extinction Coefficients at IMPROVE Monitoring Sites
from 1994-1998
Average Annual Contributions of Nitrate PM to Calculated Aerosol Light Extinction
at IMPROVE Monitoring Sites from 1994-1998
Level of Photosynthetic Activity in Vegetation during July 1988
Average Annual Organic Carbon PM Concentrations at IMPROVE Monitoring Sites
from 1994-1998
Average Annual Contributions of Organic Carbon PM to Total PM2_5 Levels
at IMPROVE Monitoring Sites from 1994-1998
Average Annual Organic Carbon Extinction Coefficients at IMPROVE Monitoring
Sites from 1994-1998
Average Annual Contributions of Organic Carbon PM to Calculated Aerosol
Light Extinction at IMPROVE Monitoring Sites from 1994-1998
Average Annual Elemental Carbon PM Concentrations at IMPROVE Monitoring
Sites from 1994-1998
Average Annual Contributions of Elemental Carbon PM to Total PM2 5 Levels
at IMPROVE Monitoring Sites from 1994-1998
Average Annual Elemental Carbon Extinction Coefficients at IMPROVE Monitoring
Sites from 1994-1998
Average Annual Contributions of Elemental Carbon PM to Calculated Aerosol
Light Extinction at IMPROVE Monitoring Sites from 1994-1998
Average Annual Fine Soil PM Concentrations at IMPROVE Monitoring Sites
from 1994-1998
Average Annual Contributions of Fine Soil PM to Total PM2.5 levels at IMPROVE
Monitoring Sites from 1994-1998
Average Annual Crustal Material Extinction Coefficients at IMPROVE Monitoring
Sites from 1994-1998
Average Annual Contributions of Crustal Material PM to Calculated Aerosol
Light Extinction at IMPROVE Monitoring Sites from 1994-1998
Mandatory Federal Class I Areas and IMPROVE Particulate Matter Samplers
Divided into Western and Eastern Regions
3-10
3-11
3-12
3-13
3-14
3-15
3-17
3-18
3-19
3-20
3-21
3-22
3-23
3-24
3-25
3-27
3-27
3-28
3-29
3-30
TOC-16
November 2001
-------
Abbreviations
Abbreviations and Acronyms
CAA Clean Air Act
'CAAA 1990 Clean Air Act Amendments
CIRA • Cooperative Institute for Research in the Atmosphere, Colorado State University
EPA United States Environmental Protection Agency
FACA Federal Advisory Committee Act Subcommittee for Ozone, Particulate Matter, and
Regional Haze Implementation Programs
f(RH) Relative humidity adjustment factor
GCVTC Grand Canyon Visibility Transport Commission
H2S Hydrogen sulfide
IMPROVE Interagency Monitoring of PROtected Visual Environments
NAAQS National Ambient Air Quality Standards
NAS National Academy of Sciences
NDVI Normalized Difference Vegetation Index
NESCAUM Northeast States for Coordinated Air Use Management
NH3 Ammonia
NM National Monument •
NO2 Nitrogen dioxide
NOX Oxides of nitrogen
NP National Park
NFS United States Department of the Interior, National Park Service
PM Particulate matter
PM2 5 Particulate matter with an aerodynamic diameter less than 2.5 microns
PM10 Particulate matter with an aerodynamic diameter less than 10 microns
SCR Selective catalytic reduction
SIP State Implementation Plan
SO2 Sulfur dioxide
STAPPA State and Territorial Air Pollution Program Association
USDA United States Department of Agriculture
VR Visual range
WESTAR Western States Air Resources Council
November 2001
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Glossary of Terms
Aerosols. Tiny liquid and/or solid particles dispersed in the air.
Coarse mass. Mass of particulate matter with an aerodynamic diameter greater than 2.5 microns but
less than 10 microns.
Crustal material. Solid particulate matter represented by the sum of the soil mass and coarse mass.
Deciview haze index (dv). Derived from calculated light extinction measurements so that uniform
changes in haziness correspond to uniform incremental changes in perception across the entire range of
conditions, from pristine to highly impaired. The deciview haze index is calculated directly from the total
light extinction coefficient, bext, expressed in inverse megameters [Mm-1]:
Elemental carbon. Often referred to as soot or light-absorbing carbon. Ambient elemental carbon
measurements represent the carbon that was not converted to carbon dioxide or carbon monoxide dur-
ing complete combustion processes.
Fine particulate matter. Particulate matter with an aerodynamic diameter less than 2.5 microns
(PM2.5).
IMPROVE particulate sampler. A series of four samplers which concurrently collect two 24-hour
particulate samples weekly on special teflon, nylon, and quartz filters for further physical and chemical
analyses. The light extinction coefficients calculated from the aerosol mass concentrations measured by
these filters are the basis for the visibility data discussions of this report (Appendix C).
Least-impaired days. Data representing a subset of the annual measurements that correspond to the
clearest, or least hazy, days of the year (Appendix B).
Light extinction coefficient. Sometimes referred to in this report as light extinction, the light extinc-
tion coefficient is a measure of how much light is absorbed or scattered as it passes through a medium,
such as the atmosphere. The aerosol light extinction coefficient refers to the absorption and scattering
by aerosols, and the total light extinction coefficient (in this report) refers to the sum of the aerosol
light extinction coefficient and the atmospheric light extinction coefficient (Rayleigh scattering).
Mandatory Federal Class I area. Certain national parks (over 6,000 acres), wilderness areas (over
5,000 acres), national memorial parks (over 5,000 acres), and international parks that were in existence
as of August 7, 1977. Appendix A lists the Mandatory Federal Class I areas where visibility is an
important value.
Mid-range. Data representing a subset of the annual measurements that correspond to the days of the
year on which ambient particulate matter concentrations are near median levels (Appendix B).
Most-impaired days. Data representing a subset of the annual measurements that correspond to the
dirtiest, or haziest, days of the year (Appendix B).
Nitrate. Solid or liquid particulate matter composed of nitric acid [HNO3] or ammonium nitrate
[NH4NO3]. Atmospheric nitrate aerosols are often formed from the atmospheric oxidation of oxides of
nitrogen (NOX) and are generally less than 2.5 microns in aerodynamic diameter.
Organic carbon. Aerosols composed of organic compounds, which may result from incomplete com-
bustion processes, solvent evaporation followed by atmospheric condensation, or the oxidation of some
vegetative emissions. _
ii November 2001
-------
Glossary of Terms
Particulate matter. Any substance, except pure water, that exists as a liquid or solid in the atmosphere
under normal conditions and has an aerodynamic diameter less than 10 microns (in the discussions of
this report).
Rayleigh scattering. Light scattering of the natural gases in the atmosphere. At an elevation of 1.8 kilo-
meters, the light extinction from Rayleigh scattering is approximately 10 inverse megameters (Mm-1).
Relative humidity. Partial pressure of water vapor at the atmospheric temperature divided by the vapor
pressure of water at that temperature, expressed as a percentage.
Soil mass. Particulate matter composed of pollutants from the earth's soil, with an aerodynamic diame-
ter less than 2.5 microns. The soil mass is calculated from chemical mass measurements of aluminum,
silicon, calcium, iron, and titanium as well as their associated oxides.
Statistically significant trend. In this report, an observed trend is statistically significant when the
probability that the trend is random is less than 5 percent. Using an example, Appendix D explains the
Theil method for determining statistically significant trends.
Sulfate. Solid or liquid particulate matter composed of sulfuric acid [H2SO4], ammonium bisulfate
[NH4HSO4], or ammonium sulfate [(NH4)2SO4]. Atmospheric sulfate aerosols are often formed from
the atmospheric oxidation of sulfur dioxide and are generally less than 2.5 microns in aerodynamic
diameter.
Total carbon. Sum of the elemental carbon and organic carbon measurements.
Visibility impairment. Any humanly perceptible change in visibility (light extinction, visual range,
deciview, contrast, coloration) from a previous cleaner condition.
Visual range (VR). Greatest distance that a large dark object can just be seen by a human observer,
under uniform lighting conditions, against the background sky.
November 2001
-------
-------
Executive Summary
Executive Summary
The national visibility goal, was established in section 169 A of the 1977 Clean Air Act (CAA) as
"the prevention of any future, and the remedying of any existing, impairment of visibility in mandatory
Federal Class I areas which impairment results from manmade air pollution." There are 156 mandatory
Federal Class I areas identified for visibility protection under this provision. Section 169B of the 1990
CAA Amendments required EPA to issue a report to Congress estimating the visibility improvement
expected in these 156 areas resulting from implementation of the 1990 Amendments. In October 1993,
EPA issued its report entitled Effects of the 1990 Clean Air Act Amendments on Visibility in Class I
Areas: An EPA Report to Congress (EPA 452/R-93-014). Section 169B also requires EPA to provide
Congress with regular assessments of the actual progress and improvements in visibility in the manda-
tory Federal Class I areas. This document is the first report to Congress that reviews past progress.
This report presents visibility trends and analyses of annual and seasonal pollutant composition based
on 1994-1998 monitoring data from 46 sites (Figure ES-1).
In this report, the term visibility refers to the clarity with which scenic vistas and landscape features
are perceived at great distances. Visibility impairment, quantified as light extinction, is caused by the
scattering and absorption of light by particles and gases hi the atmosphere. Without the effects of
human-caused air pollution, a natural visual range is estimated to be about 140 miles in the western
U.S. and 90 miles in the eastern U.S.
As part of its visibility protection program, EPA participates in the IMPROVE visibility monitoring
program (Interagency Monitoring of Protected Visual Environments) with other representatives from
Federal and regional-state organizations. The IMPROVE program was initiated in 1988 at 30 monitor-
ing sites and has been expanded to 110 sites in 2001. These sites were established to be representative
of all mandatory Federal Class I areas except the isolated Bering Sea Wilderness.
The five major types of small particles (aerosols) measured by the IMPROVE program are sulfates,
nitrates, organic carbon, elemental carbon, and crustal material. These pollutants originate from differ-
ent emission sources and impair visibility—extinguish light—to varying degrees. The calculated
aerosol light extinction coefficients are directly related to the concentrations of the aerosol pollutants,
with a correction for relative humidity. Average values are reported in Table ES-1. From 1994 to 1998,
the annual average calculated aerosol light extinction coefficients at the Eastern monitors (sites located
east of 100° W longitude) and Western monitors were 87 and 23 Mnr1, respectively. All five pollutant
species contributed more to the average light extinction in the East than in the West. Table ES-1 also
shows the calculated light extinctions, averaged from 1994 to 1998, corresponding to the lowest sam-
pler average, average sampler average, and highest sampler average. Between 1994 and 1998, sulfate
particles accounted for 23 to 78 percent of the calculated aerosol light extinction on an annual basis at
the sites. Nitrate particles accounted for 3 to 39 percent of the calculated light extinction, organic car-
bon for 9 to 38 percent, elemental carbon for 2 to 16 percent, and crustal material for 3 to 31 percent.
Sulfate and nitrate aerosols are generally formed in the atmosphere from sulfur dioxide and nitro-
gen oxide emissions. The major manmade source of sulfur dioxide is coal combustion. Fossil fuel com-
1 The Clean Air Act defines mandatory Federal Class I areas as certain national parks (over 6,000 acres), wilderness
areas (over 5,000 acres), national memorial parks (over 5,000 acres), and international parks that were in existence as of
August 7, 1977.
November 2001
ES-1
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Ro-,051
, . i \ , , , li -ji,,,:;,;;:;!,::;;'!::,1 ,",{/
'""«". •[ ! ! H i I I" "II !!•* t"T* <"! "I"'!!!1'" "i* SSB! f ».' B
-\ ' \ irCartydhlands
•m Eiyce CarryqrrAr * WemtntH
Mesa Venleir TCGreat Sand Dunss
" "VTterand Canyon '" .
^ . B^nttellet
Sin OoniSn^'V-
Dolly.Sodsi ,,"*-%^'hin!
--'• '••-•*,-' Sfi8r&dOi
"^*~~" DanaS *
Figure ES-1. Locations of IMPROVE Particulate Matter Samplers Operating Continuously from
1994-1998 (Green Shaded Areas Represent Mandatory Federal Class I Areas)
bustion (e.g., coal, natural gas, and oil, including gasoline and diesel) is the major source of nitrogen
oxides. Between 1994 and 1998, the highest calculated visibility impairment from sulfate particles
occurred at the IMPROVE monitoring sites in the eastern United States. The highest calculated aerosol
light extinction coefficients from nitrate particles occurred at sites in southern California and urban
Washington, DC.
Table ES-1. Annual Average Light Extinction (1994-1998)
Pollutant
Sulfate
Nitrate
Organic Carbon
Elemental Carbon
Crustal Material
Observed Aerosol
Extinction Coefficients
from all Monitors
Calculated Aerosol Light Extinction Coefficient (Mnr1)
Eastern Sites
Lowest
Sampler
Average
18.1
3.0
6.0
1.8
2.1
35
Average
61.4
6.8
10.0
4.8
4.2
87
Highest
Sampler
Average
101.3
13.7
15.7'
12.4
8.2
130
Western Sites
Lowest
Sampler
Average
3.0
0.5
2.3
0.9
1.9
10
Average
8.8
3.0
5.2
2.0
3.7
23
Highest
Sampler
Average
24.7
16.9
14.5
5.3
8.1
50
ES-2
November 2001
-------
Executive Summary
Organic carbon aerosols can often trace their origins to emissions from vegetative growth, vegeta-
tion burning, or solvent usage processes. The organic carbon light extinction coefficients were fairly
uniform across the United States, but the values were lowest in Denali National Park in Alaska and
near the Four Corners area in the Southwest. Elemental carbon particles are often introduced into the
atmosphere by incomplete combustion processes. The highest calculated aerosol light extinction coeffi-
cients attributed to elemental carbon were calculated at Glacier National Park in Montana and at south-
ern California, mid-Atlantic, and southeastern sites.
Crustal material is introduced to the atmosphere by disturbances to the soil, such as wind erosion,
agricultural tilling, heavy construction, and travel on unpaved roads. Fine soil particle concentrations
(particles with aerodynamic diameters less than 2.5 microns) were lowest at Denali National Park and
five coastal monitor sites. Fine soiL particle concentrations were highest at Sequoia National Park
(California) and the two Texas sites. Both the fine soil concentrations and the larger coarse mass con-
centrations, particles with aerodynamic diameters between 2.5 and 10 microns, are used to calculate the
light extinction coefficients from crastal material. Light extinction from total crustal material is calcu-
lated to be lowest at Lassen Volcanic National Park (California) and Denali National Park (Alaska) and
highest at Sequoia National Park (California) and the Brigantine Wilderness-E.B. Forsythe National
Wildlife Refuge (New Jersey).
State summaries are provided when data from more than one IMPROVE particulate sampler is
reported (Arizona, California, Colorado, Oregon, Texas, Utah, Washington, and Wyoming). The data at
the seven California sites suggested regional similarities when the sites were classified as coastal,
southern, .or eastern sites. In other states, similar light extinction coefficients were observed for the dif-
ferent monitor sites unless the relative humidities varied between sites. Higher relative humidity levels
at one site in a state resulted in the calculation of considerably higher sulfate and nitrate light extinction
coefficients and, consequently, higher calculated total aerosol light extinction coefficients.
Under the 1990 CAAA, the EPA promulgated the Regional Haze Rule to protect visibility in 156
national parks and wilderness areas (Regional Haze Regulations, Final Rule, 1999). The final rule calls
for states to establish goals aimed at improving visibility in the mandatory Federal Class I areas
(Appendix A) and to develop long-term plans for reducing pollutant emissions that contribute to visi-
bility degradation. The rule gives the states the flexibility to develop cost-effective strategies for pollu-
tion reductions and encourages states to coordinate with each other through regional planning efforts.
Instead of using the light extinction coefficient scale that is directly related to the particulate matter
concentrations, the Regional Haze Rule is based on the deciview index, a scale related to visual percep-
tion. The deciview index has a value near zero for a pristine atmosphere, and each deciview unit corre-
sponds to a small but perceptible scenic change that is observed under either clean or polluted conditions.
Like the decibel scale for sound, similar changes in deciviews are perceived as equal. Figure ES—2 shows
the relationship between the light extinction, deciview, and visual range scales.
The Regional Haze Rule calls for visibility improvements on the most-impaired days (the 20th per-
centile of the days at the site with the highest deciview index) and no additional visibility impairment
on the least-impaired days (the 20th percentile of the days at a site with the lowest calculated impair-
ment). Table ES-2 is constructed to show which sites measured statistically significant trends toward
improved visibility, decreased visibility, and no change for least-impaired, mid-range, and most-
unpaired days. The statistically significant trends in visibility were measured over the entire operational
period of the monitor.
November 2001
ES-3
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Aerosol Light Extinction (Mm"1)
23 5 10 20 30 50 100 200300
203 187 161
122
81 60 40
22
12 Visual Range (mi)
1.8 2.6 4.1 6.9 11 14 18 24 30 34
Deciview Haze Index (dv)
Figure ES-2. Relationship Between the Light Extinction, Deciview, and Visual Range Scales
Of all the IMPROVE particulate samplers, Jarbidge Wilderness Area in Nevada showed the best aver-
age visibility on the least-impaired days between 1994 and 1998, with an average of 3.9 deciviews (visual
range [VR] 165 miles). Denali National Park in Alaska showed the best visibility on the mid-range and
most-impaired days from 1994 through 1998. At the Denali site, the visibility indices on the mid-range
and most-impaired days were 6.3 deciviews (VR 130 miles) and 10.4 deciviews (VR 85 miles).
Between 1994 and 1998, the worst visibility on the least-impaired days occurred at the Sipsey
Wilderness Area in Alabama that showed an average value of 19.2 deciviews (VR 36 miles). Mammoth
Cave National Park in Kentucky displayed the worst visibility on the mid-range and most-impaired days,
with visibility indices of 25.2 deciviews (VR 20 miles) on the mid-range days and 32.1 deciviews (VR 10
miles) on the most-impaired days.
Besides the Regional Haze Rule, EPA has put in place other rules and policies that have had, and will
continue to have, a positive impact on visibility in mandatory Federal Class I areas and throughout the
country. Title IV of the CAAA (the Acid Rain Program) called for reductions in sulfur dioxide and nitro-
gen oxide emissions hi the 1990s, with additional reductions in the year 2000. Implementation of the
Particulate Matter and Ozone National Ambient Air Quality Standards (NAAQS), through their associat-
ed emission reductions of nitrogen oxides and particulate matter, is expected to improve visibility in
urban and rural areas across the country. Other efforts aimed at reducing sulfur dioxide and nitrogen
oxide emissions include the recent NOX State Implementation Plan Call (NOX SIP Call) to reduce point-
source NOX emissions and the Tier II emission reduction rules aimed at reducing mobile source emis-
sions.
ES-4
November 2001
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Executive Summary
Table ES-2. Visibility Trends at IMPROVE Monitoring Locations1
Trend
Least-Impaired Days
Mid-Range Days
Most-Impaired Days
Improved
Visibility
Acadia National Park (ME)
Badlands National Park (SD)
Great Sand Dunes National
Monument (CO)
Pinnacles National Monument (CA)
Washington (DC)2
Yellowstone National Park (WY)
Acadia National Park (ME)
Bandelier National Monument (NM)
Dolly Sods Wilderness (WV)
Great Sand Dunes National
Monument (CO)
Pinnacles National Monument (CA)
Shenandoah National Park (VA)
Washington (DC)2
Canyonlands National Park (U i)
Mammoth Cave National Park (KY)
Pinnacles National Monument (CA)
Redwood National Park (CA)
San Gorgonio Wilderness (CA)
No Statistically
Significant
Change in
Visibility
Bandelier National Monument (NM)
Big Bend National Park (TX)
Boundary Waters Canoe Area (MN)
Bridger Wilderness (WY)
Brigantine Wilderness-E.B. Forsythe
Natl. Wildlife Refuge (NJ)
Bryce Canyon National Park (UT)
Canyonlands National Park (UT)
Chassahowitzka National Wildlife
Refuge (FL)
Crater Lake National Park (OR)
Denali National Park (AK)
Dolly Sods Wilderness (WV)
Glacier National Park (MX)
Grand Canyon National Park (AZ)
Great Basin National Park (NV)2
Great Smoky Mountains National
Park (TN)
Guadalupe Mountains National Park
(TX)
Indian Garden-Grand Canyon
National Park (AZ)
Jarbidge Wilderness (NV)
Lassen Volcanic National Park (CA)
Mammoth Cave National Park (KY)
Mesa Verde National Park (CO)
Mt. Rainier National Park (WA)
Okefenokee National Wildlife
Refuge (GA)
Petrified Forest National Park (AZ)
Point Reyes National Seashore (CA)
Redwood National Park (CA)
Rocky Mountain National Park (CO)
San Gorgonio Wilderness (CA)
Snoqualmie Pass-Alpine Lakes
Wilderness (WA)
Badlands National Park (SD)
Big Bend National Park (TX)
Boundary Waters Canoe Area (MN)
Bridger Wilderness (WY)
Brigantine Wilderness-E.B. Forsythe
Natl. Wildlife Refuge (NJ)
Bryce Canyon National Park (UT)
Canyonlands National Park (UT)
Chassahowitzka National Wildlife
Refuge (FL)
Chiricahua National Monument (AZ)
Crater Lake National Park (OR)
Denali National Park (AK)
Glacier National Park (MT)
Grand Canyon National Park (AZ)
Great Basin National Park (NV)2
Great Smoky Mountains National
Park (TN)
Guadalupe Mountains National Park
(TX)
Indian Garden-Grand Canyon
National Park (AZ)
Jarbidge Wilderness (NV)
Lassen Volcanic National Park (CA)
Lye Brook Wilderness (VT)
Mammoth Cave National Park (KY)
Mesa Verde National Park (CO) '
Mt. Rainier National Park (WA)
Okefenokee National Wildlife
Refuge (GA)
Petrified Forest National Park (AZ)
Point Reyes National Seashore (CA)
Redwood National Park (CA)
Snoqualmie Pass-Alpine Lakes
Wilderness (WA)
Acadia National Park (ME)
Badlands National Park (SD)
Bandelier National Monument (NM)
Big Bend National Park (TX)
Boundary Waters Canoe Area (MN)
Bridger Wilderness (WY)
Brigantine Wilderness-E.B. Forsythe
Natl. Wildlife Refuge (NJ)
Bryce Canyon National Park (UT)
Chassahowitzka National Wildlife
Refuge (FL)
Chiricahua National Monument (AZ)
Crater Lake National Park (OR)
Denali National Park (AK)
Dolly Sods Wilderness (WV)
Glacier National Park (MT)
Grand Canyon National Park (AZ)
Great Basin National Park (NV)2
Great Sand Dunes National
Monument (CO)
Great Smoky Mountains National
Park (TN)
Guadalupe Mountains National Park
(TX)
Indian Garden-Grand Canyon
National Park (AZ)
Jarbidge Wilderness (NV)
Lassen Volcanic National Park (CA)
Lye Brook Wilderness (VT)
Mesa Verde National Park (CO)
Mt. Rainier National Park (WA)
Okefenokee National Wildlife
Refuge (GA)
November 2001
ES-5
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Table ES-2. Visibility Trends at IMPROVE Monitoring Locations1 (continued)
Trend
Least-Impaired Days
Mid-Range Days
Most-Impaired Days
No Statistically
Significant
Change in
Visibility (cont.)
Shenandoah National Park (VA)
Sipsey Wilderness (AL)
Three Sisters Wilderness (OR)
Tonto National Monument (AZ)
Upper Buffalo Wilderness (AR)
Weminuche Wilderness (CO)
Yosemite National Park (CA)
Rocky Mountain National Park (CO)
San Gorgonio Wilderness (CA)
Sipsey Wilderness (AL)
Three Sisters Wilderness (OR)
Tonto National Monument (AZ)
Upper Buffalo Wilderness (AR)
Weminuche Wilderness (CO)
Yellowstone National Park (WY)
Yosemite National Park (CA)
Petrified Forest National Park (AZ)
Point Reyes National Seashore (CA
Rocky Mountain National Park (CO
Shenandoah National Park (VA)
Sipsey Wilderness (AL)
Three Sisters Wilderness (OR)
Tonto National Monument (AZ)
Upper Buffalo Wilderness (AR)
Washington (DC)2
Weminuche Wilderness (CO)
Yellowstone National Park (WY)
Yosemite National Park (CA)
Decreased
Visibility
Snoqualmie Pass-Alpine Lakes
Wilderness (WA)
Chiricahua National Monument (AZ)
Lye Brook Wilderness (VT)
'The least-impaired days in a year were the 20th percentile with the lowest particulate matter concentrations, mid-range
days the 20th percentile nearest the median, and the most-impaired days the 20th percentile with the highest particulate
matter concentrations. In this report, an observed trend is considered statistically significant when the probability that a pat-
tern is random is less than 5 percent (Theil method).
2Not a mandatory Federal Class I area, but the data from this site are included in the national and regional analyses present-
ed in Chapter 3.
ES-6
November 2001
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Introduction to Vfsibffffy fssues
1. Introduction to Visibility Issues
The national visibility goal, established in section 169 A of the Clean Air Act (CAA) Amendments
of 1977, requires the "prevention of any future, and the remedying of any existing, impairment of visi-
bility in mandatory Federal Class I areas which impairment results from manmade air pollution." Under
section 169B of the Act, the U.S. Environmental Protection Agency (EPA) was required to issue a
report to Congress estimating the visibility improvement expected in Mandatory Federal Class I areas1
from implementation of the 1990 Clean Air Act Amendments (CAAA). In October 1993, EPA issued
its report entitled Effects of the 1990 Clean Air Act Amendments on Visibility in Class I Areas: An EPA
Report to Congress (Document EPA 452/R-93-014). The Act also requires that EPA provide Congress
with regular assessments of the actual progress and improvements in visibility in the mandatory Federal
Class I areas. This report was prepared to meet these requirements for the period 1994 through 1998,
Under the 1990 CAAA, the EPA promulgated the Regional Haze Rule to protect visibility in 156
mandatory Federal Class I areas (Regional Haze Regulations, Final Rule, 1999). Two of the 158
mandatory Federal Class I areas created by the 1997 CAAA (Rainbow Lake Wilderness Area,
Wisconsin and Bradwell Bay Wilderness Area, Florida) were determined not to have visibility as an
important value. Therefore, these two areas are not subject to the final rule. In addition, five Native
American tribes have re-designated Class II lands under their jurisdiction as Class I. Since these areas
were not identified as mandatory Federal Class I areas in 1977, these (and lands re-designated in the
future) are not subject to the final rule. The final rale calls for states to establish goals aimed at , ,
improving visibility in the mandatory Federal Class I areas (Appendix A) and also to develop long-term
plans for reducing pollutant emissions that contribute to visibility degradation. The rule gives states the
flexibility to develop cost-effective strategies for pollution reductions and encourages states to coordi-
nate through regional planning efforts.
This chapter first describes the concept of visibility and visibility impairment. The five common
pollutant species that contribute to visibility impairment (degradation) are described, along with their
emission sources. Common measurements used to quantify visibility impairment (visibility metrics) are
then discussed. The five pollutant species are routinely sampled at IMPROVE monitoring locations.
The last section of this chapter details the geographic distribution of the monitors that operated from
1994 through 1998.
A. Description of Visibility Impairment
The term visibility, when used in the context of scenic vistas at mandatory Federal Class I areas,
refers to the clarity with which distant objects are perceived. Visibility is affected by pollutant concen-
trations, the viewing angle, relative humidity,,cloud characteristics, and other physical factors such as
color contrast between objects. Without the effects of manmade air pollution, a natural visual range
would be nearly 140 miles (225 km) in western areas and 90 miles (145 km) in eastern areas.
1 The Clean Air Act defines mandatory Federal Class I areas as certain national parks (over 6,000 acres), wilderness
areas (over 5,000 acres), national memorial parks (over 5,000 acres), and international parks that were in existence as of
August?, 1977.
November 2001
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Clear Day Hazy Day
Figure 1-1. Visibility Impairment (Haze) in Glacier National Park, Montana
Clear Day Hazy Day
Figure 1-2. Visibility Impairment (Haze) in Shenandoah National Park, Virginia
The natural visual range is limited because atmospheric gases and aerosols absorb and scatter the
light traveling from the vista to the observer. Absorbed light is converted into heat, and the scattered
light is redirected from its straight-line approach. The natural light scattered from air molecules is
referred to as Rayleigh scattering and causes the blue appearance of the sky. Visibility is impaired
beyond the Rayleigh scattering as additional gases and particles are introduced into the air. Figures 1-1
and 1-2 show real examples of visibility impairment (haze) in Glacier National Park, Montana and
Shenandoah National Park, Virginia.
In mandatory Federal Class I areas (EPA, 1993), the atmospheric pollutants that most often affect
visibility exist as aerosols (tiny particles dispersed in the air). An aerosol particle is made of solid and/or
liquid molecules that are held together by intermolecular or adhesive forces and act as a single unit. Fogs
and mists are common examples of aerosols formed primarily from water vapor. Particulate matter refers
to the nonwater particles that form solid or liquid aerosols in the atmosphere. The next section discusses
the five most common particulate matter species, classified according to chemical analyses.
Light scattering and absorption by aerosols are the most important contributors to visibility impair-
ment in mandatory Federal Class I areas. The absorption and scattering by the suspended particulate
matter is dependent on the particle size, shape, and composition as well as factors such as humidity
(which affects the amount of water condensing as liquid on the particles). The suspended particles may
originate as emissions from natural sources (e.g., sea salt entrainment and wind-blown dust) or from
1-2
November 2001
-------
Introduction to Visibility Issues
manmade sources, (e.g., automobile exhaust and mining activities). Aerosol particles may also form in
the atmosphere as gases condense or react with one another. The origins of the major particulate matter
species are discussed briefly below.
B. Relevant Pollutants and Their Sources
As stated previously, visibility impairment in the mandatory Federal Class I areas usually results
from light scattering and absorption by particulate matter. The particulate matter that most greatly
affects visibility in mandatory Federal Class I areas has an aerodynamic diameter less than 2.5 microns.
(For comparison, a human hair has a diameter of about 70 microns.) The individual aerosol particles
(composed of both solid particles and liquid droplets) cannot be seen in the atmosphere, but they scat-
ter and absorb light to impair the view.
Although particulate matter less than 2.5 microns (PM2 5) is often composed of numerous chemical
species, chemical analyses have been used to identify and group five key contributors to visibility
impairment:
• sulfate,
• nitrate,
• organic carbon,
• elemental carbon, and
•, crustal material.
The concentrations of these five species are measured regularly in many mandatory Federal Class I
areas, and the light extinction coefficients and deciview visibility indices are calculated from these val-
ues (Appendix C). The emission sources for the five major constituents of PM2 5 (including precursors)
appear in the first six rows of Table 1-1 (ammonia is a chemical contained in sulfate and nitrate
aerosols). The emission sources are divided into four columns: 1) natural processes that emit the_pollu-
tant directly as particulate matter (primary particulate), 2) manmade (or controlled) sources that emit
primary particulate, 3) natural processes that emit gaseous pollutants that are converted in the atmos-
phere to particulate matter (secondary particulate), and 4) manmade sources of secondary particulate
matter. The species are described briefly below.
Sulfates most often exist as ammonium sulfate [(NH4)2SO4] and ammonium bisulfate [NH4HSO4].
When ammonia availability is low, sulfates occur as sulfuric acid [H2SO4]. The primary sources of sul-
fate emissions are sea spray and sulfate particles formed during the combustion of fossil fuels (mainly
coal).
Sulfates form in the atmosphere when sulfur gases, such as sulfur dioxide [SO2] and hydrogen sul-
fide [H2S], oxidize to sulfuric acid and then combine with ammonia [NFjy to create ammonium sulfate
particles. Sulfur gases may be emitted from natural sources such as volcanoes, oceans, wetlands, and
forest fires, or from manmade-sources such as fossil fuel combustion. Sulfate particles are relatively
stable in the atmosphere and are removed by settling and precipitation.
The ammonia that combines with the sulfate to form sulfate PM is generated from both natural and
manmade sources. Wild animals produce ammonia, and ammonia is also generated by microbial
November 2001
J-3
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
processes beneath undisturbed soil. Sources of ammonia controlled by man include animal husbandry
and dairy operations, sewage treatment, ammonia slip during selective catalytic reduction (SCR) con-
trol of NOX, and the introduction of ammonia to soil through fertilizers.
Nitrate particulate matter exists in the atmosphere mainly as ammonium nitrate [NH4NO3] but may
take the form of nitric acid [HNO3] when ammonia is not available. Nitrogen oxides (NO and NO2,
Table 1-1. Atmospheric Fine Particles (< 2.5 |jm) and Their Major Emission Sources
Atmospheric
Pollutant
Sulfate (SO4=)
Nitrate (NO3-)
Ammonia (NH3)
Organic Carbon
Elemental Carbon
Crustal Material
Metals
Bioaerosols
Primary Sources
Natural
Sea spray
Not Applicable
Not Applicable
Wildfires
Wildfires
Wind erosion and re-
entrainment of
deposited particles
Volcanic activity
Viruses, bacteria
Manmade
Fossil foel combus-
tion
Motor vehicle
exhaust
Motor vehicle
exhaust
Open burning, wood
burning, prescribed
burning, cooking,
motor vehicle
exhaust, incinera-
tion, and tire wear
Motor vehicle
exhaust, wood burn-
ing, prescribed burn-
ing, and cooking
Fugitive dust from
paved and unpaved
roads, agricultural
operations, and
forestry
Fossil fuel combus-
tion, smelting, and
brake wear
Not Applicable
Secondary Sources
Natural
Oxidation of sulfur
gases (SO2 and H2S)
emitted by volcanoes,
oceans, wetlands, and
forest fires
Oxidation of NOX pro-
duced by soils, forest
fires, and lightning
Wild animals and
undisturbed soils
Oxidation of hydro-
carbons (e.g., ter-
penes and waxes)
emitted by vegetation
and wildfires
Not Applicable
Not Applicable
Not Applicable
Not Applicable
Manmade
Oxidation of sulfur
dioxide (SO2) emitted
from fossil fuel com-
bustion
Oxidation of NOX
emitted from fossil
fuel combustion, motor
vehicle exhaust, and
prescribed burning
Animal husbandry,
sewage treatment, and
fertilized land
Oxidation of hydro-
carbons emitted by
motor vehicles, open
burning, wood burn-
ing, fuel storage and
transport, and solvent
usage (E. H. Pechan
and Associates, 1994)
Not Applicable
Not Applicable
Not Applicable
Not Applicable
Reference: USEPA, 1997a (Note: Prescribed burning of forests and agricultural fields was added to the list of sources in
the cited reference)
1-4
November 2001
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Introduction to Vis'ibiYity Issues
collectively referred to as NOX) are emitted from high-temperature combustion processes and life
processes of certain soil microbes. The nitrogen oxides are converted into nitrate in the atmosphere.
Natural sources of NOX include forest fires (wildfires), lightning, and certain soil microbes. The major
manmade sources include fossil fuel combustion and motor vehicle exhaust. The nitrogen oxides and
ammonia emitted by motor vehicles sometimes combine in the exhaust system to create nitrate
aerosols. These nitrate aerosols are primary sources of nitrate particulate matter.
Organic carbon represents the accumulation of all organic compounds existing in atmospheric
aerosol particles. Organic carbon may rise into the atmosphere under the buoyant forces of processes
such as forest and range wildfires, open burning, wood burning, cooking, incineration, and automo-
bile exhaust. The organic carbon aerosols rise into the air during incomplete combustion and represent
the major primary sources of organic carbon emissions. Tire wear is another potential source of pri-
mary organic carbon emissions, but these particles are usually larger than 2.5 microns in aerodynamic
diameter.
Organic carbon may also be released into the atmosphere as off-gases from a number of different
sources: vegetation, wildfires, motor vehicles, open burning, wood burning, fuel storage and transport,
and solvent usage. In the atmosphere, these gases are partially oxidized and converted into products
with lower saturation pressures. The organic carbon products then condense as secondary organic
aerosol particles in the atmosphere.
Elemental carbon is often referred to as light-absorbing carbon and represents the soot from com-
bustion practices. Elemental carbon is emitted directly into the atmosphere and therefore has only pri-
mary emission sources. The natural source of elemental carbon is wildfire activity, and the manmade
sources include prescribed forest and range fires, motor vehicle exhaust (especially diesel exhaust),
wood burning, and cooking operations. Industrial processes can prevent the escape of elemental carbon
to the atmosphere with control devices such as fabric filters and cyclones.
Crustal material is composed of the particulate matter entrained in the atmosphere by various phys-
ical processes and therefore has only primary emission sources. Crustal material is composed of two
measured fractions of particulate matter: fine soil and coarse mass. The fine soil particles have aerody-
namic diameters less than 2.5 microns and the coarse mass particles have a diameter between 2.5 and
10 microns. Wind erosion of the soil introduces particulate matter into the atmosphere, as does the
wind's re-entrainment of previously deposited particles. Manmade physical processes that introduce
crastal material to the atmosphere include fugitive dust from industrial processes, entrainment of dust
from vehicular traffic over paved and unpaved roads, construction and demolition activities, and agri-
cultural tilling activities. These processes also introduce considerable quantities of large, visible parti-
cles to the atmosphere; however, the larger particles quickly settle out of the air when the winds calm.
C. Visibility Measurements
Three metrics are typically used to describe visibility: visual range, light extinction coefficient, and
the deciview visibility index (USEPA, 1993; Sisler, 1996). They can be calculated from IMPROVE par-
ticulate sample data. Visual range is the most commonly used visibility metric and is defined as the,
greatest distance at which a large dark object can be seen against the background sky. To measure visu-
al range, ari observer looks at a series of visibility markers (e.g., lights at night) and determines the dis-
tance to the furthest visible object. Visual range has been measured at airports since 1919 and has been
recorded on computers since 1940.
November 2001 1-5
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Visual range is likely to remain a common metric for visibility because it is easily characterized by
sighted individuals without instrumentation and is reported in the common units of miles or kilometers.
However, its simple measurement of distance sighted to an object does not express any information
about the clarity of the perception. The clarity affects the scenic enjoyment, and noticeable degradation
of scenic appearance (including the disappearance of some features) occurs on some objects as near as
within 10 percent of the visual range.
The light extinction coefficient is a visibility metric used by scientists to describe reduced visibili-
ty. It represents the attenuation of light per unit distance due to the scattering and absorption by gases
and aerosols between the source and receptor. As a reference, the light extinction from Rayleigh scat-
tering by air is uniformly set at 10 inverse megameters (Mm-1) (USDOE, 1984). The light extinction
coefficient can be calculated directly from the concentrations of gas and aerosol species and therefore
serves as a convenient measure for relating ambient air quality to visibility impairment. The use of cal-
culated light extinction coefficients as measures of visibility impairment also allows improvements in
ambient air quality to be related directly to visibility improvement.
In this report, the light extinction coefficients were calculated directly from concentration measure-
ments of particle samples. Appendices B and C describe the methods used for these calculations. The
total light extinction coefficient is the sum of the Rayleigh scattering and light extinction from aerosol
particles. Since Rayleigh scattering is constant at any location (assuming constant atmospheric pres-
sure) and represents pristine atmospheric visibility conditions, only the calculated aerosol light extinc-
tion coefficients are reported in the subsequent chapters. Adding 10 Mm-1 to the calculated aerosol
light extinction coefficients will yield Lhe calculated total light extinction coefficient.
The inverse distance units used to describe light extinction coefficients are difficult to interpret as
humanly perceptible changes in visibility. Therefore, the deciview haze index (dv) was developed and is
calculated directly from the total light extinction coefficient (bext expressed in Mm.-1):
Jv=101n(be!Ct/10Mm-1)
The deciview scale is nearly zero for a pristine atmosphere (dv equals zero for Rayleigh scattering
at approximately 1.8 km elevation), and each deciview change corresponds to a small but perceptible
scenic change that is observed under either clean or polluted conditions. Like the decibel scale for
Aerosol Light Extinction (Mm"1)
.10 20 30 50 100 200300
203 187
161
122
81 60
40
22
12 Visual Range (mi)
1.8 2.6 4.1 6.9 11 14 18 24 30 34
Deciview Haze Index (dv)
Figure 1-3. Relationship Between the Light Extinction, Deciview, and Visual Range Scales
1-6
November 2001
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Introduction to Visibility Issues
sound, similar changes in deciviews are perceived as equal. This report includes many trends expressed
as deciview changes. Each deciview decrease approximates a perceptible improvement in visibility.
Figure 1-3 shows the relationship between the light extinction, deciview, and visual range scales.
D. National Programs to Improve Visibility
In July 1999, EPA promulgated the Regional Haze Rule to address visibility impairment in
mandatory Federal Class I areas caused by numerous manmade air pollution sources located over
broad regions. The proposed program takes into consideration scientific findings and policy recom-
mendations from a number of sources, including the National Academy of Sciences (NAS), the Grand
Canyon Visibility Transport Commission (GCVTC), and a Federal Advisory Committee on Ozone,
Particulate Matter, and Regional Haze Implementation Programs (FACA). The proposal lays out a
framework within which states can conduct regional planning and develop implementation plans to
achieve "reasonable progress" toward the national visibility goal of no human-caused impairment in
the 156 mandatory Federal Class I areas where visibility has been deemed an important value
(USEPA, 1998).
Because of the common precursors and the regional nature of the ozone, PM, and regional haze
problems, EPA is developing the implementation programs for these pollutants simultaneously in
order to integrate future planning and control strategy efforts to the greatest extent possible.
Implementation of the PM and Ozone National Ambient Air Quality Standards (NAAQS) in conjunc-
tion with the regional haze program is expected to improve visibility in urban as well as rural areas
across the country. Other air quality programs are expected to lead to emissions reductions that will
improve visibility in certain regions of the country.
The Interim Air Quality Policy on Wildland and Prescribed Fires is also intended to improve visibil-
ity conditions by reducing particulate matter emissions from managed burning in the wildlands. The
EPA has been working with the Agricultural Air Quality Task Force set up by the U.S. Department of
Agriculture (USDA) to develop a set of recommendations for a similar policy related to managed burn-
ing of agricultural lands. Once these recommendations are approved by the USDA and passed on to
EPA, the Agency will consider them carefully in developing a policy to address the emissions from this
source category.
Full implementation of the Acid Rain Program will achieve significant regional reductions in the
emissions of sulfur dioxide, which is expected to reduce sulfate haze, particularly in the eastern United
States.. The recent NOX State Implementation Plan (SIP) Call to reduce formation of ozone by reducing
emissions from manmade sources of NOX should also improve regional visibility conditions to some
degree. In addition, the NAAQS, mobile source, and woodstove programs to reduce fuel combustion
and soot emissions can benefit areas that have experienced visibility impairment from sources of
organic and elemental carbon species.
November 2001
1-7
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Redwood
• i i •( it • 'in *'ft • i nil i" !>M
*Lon«Peak , . ,
, „ *RockyMtn
'"'"
• , Great Basin
jwosemite v
jl 1 *Canydniands
•if Bryce Canyon* < WBmlnuche
b£E& "- Mesa Verde'*^ *Great Sand Dunes
' VTfcferand Canyon
*_j?L i
Dolly Sods* -', *" Washington
Figure 1-4. Locations of IMPROVE Particulate Matter Samplers Operating Continuously from
1994-1998 (Green Shaded Areas Represent Mandatory Federal Class I Areas)
E. IMPROVE Monitoring Systems in and near the Mandatory Federal
Class I Areas
Section 169(A) of the 1977 CAA Amendments established a national goal of protecting visibility
from manmade air pollution in 158 specific areas, designated as mandatory Federal Class I areas
(Figure 1-4).3 Visibility was subsequently determined to not be an important value in two areas
(Federal Register, Vol. 44, No. 232, pages 69122-7). Four Federal land management agencies are
responsible for the remaining 156 mandatory Federal Class I areas and the land surrounding them:
National Park Service, USDA-Forest Service, U.S. Fish and Wildlife Service, and the Bureau of Land
Management. Interested readers should refer to Appendix A for a list of the 156 mandatory Federal
Glass I areas where visibility is an important value.
These agencies joined the EPA in 1985 to establish a collaborative monitoring program known as
the Interagency Monitoring of Protected Visual Environments (IMPROVE) (Air Resource Specialists,
1992). In 1991, three other organizations were formally added to the IMPROVE Steering Committee:
State and Territorial Air Pollution Program Administrators (STAPPA), Western States Air Resources
Council (WESTAR), and Northeast States for Coordinated Air Use Management (NESCAUM). In
3 The reader will note that the mandatory Federal Class I areas in Figure 1—4 are divided into a western region (greater
than 100°W) and an eastern region (less than 100°W). A discussion of results based upon the regional site locations is found
in Chapter 3, Section D.
1-8
November 2001
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Introduction to Vfsi'bffify fssues
Table 1-2. IMPROVE and IMPROVE Protocol Sites Collecting Data from 1994 through 1998
IMPROVE Site
Sipsey Wilderness
Denali National Park
Chiricahua National Monument
Grand Canyon National Park (South Rim)1
Grand Canyon National.Park (Indian Garden)
Petrified Forest National Park
Tonto National Monument
Upper Buffalo Wilderness
Lassen Volcanic National Park
Pinnacles National Monument
Point Reyes National Seashore
Redwood National Park
San Gorgonio Wilderness
Sequoia National Park
Yosemite National Park
Great Sand Dunes National Monument
Mesa Verde National Park
Rocky Mountain National Park
Weminuche Wilderness
Washington (DC)2
Chassahowitzka National Wildlife Refuge
Okefenokee National Wildlife Refuge
Mammoth Cave National Park
Acadia National Park
Boundary Waters Canoe Area
Glacier National Park
Great Basin National Park2
Jarbidge Wilderness
Brigantine Wilderness -
E.B. Forsythe National Wildlife Refuge
Bandelier National Monument
Crater Lake National Park
Three Sisters Wilderness
Badlands National Park
Great Smoky Mountains National Park
Big Bend National Park
Guadalupe Mountains National Park
Bryce Canyon National Park
State
Alabama
Alaska
Arizona
Arizona
Arizona
Arizona
Arizona
Arkansas
California
California
California,
California
California
California
California
Colorado
Colorado
Colorado
Colorado
District of
Columbia
Florida
Georgia
Kentucky
Maine
Minnesota
Montana
Nevada
Nevada
New Jersey
New Mexico
Oregon
Oregon
South Dakota
Tennessee
Texas
Texas
Utah
Latitude (°N)
34.33
63.45
32.02
36.07
36.07
35.07
33.65
35.83
40.53
36.49
38.12
41.55
34.20
36.50
37.70
37.73
37.20
40.38
37.65
38.88
28.75
30.73
37.22
44.38
47.95
48.50
39.00
41.88
39.47
35.78
42.88
44.28
43.75
35.63
29.30
31.85
37.62
Longitude (°W)
87.33
148.97
109.35
112.15
112.13
109.77
111.10
93.22
121.57
121.17
122.90
124.08
116.92
118.82
119.70
105.50
108.48
105.57
107.80
77.50
82.57
82.12
86.07
68.27
91.52
113.98
114.20
115.42
74.45
106.27
122.13 .
122.05
101.93
83.92
103.18
104.82
112.17
Elevation (ft)
600
2,100
5,400
7,100
3,800
5,500
2,600
2,300
5,900
1,000 .
125
760
5,600
1,800
5,300
8,200
7,200
7,900
9,050
30
10
50
750
420
1,700
3,200
6,800
6,200
50
6,500
6,500
2,850
2,500
2,700
3,500
5,400
8,000
November 2001
1-9
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Table 1-2. IMPROVE and IMPROVE Protocol Sites Collecting Data from 1994 through 1998
(continued)
IMPROVE Site
Canyonlands National Park
Lye Brook Wilderness
Shenandoah National Park
Mount Rainier National Park
Snoqualmie Pass -Alpine Lakes Wilderness
Dolly Sods Wilderness
Bridger Wilderness
Yellowstone National Park
State
Utah
Vermont
Virginia
Washington
Washington
West Virginia
Wyoming
Wyoming
Latitude (°N)
38.45
43.17
38.55
46.75
47.43
39.10
42.95
44.55
Longitude (°W)
109.82
73.00
78.40
122.12
121.42
79.43
109.75
110.40
Elevation (ft)
5,950
3,250
3,600
, 1,400
3,600
3,800
8,000
7,700
1 Although the Grand Canyon (South Rim) monitoring site was replaced in August 1998, its results are included in this
report.
2 Not a mandatory Federal Class I area, but the data from this site are included in the national and regional analyses
presented in Chapter 3.
1999, the Mid-Atlantic Regional Air Management Association (MARAMA) was added, and the State
of Arizona also acts as an associate member.
The IMPROVE network has been collecting data since 1987 to support the visibility protection reg-
ulations for the mandatory Federal Class I areas. The objectives include establishing current visibility
levels, identifying existing sources of manmade visibility impairment, and tracking progress toward the
long-term goal of removing manmade impairment from mandatory Federal Class I areas. Monitors at
IMPROVE sites across the country document scenic conditions through photographs and obtain direct
optical measurements, particulate matter samples, temperatures, and relative humidities.
The particulate matter samples are collected on filters on Wednesdays and Saturdays. The filters are
sent to laboratories to measure the mass (weight) and chemical composition of the particulate matter.
The laboratory tests are then reported as measurements of fine mass (PM2 5), total mass (PM10), coarse
mass (difference between PM10 and PM2.5), sulfates (as ammonium sulfate), nitrates (as ammonium
nitrate), organic carbon, elemental carbon, and soil. The light extinction coefficients and the deciview
indices are calculated from the site relative humidities and the measurements of the key species: sul-
fates, nitrates, organic carbon, elemental carbon, and crustal material (calculated from soil and coarse
mass measurements). Table 1-2 lists the IMPROVE monitor sites that collected data continuously from
1994 through 1998. The following chapters describe the visibility trends in corresponding areas. Since
this report serves as a follow-on to a 1993 Congressional report on visibility issues in mandatory
Federal Class I areas, 1994 was chosen as the starting year for many of the calculated values.
The Regional Haze Rule requires states to establish goals for each affected Class I area to 1)
improve visibility on the haziest days, and 2) ensure no degradation occurs on the clearest days over the
period of each implementation plan. The haziest (most-impaired) days in this report have been classi-
fied as the 80th to 100th percentile of the measurement days based on the calculated mass concentra-
tions, but not directly on visibility impairment. The numbers reported in the following chapters repre-
sent the average characteristics of this percentile group. The clearest (least-impaired) days are repre-
sented by the 0 to 20th percentile of the measurements based on the calculated mass.concentrations.
The mid-range days are characterized by averaging the values within the 40th to 60th percentile range.
1-10
November 2001
-------
Individual Areas—Meffiodofogy
2. Visibility in Individual Mandatory Federal Glass I Areas
A. Introduction
This chapter presents the visibility-related data collected by the IMPROVE participate monitoring
network and examines the trends at the individual IMPROVE monitoring sites. The sites are presented
alphabetically by state. This state format allows readers to consider all of the data available for a state
in a single .section of this chapter. A map is presented for each state to illustrate the location of its
mandatory Federal Class I areas and IMPROVE monitoring sites. The actual locations of several
IMPROVE particulate samplers are not within the boundaries of the mandatory Federal Class I areas
that they represent. However, they are positioned at accessible locations that represent regional visibili-
ty conditions in these areas. An additional ten states and one territory have mandatory Federal Class I
Areas, but five years of data were not yet available from these areas. National and regional trends are
examined in detail in Chapter 3.
The last report to Congress on visibility in mandatory Federal Class I areas (EPA, 1993) was com-
pleted in 1993 and examined data at the IMPROVE sites collected up to that tune. Therefore, this report
concentrates on samples collected from 1994 through 1998. However, in the interest of understanding
long-term trends at the individual monitor sites, all of the data associated with monitors (some sites
began data collection as early as 1988) are included in this chapter. The IMPROVE sites included in this
report were required to operate continuously from 1994 through 1998. Data from the monitors not oper-
ating between 1994 and 1998, or not providing five full years of data, were not analyzed for this report.
B. Methodology
The data presented in this chapter were reported by the Cooperative Institute for Research in the
Atmosphere (CIRA) at Colorado State University. Both the raw and summary data are available at
ftp://alta_vista.cira.colostate.edu/DATA/IMPROVE/. This report shows only the summary data at the
seasonal and annual levels. Readers interested in a detailed examination of the data values should con-
tact CIRA directly. Some data points are missing in the graphs of this chapter, due to the data analysis
procedures followed by CIRA. This indicates that complete samples measuring all components were
not collected during that season or year.
The EPA publishes a National Air Quality and Emissions Trends Report that presents long-term
trends data for visibility impairment in the national parks and wilderness areas based on the IMPROVE
data. The 1998 Trends Report compiled the data to report annual trends for a group of 10 eastern sites
and a group of 24 western sites, but did not report on individual sites. The Trends Report required that
13 daily samples (50 percent of the sample days) be available for each of the four seasons at a site
. before data from that year was considered complete and included in the regional analysis. This criterion
was not employed for the data sets shown in this report. Instead, this report informs the reader when the
CIRA data sets contain unusually high or low data values. Referring to the first, third, and fifth figures
presenting IMPROVE data for each site, the reader is cautioned that CIRA's annual information is
based on fewer than four seasons and. will be biased toward the seasons in which data were collected.
Please refer to Appendix B for an explanation of the method used to create summary data from raw
IMPROVE data and to Appendix C for an explanation of the methodology used to calculate light
extinction from monitored aerosol mass data.
November 2001
2-1
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
The first figure for each IMPROVE monitoring site shows the annual visibility indices for the most-
impaired, least-impaired, and mid-range days from the beginning of the monitor's operation through
1998. The most-impaired and least-impaired categories reflect the subsets of data that must be examined
to determine compliance with the Regional Haze Rule. The most-impaired (haziest) days have been clas-
sified as the 80th to 100th percentile of the measurement days based on calculated fine mass concentra-
tions. The least-impaired (clearest) days are represented by the 0 to 20th percentile of the measurements
based on calculated fine mass concentrations. The mid-range days are characterized by averaging the
values within the 40th to 60th percentile range.
The discussions addressing the first figure indicate whether or not the data sets show statistically sig-
nificant trends. To determine a statistically significant trend hi a data set, the number of times each point
lies above or below its predecessors is first counted. The number of instances of increases and decreases
are then summed. If the difference between the number of increases and the number of decreases is sta-
tistically improbable to be caused by random data fluctuations, then a statistically significant trend is
noted. Appendix D provides a more detailed discussion of the Thiel method utilized to determine
whether or not the observed trend is statistically significant.
The second figure presented for each site shows the average visibility indices for each season during
the operational time of the monitor. The Regional Haze Rule describes visibility impairment in terms of
a deciview haze index. Under this index, uniform changes hi haziness correspond to uniform incremental
changes in perception across the entire range of conditions, from pristine to highly impaired (Regional
Haze Regulations, Final Rule, 1999). A single deciview unit is generally considered the minimal percep-
tible change that is observed under either clean or polluted conditions. The reader should refer to Section
l.C of this report for a discussion of the relationship between the deciview index and other scales.
The third and fourth figures presented for each site are pie charts showing the contributions of indi-
vidual pollutant species to the calculated aerosol light extinction coefficients (averaged from 1994
through 1998). At the IMPROVE sites, samples are collected on filters to measure particulate matter less
than 2.5 microns in aerodynamic diameter (PM2 5) and particulate matter less than 10 microns in diame-
ter (PMJO). Both filters are weighed, and the mass difference between PM10 and PM2 5 is referred to as
coarse mass. The PM2-5 filter is analyzed to determine the mass of its chemical components. The chemi-
cal components of PM2 5 are grouped into five categories based on their emission sources (refer to Table
1-1): sulfates, nitrates, organic carbon, elemental carbon, and fine soil (crustal material with an aerody-
namic diameter less than 2.5 microns). Based on the relative humidity at the IMPROVE site, the light
extinction coefficients are calculated for each of the categories and then summed together to obtain the
calculated aerosol light extinction coefficients. The pie charts show the percent contribution from each of
the species: sulfates, nitrates, organic carbon, elemental carbon, and crustal material (crustal material is
calculated by summing the fine soil and coarse mass light extinction coefficients).
The fifth figure presented for each site shows the annual aerosol light extinction coefficients during
the operational period of the monitor. Since this figure is presented as the sum of light extinction from
the five species, the reader can see how individual species (i.e., sulfates, nitrates, organic carbon, ele-
mental carbon, and crustal material) varied during the years of operation.
The IMPROVE particulate sampling protocol has changed certain techniques since 1988
(http://vista.cira.colostate.edu/IMPRO\TE/Data/QA_QC/qa-qc-Branch.htni). Of particular note are the
changes in filter mask size at all eastern and some western sites and the addition of glycerine to the
denuders. Because of the change to filter mask size, sulfate measurements by ion chromatography are
used to examine trends hi this report. The addition of glycerine to the denuders beginning June 1, 1996
affected nitrate measurements substantially at all sites. Therefore, this report uses a constant nitrate con-
2-2 November 2001
-------
Individual Areas—Genera) Findings
centation for all years, chosen as the average measured nitrate concentration for the data set measured
from 1997 to 1999. Therefore, no nitrate trends are reported for the fifth figure in each set.
When reviewing the visibility figures in this chapter, readers are cautioned to carefully examine
the axes on the plots. Although one figure may appear to have large fluctuations in visibility from
year to year, this may be a function of a limited scale on the axis. For example, the aerosol light
extinctions at Denali National Park are twelve times smaller than those at Mammoth Cave
National Park, so the same fluctuation in extinction at both sites would appear more pronounced
at the Denali site. Comparisons between the sites are presented in Chapter 3.
G. General Findings
Investigation into the data at the individual sites revealed some common characteristics among the
sites. These general findings may or may not be noted when examining the regional and national sum-
maries of the data, so they are presented here for the interested reader.
The first figure for each IMPROVE monitoring site presents the visibility indices for three different
data sets: the most-impaired, mid-range, and least-impaired days. When viewing the long-term trends at
the sites, it is apparent that the visibility often improved or declined for one of these data sets while
remaining constant for the other two. Of the sixteen sites that showed an increasing or declining trend
in at least one of the data sets, only the Pinnacles National Monument (CA) site showed the same trend
for all three data sets. To understand why the three data sets may behave differently, the reader must
recognize that the data set from the most-impaired days will be collected under different meteorological
conditions (e.g., wind direction, relative humidity, or temperature) than the data for the least-impaired
days. Since these meteorological conditions affect the formation and transport of ambient pollutants
(and thus visibility), actual changes in upwind emissions over the years may be observed for one data
set but not another.
Meteorological conditions and variations in emissions affect the ambient particulate matter and vis-
ibility indices. Therefore, the reader should not be surprised that the se.asonal average visibility indices
(reported in the second figure for each site) are generally different. For 32 of the 42 sites presented in
this chapter, the data from at least one season consistently had higher or lower visibility indices than
the other three seasons. It was also observed that the seasonal figures for the sites showed 29 trends
(out of 168) indicating seasonal improvements in visibility and only one that indicated seasonal
declines in visibility.
The annual and seasonal pie charts showing the contributions of each species to aerosol light
extinction (third and fourth figures for each site) are presented to illustrate the important pollutants that
influence visibility at the individual sites. If the visibility indices are higher during one season than
another, readers may notice that the annual pie chart is weighted toward the higher season and resem-
bles a particular season's pie chart more than the others. This weighted behavior is an artifact of the
method (Appendix B) by which CIRA calculates the percent contributions from the various species.
Furthermore, from the pie charts, the reader will often note that sulfate contributes more to the
aerosol light extinction than any of the other species. Indeed, ambient sulfate particles are responsible
for more than 30 percent of the light extinction at 37 sites. Both sulfates and nitrates extinguish light to
November 2001
2-3
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
a greater degree than do organic carbon, elemental carbon, and crustal material (Appendix C). For
example, at 90 percent relative humidity, sulfate particles will extinguish fourteen times more light than
a similar mass of fine crustal material.1
The fifth figure for each site presents the long-term trends in annual average light extinction for the
five species, and the total aerosol light extinction. Twenty-two sites showed statistically significant
reductions in the light extinction from at least one of the species. Four sites (Big Bend, TX; Brigantine,
NJ; Jarbidge, NV; and Mesa Verde, CO) showed statistically significant increases in the light extinction
from a single species. Only 12 sites showed statistically significant reductions in the annual average
total aerosol light extinction. Of the twelve sites that showed reduction in total aerosol light extinction,
all showed reductions in at least one of the fine species.
State summaries are provided when data from more than one IMPROVE particulate sampler is
reported (Arizona, California, Colorado, Oregon, Texas, Utah, Washington, and Wyoming). The data at
the seven California sites suggested regional similarities when the sites were classified as coastal,
southern, or eastern sites. In other states, similar light extinction coefficients were observed for the dif-
ferent monitor sites within the state unless the relative humidities varied between sites. Higher relative
humidity levels at one site in a state resulted in the calculation of considerably higher sulfate and
nitrate light extinction coefficients and, consequently, higher total aerosol light extinction coefficients.
' Appendix C shows that the sulfate concentrations (in ug/m3) are multiplied by the relative humidity correction factor
and 3 m2/g to calculate light extinction (hi Mnr1). The fine crustal material concentration is multiplied by 1 m2/g to
calculate light extinction. At 90 percent relative humidity, the correction factor is 4.67. Therefore, at 90 percent relative
humidity, the light extinction coefficient from 1 ug/m3 sulfate would be calculated as 14 Mm"1 (1 x 3 x 4.67), and the
coefficient from 1 ug/m3 fine crustal material would be calculated as only 1 Mm-1 (1 x 1).
2-4
November 2001
-------
Individual Areas—Alabama
D. Visibility Discussions by State
1. ALABAMA
The only IMPROVE monitoring site in Alabama that operated continuously from 1992 through
1998 was located near the Sipsey Wilderness Area. Figure AL—1 shows the Sipsey monitor location
(34.34°N, 87.34°W, elevation 600 feet) in the northern portion of the State.
Sipsey IMPROVE
Monitor
Sipsey Wilderness
Figure AL-1. Mandatory Federal Class I Area and IMPROVE Monitoring Site in Alabama
Sipsey Wilderness Area
The Sipsey IMPROVE particulate sampler started reporting in March of 1992. Figure AL-2 pres-
ents the calculated visibility indices for selected data sets from 1992 through 1998. The figure shows
that from 1992 through 1998 there was no significant trend in the annual average of the visibility index
for the least-impaired days, which remained near 20 deciviews (VR 33 miles). From 1992 through 1998
there was no significant trend in the annual average of the visibility index for the most-impaired days,
which also remained relatively constant near 32 deciviews (VR 10 miles). However, from 1992 to 1995,
the annual average of the visibility index for the mid-range days showed mild improvements in the visi-
bility index as the index dropped from 27 (VR 16 miles) to 24 (VR 22 miles) deciviews but rose again
to 25 deciviews through 1998. This does not represent a statistically significant trend towards improved
visibility.
Figure AL—3 shows the seasonal averages for the calculated visibility index from 1992 through
1998. The visibility indices for summer were higher than those during the autumn, while those for the
November 2001 2-5
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1988 1989 1990 1991 1992 1993 1994 1995 .1996 1997 1998
Year
Figure AL-2. Yearly Deciview Averages for Most-Impaired/ Mid-Range/ and
Least-Impaired Days from 1992-1998 for the Sipsey IMPROVE Participate Sampler
i
o
to
a
1
a
1
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
•Spring
•Summer -rfc-Autumn
•Winter
Figure AL-3. Seasonal Deciview Averages from 1992-1998 for the Sipsey IMPROVE
Particulate Sampler
2-6
November 2001
-------
fndividua/ Areas—Alabama
Nitrate Organic
7% Carbon
11%
Elemental
Carbon
5%
Crustal
Material
3%
Sulfate
74%
Figure AL-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Sipsey IMPROVE
Particulate Sampler
winter and spring remained the lowest (best visibility).
No significant seasonal trends were observed in any of
the four seasons. No data were collected from- Jan 18,
1997 through June 14, 1997 at this site. This lack of data
is reflected in Figure AL-3.
Figure AL-4 presents a chart showing the calculated
fractional contribution to Sipsey's light extinction by each
aerosol component on an annual basis. Figure AL-5
shows the same information for the four seasons. These
five pie charts show that sulfate particles were responsi-
ble for 66 to 81 percent of the light extinction at the
Sipsey site, averaging 74 percent on an annual basis over
a five-year period. The highest sulfate contributions
occurred in the summer and the lowest in the winter. The
contributions from nitrates ranged from 6 to 11 percent
depending on the season (with the highest observed
nitrate percentages in the winter). The contributions from
Nitrate
7%
Organic
Carbon
14%
Elemental
Carbon
6%
Crustal
Material
5%
Sulfate
68%
Spring
Nitrate Organic
8% Carbon
11%
Elemental
Carbon
5%
Crustal
Material
3%
Sulfate
73%
Sulfate
81%
Nitrate Organic
6% -Carbon
7%
Elemental
Carbon
3%
Crustal
Material
3%
Summer
Nitrate
11%
Organic
Carbon
13%
Sulfate
66%
Elemental
Carbon
7%
Crustal
Material
3%
Autumn
Winter
Figure AL-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Sipsey IMPROVE Particulate Sampler
November 2001
2-7
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
organic carbon ranged from 7 percent in the summer to 14 percent in the spring. Annually, elemental
carbon and crustal material measured at the Sipsey site were each responsible for approximately 5 and
3 percent of the calculated aerosol light extinction.
Figure AL-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Sipsey site from 1992 to 1998. Over the seven-year peri-
od the total annual aerosol light extinctions remained between 115 and 142 Mm-1 (no significant trend).
No statistically significant trends were noted in the annual light extinctions calculated for sulfates,
organic carbon, elemental carbon, or crustal material.
0
T———'—i—• •—i—' •—r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
a Sulfate Q Nitrate n Organic Carbon D Elemental Carbon • Crustal Material
Figure AL-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1992-1998 for Sipsey IMPROVE Particulate Sampler
2-8
November 2001
-------
Individual Areas—Alaska
2. ALASKA
The only IMPROVE monitoring site in Alaska that operated continuously from 1994 through 1998
was the one located in Denali National Park. Figure AK-1 shows the Denali monitor location
(63.73°N, 148.97°W, elevation 2100 feet) in central Alaska. The Bering Sea, Tuxedni, and Simeonof
Wilderness Areas are also covered by the Regional Haze Rule but did not have IMPROVE monitors
operating from 1994 through 1998, and thus are not included in the analysis described below.
Denali National Park
Fairbanks
Bering Sea
Wilderness
Denali IMPROVE
Monitor
Juneau
Simeonof Wilderness
0 250__ 500
miles
Figure AK-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Alaska
Denali National Park
The Denali IMPROVE particulate sampler started reporting in March of 1988. Figure AK-2 pres-
ents the calculated visibility indices for selected data sets from 1988 through 1998. From 1988 through
1998 there was no statistically significant trend in the annual average of the visibility index for the
most-impaired days, which remained relatively constant, near 11 deciviews (VR 80 miles). Similarly,
the annual average of the visibility index for the mid-range days showed no improvements in the visi-
bility index that remained near 6.3 deciviews (VR 130 miles). Figure AK—2 shows that from 1988
through 1998 (except the year 1990) the annual average of the visibility index for the least-impaired
days remained near 4.0 deciviews (VR 165 miles) with no statistically significant trend.
Figure AK—3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The visibility indices for the summer and spring were generally slightly higher than those during
the fall and winter. No significant seasonal trends were observed in the calculated visibility indices for
November 2001
2-9
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure AK-2. Yearly Deciview Averages for Most-Impaired, 'Mid-Range, and Least-
Impaired Days from 1988-1998 for the Denali IMPROVE Participate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-*-Spring -»-Summer -A-Autumn -•-Winter
Figure AK--3. Seasonal Deciview Averages from 1988-1998 for the Denali IMPROVE
Parriculate Sampler
2-10
November 2001
-------
Individual Areas—Alaska
Organic
Carbon
23%
Nitrate
5%
Elemental
Carbon
10%
Crustal
Material
19%
Sulfate
43%
Figure AK-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Denali IMPROVE Particulate Sampler
spring, summer, or autumn over this time period, but the
indices for winter showed an improvement from 7.5 to 5.5
deciviews (VR from 115 to 140 miles).
Figure AK-4 presents a chart showing the calculated
fractional contribution to Denali's light extinction by each
aerosol component on an annual basis. Figure AKr-5
shows the same information for the four seasons. These
five pie charts show that sulfate particles were responsible
for 32 to 49 percent of the light extinction at the Denali
site, averaging 43 percent on an annual basis over a five-
year period. The contributions from nitrates ranged from 4
to 7 percent depending on the season, with the highest
observed nitrate percentages in the autumn. The contribu-
tions from organic carbon remained relatively constant,
near 17 percent in the autumn, winter, and spring, but rose
to 36 percent in the summer. On an annual basis, elemen-
Organic
Carbon
17%
Elemental
Carbon
9%
Nitrate
4%
Organic
Carbon
18%
Nitrate
7%
Sulfate
49%
Spring
Elemental
Carbon
12%
Crustal
Material
21%
Crustal
Material
21%
Sulfate
42%
Autumn
Elemental
Carbon
9%
Organic
Carbon
36%
Crustal
Material
19%
Nitrate
4%
Sulfate
32%
Organic
Carbon
15%
Summer
Elemental
Carbon
11%
Nitrate
6%
Crustal
Material
20%
Sulfate
48%
Winter
Figure AK-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Denali IMPROVE Particulate Sampler
November 2001
2-11
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
tal carbon and crustal material measured at the Denali site were each responsible for approximately 10
and 19 percent of the calculated aerosol light extinction.
Figure AK-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Denali site from 1988 to 1998. Over the eleven-year
period, there was a decreasing trend in the total annual aerosol light extinctions, but it was not statisti-
cally significant. No significant trends were noted in the annual light extinctions calculated for sulfates,
organic carbon, or elemental carbon. The crustal material contribution to the aerosol light extinction
was noticeably smaller in the late 1990's than earlier years, but no statistically significant trend hi
crustal material contributions was observed over the entire eleven year period.
0 I — 1 • , • , "--• , "•= ' 1 , i 1 i , . . , Li—a ,_
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
• Sulfate El Nitrate n Organic Carbon D Elemental Carbon ffl Crustal Material
Figure AK-6. Contributions to Calculated Annual Aerosol Light Extinction from
1988-1998 for the Denali IMPROVE Particulate Sampler
The variations in visibility and light extinction from year to year appear significant in Figures
AK-2, AK-3, and AK-6 compared to the graphs shown for other IMPROVE monitor sites. However,
the calculated visibility impairment at Denali National Park was much lower than at other sites, so the
smaller scales on the figures exaggerate the variations from year to year.
2-12
November 2001
-------
Individuaf Areas—Arizona
3. ARIZONA
Arizona has twelve mandatory Federal Class I areas. The five IMPROVE particulate samplers in
Arizona that operated continuously from 1994 through 1998 were located at Chiricahua National
Monument (32.02°N, 109.35°W, elevation 5400 feet), south rim of Grand Canyon National Park
(36.07°N, 112.15°W, elevation 6800 feet), Indian Garden in Grand Canyon National Park (36.07°N,
112.13°W, elevation 3800 feet), Petrified Forest National Park (35.07°N, 109.77°W, elevation 5800
feet), andTonto National Monument (33.65°N, 111.11°W, elevation 2600 feet). Figure AZ-1 shows the
monitoring locations in the national parks and wilderness areas throughout the state. The Sycamore
Canyon, Pine Mountain, Mazatzal, Mount Baldy, Sierra Ancha, Superstition, Galiuro, and Saguaro
Wilderness Areas are also covered by the Regional Haze Rule, but did not have an IMPROVE particu-
late sampler operating from 1994 through 1998. Limited monitoring was .also done during this period
at Saguaro National Park and Sycamore Canyon, Sierra Ancha, Galiuro, Mazatzal, and Chiricahua
Wilderness Areas. The Yavapai-Apache Tribal Government has redesignated their lands as Class I,
although this area is not covered by the Regional Haze Rule.
Grand Canyon
National Park
Sycamore Canyon
Wilderness
Pine Mountain
Wilderness
Grand Canyon
IMPROVE Monitor
Indian Garden
IMPROVE Monitor
Sierra Ancha
Wilderness
Phoenix
Superstition Wilderness
Saguaro Wilderness
Mazatzal Wilderness
miles
Petrified Forest
IMPROVE Monitor
Petrified Forest
National Park
.Mount Baldy Wilderness
Tonto IMPROVE
Monitor
Galiuro Wilderness
Chiricahua IMPROVE
Monitor
Chiricahua
National Monument
Chiricahua Wilderness
Figure AZ-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Arizona
November 2001
2-13
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Chiricahua National Monument
The Chiricahua IMPROVE particulate sampler started reporting in March of 1988. Figure AZ-2
presents the calculated visibility indices for selected data sets from 1988 through 1998. From 1988
through 1998 there was no statistically significant trend in the annual average of the visibility index for
the most-impaired days, which remained between 12 and 15 deciviews (VR between 75 and 55 miles).
Similarly, from 1988 through 1998 there was no statistically significant trend in the annual average of
the visibility index for the mid-range days, which remained near 10 deciviews (VR 90 miles). However,
the visibility indices on the least-impaired days rose from 6 to 7 deciviews (VR from 135 to 120 miles),
showing a statistically significant trend toward greater visibility impairment.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure AZ-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Chiricahua IMPROVE Particulate Sampler
Figure AZ—3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The visibility indices for summer (VR 75 miles) were higher than the other seasons, followed by
autumn (VR 90 miles), then spring (VR 95 miles), and finally winter (VR 100 miles). No significant
seasonal trends were observed in any of the seasons over the time period from 1988 to 1998.
2-14
November 2001
-------
Individual Areas—Arizona
1988 1989 1990 1991 1992
1993
Year
1994 1995 1996 1997 1998
-Spring
-Summer -A-Autumn
-Winter
Figure AZ-3. Seasonal Deciview Averages from 1988-1998
for the Chiricahua IMPROVE Participate Sampler
Elemental
Carbon
7%
Crustal
Material
22%
Organic
Carbon
19%
Nitrate
5%
Sulfate
47%
Figure AZ-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for
the Chiricahua IMPROVE
Particulate Sampler
Figure AZ-4 presents a chart showing the calculat-
ed fractional contribution to Chiricahua's light extinc-
tion by each aerosol component on an annual basis.
Figure AZ-5 shows the same information for the four
seasons. These five pie charts show that sulfate parti-
cles were responsible for 33 to 52 percent of the light
extinction at the Chiricahua site, averaging 47 percent
on an annual basis over a five-year period. The contri-
butions from nitrates ranged from 4 to 8 percent over
the seasons, and the contributions from organic carbo'n
remained relatively constant, near 20 percent in all four
seasons. Elemental carbon measured at the Chiricahua
site was responsible for 6 to 9 percent of the calculated
aerosol light extinction in all four seasons. The contri-
butions from crustal material remained near 19 percent
in the summer, autumn, and winter, but rose to 34 per-
cent in the spring season.
November 2001
2-15
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
7%
Crustal
Material
34%
Organic
Carbon
21%
Organic
Carbon
19%
Elemental
Carbon
6%
Nitrate
4%
Nitrate
5%
Sulfate
33%
Crustal
Material
19%
Organic
Carbon
19%
Spring
Elemental
Carbon
8% Crustal
Material
18%
Nitrate
5%
Organic
Carbon
19%
Sulfate
52%
Summer
Elemental
Carbon
9%
Nitrate
8%
Crustal
Material
19%
Sulfate
50%
Autumn
Sulfate
45%
Winter
Figure AZ-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Chiricahua IMPROVE Particulate Sampler
Figure AZ-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Chiricahua site from 1988 to 1998. Over the eleven-year
period the total annual aerosol light extinction remained near 18 Mm-1 (no significant trend). No signif-
icant trends were noted in the annual light extinctions calculated for sulfates, organic carbon, elemental
carbon, or crustal material. .
2-16
November 2001
-------
Individual Areas—Arizona
* $Sp|||».i 'saltjgBijjiiSi^
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Q Sulfate GJ Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure AZ-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1994-1998 for the Chiricahua IMPROVE Particulate Sampler
Grand Canyon National Park (South Rim)
The Grand Canyon (South Rim) IMPROVE particulate sampler (GRCA) operated at the Hopi Fire
Tower from March 1988 through August 1998. This site discontinued monitoring in August 1998 after
the new Hance station was fully established at Grandview Point approximately 15 miles away. The
movement of the IMPROVE monitoring location was based on several factors. Two important reasons
(Bowman, 2000) included: 1) the transmissometer and nephelometer devices (instruments that monitor
light extinction) were set to operate at the Hance site, and 2) the Hopi Fire Tower site is close enough
to roads and Grand Canyon Village to be affected by local emission sources under certain wind condi-
tions. Because of the importance of the Grand Canyon to the Regional Haze Rule, the information
available from that site is included in this report despite the lack of a complete data set between 1994
and 1998.
Figure AZ-7 presents the calculated visibility indices for selected data sets from 1989 through 1997.
The figure shows that from 1989 through 1997 there was no statistically significant trend in the annual
average of the visibility index for the most-impaired days, which remained near 12 deciviews (VR 75
miles). From 1989 through 1997 there was no statistically significant trend in the annual average of the
visibility index for the mid-range days, which remained relatively constant near 9 deciviews (VR 100
miles). Similarly, from 1989 through 1997 there was no significant trend in the annual average of the
visibility index for the least-impaired days, which remained near 5.6 deciviews (VR 140 miles).
November 2001
2-17
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
IMpst-Impaired
SaM^ij^fetPBttf^&'gA J.Sifif ^^'^»^ii^^aastia
Vf iftfjijtt; ..... ;I!!I"S«5*™W J"iW!l': : v JS: ;;> •' '•'•' ; -Si'.'?:-.
«r
ii^a*^!*,! J
u ,, ..... J ..... , ............. « •! f >-^
- ............ . ........................... - ..... - [[[ __ ........... - ............................... , .......... Mid-Range
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure AZ-7. Yearly Deciview Averages for Most-Impaired, Mid-Range,
and Least-Impaired Days from 1989-1997 for the Grand Canyon IMPROVE Particulate Sampler
Figure AZ-8 shows the seasonal averages for the calculated visibility index from 1988 through
1998. No data were available for the Grand Canyon site from August 29, 1998 through December 31,
1998, so the autumn and whiter 1998 summary data points were not available for Figure AZ-8 or for
inclusion in the summaries of Figures AZ-9 and AZ-10. The visibility indices for all four seasons are
similar. From 1988 to 1998, the seasonal visibility indices ranged from 7 to 12 deciviews, and no sig-
-------
Individual Areas—Arizona
12 -m
am ' ......
1988 1989
1996 1997 1998
• Spring
-Summer
-Autumn
-Winter
Figure AZ-8. Seasonal Deciview Averages from 1989-1998
for the Grand Canyon IMPROVE Participate Sampler
Elemental
.Carbon
10%
Organic
Carbon
20%
Nitrate
8%
Crustal
Material
25%
Sulfate
37%
Figure AZ-9. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1997 for the Grand Canyon
IMPROVE Particulate Sampler
Figure AZ-9 presents a chart showing the calculat-
ed fractional contribution to Grand Canyon's light
extinction by each aerosol component on an annual
basis. Figure AZ-10 shows the same information for
the four seasons. These five pie charts show that sulfate
particles were responsible for 34 to 38 percent of the
light extinction at the Grand Canyon site, averaging 37
percent on an annual basis over a five-year period. The
contributions from nitrates ranged from 5 to 14 percent
over the seasons, and the contributions from organic
carbon ranged from 15 to 22 percent. Elemental carbon
measured at the Grand Canyon site was responsible for
9 to 12 percent of the calculated aerosol light extinc-
tion in all four seasons. The contributions from crustal
material represented between 22 and 30 percent of the
seasonal aerosol light extinctions.
November 2001
2-19
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
9%
Crustal
Material
30%
Organic
Carbon
19%
Nitrate
8%
Sulfate
34%
Elemental
Carbon
11%
Organic
Carbon
22%
Nitrate
5%
Crustal
Material
26%
Sulfate
36%
Spring
Summer
Elemental
Carbon
12%
Organic
Carbon
22%
Nitrate
7%
Crustal
Material
22%
Sulfate
37%
Autumn
Elemental
Carbon
Organic 9°/°
Carbon
15%
Nitrate
14%
Crustal
Material
24%
Sulfate
38%
Winter
Figure AZ-10. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Grand Canyon IMPROVE Particulate Sampler
Figure AZ-11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Grand Canyon site from 1989 to 1997, Over this period
there was no statistically significant trend toward improved visibility, despite the high value observed in
1990. No significant trends were noted in the annual light extinctions calculated for sulfates, elemental
carbon, or crustal material. However, the contributions from organic carbon to the light extinction coef-
ficient decreased over the time period due to a significant decrease in the concentrations of this
species.
2-20
November 2001
-------
Individual Areas—Arizona
1988 1989 1990 1991
1992
1993
Year
1994 1995 1996 1997 1998
a Sulfate m Nitrate D Organic Carbon D Elemental Carbon
I Crustal Material
Figure AZ-11. Contributions to Calculated Annual Aerosol Light Extinction
from 1989-1997 for the Grand Canyon IMPROVE Particulate Sampler
Grand Canyon National Park (Indian Garden)
The Grand Canyon (Indian Garden) IMPROVE participate sampler (INGA) started reporting in
October of 1989. Figure AZ—12 presents the calculated visibility indices for selected data sets from
1990 through 1998. The figure shows that from 1990 through 1998 there was no significant trend in
the annual average of the visibility index for the least-impaired days, which, remained near 6.5
deciviews (VR 130 miles). From 1990 through 1998 there was no significant trend in the annual aver-
age of the visibility index for the most-impaired days, which remained near 13 deciviews (VR 65
miles). Similarly, from 1990 through 1998 there was no significant trend in the annual average of the
visibility index for the mid-range days, which remained near 10 deciviews (VR 90 miles).
Figure AZ-13 shows the seasonal averages for the calculated visibility index from 1990 through
1998. The visibility indices for summer (VR 75 miles) were higher than the other seasons (VR 90
miles). No statistically significant seasonal trends were observed in spring, summer, or autumn over the
time period from 1990 to 1998. The summer coarse mass concentrations at the monitor site almost
tripled from 1996 to 1997, causing the elevated visibility index for summer 1997. Similarly, unusually
low sulfate concentrations were observed during the autumns of 1996 and 1997, causing depressed vis-
ibility indices for these two autumns (Figure AZ-13,) but no statistically significant trend resulted.
However, the winter indices did show a statistically significant improvement in visibility conditions
(VR rose from,90 to 105 miles).
November 2001
2-21
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
mm
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure AZ-12. Yearly Deciview Averages for Most-Impaired, Mid-Range,
and Least-Impaired Days from 1990-1998 for the Indian Garden IMPROVE Particulate Sampler
i
.2
j>
"5
0)
a
I
.a
'«
>
1988 1989 1990 1991
1992 1993 1994 1995 1996 1997
Year
1998
•Spring -*-Summer -A-Autumn
• Winter
Figure AZ-13. Seasonal Deciview Averages from 1990-1998
for the Indian Garden IMPROVE Particulate Sampler
2-22
November 2001
-------
Individual Areas—Arizona
Elemental
Carbon
10%
Crustal
Material
28%
Organic
Carbon
26%
Nitrate
6%
Sulfate
30%
Figure AZ-14. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the Indian
Garden IMPROVE Particulate Sampler
Figure AZ-14 presents a chart showing the calcu-
lated fractional contribution to Indian Garden's light
extinction by each aerosol component on an annual
basis. Figure AZ-15 shows the same information for
the four seasons. These five pie charts show that sulfate
particles were responsible for 27 to 35 percent of the
light extinction at the Indian Garden site, averaging 30
percent on an annual basis over a five-year period. The
contributions from nitrates ranged from 4 to 10 percent
over the seasons, and the contributions from organic
carbon remained relatively constant, between 24 and 29
percent in all four seasons. Elemental carbon measured
at the Indian Garden site was responsible for 9 to 12
percent of the calculated aerosol light extinction in all
four seasons. The contributions from crustal material
remained near 32 percent in the spring and summer,
but then dropped to 25 percent in autumn and 20 per-
cent in the winter.
Elemental
Carbon
9%
Crustal
Material
31%
Organic
Carbon
26%
Organic
Carbon
29%
Nitrate
6%
Spring
Elemental
Carbon
12%
Sulfate
28%
Crustal
Material
25%
Nitrate
6%
Autumn
Sulfate
28%
Elemental
Carbon
9%
Crustal
Material
32%
Organic
Carbon
28%
Organic
Carbon
24%
Nitrate
10%
Nitrate
4%
Summer
Elemental
Carbon
11%
Sulfate
27%
Crustal
Material
20%
Sulfate
35%
Winter
Figure AZ-15. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Indian Garden IMPROVE Particulate Sampler
November 2001
2-23
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Figure AZ-16 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Indian Garden site from 1990 to 1998. Over the nine-
year period, the total annual aerosol light extinctions remained near 18 Mm-1 (no significant trend). No
significant trends were noted in the annual light extinctions calculated for organic carbon, elemental
carbon, or crustal material. The sulfates showed significant decreases in their contribution to the light
extinction coefficients, indicating lower ambient concentrations.
-i— —i—"——J—i
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
HSulfate El Nitrate D Organic Carbon D Elemental Carbon Bl Crustal Material
Figure AZ-16. Contributions to Calculated Annual Aerosol Light Extinction
from 1990-1998 for the Indian Garden IMPROVE Particulate Sampler
Petrified Forest National Park
The Petrified Forest IMPROVE participate sampler started reporting in March of 1988. Figure
AZ-17 presents the calculated visibility indices for selected data sets from 1988 through 1998. From
1990 through 1993 there was a decreasing trend in the annual average of the visibility index for the mid-
range days, which dropped from 11 to 9.5 deciviews (VR from 80 to 95 miles). However, the trend did
not continue long enough to be considered statistically significant. From 1990 through 1993 there
appears to be a trend toward improved visibility in the annual average of the visibility index for the least-
impaired days, but this drop from values greater than 8 deciviews to 7 deciviews in the late 1990s did
not qualify as statistically significant because the downward trend did not continue after 1993. Similarly,
the drop from 14 to 13 deciviews on the most-impaired days (Figure AZ-17) was not statistically signifi-
cant because the trend did not continue.
Figure AZ-18 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The seasonal visibility indices were not discernibly higher in one season than the others. The
2-24
November 2001
-------
Individual Areas—Arizona
^
_
^^?^*™™**"^*~*a!pWM¥*-«'™te-'«™E ^^~;;^si^?aiHK»««a^it,ii^ «*
^ ^
—^ ,, --•-• ., .. -- - .
._Sia^|g«*Sta«»»»
~'*'"'*'
Most-Impaired
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure AZ-17. Yearly Deciview Averages for Most-Impaired, Mid-Range,
and Least-Impaired Days from 1988-1998 for the Petrified Forest
IMPROVE Participate Sampler
CO
I
>
"o
B
X
0)
•a
>• 10
'«
>
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
Year
1998
-Spring -•-Summer -A-Autumn
- Winter
Figure AZ-18. Seasonal Deciview Averages from 1988-1998 for
the Petrified Forest IMPROVE Particulate Sampler
November 2001
2-25
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
14%
Organic
Carbon
25%
Nitrate
7%
Crustal
Material
19%
Sulfate
35%
Figure AZ-19. Contribution
to Calculated Annual Aerosol
Light Extinction from 1994-1998
for the Petrified Forest IMPROVE
Particulate Sampler
Elemental
Carbon
12%
Crustal
Material
27%
Organic
Carbon
26%
Nitrate
6%
Sulfate
29%
Spring
Elemental
Carbon
15%
Organic
Carbon
26%
Nitrate
6%
Crustal
Material
17%
Sulfate
36%
Autumn
winter and summer seasons showed statistically signifi-
cant trends toward lower visibility indices, indicating
improvements in visibility of approximately 2.3 and 1.5
deciviews. The indices for the spring and autumn did
not show statistically significant trends toward
improved visibility.
Figure AZ—19 presents a chart showing the calculat-
ed fractional contribution to the Petrified Forest's light
extinction by each aerosol component on an annual
basis. Figure AZ-20 shows the same information for
the four seasons. These five pie charts show that sulfate
particles were responsible for 29 to 41 percent of the
light extinction at the Petrified Forest site, averaging 35
percent on an annual basis over a-five-year period. The
contributions from nitrates ranged from 5 to 10 percent
over the seasons, and the contributions from organic
carbon remained relatively constant, between 23 and 26
percent. Elemental carbon measured at the Petrified
Elemental
Carbon
11%
Organic
Carbon
24%
Nitrate
5%
Crustal
Material
19%
Sulfate
41%
Summer
Organic
Carbon
23%
Nitrate'
10%
Elemental
Carbon
16%
Crustal
Material
14%
Sulfate
37%
Winter
Figure AZ-20. Contribution to Calculated Annual Aerosol Light Extinction
from 1994-1998 for the Petrified Forest IMPROVE Particulate Sampler
2-26
November 2001
-------
Individual Areas—Arizona
Forest site was responsible for 11 to 16 percent of the calculated aerosol light extinction in all four sea-
sons. The contributions from crustal material were near 27 percent in the spring but then dropped in the
subsequent seasons to 19, 17, arid 14 percent in summer, autumn, and winter.
Figure AZ—21 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Petrified Forest site from 1988 to 1998. Over the eleven-
year period, there was a significant decreasing trend in the total annual aerosol light extinction from
approximately 20 to 17 Mm-1, indicating improved visibility. No significant trends were noted in the
annual light extinctions calculated for sulfates or crustal material. However, the organic and elemental
carbons showed significant decreases in their contribution to the light extinction coefficients, indicating
lower ambient concentrations.
1988 1989 1990
1994 1995 1996 1997 1998
Q Sulfate
Q Nitrate
-i r
1991 1992 1993
Year
O Organic Carbon D Elemental Carbon • CrustaP Material
Figure AZ-21. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for Petrified Forest IMPROVE Particulate Sampler
Tonto National Monument
The Tonto IMPROVE particulate sampler started reporting in April of 1988. Figure AZ-22 presents
the calculated visibility indices for selected data sets from 1988 through 1998. The figure shows that
between 1988 and 1998 there was no significant trend in the annual average of the visibility index for
the most-impaired days, which remained constant near 14 deciviews (VR 60 miles). From 1988 to 1998
there was no statistically significant trend toward improved visibility in the annual average of the visibil-
ity index for the mid-range days, which remained near 11 deciviews (VR 80 miles). Similarly, from 1988
to 1998 there was no statistically significant trend toward improved visibility in the annual average of
the visibility index for the least-impaired days, which remained near 7.7 deciviews (VR 110.miles).
November 2001
2-27
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
^'^^"^iSl^syfBiii^y^^^^fy^. !«' » **t**^^*!!3{KJ?'S'V ~ "-1 - "--;d;;i:S ^^^Sfij^'^jt*:
S
•n
12
Sii
a
fe feTTiT-'iBjipf'11- ';:iFi"y?;^""i'''''a^
(!) HE ST^t^STTTSSBF ! ! K~~ ~~~"~"i~3~
••; . ,. BK'jfcr-asaai T5»"j;:5:5;>--gs;»;:s:;BCT^
.2 14
p
* 10
Mid-Range
'55
Least-Impaired
H 1
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure AZ-22. Yearly Deciview Averages for Most-Impaired, Mid-Range,
and Least-Impaired Days from 1988-1998 for the Tonto IMPROVE Participate Sampler
Figure AZ—23 shows the seasonal averages for the calculated visibility index from 1988 through
1998. Coarse mass was not measured at this site between July 8, 1992 and December 2, 1992, and
therefore, no autumn 1992 value was calculated. Interested readers can view the data for other species
at http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi. No significant seasonal trends were observed
in the spring, summer, or autumn from 1988 to 1998. However, the winter season showed a statistically
significant trend toward lower visibility indices, indicating an improvement in visibility of more than 1
deciview.
2-28
November 2001
-------
Individual Areas—Arizona
14
S
0)
o
0)
I
_c
I*
'55
>
-I - 1 - 1 - 1 - 1 - 1 - 1 - 1 - : — r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Spring -H-Summer
Winter
Figure AZ-23. Seasonal DecSview Averages from 1988-1998 for the Tonto IMPROVE
Paniculate Sampler
Elemental
Carbon
12%
Crustal
Material
26%
Organic
Carbon
25%
Nitrate
7%
Sulfate
30%
Figure AZ-24. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Tonto IMPROVE
Particulate Sampler
Figure AZ-24 presents a chart showing the calcu-
lated fractional contribution to Tonto's light extinction
by each aerosol component on an annual basis. Figure
AZ-25 shows the same information for the four sea-
sons. These five pie charts show that sulfate particles
were responsible for 25 to 35 percent of the light
extinction at the Tonto site, averaging 30 percent on an
annual basis over a five-year period. The contributions
from nitrates were near 6 percent in spring, summer,
and autumn, but rose to 11 percent in the winter. The
contributions from organic carbon remained relatively
constant, between 23 and 28 percent in all four sea-
sons. Elemental carbon measured at the Tonto
National Monument site was responsible for 10 per-
cent of the calculated aerosol light extinction in spring
and summer, but rose to approximately 14 percent in
the autumn and winter. The contributions from crustal
material were near 32 percent in the spring but then
dropped in the subsequent seasons to 26, 24, and 20
percent in summer, autumn, and winter.
November 2001
2-29
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
11%
Organic
Carbon
26%
Crustal
Material
31%
Elemental
Carbon
10%
Organic
Carbon
23%
Nitrate
7%
Spring
Sulfate
25%
Nitrate
6%
Crustal
Material
26%
Sulfate
35%
Summer
Elemental
Carbon
13%
Crustal
Material
24%
Organic
Carbon
28%
Elemental
Carbon
15%
Organic
Carbon
25%
Nitrate
6%
Sulfate
29%
Crustal
Material
20%
Nitrate
11%
Sulfate
29%
Winter
Autumn
Figure AZ-25. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Tonto IMPROVE Particulate Sampler
Figure AZ-26 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Tonto National Monument site from 1988 to 1998. Over
the eleven-year period, there was a statistically significant decreasing trend in the total annual aerosol
light extinctions from approximately 22 to 20 Mm-1, indicating improved visibility. No significant
trends were noted in the annual light extinctions calculated for organic carbon, elemental carbon, or
crustal material. However, the sulfates showed statistically significant decreases in their contribution to
the light extinction coefficients, indicating lower ambient concentrations.
2-30
November 2001
-------
Individual Areas—Arizona
0 H—m^—i—L—'—i—' '—r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
BSulfate m Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure AZ-26. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Tonto IMPROVE Particulate Sampler
Arizona State Summary
The calculated annual average aerosol extinction coefficients at Arizona's IMPROVE monitoring
sites are presented in Table AZ-1. The calculated total aerosol extinction coefficients at all five sites
were within 20 percent of the average (17.6 Mm-1), indicating similar annual visibility conditions at all
sites. The extinction coefficients for the individual species were also similar at the different sites. All
five sites also showed similar rankings for contributions of the species to light extinction: sulfate, fol-
lowed by organic carbon and crustal material, then elemental carbon, and lastly nitrate. The same rank-
ings were observed for the Colorado, Texas, and Wyoming sites in Tables CO-1, TX-1, and WY-1.
Table AZ-1. Arizona Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Chiricahua NM
Grand Canyon NP (GRCA)
Grand Canyon NP (INGA)
Petrified Forest NP
Tonto NM
Average
Calculated Total
Aerosol Extinction
Coefficient (Mm"1)
18.5
14.4
18.3
16.6
20.1
17.6 ±2.2 .
Pollutant Extinction Coefficient (Mm-1)
Sulfate
8.4
5.5 ,
5.6
6.1
. 6.1
6.3 ± 1.2
Nitrate
0.9
1.1
1.1
1.1
1.4
1.1 ±0.2
Organic
Carbon
3.6
2.8
4.8
4.1
5.1
4.1 ±0.9
Elemental
Carbon
1.4
1.4
1.8
2:3
2.4
1.8 ±0.5
Crustal
Material
4.1
3.6
5.1
3.1
5.2
4.2 ± 0.9
November 2001
2-31
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
4. ARKANSAS
The only IMPROVE monitoring site in Arkansas that operated continuously from 1994 through
1998 was located near the Upper Buffalo Wilderness Area. Figure AR-1 shows the Upper Buffalo
monitor location (35.83°N, 93.21°W, elevation 2360 feet) near the wilderness area in northern
Arkansas. The Caney Creek Wilderness Area is also designated as a mandatory Federal Class I area
covered by the Regional Haze Rule, but no IMPROVE particulate sampler has been installed at this
site.
Upper Buffalo Wilderness
Fayetteville
Fort Smith
Upper Buffalo
IMPROVE Monitor
* Little Rock
Caney Creek Wilderness
50
•?=
miles
100
Figure AR-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Arkansas
Upper Buffalo Wilderness Area
The Upper Buffalo IMPROVE particulate sampler started reporting in December of 1991. Figure
AR-2 presents the calculated visibility indices for selected data sets in 1992 through 1998. The figure
shows that from 1992 through 1998 there was no significant trend in the annual average of the visibili-
ty index for the most-impaired days, which remained near 27 deciviews (VR 16 miles). From 1992
through 1998, there was no significant trend in the annual average of the visibility index for the mid-
range days, which remained relatively constant near 20 deciviews (VR 33 miles). Similarly, the annual
average of the visibility index for the least-impaired days showed no significant trend in the visibility
index of 13.5 deciviews (VR 65 miles).
Figure AR-3 shows the seasonal averages for the calculated visibility index from 1992 through
1998. Coarse mass data for spring 1992 was not reported. Therefore, no spring 1992 value is reflected
in Figure AR-3. Interested readers should consult http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi
2-32
November 2001
-------
Individual Areas—Arkansas
I 22
x
Q)
T5
•£ 18
ft
'55
> 14
Most-impaired
Mid-Range
Least-Impaired
-10 -I 1 1 1 1 1 i 1 1 i 1
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure AR-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1992-1998 for the Upper Buffalo IMPROVE Particulate Sampler
-i 1 1 1 r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-Spring -»-Summer -A-Autumn
-Winter
Figure AR-3. Seasonal Deeiview Averages from 1992-1998 for
the Upper Buffalo IMPROVE Particulate Sampler
November 2001
2-33
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress .
Nitrate
12%
Organic
Carbon
14% Elemental
Carbon
5%
Crustal
Material
6%
Sulfate
63%
Figure AR-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Upper Buffalo
IMPROVE Parficulate Sampler
Nitrate
13%
Organic
Carbon
14%
Elemental
Carbon
5%
Crustal
Material
7%
Sulfate
61%
Nitrate
13%
Spring
Organic
Carbon
14%
Elemental
Carbon
6%
Crustal
Material
5%
Sulfate
62%
Autumn
for additional data. The average visibility indices for
summer were 3 to 8 deciviews higher than those during
the autumn, winter, and spring. No statistically signifi-
cant seasonal trends were observed in the calculated
visibility indices over this time period for any of the
seasons.
Figure AR-4 presents a chart showing the calculat-
ed fractional contribution to Upper Buffalo's light
extinction by each aerosol component on an annual
basis. Figure AR-5 shows the same information for the
four seasons. These five pie charts show that sulfate
particles were responsible for 55 to 70 percent of the
light extinction at the Upper Buffalo site, averaging 63
percent on an annual basis over a five-year period. The
highest sulfate contributions occurred in the summer
and the lowest in the winter. The contributions from
nitrates were 13, 9, 13, and 19 percent for the spring,
summer, autumn, and winter, averaging just 12 percent
Organic
Carbon
12% Elemental
Carbon
3%
Crustal
Material
6%
Sulfate
70%
Nitrate
19%
Summer
Organic
Carbon
13%
Elemental
Carbon
7%
Crustal
Material
6%
Sulfate
55%
Winter
Figure AR-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Upper Buffalo IMPROVE Particulate Sampler
2-34
November 2001
-------
Individual Areas—Arkansas
on an annual basis. The contributions from organic carbon ranged from 12 to 14 percent during the
four seasons. Annually, elemental carbon and crustal material measured at the Upper Buffalo site were
responsible for approximately 5 and 6 percent of the calculated aerosol light extinction.
Figure AR-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Upper Buffalo site from 1992 to 1998. Over the seven-
year period, the total annual aerosol light extinctions remained between 63 and 80 Mm-1 (no significant
trend). No significant trends were noted in the annual light extinctions calculated for sulfates, organic
carbon, or elemental carbon. However, the crustal material showed statistically significant decreases in
its annual contribution to the light extinction coefficients, indicating lower ambient concentrations.
o
uu
H-»
o
W
Q
o>
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
QSulfate O Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure AR-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998
for the Upper Buffalo IMPROVE Particulate Sampler
November 2001
2-35
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
5. CALIFORNIA
The following seven IMPROVE participate samplers in California operated continuously from
1994 through 1998:
Lassen Volcanic National Park (40.53°N, 121.57°W, elevation 5900 feet),
Pinnacles National Monument (36.49°N, 121.21°W, elevation 1040 feet),
Point Reyes Wilderness Area (38.12°N, 122.91°W, elevation 125 feet),
Redwood National Park (41.69°N, 124.09°W, elevation 7.60 feet),
San Gorgonio Wilderness Area (34.19°N, 116.91°W, elevation 5618 feet),
Sequoia National Park (36.52°N, 118.18°W, elevation 1800 feet), and
Yosemite National Park (37.71°N, 119.70°W, elevation 5300 feet).
The IMPROVE particulate sampler at Sequoia National Park began data collection on March 4,
1992, but no summary data was provided before 1995. Since the criteria for sites to be included in this
report was a complete data set from 1994 through 1998, .the data for Sequoia National Park will not be
presented in this chapter of the report. However, this site is important when examining state, regional,
and national trends so it will be included in discussions about groups of sites.
The National Park Service also operates a monitor in Death Valley under the IMPROVE protocol,
but Death Valley National Monument is not a mandatory Federal Class I area and is not discussed in
this report. Figure CA—1 shows the IMPROVE particulate sampler locations in the mandatory Federal
Class I areas across the state. In addition, the following areas are designated as mandatory Federal
Class I areas covered by the Regional Haze Rule but did not have an IMPROVE particulate sampler
operating from 1994 through 1998:
Agua Tibia Wilderness Area,
Caribou Wilderness Area,
Cucamonga Wilderness Area,
Desolation Wilderness Area,
Dome Land Wilderness Area,
Emigrant Wilderness Area,
Hoover Wilderness Area,
John Muir Wilderness Area,
Joshua Tree Wilderness Area,
Kaiser Wilderness Area,
Kings Canyon National Park,
Lava Beds Wilderness Area,
Marble Mountain Wilderness Area,
Minarets Wilderness Area,
Mokelumne Wilderness Area,
San Gabriel Wilderness Area,
San Jacinto Wilderness Area,
San Rafael Wilderness Area,
South Warner Wilderness Area,
Thousand Lakes Wilderness Area,
Ventana Wilderness Area, and
Yolla Bolly-Middle Eel Wilderness Area.
2-36
November 2001
-------
Individual Areas—California
Marble Mountain Wilderness
Redwood IMPROVE Monitor
Redwood National Park
Lassen Volcanic
IMPROVE Monitor
Lassen Volcanic.
National Park
Yolla Bolly-Middle'Eei
Wilderness
Point Reyes
IMPROVE MonitOi
Point Reyes Wilderness
Pinnacles IMPROVE Monitor
Pinnacles Wilderness
Ventana Wilderness
San Rafael Wilderness
San Gabriel Wilderness
Cucamonga Wilderness
Lava Beds Wilderness
.South Warner Wilderness
-Thousand Lakes Wilderness
—Caribou Wilderness
Mokelumne Wilderness
Desolation
Wilderness
Dome Land
Wilderness
Emigrant Wilderness
Hoover Wilderness
-Yosemite National Park
Yosemite IMPROVE Monitor
Minarets Wilderness
"John Muir Wilderness
Kings Canyon National Park
Sequoia IMPROVE Monitor
iequoia National Park
'Joshua Tree Wilderness
-—•—.
San Jacinto Wilderness
San Gorgonio
IMPROVE Monitor
San Gorgonio Wilderness
0
150
miles
Agua Tibia Wilderness
300
Figure CA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in California
November 2001
2-37
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Lassen Volcanic National Park
The Lassen Volcanic IMPROVE participate sampler started reporting in March of 1988. Figure
CA-2 presents the calculated visibility indices at Lassen Volcanic National Park for selected data sets
from 1988 through 1998. The figure shows that from 1988 through 1998 there was no significant trend
in the annual average of the visibility index for the most-impaired days, which remained between 12
and 15.3 deciviews (VR 75 to 55 miles). From 1988 through 1998 there was no statistically significant
trend indicating improved visibility in the annual average of the visibility index for the mid-range days,
which remained near 8 or 9 deciviews (VR 110 or 100 miles) through 1997 and then rose to 10
deciviews in 1998. The 1998 rise was attributed to an increase in organic carbon and elemental carbon
concentrations, a common effect during fire episodes. For example, the total carbon concentration
measured on October 10, 1998 rose over eight times its average value; Lassen Volcanic Park personnel
(Arnold, 2000) confirmed prescribed burning activities a few miles from the monitor site during the
first full week in October 1998, The annual average of the visibility index for the least-impaired days
remained near 4.5 deciviews (VR 155 miles), indicating no statistically significant trend toward
improved visibility on the least-impaired days.
ffiS?l^MiW!^yH?H^f!?'?^ 'L^l:^ ?'^j^3w:
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CA-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Lassen Volcanic IMPROVE Participate Sampler
Figure CA-3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices for summer were 2 to 4 deciviews higher than those during the
spring and autumn, and the visibility indices for the spring and autumn were 1 to 3 deciviews above the
indices for winter. No significant seasonal trends were observed in the calculated visibility indices over
this time period for the spring, summer, or autumn. However, the winter indices decreased 2 deciviews
with a statistically significant trend, indicating improved visibility during that season.
2-38
November 200-1
-------
Individual Areas—California
1988 1989
1996 1997 1998
- Spring
-Summer
-Autumn
-Winter
Figure CA-3. Seasonal Deciview Averages from 1988-1998
for the Lassen Volcanic IMPROVE Paniculate Sampler
Organic
Carbon
35%
Elemental
Carbon
12%
Crustal
Material
13%
Nitrate
9%
Sulfate
31%
Figure CA-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Lassen Volcanic
IMPROVE Particulate Sampler
Figure CA-4 presents a chart showing the calcu-
lated fractional contribution to Lassen Volcanic
National Park's light extinction by each aerosol
species on an annual basis. Figure CA-5 shows the
same information for the four seasons. These five pie
charts show that sulfate particles were responsible for
20 to 43 percent of the light extinction at the site,
averaging 31 percent on an annual basis over a five-
year period. The highest sulfate contributions
occurred in the summer and the lowest in the winter.
The contributions from nitrates were between 7 and
18 percent over the four seasons. The contributions
from organic carbon ranged from 28 to 45 percent
during the four seasons, with the highest percentages
occurring in the autumn and winter. Annually, ele-
mental carbon measured at the Lassen Volcanic site
• was responsible for 9 to 15 percent of the calculated
aerosol light extinction. Crustal material contributions
to the light extinction coefficient varied from 11 to 16
percent in the four seasons.
Figure CA-6 shows the calculated contributions
of each of the aerosol mass components to the annual
November 2001
2-39
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
31%
Elemental
Carbon
10%
Nitrate
9%
Crustal
Material
15%
Organic
Carbon
20%
Elemental
Carbon
8%
Nitrate
17%
Sulfate
35%
Crustal
Material
18%
Sulfate
37%
Spring
Summer
Elemental
Carbon
15%
Organic
Carbon
45%
Elemental
Carbon
12%
Nitrate
7%
' Crustal
Material
11%
Sulfate
22%
Organic
Carbon
34%
Crustal
Material
16%
Sulfate
20%
Nitrate
18%
Autumn Winter
Figure CA-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Lassen Volcanic IMPROVE Particulate Sampler
average aerosol light extinctions at the Lassen Volcanic site from 1988 to 1998. Statistical analysis
shows that over the eleven-year period there was no statistically significant trend in the total annual
aerosol light extinctions. The extinction coefficients ranged from 12 to 18 Mm"1. Ignoring the 1998
value (when nearby fires affected the visibility impairment in October), the total annual aerosol light
extinction decreased from 17 to 13 Mm"1, indicating a significant trend toward improved visibility. No
significant trends were noted in the annual light extinctions calculated for sulfates, organic carbon, or
elemental carbon. However, the crustal material showed statistically significant decreases in its annual
contribution to the light extinction coefficients, indicating lower ambient concentrations.
2-40
November 2001
-------
Individual Areas—California
-i—""—-1—r
1988 1989 1990 1991
n Sulfate
a Nitrate
1992 1993 1994 1995 1996 1997 1998
Year
D Organic Carbon D Elemental Carbon • Crustal Material
Figure CA-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Lassen Volcanic IMPROVE Participate Sampler
Pinnacles National Monument
The Pinnacles IMPROVE participate sampler started reporting in March of 1988. Figure CA-7
presents the calculated visibility indices at Pinnacles National Monument for selected data sets from
1988 through 1998. The figure shows that from 1988 through 1998 there was a significant trend indi-
cating improved visibility in the annual average of the visibility index for the most-impaired days,
which dropped from a high of 19.5 deciviews in 1989 to 17.5 deciviews in 1998 (VR from 35 to 40
miles). From 1988 through 1998 there was a significant trend indicating improved visibility in the
annual average of the visibility index for the mid-range days, which decreased from 15 (VR 55 miles)
to 13 deciviews (VR 65 miles). Similarly, the annual average of the visibility index for the least-
impaired days decreased from 10 to 9 deciviews (VR from 90 to 100 miles), indicating a significant
improvement in visibility on the least-impaired days.
Figure CA-8 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices were similar during all four seasons. The indices for winter
dropped 3 deciviews. The statistically significant seasonal trend indicates significant improvements in
visibility occurred. Even though the indices for spring, summer, and autumn decreased from 1 to 1.4
deciviews over all years, the drops were not uniform enough to be judged statistically significant
trends.
November 2001
2-41
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to-Congress
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CA-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Pinnacles IMPROVE Participate Sampler
! i] 1 wlfKi:'j"'Irfjf ™i|pft^,i'Fi jf*jfo*17"jwTfifit""''^"S^ ?' ^ ^'"'tn?^""'" |fiy|f!''^ffi **"^v^";"^
"" |F * ...... ""ir"" ''frvrtff^'wirtM tf"v«"w» "tj fur? W'av.?fl^av^
..... !r5iii!"™i!!!i!i!iSi^l»5il!SSiiiili»
. . , ,,
•iriil ..... iirriii'iiiiiiipiii'iiii1! ...... vidVw ..... !r5iii!"™i!!!i!i!iSi^l»5ili!SSiiiipli»^
"ii; ...... s™ ,MI,s.:iii,iii!ii; ;e:i, •* j™ • j; * aaJiiaji^s :;;:.: S^g:^:;::'-;:; tfciillili! ittsid;!, Jiatlji^^ ' i:::; :;f i-i;;ii*« ,;; ;,,:i ;; .iaWfc i;X . : .aja^*: £; ;„ ,:„ .i; ;,,a
1988 1989
1997 1998
-Spring
-Summer -A-Autumn
-Winter
Figure CA-8. Seasonal Deciview Averages from 1988-1998
for the Pinnacles IMPROVE Particulate Sampler
2-42
November 2001
-------
Individual Areas—California
Organic
Carbon
' 23%
Elemental
Carbon
11%
Nitrate
21%
Crustal
Material
15%
Sulfate
30%
Figure CA-9. Contribution to Calculated
Annual Aerosol Light Extinction Averaged
from 1994-1998 for the Pinnacles
IMPROVE Particulate Sampler
Organic
Carbon
21%
Elemental
Carbon
10%
Crustal
Material
13%
Nitrate
23%
Sulfate
33%
Spring
Elemental
Carbon
15%
Organic
Carbon
26%
Crustal
Material
18%
Nitrate
17%
Sulfate
24%
Autumn
Figure CA-9 presents a chart showing the calcu-
lated fractional contribution to Pinnacle's light
extinction by each aerosol component on an annual
basis. Figure CA—10 shows the same information
for the four seasons. These five pie charts show that
sulfate particles were responsible for 22 to 37 per-
cent of the light extinction at the site, averaging 30 .
percent on an annual basis over a five-year period.
The highest sulfate contributions occurred in the
summer and the lowest in the winter. The contribu-
tions from nitrates ranged between 17 and 30 per-
cent, with the highest percentages observed in the
winter. The contributions from organic carbon
ranged from 20 to 26 percent during the four sea-
sons, averaging 23 percent. Seasonally, elemental
carbon measured at the Pinnacles site was responsi-
ble for 8 to 15 percent of the calculated aerosol light
extinction. Crustal material contributions to the light
extinction coefficient varied from 11 to 18 percent
in the four seasons.
Organic
Carbon
20%
Elemental
Carbon
8%
Nitrate
17%
Crustal
Material
18%
Sulfate
37%
Summer
Organic
Carbon
24%
Elemental
Carbon
13%
Nitrate
30%
Crustal
Material
11%
Sulfate
22%
Winter
Figure CA-10. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Pinnacles IMPROVE Particulate Sampler
November 2001
2-43
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Figure CA—11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Pinnacles site from 1988 to 1998. Over the eleven-year
period, there was a statistically significant trend in the total annual aerosol light from approximately 36
to 30 Mm"1, indicating improved visibility. The sulfate and crustal material aerosol species also showed
significant decreases in their contributions to the annual light extinction coefficients. However, the
decreases in organic and elemental carbon light extinction were not statistically significant.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
B Sulfate a Nitrate D Organic Carbon D Elemental Carbon " II Crustal Material
Figure CA-11. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Pinnacles IMPROVE Particulate Sampler
2-44
November 2001
-------
Individual Areas—California
Point Reyes Wilderness
The Point Reyes IMPROVE particulate sampler started reporting in March of 1988. Figure CA-12
presents the calculated visibility indices at Point Reyes National Seashore for selected data sets in 1988
through 1998. The figure shows that from 1988 through 1998 there was no significant trend in the
annual average of the visibility index for the most-impaired days, which remained near 22 deciviews
(VR 27 miles). From 1988 through 1998 there was no significant trend indicating improved visibility in
the annual average of the visibility index for the mid-range days, despite the decrease from 16 (VR 50
miles) to 15 deciviews (VR 55 miles). The annual average of the visibility index for the least-impaired
days remained near 12 deciviews (VR 75 miles) over the eleven-year period.
CO
>
12
10
Least-Impaired
H 1 1—
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CA-12. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Point Reyes IMPROVE Particulate Sampler
Figure CA—13 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices spanned similar ranges during spring, autumn, and winter, all the
values typically 2 to 4 deciviews lower than summer values. The visibility indices for winter showed a
statistically significant trend toward improved visibility (2.5-deciview improvement over 11 years). The
visibility indices for spring, summer, and autumn showed no statistically significant trends over the
eleven-year period, despite the decreases in the deciview indices for spring and autumn.
November 2001
2-45
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
«
-1 1 1 1 1 1 1 1 1 T
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-*-Spring -•-Summer -±-Autumn -•-Winter
Figure CA-13. Seasonal Deciview Averages from 1988-1998 for the
Point Reyes IMPROVE Particulate Sampler
Nitrate
25%
Organic
Carbon
11%
Elemental
Carbon
3%
Crustal
Material
12%
Sulfate
49%
Figure CA-14. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998
for the Point Reyes
IMPROVE Particulate Sampler
Figure CA—14 presents a chart showing the calculated
fractional contribution to Point Reyes' light extinction by
each aerosol species on an annual basis. Figure CA—15
shows the same information for the four seasons. These
five pie charts show that sulfate particles were responsible
for 35 to 63 percent of the light extinction at the site, aver-
aging 49 percent on an annual basis over a five-year peri-
od. The highest sulfate contributions occurred in the sum-
mer and the lowest in the winter. The contributions from
nitrates ranged between 23 and 27 percent. The contribu-
tions from organic carbon ranged from 5 to 18 percent dur-
ing the four seasons, averaging 11 percent. Annually, ele-
mental carbon measured at the Point Reyes site was
responsible for just 1 to 7 percent of the calculated aerosol
light extinction. Crustal material contributions to the light
extinction coefficient varied from 8 to 15 percent in the
four seasons.
2-46
November 2001
-------
Individual Areas—California
Nitrate
27%
Sulfate
47%
Spring
Elemental
Carbon
3%
Crustal
Material
15%
Organic
Carbon Elemental
1 5% Carbon
Nitrate
24%
Crustal
Material
14%
Nitrate
23%
Organic
Carbon
5%
Elemental
Carbon
1%
Crustal
Material
8%
Sulfate
63%
Summer
Organic
Carbon
18%
Elemental
Carbon
7%
Crustal
Material
14%
Nitrate
26%
Sulfate
43%
Sulfate
35%
Autumn
Winter
Figure CA-15. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Point Reyes IMPROVE Particulate Sampler
Figure CA-16 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Point Reyes site from 1988 to 1998. Over the eleven-
year period,-there was a significant trend in the total annual aerosol light extinctions, decreasing
approximately 6 Mm"1, indicating improved visibility. The sulfate and organic carbon light extinction
coefficients did not change significantly during the eleven-year period. The other aerosol species (ele-
mental carbon and crustal material) showed significant decreases in their contributions to the annual
light extinction coefficients.
November 2001
2-47
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 . 1998
Year
BSulfate H Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure CA-16. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Point Reyes IMPROVE Particulate Sampler
Redwood National Park
The Redwood IMPROVE particulate sampler started reporting in March of 1988. Figure CA-17
presents the calculated visibility indices at Redwood National Park for selected data sets from 1988
through 1998. The figure shows that from 1988 through 1998 there was a significant trend indicating
improved visibility hi the annual average of the visibility index for the most-impaired days, which
decreased from approximately 23 to 21 deciviews (VR from 24 to 30 miles). From 1988 through 1998
there was no significant trend indicating unproved visibility in the annual average of the visibility
index for the mid-range days, which remained near 16 deciviews (VR 50 miles). Similarly, the annual
average of the visibility index for the least-impaired days remained near 9 deciviews (VR from 100
miles), with no statistically significant trend.
Figure CA-18 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices are discernibly lower (better visibility) in winter than in the other
three seasons. The indices for spring and summer remained relatively constant over the eleven-year
period. The indices for autumn dropped 2 deciviews, with a statistically significant trend indicating
improved visibility. The indices for winter dropped nearly 3 deciviews over this period and also repre-
sented a statistically significant trend toward improved visibility.
2-48
November 2001
-------
Individual Areas—California
1
_
I 16
I
.0
'55
> 8
Mid-Range
Least-Impaired
4-
4-
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year .
Figure CA-17. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Redwood IMPROVE Particulate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-*-Spring -»-Summer -A-Autumn -•-Winter
Figure CA-18. Seasonal Deciview Averages from 1988-1998 for the
Redwood IMPROVE Particulate Sampler
November 2001
2-49
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate
19%
Organic
Carbon
10% Elemental
Carbon
2%
Crustal
Material
8%
Sulfate
61%
Figure CA-19. Contribution to Calculated
Annual Aerosol Light Extinction
from 1994-1998 for the
Redwood IMPROVE Particulate Sampler
Nitrate
18%
Organic
Carbon
8% Elemental
Carbon
2%
Crustal
Material
10%
Sulfate
62%
Spring
Nitrate
18%
Organic
Carbon
17%
Elemental'
Carbon
4%
Crustal
Material
8%
Sulfate
53%
Autumn
Figure CA-19 presents a chart showing the cal-
culated fractional contribution to Redwood's light
extinction by each aerosol species on an annual
basis. Figure CA-20 shows the same information
for the four seasons. Since the winter light extinc-
tion coefficients were less than half those in the
other seasons, the annual averages presented in
Figure CA-19 appear weighted to the spring, sum-
mer, and autumn readings shown hi Figure CA—20.
These five pie charts show that sulfate particles
were responsible for 40 to 67 percent of the light
extinction at the site, averaging 61 percent on an
annual basis over a five-year period. The highest
sulfate contributions occurred in the summer and
the lowest in the winter. The contributions from
nitrates ranged from 13 to 29 percent. The contri-
butions from organic carbon ranged from 8 to 17
percent during the four seasons, averaging 10 per-
cent. Seasonally, elemental carbon measured at the
Nitrate Or9anic
13% Carbon
Elemental
Carbon
•2%
Crustal
Material
9%
Sulfate
67%
Summer
Organic
Carbon
12%
Nitrate
29%
Elemental
Carbon
4%
Crustal
Material
15%
Sulfate
40%
Winter
Figure CA-20. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Redwood IMPROVE Particulate Sampler
2-^0
November 2001
-------
Individual Areas—California
Redwood site was responsible for just 2 to 4 percent of the calculated aerosol light extinction. Crustal
material contributions to the light extinction coefficient varied from 8 to 15 percent in the four seasons,
with the winter contribution being the highest.
Figure CA-21 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Redwood site from 1988 to 1998. Over the eleven-year
period, there was a significant trend in the total annual aerosol light extinctions from 48 to 39.
Mm", indicating improved visibility. The sulfates and crustal material extinction coefficients did not
show significant trends over this time period. The organic and elemental carbon aerosol species showed
significant decreases in their contributions to the annual light extinction coefficients.
'- iY"'i!v-" "-,v-*~- v -'"'' ,/ •-,f-' - - ""-. '^:
^=^^
w-'Wg!S^:'?g&f^>j^if!i^:^^
S!S§fsd!iKS&«;^«f™ *»«»^
0
T — 1 " • 1 •=—™ r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
H Sulfate H Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure CA-21. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Redwood IMPROVE Particulate Sampler
San Gorgonio Wilderness Area
The San Gorgonio IMPROVE particulate sampler started reporting in March of 1988. Figure •
CA-22 presents the calculated visibility indices at San Gorgonio Wilderness Area for selected data sets
from 1988 through 1998. The figure shows that from 1988 through 1998 there was a significant trend
indicating improved visibility in the annual average of the visibility index for the most-impaired days,
which dropped from 24 to 22 deciviews (VR 22 to 27 miles). From 1988 through 1998, there was no
significant trend in the annual average of the visibility index for the mid-range days, which mostly
remained between 16 (VR 50 miles) and 19 deciviews (VR 36 miles). The annual average of the visi-
November 2001
2-51
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
I
Q>
O
0)
9.
X
fl>
tJ
, Bp- IS^wST^SKsi; i«_=^2Mh. ™,7lH= aF- —i ™ HHknjUjjl HMBJgjjjijiflf
! yi Bffij1 TBffffffli^HB B-^fiifip ifny i
T^SiS
J/m ill* 1||
I ttW 4 - U;T ± *« ^ [ jp|[i j
(I
Mid-Range
--**
Least-Impaired
1 h
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CA-22. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the San Gorgonio IMPROVE Participate Sampler
bility index for the least-impaired days remained near 8 deciviews (VR 110 miles), indicating no signif-
icant trend on the least-impaired days.
Figure CA-23 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices are discernibly lower (better visibility) in autumn and winter than
in the spring and summer. The indices for the autumn and winter did not fluctuate greatly over the
eleven-year period and no statistically significant trend was observed. Both the indices for spring and
summer showed significant trends indicating improved visibility by an average decrease of 2.5
deciviews between 1988 and 1998.
Figure CA—24 presents a chart showing the calculated fractional contribution to San Gorgonio's
light extinction by each aerosol species on an annual basis. Figure CA-25 shows the same information
for the four seasons. Since the autumn and winter light extinction coefficients were much smaller than
those in spring and summer, the annual averages presented in Figure CA-24 appear weighted to the
spring and summer. These five pie charts show that sulfate particles were responsible for 13 to 25 per-
cent of the light extinction at the site, averaging 23 percent on an annual basis over a five-year period.
The contributions from nitrates ranged between 25 and 65 percent, with the highest percentages in win-
ter. From all of the IMPROVE monitors, the San Gorgonio site has the highest annual nitrate concen-
trations and the highest fractional contributions to light extinction from nitrates. Nitrates represented 39
percent of the light extinction at this site on an annual basis over a five-year period. The contributions
from organic carbon ranged from 10 to 26 percent during the four seasons, with the summer's percent
contribution being the highest. Seasonally, elemental carbon measured at the San Gorgonio site was
responsible for 6 to 11 percent of the calculated aerosol light extinction. Crustal material contributions
to the light extinction coefficient varied from 6 to 15 percent in the four seasons, with the autumn con-
tribution being the highest.
2-52
November 2001
-------
Individual Areas—California
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
Year
1998
-Spring
-Summer -A-Autumn
-Winter
Figure CA-23. Seasonal Deciview Averages from 1988-1998
for the San Gorgonio IMPROVE Participate Sampler
Organic
Carbon
• 18%
Nitrate
39%
Elemental
Carbon
9%
Crustal
Material
11%
Sulfate
23%
Figure CA-26 shows the calculated contributions of
each of the aerosol mass components to the annual average
aerosol light extinctions at the San Gorgonio site from
1988 to 1998. Over the eleven-year period, there was a sig-
nificant trend in the total annual aerosol light extinctions
from 50 to 42 Mm"1, indicating improved visibility. The
sulfate extinction coefficients did not show a significant
trend over this time period. The other aerosol species
(organic carbon, elemental carbon, and crustal material)
showed significant decreases in their contributions to the
annual light extinction coefficients.
Figure CA-24. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for
the San Gorgonio
IMPROVE Particulate Sampler
November 2001
2-53
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate
40%
Organic
Carbon Elemental
17% Carbon
Spring
8%
Crustal
Material
10%
Sulfate
25%
Organic
Carbon
26%
Nitrate
25%
Elemental
Carbon
11%
Crustal
Material
14%
Sulfate
24%
Summer
Organic
Carbon
19%
Nitrate
37%
Elemental
Carbon
10%
Crustal
Material
15%
Sulfate
19%
Nitrate
65%
Organic
Carbon
10% Elemental
Carbon
6%
Crustal
Material
6%
Sulfate
13%
Autumn
Winter
Figure CA-25. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the San Gorgonio IMPROVE Particulate Sampler
2-54
November 2001
-------
Individual Areas—California
1988 1989 1990 1991
1992
1993
Year
1994 1995 1996 1997 1998
HSulfate a Nitrate D Organic Carbon D Elemental Carbon
I Crustal Material
Figure CA-26. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998
for the San Gorgonio IMPROVE Particulate Sampler
Yosemite National Park
The Yosemite IMPROVE particulate sampler started reporting in March of 1988. Figure CA—27
presents the calculated visibility indices at Yosemite National Park for selected data sets from 1988
through 1998. The figure shows from 1988 through 1998 there was no significant trend in the annual
average of the visibility index for the most-impaired days, which remained between 16 and 20
deciviews (VR 50 to 33 miles). From 1988 through 1998, there was no significant trend in the annual
average of the visibility index for the mid-range days, which remained near 11 deciviews (VR 80
miles). Similarly, the annual average of the visibility index for the least-impaired days remained near 5
deciviews (VR 150 miles), indicating no significant trend on the least-impaired days.
Figure CA—28 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices are discernibly lower (better visibility) in winter than in the other
three seasons. Statistical analysis shows that, over the eleven-year period, there was 'no significant trend
in visibility in any of the four seasons.
Figure CA-29 presents a chart showing the calculated fractional contribution to Yosemite's light
extinction by each aerosol component on an annual basis. Figure CA-30 shows the same information
for the four seasons. These five pie charts show that sulfate particles were responsible for 18 to 33 per-
cent of the light extinction at the site (highest percentage in the spring), averaging 26 percent on an
November 2001
2-55
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CA-27. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Yosemite IMPROVE Particulate Sampler
li«
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-*- Spring -M- Summer -A- Autumn -•- Winter
Figure CA-28. Seasonal Deciview Averages from 1988-1998 for the
Yosemite IMPROVE Particulate Sampler
2-56
November 2001
-------
Individual Areas—California
Organic
Carbon
38%
Elemental
Carbon
10%
Crustal
Material
14%
Nitrate
12%
Sulfate
26%
Figure CA-29. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the
Yosemite IMPROVE Particulate Sampler
annual basis over a five-year period. The contribu-
tions from nitrates ranged between 6 and 31 percent,
with the highest percentage in winter. The contribu-
tions from organic carbon ranged from 26 to 46 per-
cent during the four seasons, with the summer's and
autumn's percent contributions being the highest.
Elemental carbon measured at the Yosemite site was
responsible for 8 to 12 percent of the calculated
aerosol light extinction year-round. Crustal material
contributions to the light extinction coefficient varied
from 1.4 to 16 percent in the four seasons.
Figure CA-31 shows the calculated contributions
of each of the aerosol mass components to the annual
average aerosol light extinctions at the Yosemite site
from 1988 to 1998. Over the eleven-year period, the
total annual aerosol light extinctions ranged between
21 and 27 Mm"1. Statistical analysis determined that
Organic
Carbon
26%
Elemental
Carbon
8%
Nitrate
17%
Crustal
Material
16%
Sulfate
33%
Spring
Elemental
Carbon
12%
Organic
Carbon
46%
Crustal
Material
14%
Sulfate
19%
Nitrate
9%
Autumn
Elemental
Carbon
12% ,
Organic
Carbon
45%
Crustal
Material
14%
Nitrate
6%
Summer
Sulfate
23%
Organic
Carbon
27%
Elemental
Carbon
8%
Crustal
Material
16%
Sulfate
18%
Nitrate
31%
Winter
Figure CA-30. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Yosemite IMPROVE Particulate Sampler
November 2001
2-57
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
no significant trend occurred. The sulfate, organic carbon, elemental carbon, and crustal material
extinction coefficients did not show significant trend over this time period.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
m Sulfate H Nitrate D Organic Carbon D Elemental Carbon H Crustal Material
Figure CA-31. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Yosemite IMPROVE Particulate Sampler
California State Summary
The calculated annual average aerosol extinction coefficients at California's IMPROVE monitoring
sites are presented in Table CA-1. The 1995-1998 data from Sequoia National Park also are included
here. The coefficient at Lassen Volcanic National Park was less than half the average coefficient, and
the coefficient from Sequoia National Park more than 40 percent higher than the average. These obser-
vations suggest that visibility across the state varies significantly on an annual basis. The annual aver-
age VR varied from 40 to 100 miles.
The pollutant species that contributed most to calculated light extinction also varied between moni-
toring sites. The coastal sites (Pinnacles, Point Reyes, and Redwood) showed high contributions from
sulfates. Nitrates represented 39 percent of the calculated aerosol light extinction at the southern
California site (San Gorgonio). The eastern sites (Lassen Volcanic, Sequoia, and Yosemite) showed high
contributions from organic carbon.
2-58
November 2001
-------
Individual Areas—California
Table CA-1. California Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Lassen Volcanic NP
Pinnacles NM
Point Reyes NS
Redwood NP
San Gorgonio Wilderness
Sequoia NP
Yosemite NP
Average
Calculated Total
Aerosol Extinction
Coefficient (Mm"1)
14.6
30.6
42.1
40.7
42.9
50.5
23.2
34.9 ± 12.7
Pollutant Extinction Coefficient (Mm"1)
Sulfate
4.5
9.3
20.5
24.7
9.7
11.4
6.0
12.3 ±7.5
Nitrate
1.3
6.3
10.6
7.5
16.9
11.2
2.8
8.1 ±5.3
Organic
Carbon
5.2
6.9
4.5
4.1
7.8
14.5
8.8
7.4 ±3.6
Elemental
Carbon
1.7
3.5
1.4
1.0
3.7
5.3
2.4
2.7 ±1.5
Crustal
Material
1.9
4.6
5.1
3.4
4.8
8.1
3.2
4.4 ± 2.0
November 2001
2-59
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
6. COLORADO
Twelve mandatory Federal Class I areas are located in Colorado. Four IMPROVE particulate sam-
plers in Colorado operated continuously from 1994 through 1998. They were located at Great Sand
Dimes National Monument (37.73°N, 105.51°W, elevation 8200 feet), Mesa Verde National Park
(37.20°N, 108.48°W, elevation 7200 feet), Rocky Mountain National Park (40.36°N, 105.60°W, eleva-
tion 7900 feet), and Weminuche Wilderness Area (37.66°N, 107.80°W, elevation 9050 feet).
Figure CO-1 shows the Rocky Mountain monitoring location in the northern portion of the state
and the other three locations in the south. An additional particulate sampler began collecting data near
the Mount Zirkel Wilderness Area in July 1994; however, it is not discussed in this section since it did
not have five full years of data between 1994 and 1998.
Mount Zirkel Wilderness Rawah Wilderness
Black Canyon
of the Gunnison
Wilderness
Mesa Verde
National Park-
Mount Zirkel \|
IMPROVE Monitor 1
-~Er
Flat Tops Wilderness
Fort Collins
p
Rocky Mountain
(\ IMPROVE Monitor
Rocky Mountain National Park
Eagles Nest Wilderness
Denver
West Elk
Wilderness
%L_Maroon Bells-Snowmass
Wilderness
Weminuche
IMPROVE Monitor
Garita Wilderness
reat Sand Dunes Wilderness
Great Sand Dunes
Weminuche Wilderness IMPROVE Monitor
Mesa Verde IMPROVE Monitor
Figure CO-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Colorado
Other Colorado mandatory Federal Class I areas covered by the Regional Haze Rule (but not col-
lecting IMPROVE data) include:
Rawah Wilderness Area,
Flat Tops Wilderness Area,
Eagles Nest Wilderness Area,
Black Canyon of the Gunnison Wilderness Area,
Maroon Bells-Snowmass Wilderness Area (data collected for the USDA Forest Service according
to the IMPROVE protocol),
West Elk Wilderness Area, and
La Garita Wilderness Area.
2-60
November 2001
-------
Individual Areas—Colorado
Great Sand Dunes National Monument
The Great Sand Dunes IMPROVE particulate sampler started recording in May of 1988. Figure
CO-2 presents the calculated visibility indices for selected data sets from 1988 through 1998. The fig-
ure shows that from 1988 through 1998 there was no statistically significant trend in the annual average
of the visibility index for the most-impaired days, which remained between approximately 11 and 14
deciviews (VR 80 to 60 miles). The coarse mass fraction was responsible for the spike in 1994 at Great
Sand Dunes National Monument. The April 23, 1994 sample recorded 352 u,g/m3 total mass (PM10),
which is five standard deviations (s.d. = 67 |ig/m3) higher than the spring average of 24 (ig/m3. The
next highest reading at the site over the eleven-year period was only 71 (ig/m3. Without this point
recorded for April 23, 1994, the average total mass drops to 12 u.g/m3, and the 1994 numbers line up
closer with other years.
From 1988 through 1998, Figure CO-2 shows a significant trend toward improved visibility in the
annual average of the visibility index for the mid-range days, which decreased from 10 to 9 deciviews
(VR 90 to 100 miles). Similarly, the annual average of the visibility indices for the least-impaired days
decreased from 7 to 6 deciviews (VR 120 to. 135 miles), indicating a statistically significant trend
toward improved visibility.
I
12
p- ™
".' ' ~—>"*•*-—"-^- — —----.--. ""^^St^ -"': ~*1~ * .-* • *-'"^~-_ •"'-' s-™^^--./**.-....!--^^ ^..s«.^«~rf-A-.-»i.a--i.^i_-- „=,-, "-•-—*_"?^:- T5-^-- -w "-. ^°" = -»*-." '..'V^.'--f :•-? ^^.-,'~_ •.-.. ,a = t --f.. -.:- /^j
-•• '•---- - ••---- -- -
10
~Q
'«
>
Most-Impaired
Least-Impaired
—I 1—
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CO-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Great Sand Dunes IMPROVE Particulate Sampler
Figure CO-3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices for spring are on average 3 deciviews higher than those during the
summer, autumn, and winter. The National Park Service indicated that wind events are more common
in the spring than in other seasons at Great Sand Dunes (Bunch, 2000). Wind events can increase wind
erosion and introduce substantial crustal material to the atmosphere. No significant seasonal trends
November 2001
2-61
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
were observed in the calculated visibility indices over this time period for any of the seasons. However,
if the 1994 spring value was removed from Figure CO-3, the spring trend would be statistically signifi-
cant toward unproved visibility.
"
-I 1 1 1 1 1—: i 1 r
1988 ' 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-*-Spring -»-Summer -*-Autumn -•-Winter
Figure CO-3. Seasonal Deciview Averages from 1988-1998
for the Great Sand Dunes IMPROVE Particulate Sampler
Elemental
Carbon
7%
Organic
Carbon
23%
Nitrate
8%
Crustal
Material
24%
Sulfate
38%
Figure CO-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Great Sand Dunes
IMPROVE Particulate Sampler
Figure CCMl presents a chart showing the calculat-
ed fractional contribution to Great Sand Dunes'
light extinction by each aerosol species on an annual
basis. Figure CO-5 shows the same information for
the four seasons. These five pie charts show that sul-
fate particles were responsible for 34 to 48 percent of
the light extinction at the site, averaging 38 percent on
an annual basis over a five-year period. The highest
sulfate contributions occurred in the spring and the
lowest in the winter. The contributions from nitrates
were 9, 5, 8, and 10 percent for the spring, summer,
autumn, and winter, averaging just 8 percent on an
annual basis. The contributions from organic carbon
ranged from 13 percent in the spring up to 24 to 29
percent during the other three seasons. Annually, ele-
mental carbon and crustal material measured at the
Great Sand Dunes site were responsible for approxi-
mately 7 and 24 percent of the calculated aerosol light
extinction.
2-62
November 2001
-------
Individual Areas—Colorado
Organic
Carbon
13%
Elemental
Carbon
5%
Crustal
Material
25%
Elemental
Carbon
7%
Nitrate
. 9%
Organic
Carbon
29%
Nitrate
5%
Crustal
Material
23%
Sulfate
48%
Spring
Elemental
Carbon
Sulfate
36%
Organic
Carbon
24%
Nitrate
8%
Crustal
Material
19%
Summer
Elemental
Carbon
10%
Organic
Carbon
26%
Sulfate
40%
Nitrate
10%
Crustal
Material
20%
Sulfate
34%
Autumn
Winter
Figure CO-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Great Sand Dunes IMPROVE Particulate Sampler
Figure CO—6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Great Sand Dunes site from 1988 to 1998. Over the
eleven-year period, the total annual aerosol light extinctions decreased from approximately 17 to 15
Mm-1, and the trend was statistically significant. No significant trends were noted in the annual light
extinctions calculated for sulfates or elemental carbon. However, the organic carbon and crustal materi-
al showed statistically significant decreases in their annual contributions to the light extinction coeffi-
cients, indicating lower ambient concentrations.
November 2001
2-63
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1988 1989 1990 1991
1992
HSulfate
H Nitrate
1993 1994 .1995 1996 1997 1998
Year
D Organic Carbon D Elemental Carbon HCrustal Material
Figure CO-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998
for the Great Sand Dunes IMPROVE Particulate Sampler
Mesa Verde National Park
The Mesa Verde IMPROVE particulate sampler started reporting in March of 1988. Figure CO-7
presents the calculated visibility indices for selected data sets at Mesa Verde from 1988 through 1998.
The figure shows that from 1988 through 1998 there was no significant trend in the annual average of
the visibility index for the most-impaired days, which remained near 11.5. deciviews (VR 80 miles).
From 1988 through 1998, there was no significant trend in the annual average of the visibility index for
the mid-range days, which remained relatively constant near 8.5 deciviews (VR 105 miles). The annual
average of the visibility index for the least-impaired days remained near 6 deciviews (VR 135 miles)
over the period and did not demonstrate a statistically significant trend in the visibility index.
Figure CO—8 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices for summer were generally 1 or 2 deciviews higher than those dur-
ing the autumn, winter, and spring. No significant seasonal trends were observed in the calculated visi-
bility indices over this tune period for any of the seasons. The average indices for spring increased 1
deciview over the eleven-year period, but this trend toward decreased visibility was not statistically sig-
nificant.
2-64
November 2001
-------
Individual Areas—Colorado
^^-£ ^jpfeST^^Tl^^
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CO-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Mesa Verde IMPROVE Particulate Sampler
0)
o
a>
•o
-Q
'55
1988 1989 1990 1991
1992 1993 1994 1995 1996 1997
Year
1998
-Spring -»-Summer -A-Autumn
-Winter
Figure CO-8. Seasonal Deciview Averages from 1988-1998 for the
Mesa Verde IMPROVE Particulate Sampler
November 2001
2-65
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
10%
Crustal
Material
19%
Organic
Carbon
24%
Nitrate
6%
Sulfate
41%
Figure CO-9. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Mesa Verde IMPROVE
Participate Sampler
Figure CO-9 presents a chart showing the calcu-
lated fractional contribution to Mesa Verde's light
extinction by each aerosol species on an annual basis.
Figure CO-10 shows the same information for the,
four seasons. These five pie charts show that sulfate
particles were responsible for 34 to 43 percent of the
light extinction at the Mesa Verde site, averaging 41
percent on an annual basis over a five-year period.
The highest sulfate contributions occurred in the
autumn and winter, but most other IMPROVE partic-
ulate samplers showed the lowest contributions from
sulfates in the winter. The average contributions from
nitrates ranged from 4 to 9 percent in the four sea-
sons. The contributions from organic carbon ranged
from 22 to 27 percent during the four seasons.
Elemental carbon measured at the Mesa Verde site
was responsible for 9 to 12 percent of the calculated
Elemental
Carbon
10%
Crustal
Material
26%
Organic
Carbon
24%
Nitrate
6%
Sulfate
34%
Spring
Organic
Carbon
23%
Nitrate
6%
Elemental
Carbon
12%
Crustal
Material
16%
Sulfate
43%
Autumn
Organic
Carbon
27%
Nitrate
4%
Organic
Carbon
22%
Nitrate
9%
Elemental
Carbon
9% Crustal
Material
19%
Sulfate
41%
Summer
Elemental
Carbon
12%
Crustal
Material
14%
Sulfate
43%
Winter
Figure CO-10. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Mesa Verde IMPROVE Particulate Sampler
2-66
November 2001
-------
Individual Areas—Colorado
aerosol light extinction. The crustal material contributions range from 14 to 26 percent, with the high-
est contributions during the spring season.
Figure CO-11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Mesa Verde site from 1988 to 1998. Over the eleven-year
period, the calculated total annual aerosol light extinctions remained near 14 Mm-1. Statistical analysis
determined that no significant trend occurred. In addition, no significant trends were noted in the annu-
al light extinctions calculated for sulfates, organic carbon, or crustal material. However, the elemental
carbon showed statistically significant increases in its annual contribution to the light extinction coeffi-
cients (from 0.9 to 1.6 Mm-1), indicating higher ambient concentrations.
1988 1989 1990 1991
1992
1993 1994 1995
Year
n Sulfate n Nitrate D Organic Carbon D Elemental Carbon
1996 1997 1998
B Crustal Material
Figure CO-11. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Mesa Verde IMPROVE Particulate Sampler
Rocky Mountain National Park
The Rocky Mountain IMPROVE particulate sampler started reporting in March of 1988. Figure
CO-12 presents the calculated visibility indices for selected data sets at Rocky Mountain National Park
from 1988 through 1998. From 1988 through 1998, there was no significant trend in the annual average
of the visibility index for the most-impaired days, which remained near 13 deciviews (VR 65 miles).
From 1988 through 1998, there was also no significant trend in the annual average of the visibility
index for the mid-range days, which remained near 9 deciviews (VR 100 miles). The annual average of
the visibility index for the least-impaired days remained near 5 deciviews (VR 150 miles).
November 2001
2-67
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
iSSrlMost-lmpaired
i;I:Z^ ^'.'sw^'s-'•;••" 'Kt
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CO-12. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Rocky Mountain IMPROVE Particulars Sampler
Figure CO—13 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices for summer were 1 to 4 deciviews higher than those during the
spring and autumn. The visibility indices for the spring and autumn were generally 2 or 3 deciviews
higher than the winter numbers. No significant seasonal trends were observed in the calculated visibili-
ty indices over this time period for the spring and autumn. The average indices for the summer and
winter each declined 1 deciview unit over the eleven-year period (significant trend indicating improved
visibility).
2-68
November 2001
-------
/ndivrdua/ Areas—Colorado
I
a>
\>
'o
a
X
0>
•o
-Q
"(0
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
Year
1998
-Spring -•-Summer -A-Autumn
-Winter
Figure CO-13. Seasonal Dec!view Averages from 1988-1998
for the Rocky Mountain IMPROVE Particulate Sampler
Figure CO-14 presents a chart showing the calculated fractional contribution to Rocky Mountain's
light extinction by each aerosol component on an annual basis. Figure CO-15 shows the same informa-
tion for the four seasons. These five pie charts show that sulfate particles were responsible for 29 to 41
percent of the light extinction at the R:ocky Mountain site, averaging 34 percent on an annual basis over
a five-year period. The highest sulfate contributions occurred in the spring. This is different from most
other sites, where sulfate contributions typically peaked in summer. The average contributions from
nitrates ranged from 6 to 14 percent in the four seasons. The contributions from organic carbon ranged
from 22 to 31 percent during the four seasons. Elemental carbon measured at the Rocky Mountain site
was responsible for 9 to 13 percent of the calculated
aerosol light extinction. The crustal material contribu-
tions ranged from 19 to 22 percent, with the highest
contributions during the winter season.
Elemental
Carbon
10%
Organic
Carbon
27%
Nitrate
9% ,
Crustal
Material
20%
Sulfate
34%
Figure CO-14. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the Rocky
Mountain IMPROVE Particulate Sampler
November 2001
2-69
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
22%
Elemental
Carbon
9%
Nitrate
9%
Crustal
Material
19%
Elemental
Carbon
9%
Organic
Carbon
31%
Crustal
Material
20%
Sulfate
41%
Nitrate
6%
Sulfate
34%
Spring
Elemental
Carbon
13%
Organic
Carbon
26%
Crustal
Material
20%
Summer
Elemental
Carbon
12%
Organic
Carbon
23%
Nitrate
9%
Sulfate
32%
Crustal
Material
22%
Nitrate
14%
Sulfate
29%
Autumn
Winter
Figure CO-15. Contribution to Calculated Seasonal Aerosol Light ixtinction
from 1994-1998 for the Rocky Mountain IMPROVE Particulate Sampler
Figure CO—16 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Rocky Mountain site from 1988 to 1998. Over the
eleven-year period, there was no significant trend in the total annual aerosol light extinctions which
remained near 15 Mm-1. No significant trends were noted in the annual light extinctions calculated for
sulfates, organic carbon, elemental carbon, or crustal material.
2-70
November 2001
-------
Individual Areas—Colorado
_g
"*3
O
C
HI
O)
O
(0
2
0>
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
n Sulfate H Nitrate D Organic Carbon D Elemental Carbon
ICrustal Material
Figure CO-16. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Rocky Mountain IMPROVE Particulate Sampler
Weminuche Wilderness Area
The Weminuche IMPROVE particulate sampler started reporting in March of 1988. Figure CO-17
presents the calculated visibility indices for selected data sets at Weminuche Wilderness Area from
1988 through 1998. The figure shows that from 1988 through 1998 there was no statistically significant
trend in the annual average of the visibility index for the most-impaired days, which remained near 12
deciviews (VR 75 miles). The annual average of the visibility index for the mid-range days remained
near 9 deciviews (VR 100 miles) over the same time period, with no statistically significant improve-
ment in visibility. From 1988 through 1998, there was no significant trend in the annual average of the
visibility index for the least-impaired days, which remained near 5 deciviews (VR 150 miles).
Figure CO-18 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The average visibility indices for spring were 1 to 4 deciviews higher than those during the sum-
mer and autumn. The visibility indices for the summer and autumn were generally 2 or 3 deciviews
higher than the winter numbers. No significant seasonal trends were observed in the calculated visibili-
ty indices over this time period for the spring, autumn, or winter. The average indices for the summer
showed a significant trend indicating improved visibility as the indices declined 1 deciview unit over
the eleven-year period.
November 2001
2-71
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure CO-17. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Weminuche IMPROVE Participate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
•Spring -»-Summer -A-Autumn
Winter
Figure CO-18. Seasonal Deciview Averages from 1988-1998 for the
Weminuche IMPROVE Particulate Sampler
2-72
November 2001
-------
Individual Areas—Colorado
Elemental
Carbon
12%
Crustal
Material
19%
Organic
Carbon
21%
Nitrate
6%
Sulfate
42%
Figure CO-19. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for
the Weminuche IMPROVE
Particulate Sampler
Organic
Carbon
13%
Nitrate
8%
Elemental
Carbon
6%
Crustal
Material
15%
Sulfate
58%
Figure CO—19 presents a chart showing the calculat-
ed fractional contribution to Weminuche's light extinc-
tion by each aerosol species on an annual basis. Figure
CO-20 shows the same information for the four sea-
sons. These five pie charts show that sulfate particles
were responsible for 36 to 58 percent of the light extinc-
tion at the Weminuche site, averaging 42 percent on an
annual basis over a five-year period. The highest sulfate
contributions occurred in the spring, which is different
from most other sites where sulfate typically peaked in
summer. The average contributions from nitrates ranged
from 4 to 8 percent in the four seasons. The contribu-
tions from organic carbon ranged from 13 to 29 percent
during the four seasons. Elemental carbon measured at
the Weminuche site was responsible for 6 to 15 percent
of the calculated aerosol light extinction. The crustal
material contributions ranged from 15 to 21 percent,
with the' highest contributions during the winter season.
Elemental
Carbon
12%
Organic
Carbon
29%
Crustal
Material
19%
Nitrate
4%
Sulfate
36%
Spring
Summer
Organic
Carbon
22%
Nitrate
6%
Elemental
Carbon
14%
Crustal
Material
17% •
Sulfate
41%
Autumn
Organic
Carbon
20%
Elemental
Carbon
15%
Nitrate
8%
Crustal
Material
21%
Sulfate
36%
Winter
Figure CO-20. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Weminuche IMPROVE Particulate Sampler
November 2001
2-73
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Figure CO-21 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Weminuche site from 1988 to 1998. Over the eleven-year
period, there was no statistically significant trend in the total annual aerosol light extinctions, which
remained near 14 Mm-1. No significant trends were noted in the annual light extinctions calculated for
sulfates, elemental carbon, or crustal material. However, the organic carbon contributions showed sta-
tistically significant decreases in their annual contribution to the light extinction coefficients, indicating
lower ambient concentrations.
i—' '—i—^ '—i—' '—i—' •—i—' •—i—• •—i—1-—*—i—"—•—r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
O Sulfate 00 Nitrate D Organic Carbon D Elemental Carbon il Crustal Material
Figure CO-21. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Weminuche IMPROVE Particulate Sampler
Colorado State Summary
The calculated annual average aerosol extinction coefficients at Colorado's IMPROVE monitoring
sites are presented in Table CO—1. The calculated total aerosol extinction coefficients at all four sites
were within 5 percent of the average (14.5 Mm-1), indicating similar annual visibility conditions at all
sites. The extinction coefficients for the individual species were also similar at the different sites. All
five sites also showed similar rankings for contributions of the species to light extinction: sulfate, fol-
lowed by organic carbon and crustal material, then elemental carbon, and lastly nitrate. These rankings
are identical to those presented for the Arizona, Texas, and Wyoming IMPROVE monitors in Tables
AZ-l,TX-l,andWY-l.
2-74
November 2001
-------
Individual Areas—Colorado
Table CO-1. Colorado Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Great Sand Dunes NM
Mesa Verde NP
Rocky Mountain NP
Weminuche Wilderness
Average
Calculated Total
Aerosol Extinction
Coefficient (Mm'1)
15.3 '
14.3
14.7
13.9
14.5 ± 0.6
Pollutant Extinction Coefficient (Mur1)
Sulfate
5.8
5.8
5.1
5.8
5.6 ± 0.4
Nitrate.
1.1
0.8-
1,3
0.8
1.0 ±0.2
Organic
Carbon
3.5
3.4
3.9
2.9
3.5 ±0.4
Elemental
Carbon
1.1
1.5
1.5
1.6
1.4 ± 0.2
Crustal •
Material
• 3.7
2.7
2.9
2.7
3.0 ±0.5
November 2001
2-75
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
7. FLORIDA
The only IMPROVE particulate sampler in Florida that operated continuously from 1994 through
1998 was the one located in the Chassahowitzka National Wildlife Refuge. Figure FL-1 shows the
Chassahowitzka monitor location (28.75°N, 82.57°W, elevation 10 feet) near the Gulf of Mexico. An
IMPROVE particulate sampler also collects data in the Everglades National Park. However, it was not
operational for two months in 1998, so its data were not included in this report. The Saint Marks
Wilderness Area is also a mandatory Federal Class I area covered by the Regional Haze Rule, but it
does not have an operating IMPROVE particulate sampler. In 1980 the Bradwell Bay Wilderness Area
was excluded as a mandatory Federal Class I area for purposes of visibility protection, so it is not cov-
ered by the Regional Haze Rule.
(Bradwell Bay Wilderness)
St. Marks Wilderness'
Chassahowitzka IMPROVE Monitc
Chassahowitzka
Wilderness
Everglades National Park
Miami
Figure FL-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Florida
Chassahowitzka National Wildlife Refuge
The Chassahowitzka IMPROVE particulate sampler started recording in April of 1993. Figure FL-2
presents the calculated visibility indices for selected data sets from 1993 through 1998. The figure
shows that from 1993 through 1998 there was no significant trend hi the annual average of the visibili-
ty index for the most-unpaired days, which remained near 27 deciviews (VR 16 miles). From 1993
through 1998, there was no significant trend in the annual average of the visibility index for the mid-
range days, which remained near 23 deciviews (VR 24 miles). The annual average of the visibility
index for the least-unpaired days remained near 18 deciviews (VR 40 miles), indicating no statistically
significant trend in visibility.
Figure FL-3 shows the seasonal averages for the calculated visibility index from 1993 through
1998. The visibility indices for the four seasons all covered the nearly same range, from 21 to 24
deciviews. No significant seasonal trends were observed in the calculated visibility indices over this
time period for any of the seasons.
2-76 November 2001
-------
Individual Areas—Florida
30
28
I 26
"5
Q 24
c 22
3 20
"55
>
18
16
..^^gSlpllf^f^,
?--L. ^^'rL-^^^g^^.^^^^^--^^^^^^^
„_ -"-"- -***-
Mid-Range
Least-Impaired *"
1 1
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure FL-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1993-1998 for the Chassahowitzka IMPROVE Particulate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-Spring -•-Summer -rde-Autumn
-Winter
Figure FL-3. Seasonal Deciview Averages from 1993-1998 for the
Chassahowitzka IMPROVE Particulate Sampler
November 2001
2-77
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Nitrate Carbon
7%
Elemental
Carbon
6%
Crustal
Material
7%
Sulfate
68%
Figure FL-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Chassahowitzka
IMPROVE Particulate Sampler
Figure FL-4 presents a chart showing the calculated
fractional contribution to Chassahowitzka's light extinc-
tion by each aerosol species on an annual basis. Figure
FL-5 shows the same information for the four seasons.
These five pie charts show that sulfate particles were
responsible for 59 to 69 percent of the light extinction
at the Chassahowitzka site, averaging 68 percent on an
annual basis over a five-year period. The highest sulfate
contributions occurred in the summer and the lowest in
the winter. The contributions from organic carbon
ranged from 10 to 16 percent during the four seasons,
with winter showing the highest values. Nitrate, ele-
mental carbon, and crustal material measured at the
Chassahowitzka site were each responsible for approxi-
mately 7 percent of the calculated aerosol light extinc-
tion year-round.
Nitrate
6%
Organic
Carbon
12%
Sulfate
67%
Spring
Sulfate
68%
Autumn
Elemental
Carbon
7%
Crustal
Material
8%
Organic
Carbon Elemental
Carbon
7%
Crustal
Material
6%
Nitrate
7%
Organic
Carbon
10%
Elemental
Carbon
4%
Crustal
Material
10%
Sulfate
69%
Nitrate
7%
Summer
Organic
Carbon
16%
Elemental
Carbon
11%
Crustal
Material
7%
Sulfate
59%
Winter
Figure FL-5. Contribution to Calculated Seasonal Aerosol Light Extinction from
1994-1998 for the Chassahowitzka IMPROVE Particulate Sampler
2-78
November 2001
-------
Individual Areas—Florida
Figure FL-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Chassahowitzka site from 1993 to 1998. Over the six-
year period, the total annual aerosol light extinctions remained near 90 Mm-1 (no statistically signifi-
cant trend). Similarly, no significant trends were noted in the annual light extinctions calculated for sul-
fates, organic carbon, elemental carbon, or crustal material.
120
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
DSulfate EH Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure FL-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1993-1998 .for the Chassahowitzka IMPROVE Particulate Sampler
November 2001
2-79
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
8. GEORGIA
The only IMPROVE particulate sampler in Georgia that operated continuously from 1994 through
1998 was the one located in the Okefenokee National Wildlife Refuge. Figure GA-1 shows the
Okefenokee monitor location (30.74°N, 82.12°W, elevation 50 feet) in the southeast corner of the state.
The Cohutta and Wolf Island Wilderness Areas are additional Class I areas covered by the Regional
Haze Rule, but they do not have operating IMPROVE particulate samplers.
Cohutta Wilderness
Athens
Wolf Island
Wilderness
Okefenokee
Wilderness
Savannah
Okefenokee
IMPROVE Monitor
50 100
—i' ''"'
miles
Figure GA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Georgia
Okefenokee National Wildlife Refuge
The Okefenokee IMPROVE particulate sampler started reporting in September of 1991. Figure
GA—2 presents the calculated visibility indices for selected data sets from 1992 through 1998. The fig-
ure shows that from 1992 through 1998 there was no significant trend in the annual average of the visi-
bility index for the most-impaired days, which remained near 29 deciviews (VR 13 miles). From 1992
through 1998 there was no significant trend in the annual average of the visibility index for the mid-
range days, which remained near 23 deciviews (VR 24 miles). The annual average of the visibility
index for the least-impaired days remained near 18 deciviews (VR 40 miles) for most years, with no
statistically significant trend in visibility.
Figure GA-3 shows the seasonal averages for the calculated visibility index from 1992 through
1998. The visibility indices for the four seasons ranged from 21 to 27 deciviews. Summer indices were
higher than all other seasons in four of the seven years, and winter indices were lowest in six of the
2-80
November 2001
-------
Individual Areas—Georgia
tn
26
Most-impaired
g 24
« 20
18
16
Mid-Range
Least-Impaired
i 1
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure GA-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1992-1998 for the Okefenokee IMPROVE Participate Sampler
i
a>
X
Q)
•a
.a
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-Spring
•Summer -Ar-Autumn
- Winter
Figure GA-3. Seasonal Deciview Averages from 1992-1998 for the
Okefenokee IMPROVE Particulate Sampler
November 2001
2-81
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate Organic
6% Carbon Elemental
Carbon
5%
Crustal
Material
6%
Sulfate
72%
Figure GA-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Okefenokee IMPROVE
Particulate Sampler
seven years. No significant seasonal trends were
observed in the calculated visibility indices over this
time period for summer, autumn, or winter. However,
the spring indices showed a statistically significant
decrease, indicating a 2 deciview improvement over
seven years.
Figure GA-4 presents a chart showing the calcu-
lated fractional contribution to Okefenokee's light
extinction by each aerosol species on an annual basis.
Figure GA-5 shows the same information for the four
seasons. These five pie charts show that sulfate parti-
cles were responsible for 64 to 76 percent of the light
extinction at the Okefenokee site, averaging 72 per-
cent on an annual basis over a five-year period. The
highest sulfate contributions occurred in the summer
and autumn and the lowest in the winter. The contri-
butions from organic carbon ranged from 9 to 16 per-
cent during the four seasons, with winter showing the
.... .
Nitrate
5/o
Organic
Carbon
Suifate
71%
Spring
Nitrate
6%
Elemental
Carbon
5%
Crustal
Material
7%
Organic
Carbon
10%
Sulfate
75%
Elemental
Carbon
4%
Crustal
Material
5%
Autumn
Organic
Nitrate Carbon
5% 9%
Sulfate
76%
Nitrate
6%
Summer
Organic
Carbon
16%
Sulfate
64%
Winter
Elemental
Carbon
2%
Crustal
Material
8%
Elemental
Carbon
8%
Crustal
Material
6%
Figure GA-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Okefenokee IMPROVE Particulate Sampler
2-82
November 2001
-------
Individual Areas—Georgia
highest values. Nitrate, elemental carbon, and crustal material measured at the Okefenokee site were
each responsible for approximately 6, 5, and 6 percent of the calculated aerosol light extinction year-
round.
Figure GA-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Okefenokee site from 1992 to 1998. Over the seven-year
period, the total annual aerosol light extinctions remained near 100 Mm-1 (no significant trend).
Similarly, no significant trends were noted in the annual light extinctions calculated for sulfates, organ-
ic carbon, elemental carbon, or crustal material.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
HSulfate O Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure GA-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998
for the Okefenokee IMPROVE Particulate Sampler
November 2001
2-83
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
9. KENTUCKY
The only IMPROVE monitoring site in Kentucky that operated continuously from 1994 through
1998 was the one located in the Mammoth Cave National Park. Figure KY-1 shows the Mammoth
Cave particulate sampler location (37.21°N, 86.07°W, elevation 750 feet) in central Kentucky. There are
no additional mandatory Federal Class I areas in Kentucky covered by the Regional Haze Rule.
Mammoth Cave
MPROVE Monitor
Mammoth Cave
National Park
0
OO
miles
Figure KY-1 . Mandatory Federal Class I Area and IMPROVE Monitoring Site in Kentucky
Mammoth Cave National Park
The Mammoth Cave IMPROVE particulate sampler started recording in September of 1991. Figure
KY-2 presents the calculated visibility indices for selected data sets from 1992 through 1998. The fig-
ure shows that from 1992 through 1998 there was a statistically significant trend in the annual average
of the visibility index for the most-impaired days, which decreased from 33 to 32 deciviews (VR from
9 to 10 miles). From 1992 through 1998, there was no significant trend in the annual average of the
visibility index for the mid-range days, which remained near 26 deciviews (VR 18 miles). The annual
average of the visibility index for the least-impaired days remained near 19 deciviews (VR 36 miles)
for most years, with no statistically significant trend in visibility.
Figure KY-3 shows the seasonal averages for the calculated visibility index from 1992 through
1998. The visibility indices for the summer were at least 5 deciviews higher than the other seasons;
visual range was 21 miles for spring 1992, but only 9 miles in the summer of the same year. The lowest
2-84
November 2001
-------
Individual Areas—Kentucky
op _
i/r so -
.2
28
X
0)
c
*•> oo -
1=
H Q -
It)
•Ifi -
?-- -...-.. .- .-• --...-• .... •,„ -- — „!- .---.,,.-,.-,:,,-,,,. -„.„,.„,-.,,-,,,,-, •-.-."-•••" .; •-- --•--••••- - - -: -
a • --. ---. •:. .--•:.,:. -.v:"--. •-::. ~~:-\:. ••"•. \-^:"^..^ •;..--."r-^-y:r:^--:-^-^::-: ^.••:^:-^:-M"^^"/"-^;.;_,-^^-^et--
Mid-Rarige ~ ,13"
— • -- ----- : - ...;-.-:.-;.. - ..-...:-...:.•.... :.-.:•.... ._ • -..
_ ___ — ft—— ___
w '- _.A — w ft
Least-Impaired
1 1 1 1 '-i 1 1 1.. i i
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure KY-2. Yearly Dedview Averages for Most-Impaired, Mid-Range, and
Least-Impaired Days from 1992-1998 for the Mammoth Cave IMPROVE Particulate Sampler
i
a>
o
a>
73
C
-Q
iE^?!, •>• i7«^:''l--^'^™^rT?:le^e^„;i•*s'Sv^^"-^_i-•^•.^••i•f
Err;'--"
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
Year
1998
-Spring
-Summer
-Autumn
-Winter
Figure KY-3. Seasonal Deciview Averages from 1992-1998
for the Mammoth Cave IMPROVE Particulate Sampler
November 2001
2-85
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate Organic
6% Carbon
9%
Sulfate
78%
Elemental
Carbon
4%
Crustal
Material
3%
Figure KY-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Mammoth Cave
IMPROVE Particulate Sampler
visibility indices (best visibility) were observed dur-
ing the winter seasons. No significant seasonal trends
were observed in the calculated visibility indices over
this time period for any of the seasons.
Figure KY-4 presents a chart showing the calcu-
lated fractional contribution to Mammoth Cave's light
extinction by each aerosol species on an annual basis.
Figure KY- 5 shows the same information for the
four seasons. These five pie charts show that sulfate
particles were responsible for 67 to 87 percent of the
light extinction at the Mammoth Cave site, averaging
78 percent on an annual basis over a five-year period.
The highest sulfate contributions occured in the sum-
mer and the lowest in the winter. During the summer
season, the other four components combined (nitrates,
organic and elemental carbon, and crustal material)
represented only 13 percent of the light extinction.
The contributions from nitrate tanged from 4 to 9
Nitrate Organic
•ja/0 Carbon
12%
Sulfate
72%
Elemental
Carbon
5%
Crustal
Material
4%
Nitrate
4%
Sulfate
87%
Organic
- Carbon
5%
Elemental
Carbon
2%
Crustal
Material
2%
Spring
Summer
Organic
Nitrate Carbon
7% 9%
Sulfate
77%
Autumn
Elemental
Carbon
4%
Crustal
Material
3%
Nitrate
9%
Organic
Carbon
13%
Sulfate
67%
Winter
Elemental
Carbon
7%
Crustal
Material
4%
Figure KY-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Mammoth Cave IMPROVE Particulate Sampler
2-86
November 2001
-------
Individual Areas—Kentucky
percent during the four seasons, with winter showing the highest values. Organic carbon percentages
varied from 5 to 13 percent for the seasons. Elemental carbon and crustal material measured at the
Mammoth Cave site were responsible for approximately 4 and 3 percent of the calculated aerosol light
extinction year-round.
Figure KY-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Mammoth Cave site from 1992 to 1998. Over the seven-
year period, the total annual aerosol light extinctions remained near 130 Mm-1 (no significant trend).
Similarly, no significant trends were noted in the annual light extinctions calculated for sulfates, organ-
ic carbon, elemental carbon, or .crustal material.
160
140
120
• 100
c
tJ
w 80
O)
60
o
(0
I 40
20
0
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
GISulfate 0 Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure KY-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1992-1998 for the Mammoth Cave IMPROVE Particulate Sampler
November 2001
.2-87
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
10. MAINE
The only IMPROVE participate sampler in Maine that operated continuously from 1994 through
1998 was the one located in Acadia National Park. Figure ME—1 shows the Acadia particulate sampler
location (44.37°N, 68.26°W, elevation 400 feet) near the Maine coast. The Moosehorn Wilderness Area
is an additional Class I area covered by the Regional Haze Rule, but its IMPROVE monitor did not
begin operation until July 1994. Since the Moosehorn sampler did not have five continuous years of
data from 1994 to 1998, it was not included in this report. Roosevelt Campobello International Park is
another mandatory Federal Class I area located just outside Maine in New Brunswick, Canada, but it
does not have an operating IMPROVE particulate sampler.
Moosehorn
IMPROVE Monitor
Moosehorn
Wilderness^
Bangor°
Augusta
Roosevelt Campobello
Internationa! Park
•Acadia IMPROVE Monitor
Acadia National Park
50 100
miles
Figure ME-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Maine
Acadia National Park
The Acadia IMPROVE particulate sampler started reporting in March of 1988. Figure ME-2 pres-
ents the calculated visibility indices for selected data sets from 1988 through 1998. The figure shows
that the visibility index for the most-impaired days varied from 23 to 27 deciviews (VR from 24 to 16
miles), but there was no statistically significant trend. The visibility indices on the mid-range days
improved from 17 to 15 deciviews (VR from 45 to 55 miles), and the indices on the least-impaired days
improved from 12 to 10 deciviews (VR from 76 to 90 miles). The visibility trends were statistically sig-
nificant improvements for the mid-range and least-impaired days over the time period examined.
2-88
November 2001
-------
Individual Areas—Maine
CO
1
2°
16
tn
> 12
to*
_-w*"ii—ur££.™r i_i.™™ ^H^^S^^V-a-J-'P- -^-^^^-
- Mpst-lmpaired
Mid-Range
""S* j*~
—,—m^
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure ME-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Acadia IMPROVE Participate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-Spring -•-Summer -A-Autumn
-Winter
Figure ME-3. Seasonal Deciview Averages from 1988-1998 for the Acadia IMPROVE
Particulate Sampler
November 2001
2-89
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate'
6%
Organic
Carbon
13%
Elemental
Carbon
5%
Crustal
Material
7%
Sulfate
69%
Figure ME-4. Contribution to Calculated
Annual Aerosol Light Extinction Averaged
from 1994-1998 for the
Acadia IMPROVE Particulate Sampler
Figure ME-3 shows the seasonal averages for the
calculated visibility index from 1988 through 1998.
After 1992, the visibility indices for summer were at
least 2 deciviews higher than those during the other
three seasons. The visibility indices for summer and
autumn showed no significant trend over the eleven-
year period, but the indices for winter and spring
showed significant trends toward increased visibility
(with decreases of 4 and 3 deciviews over the eleven-
year period for the winter and spring seasons).
Figure ME-4 presents a chart showing the calcu-
lated fractional contribution to Acadia's light extinc-
tion by each aerosol species on an annual basis.
Figure ME—5 shows the same information for four
seasons. These five pie charts show that sulfate parti-
cles were responsible for 65 to 70 percent of the light
Nitrate
7%
Organic
Carbon
11%
Sulfate
68%
Spring
Organic
Nitrate Carbon
8%
Elemental
Carbon
5%
Crustal
Material
9%
Sulfate
65%
Autumn
Elemental
Carbon
. 6%
Crustal
Material
9%
Nitrate
4%
Organic
Carbon
16%
Sulfate
70%
Nitrate
8%
Summer
Organic
Carbon
12%
Sulfate
66%
Winter
Elemental
Carbon
5%
Crustal
Material
5%
Elemental
Carbon
6%
Crustal
Material
8%
Figure ME-5. Contribution to Calculated Seasonal Aerosol Light Extinction from
1994-1998 for the Acadia IMPROVE Particulate Sampler
2-90
November 2001
-------
Individual Areas—Maine
extinction at the Acadia site, averaging 69 percent on an annual basis over a five-year period. The high-
est sulfate contributions occurred in the summer the lowest in the autumn and whiter. The contributions
from nitrate ranged from 4 to 8 percent during the four seasons. Organic carbon percentages varied
from 11 to 16 percent for the seasons. Elemental carbon and crustal material measured at the Acadia
site were responsible for approximately 5 and 7 percent of the calculated aerosol light extinction year-
round.
Figure ME-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Acadia site from 1988 to 1998. During the first seven
years and the last four years, the aerosol light extinctions averaged 54 and 45 Mm-1, but no statistically
significant trend was observed by the Thiel test method. The large drop occurred between 1994 and
1995 and can be attributed to the decrease in sulfate contributions during the same time frame. Phase I
of the EPA Acid Rain Program was instituted in 1995 and targeted emission reductions of sulfate parti-
cle precursors. The organic and elemental contributions indicated a significant trend toward improved
visibility. However, no significant trends were noted in the annual light extinctions calculated for sul-
fates or crustal material.
C
_o
"is
O
i
o
W
2
0)
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Q Sulfate n Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure ME-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Acadia IMPROVE Particulate Sampler
November 2001
2-91
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
11. MINNESOTA
The only IMPROVE particulate sampler in Minnesota that operated continuously from 1994
through 1998 was the one located in the Boundary Waters Canoe Area. Figure MN-1 shows the
Boundary Waters particulate sampler location (47.95°N, 91.95°W, elevation 1700 feet) near the
Canadian border. Voyageurs National Park is an additional Class I area covered by the Regional Haze
Rule, but the IMPROVE particualte sampler at this location stopped collecting data in August 1993.
Therefore, only data from the Boundary Waters Canoe Area monitor is included in this report.
Boundary Waters Canoe Area
Voyageurs National
Park
Boundary Waters
IMPROVE Monitor
Minneapolis <*, St. Paul
0
100
200
miles
Figure MN-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Minnesota
Boundary Waters Canoe Area
The Boundary Waters IMPROVE particulate sampler started reporting in August of 1991. Figure
MN-2 presents the calculated visibility indices for selected data sets from 1992 through 1998. The fig-
ure shows that the visibility index for the most-impaired days remained near 21 deciviews (VR 30
miles). The visibility indices on the mid-range days remained near 13 deciviews (VR 65 miles), and the
indices on the least-impaired days stayed close to 8 deciviews (VR 110 miles). The visibility indices for
the most-impaired, mid-range, and least-unpaired days showed no statistically significant trends over
the time period examined.
Figure MN—3 shows the seasonal averages for the calculated visibility index from 1992 through
1998. A summary value for summer 1996 was not reported because carbon measurements were not col-
2-92
November 2001
-------
Individual Areas—Mmnesofa
8
•a
.Q
'55
> 8
Mid-Range
Least-Impaired
4-
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure MN-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1992-1998 for the Boundary Waters IMPROVE Particulate Sampler
S
%
Q
I
.a
"35
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-Spring -»-Summer -A-Autumn
-Winter
Figure MN-3. Seasonal Deciview Averages from 1992-1998
for the Boundary Waters IMPROVE Particulate Sampler
November 2001
2-93
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate
18%
Organic
Carbon
17%
Elemental
Carbon
5%
Crustal
Material
7%
Sulfate
53%
Figure MN-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Boundary
Waters IMPROVE Particulate Sampler
lected. This is reflected in Figure MN-3. Interested
readers can view the data for other species at
http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi.
All four seasons showed similar visibility indices
through 1994, but the spring indices dropped consider-
ably in later years. The statistically significant decrease
in spring indices corresponds to a drop in spring sulfate
concentrations and may be correlated to Phase 1 of the
EPA's Acid Rain Program. The other seasonal visibility
indices showed no statistically significant trends over
the seven-year period.
Figure MN-4 presents a chart showing the calculat-
ed fractional contribution to Boundary Water's light
extinction that each aerosol species is calculated to
contribute on an annual basis. Figure MN-5 shows the
Nitrate
17%
Organic
Carbon
15%
Sulfate
55%
Spring
Nitrate
21%
Organic
Carbon
17%
Sulfate
49%
Autumn
Elemental.
Carbon
5%
Crustal
Material
8%
Elemental
Carbon
6%
Crustal
Material
7%
Organic
Carbon
31%
Nitrate
15%
Elemental
Carbon
6%
Crustal
Material
6%
Sulfate
42%
Summer
Nitrate
19%
Organic
Carbon
11 % Elemental
Carbon
5%
Crustal
Material
5%
Sulfate
60%
Winter
Figure MN-5. Contribution to Calculated Seasonal Aerosol Light ixtinction
from 1994-1998 for the Boundary Waters IMPROVE Particulate Sampler
2-94
November 2001
-------
Individual Areas—Minnesota
same information for the four seasons. These five pie charts show that sulfate particles were responsi-
ble for 42 to 60 percent of the light extinction at the Boundary Waters site, averaging 53 percent on an
annual basis over a five-year period. The highest sulfate contributions occurred in the winter, and the
lowest in the summer. The contributions from nitrate ranged from 15 to 21 percent during the four sea-
sons, with winter showing the highest values. Organic carbon percentages varied from 11 to 31 percent
for the seasons, with the summer percent contributions being double those during other seasons.
Elemental carbon and crustal material measured at the Boundary Waters site were responsible for
approximately 5 and 7 percent of the calculated aerosol light extinction year-round.
Figure MN-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Boundary Waters site from 1992 to 1998. Over the
seven-year period, the total annual aerosol light extinctions ranged from 30 to 40 Mm-1-No statistically
significant trends indicated long-term changes in visibility. Also, no significant trends were noted in
the annual light extinctions calculated for sulfates, organic carbon, elemental carbon, or crustal materi-
al. Since the Boundary Waters site collected only about one half of the scheduled measurements during
summer 1995, summer 1996, autumn 1998, and winter 1998, the reader should be cautioned that the
annual values reported in Figure MN-6 may not be representative of the true annual averages.
t? ^^^W^-S^^i^^c^^^^^fc^^^^-T^*^-tBs^!*Bi^^^
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
a Sulfate El Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure MN-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1992-1998 for the Boundary Waters IMPROVE Particulate Sampler
November 2001
2-95
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to:Congress
12. MONTANA
The only IMPROVE particulate sampler site in Montana that operated continuously from 1994
through 1998 was the one located in Glacier National Park. Figure MT—1 shows the Glacier Park par-
ticulate sampler location (48.51°N, 113.99°W, elevation 4500 feet) near the Canadian border. Sula Peak
(near the Selway-Bitterroot Wilderness Area) began operation of an IMPROVE particulate sampler in
August 1994 and therefore did not have five complete years of data collected for this report. Additional
mandatory Federal Class I areas include Cabinet Mountains Wilderness, Bob Marshall Wilderness,
Scapegoat Wilderness, U.L. Bend Wilderness, Medicine Lake Wilderness, Gates of the Mountains
Wilderness, Anaconda-Pintlar Wilderness, and Red Rock Lakes Wilderness, but IMPROVE particulate
samplers have not been established at these sites. The northeastern border of the Selway-Bitterroot
Wilderness is located in Montana, and the western and northern borders of Yellowstone National Park
are located in Montana. The Flathead Fort Peak and Northern Cheyenne Tribal Governments have
redesignated their lands as Class I, but these areas are not covered by the Regional Haze Rule.
Glacier IMPROVE Monitor Glacier National Park
Cabinet
Mountains
Wilderness
Mission
Mountains
Wilderness
Bob Marshall Wilderness
Selway-Bitterroot'
Wilderness
Medicine Lake
Wilderness,•*
UL Bend Wilderness
Scapegoat Wilderness
'Missoula *—Gates of the Mountains Wilderness
®
Helena
Anaconda-Pintlar
Wilderness
Red Rock Lakes
Wilderness
Figure MT-1,
-Yellowstone National Park
_ _ ™—
miles
Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Montana
Glacier National Park
The Glacier IMPROVE particulate-sampler started reporting in March of 1988. Figure MT-2 pres-
ents the calculated visibility indices for selected data sets from 1988 through 1998. The figure shows
that the visibility index for the most-impaired days remained near 19 deciviews (VR 36 miles). No sta-
tistically significant trend in visibility occurred. Similarly, statistical analysis indicated no significant
trend when examining the visibility indices on the mid-range days; the index values remained near 14
deciviews (VR 60 miles). The indices on the least-impaired days remained near 9 deciviews (VR 100
miles) and showed no significant trend in visibility.
Figure MT—3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The visibility indices for all four seasons generally covered the same range of values. The visibil-
2-96
November 2001
-------
Individual Areas—Montana
in
r» j o la^ ,^~.s,'.^^~^ *HJ -'/^ -W~'** ^"^^.^^--^^—-v,;^-^...,,,^.^^.--^ ,^;^^-^:^^^^^,-^^.^^:iwv..^.'-^-^..^^^>^^.—--^^^--:-^:-:i ^-^•i^..i^-^z^j^?^^^^gafe^^^'^^-^SSM>»Bv>-j-i^w''ilfe^w^»^^':
5 I o v^sisJfSKt^its^sessiesssaaiafiss^asif^
o> ES:,: ;.::j:::;\:::;:::/;::;r_i:±:::r;::v;;:;r:::^:,gyos|-trnp^a!red """"" " "^""'"•'-'
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure MT-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Glacier IMPROVE Particulate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
•Spring -•-Summer -Ar-Autumn
• Winter
Figure MT-3. Seasonal Deciview Averages from 1988-1998 for the Glacier IMPROVE
Particulate Sampler
November 2001
2-97
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
32%
Elemental
Carbon
12%
Nitrate
8%
Crustal
Material
13%
Sulfate
35%
Figure MT-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Glacier IMPROVE Particulate Sampler
ity indices for winter showed a statistically significant
trend, indicating an improvement in winter visibility at
the Glacier Park site. The seasonal visibility indices for
the other seasons showed no statistically significant
trends over the eleven-year period. The spring, summer,
and autumn seasons all showed sharp increases in the
visibility indices in 1998 (marked by a fifty percent
increase in organic carbon concentrations from 1997 to
1998), but no statistically significant trends were
observed even when the 1998 values were ignored
Figure MT—4 presents a chart showing the calculated
fractional contribution to Glacier Park's light extinction
by each aerosol species on an annual basis. Figure
MT—5 shows the same information for the four seasons.
These five pie charts show the two largest contributors
to light extinction were sulfate particles and organic car-
bon. The sulfate particles were responsible for 29 to 43
Organic
Carbon
27%
Elemental
Carbon
10%
Crustal
Material
11%
Nitrate
9%
Sulfate
43%
Spring
Elemental
Carbon
10%
Organic
Carbon
33%
Nitrate
7%
Crustal
Material
21%
Sulfate
29%
Summer
Elemental
Carbon
15%
Organic
Carbon
38%
Crustal
Material
11%
Nitrate
7%
Sulfate
29%
Autumn
Organic
Carbon
28%
Nitrate
11%
Elemental
Carbon
14%
Crustal
Material
7%
Sulfate
40%
Winter
Figure MT-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Glacier IMPROVE Particulate Sampler
2-98
November 2001
-------
Individual Areas—Montana
percent of the light extinction at the Glacier Park site, averaging 35 percent on an annual basis over a
five-year period. The highest sulfate contributions occured in the spring, and the lowest in the summer
and autumn. Organic carbon percentages varied from 27 to 38 percent for the seasons, with the autumn
contributions 10 percent higher than winter and spring. The contributions from nitrate ranged from 7 to
11 percent during the four seasons, with winter showing the highest percentage. Elemental carbon
measured at the Glacier Park site was responsible for approximately 12 percent of the calculated
aerosol light extinction year-round. The percent contributions from crustal material ranged from 7 to 21
percent.
Figure MT-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Glacier Park site from 1988 to 1998. Over the eleven-
year period, the total annual aerosol light extinctions ranged from 28 to 37 Mm-1 with no statistically
significant trend toward improved visibility. No significant trends were noted in the annual light extinc-
tions calculated for sulfates, organic carbon, elemental carbon, or crustal material. The abrupt increase
in the light extinction coefficient from 1997 to 1998 was caused by marked jumps in the ambient
organic carbon and crustal material concentrations during spring, summer, and autumn.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
H Sulfate E3 Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure MT-6. Contributions to Calculated Annual Aerosol Light Extinction From
1988-1998 for Glacier IMPROVE Particulate Sampler
November 2001
2-99
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
13. NEVADA
An IMPROVE particulate sampler in Nevada's Jarbidge Wilderness Area operated continuously
from 1988 through 1998. Figure NV-1 shows the Jarbidge monitoring location (41.89°N, 115.43°W,
elevation 6300 feet) in northern Nevada. The Jarbidge Wilderness Area is Nevada's only mandatory
Federal Class I area. An IMPROVE monitor (39.00°N, 114.22°W, elevation 6800 feet) operates in Great
Basin National Park, but Great Basin is not a mandatory Federal Class I area. Therefore, the results
from the Great Basin monitor site will not be detailed in this section. However, data from the Great
Basin IMPROVE particulate sampler are included in the national and regional analyses discussed in
Chapters.
Jarbidge IMPROVE Monitor
Carson City
7
Jarbidge Wilderness
•Reno
Great Basin
IMPROVE Monitor
—®
miles
Figure NV-1. Mandatory Federal Class I Area and IMPROVE Monitoring Sites in Nevada
Jarbidge Wilderness Area
The Jarbidge IMPROVE particulate sampler started reporting in March of 1988. Figure NV-2 pres-
ents the calculated visibility indices for selected data sets from 1988 through 1998. The figure shows
that the visibility index for the most-impaired days remained near 12 deciviews (VR 75 miles). There
was no statistically significant trend in visibility. The visibility indices on the mid-range days remained
near 7 deciviews (VR 120 miles), with no significant trend in visibility. The indices on the least-
impaired days remained near 4 deciviews (VR 165 miles), with no significant trend in visibility.
Jarbidge's annual visibility indices for the least-impaired days were among the lowest index sets calcu-
lated at IMPROVE stations across the United States. No data samples were collected between October
12, 1996 and April 30, 1997 (the time of year with the lowest readings), so the 1996 average visibility
indices for the most-impaired, mid-range, and least-impaired days rose markedly.
Figure NV—3 shows the seasonal averages for the calculated visibility indices from 1988 through
1998. A summary value for winter 1996 was not reported because the site did not collect data between
2-100
'November 2001
-------
Individual Areas—Nevada
16
i^^sfi.,i^^t.iju^^
•ap^ -,.-5- S^lirT^-w-jas:*;?^-:
r_*%S^^^.-^:"v^r-J'^^
Most-Impaired
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure NV-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1993 for the Jarbidge IMPROVE Participate Sampler
1988 1989 1990 1991 1992
1993
Year
1994 1995 1996 1997 1998
-Spring -B-Summer -A-Autumn
-Winter
Figure NV-3. Seasonal Deciview Averages from 1988-1998 for the
Jarbidge IMPROVE Participate Sampler
November 2001
2-101
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
9%
Crustal
Material
Organic
Carbon
32%
Nitrate
5%
Sulfate
23%
Figure NV-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Jarbidge IMPROVE Particulate Sampler
Elemental
Carbon
9%
Organic
Carbon
27%
Crustal
Material
24%
Nitrate
7%
Sulfate
33%
October 12, 1996 and April 30, 1997. This is reflected
in Figure NV—3. The visibility indices for the winter
season were generally at least 2 deciviews lower than
those for the other three seasons (indicating better visi-
bility during the winter). None of the seasonal visibility
indices (spring, summer, autumn, and winter) showed
statistically significant trends over the eleven year peri-
od.
Figure NV—4 presents a chart showing the calculated
fractional contribution to Jarbidge's light extinction by
each aerosol species on .an annual basis. Figure NV—5
shows the same information for the four seasons. These
five pie charts show that the three largest contributors to
light extinction were sulfate particles, organic carbon,
and crustal material. The sulfate particles were responsi-
ble for 18 to 33 percent of the light extinction at the
Crustal
Material
___ 37%
^•dBBHBSk*
Elemental
Carbon
8%
Organic
Carbon
34%
Sulfate
18%
Nitrate
3%
Spring
Summer
Elemental
Carbon
9%
Organ!
Carbon
35%
Crustal
Material
30%
Nitrate
5%
Autumn
Sulfate
21%
Elemental
Carbon
10%
Organic
Carbon
27%
Nitrate
12%
Winter
Crustal
Material
24%
Sulfate
27%
Figure NV-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Jarbidge IMPROVE Particulate Sampler
2-102
November 2001
-------
Individual Areas—Nevada
Jarbidge site, averaging 23 percent on an annual basis over a five-year period. Organic carbon percent-
ages varied from 27 to 35 percent for the seasons, with summer and autumn percent contributions 8
percent higher than winter and spring. Crustal material represented between 24 and 37 percent of the
calculated light extinction, with its highest contributions in the summer seasons. The contributions
from nitrate ranged from 3 to 12 percent during the four seasons, with winter showing the highest per-
centages. Elemental carbon measured at the Jarbidge site was responsible for approximately 9 percent
of the calculated aerosol light extinction year-round.
Figure NV-6 shows the calculated contributions of each of the aerosol mass components to the
annual averaged aerosol light extinctions at the Jarbidge site from 1988 to 1998. Over the eleven-year
period, the total annual aerosol light extinctions ranged from 11 to 14 Mm-1 (except for 1996 when
more than four months of autumn and winter data were missing) with no statistically significant trend
in visibility. No significant trends were noted in the annual light extinctions calculated for sulfates,
organic carbon, or crustal material. However, the annual light extinctions for elemental carbon showed
a statistically increasing trend over the eleven-year period, indicating an increase in the ambient con-
centrations of elemental carbon.
LJJ
O
O
8
I
1988 1989 1990 1991 1992. 1993 1994 1995 1996 1997 1998
Year
DSulfate H Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure NV-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Jarbidge IMPROVE Particulate Sampler
November 2001
2-103
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
14. NEW JERSEY
The only IMPROVE participate sampler site in New Jersey is near the Brigantine Wilderness, locat-
ed within the Edwin B. Forsythe National Wildlife Refuge. Figure NJ—1 shows the Brigantine particu-
lale sampler location (39.47°N, 74.45°W, elevation 50 feet) near the Atlantic Coast. The Brigantine
Wilderness Area is New Jersey's only mandatory Federal Class I area covered under the Regional Haze
Rule.
Figure NJ-1.
Brigantine Wilderness
——_
Brigantine IMPROVE Monitor
0 50 100
miles
Mandatory Federal Class I Area and IMPROVE Monitoring Site in New Jersey
Brigantine Wilderness Area, Edwin B. Forsythe National Wildlife Refuge
The Brigantine IMPROVE particulate sampler started collecting data in September of 1991. Figure
NJ—2 presents the calculated visibility indices for selected data sets from 1992 through 1998. The fig-
ure shows that the visibility index for the most-impaired days remained near 30 deciviews (VR 12
miles). There was no statistically significant trend in visibility. The visibility indices on the mid-range
days remained between 21 and 23 deciviews (VR from 30 to 24 miles), with no significant trend in vis-
ibility. The indices on the least-impaired days remained near 17 deciviews (VR 45 miles), with no sig-
nificant trend in visibility.
Figure NJ-3 shows the seasonal averages for the calculated visibility index from 1992 through
1998. The visibility indices for the summer season were generally 3 deciviews higher than those for the
spring season, and the spring values were 1 or 2 deciviews higher than autumn and winter. The season-
al visibility indices for spring, autumn, and winter showed no statistically significant trends over the
2-104
November 2001
-------
Individual Areas—N/ew Jersey
0)
I
>
X
0)
32
28
24
120
.a -
'35
> 16
12
Mid-Range
-• •
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure NJ-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1992-1998 for the Brigantine IMPROVE Particulate Sampler
SteiS?»*^s^i!ff'iiHS*S3*:it:Si^
1988 1989 1990 1991
• Spring
1992 1993
Year
1994 1995 1996 1997 1998
-Summer -A-Autumn
-Winter
Figure NJ-3. Seasonal Deciview Averages from 1992-1998 for the
Brigantine IMPROVE Particulate Sampler
November 2001
2-105
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Nitrate Carbon
10%
Elemental
Carbon
6%
Crustal
Material
9%
Sulfate
65%
Figure NJ-4. Contribution to Calculated
Annual Aerosol Light Extinction
Averaged from 1994-1998 for the the
Brigantine IMPROVE Particulate Sampler
seven-year period, but the summer indices dropped 2
deciviews with a statistically significant decrease.
Figure NJ-4 presents a chart showing the calculated
fractional contribution to Brigantine's light extinction of
each aerosol species on an annual basis. Figure NJ-5
shows the same information for the four seasons. These
five pie charts show the largest contributors to light
extinction were sulfate particles. The sulfate particles
were responsible for 55 to 76 percent of the light extinc-
tion at the Brigantine site, averaging 65 percent on an
annual-basis over a five-year period. The contributions
from sulfates were highest in the summer and lowest
during the winter season. The contributions from nitrate
ranged from 7 to 11 percent during the four seasons,
with autumn and winter showing the highest percent-
ages.
Nitrate °r9*nic
10% Carobon Elemental
Carbon
5%
Crustal
Material
10%
Sulfate
68%
Nitrate
11%
Spring
Organic
Carbon
12%
Sulfate
60%
Autumn
Elemental
Carbon
8%
Crustal
Material
9%
Organic
Nitrate r carbon
7% I 8%
Sulfate
76%
Elemental
Carbon
3%
Crustal
Material
6%
Nitrate
11%
Summer
. Organic
Carbon Elemental
15% Carbon
9%
Crustal
Material
10%
Sulfate
55%
Winter
Figure NJ-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Brigantine IMPROVE Particulate Sampler
2-106
November 2001
-------
Individual Areas—New Jersey
Organic carbon percentages remained between 7 and 15 percent for the seasons. Elemental carbon and
crustal material measured at the Brigantine site were responsible for 6 and 9 percent of the calculated
aerosol light extinction year-round.
Figure NJ-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Brigantine site from 1992 to 1998. Over the seven-year
period, the total annual aerosol light extinctions ranged from 89 to 110 Mm.-1 with no statistically sig-
nificant trend in visibility. Similarly, no significant trends were noted in the annual light extinctions
calculated for sulfates, organic carbon, or elemental carbon. The light extinction from sulfate aerosols
dropped 16 percent between the first three and last four years, coinciding with the emission reductions
of Phase I of the Acid Rain Program. However, the decrease was not statistically significant according
to the Theil test method. The annual light extinctions for crustal material increased approximately 4
Mm.-1 over the same period, a statistically significant trend indicating higher crustal material concentra-
tions in the ambient air.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
a Sulfate GJ Nitrate D Organic Carbon D Elemental Carbon B Crustal Material
Figure NJ-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1992-1998 for the Brigantine IMPROVE Particulate Sampler
November 2001
2-107
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
15. NEW MEXICO
Nine mandatory Federal Class I areas are located in New Mexico. The only IMPROVE particulate
sampler in New Mexico that operated continuously from 1994 through 1998 is located at Bandelier
Wilderness Area. Figure NM—1 shows the Bandelier particulate sampler location (35.79°N, 106.26°W,
elevation 6500 feet) west of Santa Fe. Additional mandatory Federal Class I areas in New Mexico
include Carlsbad Caverns National Park and the following wilderness areas: Wheeler Peak, San Pedro
Parks, Pecos, Bosque del Apache, Gila, White Mountain, and Salt Creek. An IMPROVE particulate
sampler in the Gila Cliff Dwellings National Monument near the Gila Wilderness Area began reporting
data in June 1994, so five complete years of data were not available for its inclusion in this report. The
other mandatory Federal Class I areas do not have IMPROVE monitoring data for the years prior to
1999.
Gila Wilderness.
San Pedro Parks
Wilderness
Bandelier
Wilderness
Bandelier IMPROVE
Monitor
Wheeler Peak Wilderness
Pecos
aft Wilderness
f*
Santa Fe
Bosque del Apache Wilderness
f o Roswell
White Mountain Wilderness
Carlsbad Caverns National Park
Las Cruces •
V
Salt Creek
.Wilderness
100
miles
200
Figure NM-1. Mandatory Federal Glass I Areas and IMPROVE Monitoring Site
in New Mexico
Bandelier Wilderness Area
The Bandelier IMPROVE particulate sampler started reporting in March of 1988. Figure NM-2
presents the calculated visibility indices for selected data sets from 1988 through 1998. The figure
shows that the visibility index for the most-impaired days remained between 10 and 14 deciviews
(VR 90 to 60 miles). There was no statistically significant trend in visibility. However, the visibility
indices on the mid-range days decreased from 10 to 9 deciviews (VR 90 to 100 miles), with a signifi-
cant trend toward improved visibility. The indices on the least-impaired days remained near 7 deciviews
(VR 120 miles), with no significant trend in the visibility indices. Readers may note that the 1990
most-impared average deciview index was lower than the mid-range index; this crossover occurred
because the data were sorted based on mass, not based on visibility impairment.
2-108
November 2001
-------
Individual Areas—New Mexico
1 ^
"TT* j^^T^,^Ir_-—=^-Jj^,v--^v=^^
10
I"
"35
Mid-Range
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure NM-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Bandelier IMPROVE Particulate Sampler
1988 1989 1990 1991 1992
1993 1994
Year
1995 1996 1997 1998
- Spring
-Summer
-Autumn
-Winter
Figure NM-3. Seasonal Deciview Averages from 1988-1998 for the
BandeBier IMPROVE Particulate Sampler
November 2001
2-109
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
26%
Nitrate
7%
Elemental
Carbon
10%
Crustal
Material
19%
Sulfate
38%
Figure NM-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Bandelier IMPROVE Particulate
Sampler
Elemental
Carbon
9%
Crustal
Material
27%
Organic
Carbon
24%
Nitrate
7%
Sulfate
33%
Figure NM-3 shows the seasonal averages for the calcu-
lated visibility index from 1988 through 1998. The visibility
indices for all four seasons were generally between 8 and
12 deciviews. The visibility indices for spring, summer, and
autumn showed no statistically significant trends over the
eleven-year period. However, the winter indicies decreased
more than 1 deciview within a statistically significant trend.
Figure NM-4 presents a chart showing the calculated
fractional contribution to Bandelier's light extinction by
each aerosol species on an annual basis. Figure NM-5
shows the same information for the four seasons. These five
pie charts show the largest contributors to light extinction
were sulfate particles and organic carbon. The sulfate parti-
cles were responsible for 33 to 41 percent of the light
extinction at the Bandelier site, averaging 38 percent on an
annual basis over a five-year period. The contributions from
sulfates were highest in the summer and lowest during the
Organic
Carbon
28%
Nitrate
6%
Elemental
Carbon
8%
Crustal
Material
17%
Sulfate
41%
Spring
Summer
Organic
Carbon
27%
Nitrate1
7%
Elemental
Carbon
11% Crustal
Material
15%
Sulfate
40%
Elemental
Carbon
13%
Organic
Carbon
24%
Nitrate
10%
Crustal
Material
18%
Sulfate
35%
Autumn Winter
Figure NM-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Bandelier IMPROVE Particulate Sampler
2-110
November 2001
-------
JndiViduaf Areas—New Mexico
spring season. Organic carbon percentages remained between 24 and 28 percent for the seasons. The
contributions from nitrate ranged from 6 to 10 percent during the four seasons, with winter showing the
highest percentages. Elemental carbon measured at the Bandelier site was responsible for approximate-
ly 10 percent of the calculated aerosol light extinction year-round. Crustal material represented 27 per-
cent of the light extinction at the monitor in the spring but only approximately 17 percent during the
remaining three seasons.
Figure NM—6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Bandelier site from 1988 to 1998. Over the eleven-year
period, the total annual aerosol light extinctions remained near 17 Mm-1 with no statistically significant
trend in visibility. Similarly, the annual light extinctions for sulfates, organic carbon, elemental carbon,
and crustal material showed no significant trends in their values.
1988 1989 1990 1991
1992
1993 1994 1995 1996 1997 1998
Year
a Sulfate 0 Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure NM-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Bandelier IMPROVE Particulate Sampler
November 2001
2-111
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
16. OREGON
Two IMPROVE particulate samplers in Oregon operated continuously from 1994 through 1998 and
are located at the Three Sisters Wilderness Area (monitor at 44.28°N, 122.05°W, elevation 2850 feet)
and Crater Lake National Park (42.88°N, 122.13°W, elevation 6500 feet). Figure OR-1 shows the
Three Sisters and Crater Lake particulate sampler locations east and southeast of Eugene. Additional
mandatory Federal Class I areas in Oregon covered under the Regional Haze Rule include the follow-
ing wilderness areas: Mount Hood, Eagle Cap, Hells Canyon, Mount Jefferson, Mount Washington,
Strawberry Mountain, Diamond Peak, Kalmiopsis, Mountain Lakes, and Gearhart Mountains. These
Class I areas do not have IMPROVE particulate sampler data for the years prior to 1999.
. Mount Hood Wilderness
Hells Canyon Wilderness
Eagle Cap Wilderness
Portland
Mount Jefferson Wilderness
[Salem
Three Sisters IMPROVE Monitor-
9
Eugene
-^- w
Strawberry Mountai
Mount Washington 1^
Wilderness ""^
ilderness
sjsters Wi|derness
l^Crater Lake National Park
g__CraterLa/ce IMPROVE Monitor
Mountain Lakes Wilderness
<*- — Gearhart Mountain
Wilderness
Kalmiopsis Wilderness
100
=3^
miles
200
Figure OR-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Oregon
Crater Lake National Park
The Crater Lake IMPROVE particulate sampler started operating in March of 1988. Figure OR-2
presents the calculated visibility indices for selected data sets from 1988 through 1998. The figure
shows that the visibility index for the most-impaired days generally remained near 13 deciviews (VR
65 miles). There was no statistically significant trend in visibility for the most-impaired days. The visi-
bility indices on the mid-range days remained near 8 deciviews (VR 110 miles), with no significant
trend in visibility. The indices on the least-impaired days remained near 4.5 deciviews (VR 155 miles),
with no significant trend in visibility.
Figure OR—3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The visibility indices for all four seasons were generally between 5 and 11 deciviews. The indices
2-112
November 2001
-------
Individual Areas—Oregon
16
-~'•' ""'''"'" '''" "^''''''"'' '''''
o
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
16%
Organic
Carbon
33%
Crustal
Material
18%
Nitrate
6%
Sulfate
27%
Figure OR-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Crater Lake IMPROVE
Particulate Sampler
for summer were most frequently the highest, and the
indices for winter the lowest. The visibility indices for
each of the seasons showed no statistically significant
trends over the eleven-year period.
Figure OR-4 presents a chart showing the calculated
fractional contribution to Crater Lake's light extinction
by each aerosol species on an annual basis. Figure
OR—5 shows the same information for the four seasons.
These five pie charts show that the largest contributor to
light extinction was organic carbon. Organic carbon per-
centages ranged from 20 to 41 percent for the seasons,
averaging 33 percent over a five-year period. The sum-
mer and autumn percent contributions from organic car-
bon were double those of winter. Sulfate particles were
responsible for 20 to 36 percent of the light extinction at
the Crater Lake site, averaging 27 percent on an annual
Elemental
Carbon
12%
Organic
Carbon
25%
Nitrate
7%
Crustal
Material
20%
Sulfate
36%
Organic
Carbon
41%
Elemental
Carbon
13%
Nitrate
4%
Crustal
Material
16%
Sulfate
26%
Spring
Elemental
Carbon
16%
Summer
Organic
Carbon
41%
Crustal
Material
18%
Elemental
Carbon
29%
Organi
Carbon
20%
Nitrate
11%
Winter
Crustal
Material
19%
Sulfate
21%
Sulfate
20%
Nitrate
5%
Autumn
Figure OR-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Crater Lake IMPROVE Particulate Sampler
2-114
November 2001
-------
lnd;'viduaJ Areas—Oregon
basis over a five-year period. The contributions from sulfates were highest in the spring and lowest dur-
ing the autumn. The contributions from nitrate and crustal material were near 6 and 18 percent year-
round. Elemental carbon measured at the Crater Lake site was responsible for 12 to 29 percent of the
calculated aerosol light extinction, with the highest contributions occurring during the winter.
Figure OR-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Crater Lake site from 1988 to 1998. Over the eleven-year
period, the total annual aerosol light extinctions remained near 14 Mm"1 with no statistically significant
trend toward improved visibility. Similarly, the annual light extinctions for sulfates, organic carbon, ele-
mental carbon, and crustal material showed no significant trends in their values.
o
S
UJ
•l-l
O>
o
2
0>
<
1988 1989 1990 1991
1992
1993
Year
1994 1995 1996 1997 1998
m Sulfate
El Nitrate D Organic Carbon D Elemental Carbon
\ Crustal Material
Figure OR-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998
for the Crater Lake IMPROVE Particulate Sampler
Three Sisters Wilderness Area
The Three Sisters IMPROVE particulate sampler started reporting data in July of 1993. Figure
OR-7 presents the calculated visibility indices for selected data sets from 1994 through 1998. The fig-
ure shows that the visibility index for the most-impaired days remained near 18 deciviews (VR 40
miles). There was no statistically significant trend in visibility. The visibility indices on the mid-range
and least-impaired days remained near 10 and 4.5 deciviews (VR 90 and 155 miles), respectively, with
no significant trend in visibility.
Figure OR-8 shows the seasonal averages for the calculated visibility index from 1994 through
1998. Because coarse mass measurements were not available for spring 1994, no visibility index was
November 2001
2-115
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1
o
CU
Q
|
Mftfit^4*W£i4MiW&t*»'3tf-fc':.: -''iSsS-iH^S-aii:.!:
..y^^i-xrf,,.,,.^,,- ^ ^
"""siSSiaipgigt&jSvasii
,".-.--, :.-.-; Most-Impaired
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure OR-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1994-1998 for the Three Sisters IMPROVE Particulate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
- Spring
•Summer
•Autumn
Winter
Figure OR-8. Seasonal Deciview Averages from 1994-1998 for the
Three Sisters IMPROVE Particulate Sampler
2-116
November 2001
-------
(ndividuaf Areas—Oregon
Organic
Carbon
27%
Elemental
Carbon
8%
Nitrate
8%
Crustal
Material
11%
Sulfate
46%
Figure OR-9. Contribution to
Calculated Annual Light Extinction from
1994-1998 for the Three Sisters
IMPROVE Particulate Sampler
calculated for this season. Interested readers can view the
data for other species at
http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi. The
indices for summer were 1 to 5 deciviews higher than the
indices for spring and autumn, and the indices for the
spring and autumn were 2 to 5 deciviews higher than
those of winter. No statistically significant trends were
observed in the spring, summer, or autumn. The winter
indices showed a statistically significant decrease of more
than 1 deciview over five years.
Figure OR-9 presents a chart showing the calculated
fractional contribution to Three Sister's light extinction by
each aerosol species on an annual basis. Figure OR-10
shows the same information for the four seasons. These
five, pie charts show that the largest contributors to light
extinction were sulfate particles and organic carbon.
Sulfate particles were responsible for 39 to 52 percent of
Organic
Carbon
19%
Nitrate
10%
Elemental
Carbon
7%
Crustal
Material
12%
Sulfate
52%
Spring
Organic
Carbon
32%
Elemental
Carbon
10%
Nitrate*
8%
Crustal
Material
11%
Sulfate
39%
Autumn
Organic
Carbon
33%
Elemental
Carbon
9%
Nitrate
3%
Crustal
Material
14%
Sulfate
41%
Summer
Organic
Carbon
18%
Nitrate
23%
Elemental
Carbon
7%
Crustal
Material
11%
Sulfate
41%
Winter
Figure OR-10. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Three Sisters IMPROVE Particulate Sampler
November 2001
2-117
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
the light extinction at the Three Sisters site, averaging 46 percent on an annual basis over a five-year
period. The contributions from sulfates were highest in the spring and lowest during the autumn.
Organic carbon percentages ranged from 18 to 33 percent for the seasons, averaging 27 percent. The
percent contributions from organic carbon were highest in the "summer and autumn. The nitrate contri-
butions ranged from 3 to 23 percent with the highest contributions in winter. Annually, the contribu-
tions from elemental carbon and crustal material were near 8 and 11 percent.
Figure OR-11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Three Sisters site from 1994 to 1998. Over the five-year
period, the total annual aerosol light extinctions ranged from 20 to 25 Mm"1 with no statistically signifi-
cant trend in visibility. Similarly, the annual light extinctions for sulfates, organic carbon, elemental
carbon, and crustal material showed no significant trends in their values.
28
1988 1989 1990 1991
• Sulfate H Nitrate
1992 1993 1994 1995 1996 1997 1998
Year
D Organic Carbon D Elemental Carbon • Crustal Material
Figure OR-1 1. Contributions to Calculated Annual Aerosol Light Extinction from 1994-1998
for the Three Sisters IMPROVE Particulate Sampler
Oregon State Summary
The two IMPROVE monitoring sites in Oregon are just 100 miles apart, but the calculated visibility
is considerably more impaired at Three Sisters Wilderness than at Crater Lake National Park. Table
OR— 1 shows the calculated aerosol light extinction coefficients for the two sites. The average visual
ranges for the Three Sisters and Crater Lake sites are 75 and 105 miles.
2-118
November 2001
-------
Individual Areas—Oregon
The average measured concentrations of sulfate at the Three Sisters and Crater Lake sites were 0.45
and 0.71 |ig/m3. The annual average relative humidities used to calculate light extinction at the Crater
Lake and Three Sisters sites correspond to relative humidity adjustment factors (Appendix C) of 2.60
and 4.91. As a result, although the ambient concentrations of sulfate and nitrate were only about 30
percent lower at the Crater Lake site than at Three Sisters, the calculated extinction coefficients for sul-
fates and nitrates at the Three Sisters site were almost triple those at the Crater Lake site (Table OR-1).
This example illustrates the importance of meteorological conditions (e.g., relative humidity) to visibil-
ity impairment.
Table OR-1. Oregon Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Crater Lake NP
Three Sisters Wilderness
Calculated Total
Aerosol Extinction
Coefficient (Mm" )
13.2
22.5
Pollutant Extinction Coefficient (Mm"1)
Sulfate
3.5
10.4
Nitrate
0.7
1.8
Organic
Carbon
4.5
6.0
Elemental
Carbon
2.1
1.8
Crustal
Material
2.3
.2.5
November 2001
2-119
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
17. SOUTH DAKOTA
The only IMPROVE participate sampler in South Dakota is located in Badlands National Park.
Figure SD-1 shows the Badlands monitor location (43.74°N, 101.94°W, elevation 2493 feet) in the
southwestern portion of the state. The only additional mandatory Federal Class I area in South Dakota
covered under the Regional Haze Rule is Wind Cave National Park. Wind Cave did not have IMPROVE
monitor data for the years prior to 1999.
Rapid City
Pierre^,
IMPROVE Monitor
Badlands Wilderness
Sioux Falls
Wind Cave National Park
0
100
200
miles
Figure SD-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sale in South Dakota
Badlands National Park
The Badlands IMPROVE particulate sampler started reporting data in March of 1988. Figure SD-2
presents the calculated visibility indices for selected data sets from 1988 through 1998. The figure
shows that the visibility index for the most-impaired days was generally between 17 and 19 deciviews
(VR between 45 and 36 miles), with no statistically significant trend in visibility. The visibility indices
on the mid-range days remained near 12 deciviews (VR 75 miles), with no significant trend in visibili-
ty. The indices on the least-impaired days decreased from 8.3 to 7.4 deciviews (VR from 105 to 115
miles), with a significant trend toward improved visibility.
Figure SD-3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The visibility indices for all four seasons were generally between 11 and 15 deciviews. The
indices for summer were most frequently the highest, and indices for winter the lowest. The visibility
indices for all four seasons showed no statistically significant trends over the eleven-year period.
2-120
November 2001
-------
Individual Areas—South Dakota
I 16
'>
'o
Q)
Q 14
X
Q)
I 12
|-
S 10
8
Lj^^-^S^^B$B?i*F'ii'itM;
~ .MQ$t-]mpaired
-if-
Mid-Range
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure SD-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Badlands IMPROVE Particulate Sampler
10
~T 1 i 1 1 T
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
- Spring
-Summer -A-Autumn
-Winter
Figure SD-3. Seasonal Deciview Averages from 1988-1998
for the Badlands IMPROVE Particulate Sampler
November 2001
2-121
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
19%
Nitrate
14%
Elemental
Carbon
6%
Crustal
.Material
14%
Sulfate
47%
Figure SD-4. Contribution to Calculated
Annual Aerosol Light Extinction from .
1994-1998 for the Badlands IMPROVE
Particulate Sampler
Nitrate
14%
Organic
Carbon
13%
Elemental
Carbon
5%
Crustal
Material
13%
Sulfate
55%
Spring
Organic
Carbon
21%
Elemental
Carbon
7%
Nitrate
14%
Crustal
Material
15%
Sulfate
43%
Autumn
Figure SD^4- presents a chart showing the calcu-
lated fractional contribution to Badland's light
extinction by each aerosol species on an annual
basis. Figure SD-5 shows the same information for
the four seasons. These five pie charts show that the
largest contributors to light extinction were sulfate
particles. Sulfate particles were responsible for 43 to
55 percent of the light extinction at the Badlands
site, averaging 47 percent on an annual basis over a
five-year period. The contributions from sulfates
were highest in the spring and lowest during the
autumn. The contributions from nitrate ranged from
11 to 18 percent, with the highest concentrations in
the winter and the lowest concentrations in the sum-
mer. Organic carbon percentages ranged from 13 to
25 percent for the seasons, averaging 19 percent.
The summer and autumn percent contributions from
Organic
Carbon
25%
Nitrate
11%
Elemental
Carbon
5%
Crustal
Material
14%
Sulfate
45%
Summer
Organic
Carbon
13%
Elemental
Carbon
6%
Nitrate
18%
Crustal
Material
13%
Sulfate
50%
Winter
Figure SD-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Badlands IMPROVE Particulate Sampler
2-122
November 2001
-------
Individual Areas—South Dakota
organic carbon were double those of the winter and spring. Elemental carbon and crustal material
measured at the Badlands site were responsible for 6 and 14 percent of the calculated aerosol light
extinction, with only small percent differences between the seasons.
Figure SD-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Badlands site from 1988 to 1998. Over the eleven-year
period, the total annual aerosol light extinctions remained between 23 and 28 Mm-1 with no statistically
significant trend in visibility. Similarly, the annual light extinction contributions from the sulfate,
organic carbon, and elemental carbon species showed no statistically significant trend. However, the
annual light extinctions for crustal material showed a significant trend in its values toward smaller con-
tributions to the light extinction coefficient, indicating lower ambient concentrations.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
n Sulfate H Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure SD-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Badlands IMPROVE Particulate Sampler
November 2001
2-123
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
18. TENNESSEE
The only IMPROVE particulate sampler in Tennessee that collected data between 1994 and 1998 is
located in Great Smoky Mountains National Park. Figure TN— 1 shows the Great Smoky Mountains par-
ticulate sampler location (35.63°N, 83.94°W, elevation 2500 feet) on the Tennessee-North Carolina bor-
der. The Great Smoky Mountains National Park and the Joyce Kilmer-Slickrock Wilderness Area are
both located in Tennessee and North Carolina. Joyce Kilmer-Slickrock Wilderness Area is a mandatory
Federal Class I area covered under the Regional Haze Rule. The wilderness area did not have
IMPROVE monitor data for the years prior to 1999.
Great Smoky Mountains National Park
Nashville® Knoxvilie
Great Smoky Mountains
IMPROVE Monitor
Chattanooga.
Joyce Kilmer-Slickrock Wilderness
0
100
miles
200
Figure TN-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Tennessee
Great Smoky Mountains National Park
The Great Smoky Mountains IMPROVE particulate sampler started reporting in March of 1988.
Figure TN-2 presents the calculated visibility indices for selected data sets from 1988 through 1998.
The figure shows that the visibility index for the most-impaired days generally remained near 30
deciviews (VR 12 miles), with no statistically significant trend in visibility. Similarly, the visibility
indices on the mid-range days remained relatively constant, near 21 deciviews (VR 30 miles), with no
significant trend in visibility. The indices on the least-impaired days remained near 15 deciviews (VR
55 miles), with no significant trend in visibility.
Figure TN-3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. The visibility indices for the summer season were generally at least 5 deciviews higher than those
during the other seasons. Winter registered the lowest visibility indices. The visibility indices for all
four seasons showed no statistically significant trends over the eleven-year period.
2-124
November 2001
-------
Individual Areas—Tennessee
8SS8SS|!SS«3B6S2£2!3j£s^^
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure TN-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Great Smoky Mountains IMPROVE Particulate Sampler
I
0)
o
a>
X
0)
T3
17
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-*- Spring -•- Summer -A- Autumn -•- Winter
Figure TN-3. Seasonal Deciview Averages from 1988-1998
for the Great Smoky Mountains IMPROVE Particulate Sampler
November 2001
2-125
-------
Visibility in Mandatory Federal Class 1 Areas (1994-1998): A Report to Congress
Nitrate
3%
Organic
Carbon
12%
Elemental
Carbon
5%
Crustal
Material
4%
Sulfate
76%
Figure TN-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Great Smoky Mountains
IMPROVE Particulate Sampler
Figure TN-4 presents a chart showing the calcu-
lated fractional contribution to the Great Smoky
Mountains' light extinction by each aerosol species
on an annual basis. Figure TN-5 shows the same
information for the four seasons. Since the summer
light extinction coefficients were much larger than
those in other seasons, the annual averages present-
ed in TN-4 appear weighted to the summer. These
five pie charts show that sulfate particles were the
largest contributor to light extinction. Sulfate parti-
cles were responsible for 66 to 82 percent of the
light extinction at the Great Smoky Mountains site,
averaging 76 percent on an annual basis over a five-
year period. The contributions from sulfates were
highest in the summer and lowest in the winter. The
Organic
Nitrate Carbon
4% 15%
Sulfate
68%
Elemental
Carbon
7%
Crustal
Material
6%
Nitrate Organic
2,/0 Carbon
10%
Sulfate
82%
Elemental
Carbon
3%
Crustal
Material
3%
Spring
Summer
Nitrate Organic
4% Carbon
13%
Sulfate
72%
Elemental
Carbon
6%
Crustal
Material
5%
Organic
Nitrate Carbon
6% 15%
Sulfate
66%
Elemental
Carbon
8%
Crustal
Material
5%
Autumn Winter
Figure TN-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Great Smoky Mountains IMPROVE Particulate Sampler
2-126
November 2001
-------
Individual Areas—Tennessee
contributions from nitrate ranged from 2 to 6 percent, with the highest concentrations in the winter.
Organic carbon, elemental carbon, and crustal material percentage contributions remained near 12, 5,
and 4 percent year-round.
Figure TN-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Great Smoky Mountains site from 1988 to 1998. The
total annual aerosol light extinctions remained between 75 and 100 Mm-1 with no statistically signifi-
cant trend in visibility. Similarly, the annual light extinctions for sulfates, organic carbon, elemental
carbon, and crustal material showed no significant trends over this time period.
120
i— —r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
B Sulfate O Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure TN-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Great Smoky Mountains IMPROVE Particulate Sampler
November 2001
2-127
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
19. TEXAS
Two Texas national parks, Big Bend and Guadalupe Mountains, are mandatory Federal Class I areas
covered by the Regional Haze Rule. IMPROVE particulate samplers are located in Big Bend (29.33°N,
103.55°W, elevation 3500 feet) and Guadalupe Mountains (31.83°N, 104.81°W, elevation 5400 feet).
Both monitors collected data between 1992 and 1998. Figure TX-1 shows the monitor locations near
the Mexican and New Mexican borders.
^ —Guadalupe Mountains
National Park
Guadalupe Mountain
IMPROVE Monitor
El Paso
Big Bend IMPROVE Monito,
Big Bend National Park
150
mif
miles
300
Figure TX-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Texas
Big Bend National Park
The Big Bend IMPROVE particulate sampler started reporting data in March of 1988. Figure TX-2
presents the calculated visibility indices for selected data sets from 1988 through 1998. The figure
shows that the visibility index for the most impaired days increased from 16 to 20 deciviews (VR 50 to
33 miles), but the trend was not classified as statistically significant. The visibility indices on the mid-
range days remained relatively constant between 12 and 13 deciviews (VR between 75 and 65 miles),
with no significant trend in visibility. The indices on the least-impaired days remained near 8 deciviews
(VR 110 miles), with no significant trend in visibility.
Figure TX—3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. Most of the visibility indices for the four seasons were between 10 and 15 deciviews, with winter
values most frequently the smallest. The visibility indices for spring, autumn, and winter showed no
Statistically significant trends over the eleven-year period. However, the summer indices increased over
the eleven-year period with a statistically significant trend, indicating additional visibility impairment
in later years.
2-128
November 2001
-------
Individual Areas—Texas
20
rf*~r^-*^*'¥i^^f-^^fe™'!|r|^7^~3^^^
S|§;ttfR«¥E?^'fiW;SSifi^3S
X 14
Q) 'T1
_C
>, 12
**
5
w 10
--""'-•-• - - --f~:"i-:,---••;- > / : ~,;---->=^~ -~* " •- - ...-;,-.:.'..-_._ _„:-;.-'.-- ^Y/'i^^^^^7^^^"^^^^^-?^-" :"^' ^'""'V---''-^---"
^^^^^^•^^f^i^s^K^^^ ^^S^sJi^i^^^W'^!fi:%t^ffl^S^^J§'i^|^
tr^?^^T>'rr.-"'-":!g^^^^'!'^^^^^^A'?^^^
L~-- .i- . • .^---.ii;-"-"-"-T-"""" " -i ~i "~J~*r ''.1,^-1 iJ^ri'.ii.-e-^J^,5^ -r- -, -. •_...,...;.„...;.... r'.i.n '. ,~ "' " •—' " " -r-JIL]-- - '-• :....-••.'—"^_
Most-Impaired
Mid-Range
Least-Impaired
H 1 I-
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure TX-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Big Bend IMPROVE Particulate Sampler
i
a>
'5
0)
Q,
¥
•a
c
.Q
'(0
T 1 1 1 r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-•-Spring -m-Summer -*r-Autumn -•-Winter
Figure TX-3. Seasonal Deciview Averages from 1988-1998 for the
Big Bend IMPROVE Particulate Sampler
November 2001
2-129
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
19%
Elemental
Carbon
6%
Nitrate
5%
Crustal
Material
22%
Sulfate
48%
Figure TX-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the Big
Bend IMPROVE Particulate Sampler
Figure TX-4 presents a chart showing the calculated
fractional contribution to Big Bend's light extinction by
each aerosol species on an annual basis. Figure TX-5
shows the same information for the four seasons. These
five pie charts show that the largest contributors to light
extinction were sulfate particles. Sulfate particles were
responsible for 39 to 59 percent of the light extinction at
the Big Bend site, averaging 48 percent on an annual basis
over a five-year period. The contributions from sulfates
were highest in the autumn and lowest in the spring.
Organic carbon contributions ranged from 16 to 24 per-
cent. The contributions from nitrate and elemental carbon
were near 5 and 6 percent year-round. Crustal material
percentage contributions were only 14 percent in the
autumn, but near 24 percent for the rest of the year.
Organic
Carbon,
24%
Nitrate"
4%
Elemental
Carbon
7%
Crustal
Material
26%
Sulfate
39%
Spring
Nitrate
4% '
Elemental
Carbon
Organic
Carbon 4/c
18%
Sulfate
51%
Summer
Crustal
Material
23%
Organic Elemental
Carbon Carbon
Nitrate
5%
16%
Crustal
Material
14%
Elemental
Carbon
Organic 8o/o
Carbon
17%
Nitrate
6%
Sulfate
59%
Autumn
Crustal
Material
22%
Sulfate
47%
Winter
Figure TX-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Big Bend IMPROVE Particulate Sampler
2-130
November 2001
-------
Individual Areas—Texas
Figure TX-6 shows the calculated, contributions of each of the aerosol mass components to the .
annual average aerosol light extinctions at the Big Bend site from 1988 to 1998. The total annual
aerosol light extinctions remained between 24 and 34 Mm-1. The 1998 average showed considerably
higher concentrations of sulfate, organic carbon, and elemental carbon. Despite a higher value in 1998,
there was no statistically significant trend in visibility. The sulfate contribution during this time period
increased from 11 to 14 Mm-1, with a significant trend toward higher sulfate concentrations and greater
contributions to light extinction coefficients. The annual light extinctions for organic carbon, elemental
carbon, and crustal material showed no significant trends over this time period.
o
I
O)
2
o
<5
<
liujW'.'lii'v frtj :-&-j&j&«T
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
18
16
"w
3
.2
> 14
o
&
^**
X 10
a> i^
•Q
I 10
3
w
r •
a™= Most-Impaired
'Vi
Mid-Range
Least-Impaired
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure TX-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Guadalupe Mountains IMPROVE Particulate Sampler
W lit
;.'?! ' V-'n
'S a'':*!: Is
0)
1
| 1«i' 1 'fn!|l|l" "Ujj . ;n
-------
Individual Areas—Texas
Crustal
Material
26%
Elemental
Carbon
Organic 6%
Carbon
17%
Nitrate
6%
Sulfate
45%
Figure TX-9. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Guadalupe Mountains
IMPROVE Participate Sampler
Elemental
Carbon
6%
Crustal
Material
34%
Organic]
Carbon
21%
Nitrate
6%
Sulfate
33%
deciviews, with winter values always being the low-
est and summer most frequently the highest. The
visibility indices for all four seasons showed no sta-
tistically significant trends over the eleven-year peri-
od.
Figure TX—9 presents a chart showing the calcu-
lated fractional contribution to Guadalupe,
Mountain's light extinction by each aerosol species
on an annual basis. Figure TX—10 shows the same
information for the four seasons. These five pie
charts show that the largest contributors to light
extinction were sulfate particles. Sulfate particles
were responsible for 33 to 53 percent of the light
extinction at the Guadalupe Mountains site, averag-
ing 45 percent on an annual basis over a five-year
Organic
Carbon
16%
Elemental
Carbon
5%
Nitrate
5%
Crustal
Material
21%
Spring
Sulfate
53%
Summer
Elemental
Carbon
Organic Q%
Carbon
15%.
Nitrate
6%
Crustal
Material
24%
Sulfate
49%
Autumn
Elemental
Carbon
9%
Organic
Carbon
16%
Nitrate
9%
Crustal
Material
27%
Sulfate
39%
Winter
Figure TX-10. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Guadalupe Mountains IMPROVE Particulate Sampler
November 2001
2-133
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
period. The contributions from sulfates were lower in the spring than the other three seasons. The con-
tributions from nitrate, organic carbon, and elemental carbon were near 6, 17, and 6 percent year-round.
Crustal material percentage contributions were 34 percent in the spring but near 21 percent for the rest
of the year.
Figure TX—11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Guadalupe Mountains site from 1988 to 1998. During
the eleven-year period, the total annual aerosol light extinctions ranged from 20 to 26 Mm-1 with no
statistically significant trend in visibility. The annual light extinctions for sulfates, elemental carbon,
and crustal material showed no significant trends over this time period. However, the annual light
extinction contributions from the organic carbon species showed a statistically significant trend toward
lower concentrations and lower contributions to light extinction coefficients.
5.
6
D>
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
BSuIfate H Nitrate D Organic Carbon D Elemental Carbon H CrUstal Material
Figure TX-11. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Guadalupe Mountains IMPROVE Particulars Sampler
Texas State Summary
The calculated annual average aerosol light extinction coefficients at the two Texas IMPROVE
monitoring sites are presented hi Table TX—1. The calculated total aerosol extinction coefficient at the
Guadalupe Mountains site was just fifteen percent lower than that at Big Bend. The extinction coeffi-
cients for the individual species were also similar (within 30 percent of one another) at both sites. Both
sites showed similar rankings for contributions of the species to light extinction: sulfate, followed by
crustal material, organic carbon, elemental carbon, and lastly nitrate. The same general rankings were
observed for the Arizona, Colorado, and Wyoming sites in Tables AZ-1, CO-1, and WY—1.
2-134
November 2001
-------
Individual Areas—Texas
Table TX-1. Texas Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Big Bend NP
Guadalupe Mtns NP
Calculated Total
Aerosol Extinction
Coefficient (Mnr1)
28.0
23.9
Pollutant Extinction Coefficient (Mm-1)
Sulfate
13.4
10.7
Nitrate
1.2
1.5
Organic
Carbon
5.5
4.0
Elemental
Carbon
1.8
1.5
Crustal
Material
6.1
6.1
November 2001
2-135
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
20. UTAH
Figure UT—1 shows the five national parks located in Utah that are mandatory Federal Class I
areas: Zion, Bryce Canyon, Capitol Reef, Canyonlands, and Arches. IMPROVE participate samplers
that operated between 1994 and 1998 are located in Bryce Canyon (37.62°N, 112.17°W, elevation 8000
feet) and Canyonlands (38.45°N, 109.82°W, elevation 5900 feet). Additional monitors are expected to
be installed in Arches and Capitol Reef. An additional IMPROVE protocol particulate sampler is locat-
ed near the Lone Peak Wilderness Area at Timpanogas Caves National Monument (between Salt Lake
City and Provo), but this area is not a mandatory Federal Class I area and is not discussed in this chap-
ter of the report.
Zion National
Park
Ogden<
* Salt Lake City
Provo •
Arches National Park
Capitol Reef National Park
Bryce Canyon
IMPROVE Monitor
Canyonlands
IMPROVE Monitor
Bryce Canyon National Park
Canyonlands National Park
0 100 200
mUS^
miles
Figure UT-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Utah
Bryce Canyon National Park
The Bryce Canyon IMPROVE particulate sampler started reporting data in March of 1988. Figure
UT-2 presents the calculated visibility indices for selected data sets from 1988 through 1998. The fig-
ure shows that the visibility index for the most-impaired days generally remained between 12 and 14
deciviews (VR 75 to 60 miles). There was no statistically significant trend in visibility. The visibility
indices on the mid-range days ranged from 8 to 10 deciviews (VR 110 to 90 miles), with no significant
trend toward unproved visibility. The indices on the least-impaired days remained near 5 deciviews (VR
150 miles), with no significant trend toward unproved visibility.
Figure UT—3 shows the seasonal averages for the calculated visibility indices from 1988 through
1998. The indices for the spring and summer were generally 2 deciviews higher the autumn values, and
2-136
November 2001
-------
Individual Areas—Utah
I
>
o
10
- - Most-Impaired
x
0)
•a
c
Mid-Range
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure UT-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Bryce Canyon IMPROVE Participate Sampler
13
0)
a>
o
a>
•a
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
•Spring -»-Summer -A-Autumn
- Winter
Figure UT-3. Seasonal Deciview Averages from 1988-1998
for the Bryce Canyon IMPROVE Particulate Sampler
November 2001
2-137
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
24%
Elemental
Carbon
9%
Crustal
.Material
16%
Nitrate
11%
Sulfate
40%
Figure UT-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Bryce Canyon IMPROVE Particulate
Sampler
the autumn values were approximately 2 deciviews high-
er than the indices for winter. The visibility indices for
the spring, summer, and autumn showed no statistically
significant trends over the eleven-year period. However,
the indices for winter decreased approximately 1.5
deciviews from 1989 to 1998, indicating a statistically
significant trend toward improved visibility.
Figure UT-4 presents a chart showing the calculated
fractional contribution to Bryce Canyon's light extinction
by each aerosol species on an annual basis. Figure UT-5
shows the same information for the four seasons. These
five pie charts show that the largest contributors to light
extinction were sulfate particles. Sulfate particles were
responsible for 37 to 45 percent of the light extinction at
the Bryce Canyon site, averaging 40 percent on an annu-
al basis over a five-year period. The contributions from
sulfates were slightly lower in the winter than the other
Organic
Carbon
20%
Elemental
Carbon
7%
Nitrate
13%
Crustal
Material
15%
Spring
Sulfate
45%
Organic
Carbon
24%
Elemental
Carbon
11%
Nitrate
10%
Crustal
Material
15%
Organic
Carbon
26%
Elemental
Carbon
9%
Nitrate
8%
Crustal
Material
17%
Sulfate
40%
Summer
Organic
Carbon
20%
Elemental
Carbon
8%
Nitrate
19%
Crustal
Material
16%
Sulfate
40%
Sulfate
37%
Autumn Winter
Figure UT-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Bryce Canyon IMPROVE Particulate Sampler
2-138
November 2001
-------
Individual Areas—Utoh
seasons. Nitrate contributions were near 9 percent in the summer and autumn, but rose to 19 percent
during winter. The contributions from organic carbon, elemental carbon, and crustal material were near
24, 9, and 16 percent year-round.
Figure UT-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Bryce Canyon site from 1988 to 1998. The total annual
aerosol light extinction remained near 15 Mm-1 with no statistically significant trend that would indi-
cate improved visibility. The sulfate contributions during this time period decreased approximately 1
Mm-1, indicating a significant trend toward lower sulfate concentrations and contributions to light
extinction coefficients. The annual light extinctions for organic carbon, elemental carbon, and crustal
material showed no significant trends over this time period.
HI
S
O)
o
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Canyonlands National Park
The Canyonlands IMPROVE participate sampler started reporting data in March of 1988. Figure
UT—7 presents the calculated visibility indices for selected data sets from 1988 through 1998. The
indices for the most-impaired days showed a statistically significant trend indicating improvements in
visibility. The figure shows that the visibility index for the most-impaired days decreased from more
than 12 to nearly 11 deciviews (VR 75 to 80 miles). The visibility indices on the mid-range days
remained near 9 deciviews (VR 100 miles), exhibiting no significant trend. The indices on the least-
impaired days remained near 6 deciviews (VR 135 miles).
Figure UT-8 shows the seasonal averages for the calculated visibility index from 1988 through
1998. CIRA did not report a summary value for winter 1988, so it was not included in Figure UT-8.
Interested readers can view the species data at http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi.
Most of the visibility indices for the four seasons were between 8 and 11 deciviews, with no single sea-
son continually showing the highest or lowest values. Despite the drop in winter values from 1990 to
1995, the visibility indices for all four seasons showed no statistically significant trends over the
eleven-year period.
."-„/. ..'ZZT J^^^=-iJsSg5^^i^Mo§t'lrpp.a''r6(:' '
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 - 1998
Year
Figure UT-7. Yearly Deciview Averages for Most-Impaired, Mid-Range/ and Least-Impaired
Days from 1988-1998 for the Canyonlands IMPROVE Participate Sampler
2-140
November 2001
-------
Individual Areas—Utah
1988 1989 1990 1991 1992
1993
Year
1994 1995 1996 1997 1998
-Spring
-Summer
-Autumn
-Winter
Figure UT-8. Seasonal Deciview Averages from 1988-1998 for the
Canyonlands IMPROVE Particulate Sampler
Figure UT-9 presents a chart showing the calculated fractional contribution to Canyonland's light
extinction by each aerosol species on an annual basis. Figure UT—10 shows the same information for
the four seasons. These five pie charts show that the largest contributors to light extinction were sulfate
particles and crustal material. Sulfate particles were responsible for 29 to 38 percent of the light extinc-
tion at the Canyonlands site, averaging 34 percent on an annual basis over a five-year period. The con-
tributions from sulfates were lower in the spring
and summer than in the other seasons. Crustal
material percentage contributions were 33 per-
cent in the spring but 22 percent in the winter,
and the average annual contribution was calculat-
ed to be 27 percent. The nitrate contributions
were 12 percent in the winter but only near 6
percent through the rest of the year. The organic
carbon contributions ranged from 17 percent in
the winter to 28 percent in the summer. The con-
tributions from elemental carbon were close to
Elemental
Carbon
10%
Crustal
Material
27%
Organic
Carbon
22%
Nitrate
7%
Sulfate
34%
10 percent year-round.
Figure UT-9. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Canyonlands
IMPROVE Particulate Sampler
November 2001
2-141
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental
Carbon
9%
Organic
Carbon
20%
Nitrate
7%
Crustal
Material
33%
Elemental
Carbon
9%
Sulfate
31%
Organic
Carbon
28%
Crustal
Material
29%
Nitrate
5%
Sulfate
29%
Spring
Summer
Elemental
" Carbon
10%
Organic
Carbon
21%
Nitrate
7%
Figure UT-10.
Crustal
Material
24%
Sulfate
38%
Organic
Carbon
17%
Nitrate'
12%
Elemental
Carbon
11%
Crustal
Material
22%
Sulfate
38%
Winter
Autumn
Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998
for the Canyonlands IMPROVE Particulate Sampler
Figure UT—11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Canyonlands site from 1988 to 1998. The total annual
aerosol light extinctions dropped from near 16 to near 14 Mm-1 with a statistically significant trend
toward improved visibility. The annual light extinctions for organic carbon, elemental carbon, and
crustal material showed no significant trends over this time period. However, contributions of the sul-
fate species to the annual light extinction showed a statistically significant trend toward lower concen-
trations and contributions to light extinction coefficients.
2-142
November 2001
-------
Individual Areas-^-Utah
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
a Sulfate a Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure UT-11. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998
for the Canyonlands IMPROVE Particulate Sampler
Utah State Summary
The calculated annual average aerosol extinction coefficients at Utah's IMPROVE monitor sites are
presented in Table UT-1. The sites are located 140 miles apart. The calculated total aerosol extinction
coefficients at the sites were within 5 percent of each other, indicating similar annual visibility condi-
tions at both sites. The extinction coefficients for the individual species were also similar (within 40
percent) at the different sites. The ambient nitrate concentrations at both sites were similar (near 0.2
p,g/m3), but the nitrate extinction coefficient at Canyonlands was much lower than that at Bryce Canyon
because the relative humidity was much lower at Canyonlands (Appendix C). Both sites also showed
similar rankings for contributions of the species to light extinction: sulfate, followed by organic carbon
and crustal material, and lastly, nitrate and elemental carbon.
Table UT-1. Utah Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Bryce Canyon NP
Canyonlands NP
Calculated Total
Aerosol Extinction
Coefficient (Mnr1)
15.0
14.4
Pollutant Extinction Coefficient (Mm-1)
Sulfate
6.1
5.0
Nitrate
1.6
1.0
Organic
Carbon
3.6
3.1
Elemental
Carbon
1.3
1.4
Crustal
Material
2.4
3.9
November 2001
2-143
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
21. VERMONT
Figure VT-1 shows the Lye Brook Wilderness Area in southern Vermont, Vermont's only mandato-
ry Federal Class I area covered by the Regional Haze Rule. An IMPROVE particulate sampler
(43.17°N, 73.12°W, elevation 3250 feet) is located at Lye Brook and has been operating since
September 1991.
„Burlington
®
Montpelier
Lye Brook IMPROVE Monitor
Lye Brook Wilderness
100
miles
Figure VT-1. Mandatory Federal Class I Area and IMPROVE Monitoring Site in Vermont
Lye Brook Wilderness Area
The Lye Brook IMPROVE particulate sampler began reporting data in September of 1991. Figure
VT—2 presents the calculated visibility indices for selected data sets from 1992 through 1998. The fig-
ure shows that the visibility index for the most-impaired days remained near 26 deciviews (VR 18
miles). There was no statistically significant trend in visibility. The visibility indices on the mid-range
days remained near 16 deciviews (VR 50 miles), with no significant trend in visibility. The indices on
the least-impaired days increased from 9 to 10 deciviews (VR 100 to 90 miles), with a significant trend
toward declining visibility.
Figure VT—3 shows the seasonal averages for the calculated visibility indices from 1992 through
1998. Coarse mass measurements were not available for spring and summer 1992, so Figure VT-3
reports no values for these seasons. Interested readers can view the data for other species at
http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi. The indices for summer were generally 5
deciviews higher the autumn values, and the autumn values were approximately 3 deciviews higher
2-144
November 2001
-------
fncffvfduaf Areas—Vermont
Q 2°
¥
•a
- 15
> 10
Mid-Range
4-
Least-Impaired
1 I—
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure VT-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1992-1998 for the Lye Brook IMPROVE Particulate Sampler
26
12
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
• Spring
-Summer -A-Autumn
-Winter
Figure VT-3. Seasonal Deciview Averages from 1992-1998 for the
Lye Brook IMPROVE Particulate Sampler
November 2001
2-145
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate
9%
Organic
Carbon
Elemental
Carbon
5%
Crustal
Material
4%
Sulfate
70%
Figure VT-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Lye Brook
IMPROVE Particulate Sampler
Nitrate
10%
Organic
Carbon
14%
Elemental
Carbon
7%
Crustal
Material
6%
Sulfate
63%
Spring
Nitrate
12%
Organic
Carbon
11% Elemental
Carbon
6%
Crustal
Material
4%
Sulfate
67%
than the winter and spring indices. The visibility
indices for all four seasons showed no statistically sig-
nificant trends over the seven-year period.
Figure VT—4 presents a chart showing the calculat-
ed fractional contribution to the light extinction by
each aerosol species on an annual basis. Figure VT-5
shows the same information for the four seasons.
These five pie charts show that the largest contributors
to light extinction were sulfate particles. Sulfate parti-
cles were responsible for 60 to 78 percent of the light
extinction at the Lye Brook site, averaging 70 percent
on an annual basis over a five-year period. The contri-
butions from sulfates were lower in the winter and
higher in the summer. Nitrate contributions were near
6 percent in the summer, but rose to 13 percent during
the winter. The contributions from organic carbon, ele-
mental carbon, and crustal material were near 12, 5,
and 4 percent year-round.
Nitrate Organic
Carbon
11%
Sulfate
78%
Elemental
Carbon
3%
Crustal
Material
2%
Nitrate
13%
Summer
Organic
Carbon
13%
Elemental
Carbon
8%
Crustal
Material
6%
Sulfate
60%
Winter
Autumn
Figure VT-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Lye Brook IMPROVE Particulate Sampler
2-146
November 2001
-------
Individual Areas—Vermont
Figure VT-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Lye Brook site from 1992 to 1998. The total annual
aerosol light extinctions remained near 50 Mm-1 with no statistically significant trend in visibility. The
annual light extinctions for sulfates, organic carbon, elemental carbon, and crustal material showed no
significant trends over this time period.
o
'•s
c
*
LJU
4-1
O)
o
0)
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
QSulfate H Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure VT-6. Contributions to Calculated Annual Aerosol Light Extinction
from. 1992-1998 for the Lye Brook IMPROVE Particulate Sampler
November 2001
2-147
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
22. VIRGINIA
The only IMPROVE participate sampler in Virginia that operated continuously from 1994 through
1998 was the one located hi the Shenandoah National Park. Figure VA-1 shows the Shenandoah partic-
ulate sampler location (38.48°N, 78.12°W, elevation 3600 feet) in north-central Virginia. The James
River Face Wilderness Area is also covered by the Regional Haze Rule but did not have an IMPROVE
particulate sampler operating from 1994 through 1998.
Arlington
Shenandoah IMPROVE Monitor
"-^
Shenandoah National Park
James River Face Wilderness
100
SEE
miles
200
Figure VA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site in Virginia
Shenandoah National Park
The Shenandoah IMPROVE particulate sampler started reporting data in March of 1988. Figure
VA-2 presents the calculated visibility indices for selected data sets from 1988 through 1998. The fig-
ure shows that from 1988 through 1998 there was no statistically significant trend in the annual average
of the visibility index for the least-impaired days, which remained between 14 and 17 deciviews (VR
60 to 45 miles). From 1988 through 1998 there was no significant trend in the annual average of the
visibility index for the most-unpaired days, which remained relatively constant, near 31 deciviews (VR
11 miles). However, the annual average of the visibility index for the mid-range days showed an
improvement as the indices dropped from 23 to 21 deciviews (VR from 24 to 30 miles) over this peri-
od, a significant trend toward unproved visibility.
Figure VA-3 shows the seasonal averages for the calculated visibility index from 1988 through
1998. During all four years at Shenandoah, the visibility was considerably more impaired during the
summer (at least 3 deciviews) than during the autumn. The autumn numbers were 1 or 2 deciviews
2-148 November 2001
-------
Individual Areas—Virginia
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure VA-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Daysfrom 1988-1998 for the Shenandoah IMPROVE Particulate Sampler
I
a>
o
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate Organic
6% Carbon
10%
Elemental
Carbon
4%
Crustal
Material
3%
W. ^T
Sulfate
77%
Figure VA-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the
Shenandoah IMPROVE
Particulate Sampler
higher than the spring on average, and the indices for
spring were more than 2 deciviews higher than the
winter numbers. No significant seasonal trends were
observed when the years 1988 through 1998 were
compared for the summer, autumn, and whiter.
However, the indices for spring decreased 3 deciviews
over this period with a statistically significant trend
toward improved visibility.
Figure VA-^4- presents a chart showing the calculat-
ed fractional contribution to Shenandoah's light extinc-
tion by each aerosol component on an annual basis.
Figure VA-5 shows the same information for the four
seasons. These five pie charts show that sulfate was
responsible for 67 to 84 percent of the light extinction
at the Shenandoah site, averaging 77 percent on an
annual basis. The contributions from nitrates ranged
from 4 to 12 percent depending on the season. The
highest observed nitrate percentages occurred in the
Nitrate Organic
8% Carbon
Sulfate
71%
Spring
Elemental
Carbon
5%
Crustal
Material
5%
Nitrate Organic
4% |- Carbon
8%
Sulfate
84%
Elemental
Carbon
2%
Crustal
Material
2%.
Summer
Sulfate
74%
Organic
Nitrate Carbon
7% 10%
Elemental
Carbon
5%
Crustal
Material
4%
Nitrate Organic
12% Carbon
11% Elemental
Carbon
6%
Crustal
Material
4%
Sulfate
67%
Winter
Autumn
Figure VA-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Shenandoah IMPROVE Particulate Sampler
2-150
November 2001
-------
Individual Areas—Virginia
winter. The contributions from organic carbon remained relatively constant, near 10 percent year-round.
Elemental carbon and crustal material measured at the Shenandoah site were each responsible for less .
than 6 percent of the calculated aerosol light extinction year round.
Figure VA-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinction at the Shenandoah site from 1988 to 1998. Over the eleven-year
period, the total annual aerosol light extinctions rose in the early 1990s and then dropped (mainly due
to sulfates), but no statistically significant trend was indicated. The sulfate, organic carbon, and crustal
material contributions to the aerosol light extinction did not change significantly over this eleven-year
period. However, the elemental carbon contributions dropped 1 Mm-1, a statistically significant trend
toward lower concentrations.
120
UJ 60 t
o 40
0)
o
CD
20
0
T —' ' 1 "- " 1 ^ ' 1 " J 1 " ' 1 " ' T
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
BJ Sulfate H Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure VA-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Shenandoah IMPROVE Particulate Sampler
November 2001
2-151
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
23. WASHINGTON
Figure WA-1 shows Washington's national parks (Olympic, North Cascades, and Mount Rainier) and
wilderness areas (Pasayten, Glacier Peak, Alpine Lakes, Goat Rocks, and Mount Adams) designated as
mandatory Federal Class I areas covered by the Regional Haze Rule. The IMPROVE particulate sam-
plers are located near Mount Rainier's headquarters (46.75°N, 122.12°W, elevation 1430 feet) and at
Snoqualmie Pass-Alpine Lakes Wilderness Area (47.43°N, 121.42°W, elevation 3600 feet). An additional
IMPROVE protocol particulate sampler is located at the Columbia River Gorge National Scenic Area
(45.67°N, 120.98°W, elevation 300 feet), but this area is not a mandatory Federal Class I area and is not
discussed hi this report. Since the Mount Rainier and Snoqualmie Pass monitors are adjacent to manda-
tory Federal Class I areas, their measurements are discussed in this report. The Spokane Tribal
Government has redesignated their lands as Class I, but these areas are not covered by the Regional
Haze Rule.
North Cascades
National Park
Olympic
National Park
• • •*
Olympia
Mount Rainier
IMPROVE Monitor
isayten Wilderness !
•Glacier Peak Wilderness '
Lake Wilderness Spok^ej
Snoqualmie Pass j
IMPROVE Monitor \
. ' !
•|L_Mount Rainier National Park |
pup ^
m—Goat Rocks Wilderness
"•^"Mount Adams Wilderness
100
miles
200
Figure WA-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Washington
Mount Rainier National Park
The Mount Rainier IMPROVE particulate sampler started reporting data in March of 1988. Figure
WA—2 presents the calculated visibility indices for selected data sets from 1988 through 1998. The visi-
bility index for the most-impaired days remained near 23 deciviews (VR 24 miles), with no statistically
significant trend in visibility. The visibility indices on the mid-range days remained near 16 deciviews
(VR 50 miles), with no significant trend in visibility. The indices on the least-impaired days averaged
7.7 deciviews (VR 110 miles), with no statistically significant trend in visibility.
Figure WA—3 shows the seasonal averages for the calculated visibility indices from 1988 through
1998. Since only one sample was collected during summer 1990, that point was omitted from Figure
WA—3. The indices for winter were, on average, almost 5 deciviews lower than the values for the other
three seasons. The visibility indices for the spring, summer, and autumn showed no statistically signifi-
cant trends over the eleven-year period. The indices for whiter dropped from 15 to 11 deciviews (VR
2-152
November 2001
-------
Individual Areas—Washington
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure WA-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Mount Rainier IMPROVE Particulate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
•Spring -*-Summer -^-Autumn
- Winter
Figure WA-3. Seasonal Deciview Averages from 1988-1998
for the Mount Rainier IMPROVE Particulate Sampler
November 2001
2-153
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate
9%
Organic
Carbon
20%
Elemental
Carbon
8%
Crustal
Material
5%
Sulfate
58%
Figure WA-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Mount Rainier IMPROVE Particulate
Sampler
from 55 to 80 miles) from 1988 to 1998, indicating a sig-
nificant trend toward improved visibility.
Figure WA.—4 presents a chart showing the calculated
fractional contribution to Mount Rainier's light extinction
by each aerosol species on an annual basis. Figure WA-5
shows the same information for the four seasons. These
five pie charts show that the largest contributors to light
extinction were sulfate particles. Sulfate particles were
responsible for 38 to 62 percent of the light extinction at
the Mount Rainier site, averaging 58 percent on an annu-
al basis over a five-year period. The contributions from
sulfates were lower in the winter and higher in the spring
and summer. The contributions from organic carbon rose
from 18 percent in the spring to 24 percent in the autumn
and winter. Elemental carbon contributions were near 7
percent in the spring and summer but rose to 11 percent
in the winter. Nitrate contributions were under 10 percent
Nitrate
9%
Organic
Carbon
18%
Sulfate
61%
Elemental
Carbon
7%
Crustal
Material
5%
Nitrate
5%
Sulfate
62%
Organic
Carbon
20%
Elemental
Carbon
8%
Crustal
Material
5%
Spring
Summer
Nitrate
9%
Organic
Carbon
24%
Elemental
Carbon
10%
Crustal
Material
5%
Sulfate
52%
Autumn
Organic
Carbon
24%
Nitrate
20%
Elemental
Carbon
11%
Crustal
Material
7%
Sulfate
38%
Winter
Figure WA-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Mount Rainier IMPROVE Particulate Sampler
2-154
November 2001
-------
Individual Areas—Washington
in spring, summer, and autumn but rose to 20 percent in the winter. Crustal material contributions aver-
aged 5 percent year-round.
Figure WA-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Mount Rainier site from 1988 to 1998. The total annual
aerosol light extinction dropped from near 50 to 40 Mm-1, with a statistically significant trend toward
lower light extinction coefficients. The annual light extinctions attributed to sulfates and crustal materi-
al showed no significant trends over this time period. However, the annual light extinctions attributed to
organic carbon and elemental carbon both showed statistically significant trends toward lower light
extinctions and ambient concentrations.
60
^S^^§Kr^Iir^I?"1 - -" ™ 'J!"'L "s -j"V"L~ ffisgtt?^?^ iSar^f• r» s^ife8"^1 ^? tT7'r''i™->"i-1"Sj ?'-'^v1**- ~ "'"ii'Si^'R?. *^^^i ^w^'ifej^ •^-^>y
®w^.s«?w;^3™g]g!r2^g^M5^^^^
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
nSulfate n Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure WA-6. Contributions to Calculated Annual Aerosol Light Extinction
from 1988-1998 for the Mount Rainier IMPROVE Particulate Sampler
Snoqualmie Pass - Alpine Lakes Wilderness Area
The Snoqualmie Pass IMPROVE particulate sampler started reporting in July of 1993. Figure
WA-7 presents the calculated visibility indices for selected data sets from 1994 through 1998. The fig-
ure shows that the visibility index for the most-impaired days remained near 19 deciviews (VR 35
miles), with no statistically significant trend in visibility. The visibility indices on the mid-range days
remained near 13 deciviews (VR 65 miles), with no significant trend in visibility. The indices on the
least-impaired days increased from 7 to 8 deciviews (VR from 120 to 110 miles), with a significant
trend toward declining visibility.
Figure WA—8 shows the seasonal averages for the calculated visibility indices from 1994 through
1998. Coarse mass and nitrate measurements were not available simultaneously at this site before
November 2001
2-155
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure WA-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1994-1998 for the Snoqualmie Pass IMPROVE Particulate Sampler
CD
*>
'3
s
I
.a
'55
, 11
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
•Spring
•Summer -A-Autumn
-Winter
Figure WA-8. Seasonal Deciview Averages from 1994-1998 for the
Snoqualmie Pass IMPROVE Particulate Sampler
2-156
November 2001
-------
Individual Areas—Washington
Organic
Carbon
17%
Nitrate
14%
Elemental
Carbon
9%
Crustal
Material
7%
Sulfate
53%
Figure WA-9. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Snoqualmie Pass IMPROVE Participate
Sampler
September 3, 1994, so Figure WA-8 does not include cal-
culated deciviews for spring and summer 1994. Interested
readers can view the data for other species at
http ://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi. The
average seasonal indices were near 13, 15, 14, and 12
deciviews for the spring, summer, autumn, and winter.
The visibility indices for the four seasons showed no sta-
tistically significant trends over the five-year period.
Figure WA-9 presents a chart showing the calculated
fractional contribution to Snoqualmie Pass's light extinc-
tion by each aerosol species on an annual basis. Figure ,
WA—10 shows the same information for the four seasons.
These five pie charts show that the largest contributors to
light extinction were sulfate particles. Sulfate particles
were responsible for 43 to 57 percent of the light extinc- •
tion at the Snoqualmie Pass site, averaging 53 percent on
Nitrate
15°'
Organic
Carbon
13%
Sulfate
57%
Elemental
Carbon
8%
Spring
Crustal
' Material
7%
Organic
Carbon
21%
Nitrate
9%
Elemental
Carbon
10%
Crustal
Material
7%
Sulfate
53%
Summer
Organic
Carbon
22%
Nitrate
16%
Elemental
Carbon
11%
Crustal
Material
7%
Sulfate
44%
Autumn
Nitrate
26%
Organic
Carbon
14% Elemental
Carbon
.10%
Crustal
Material
7%
Sulfate
43%
Winter
Figure WA-10.
Contribution to Calculated Seasonal Aerosol Light Extinction from 1994-1998
for the Snoqualmie Pass IMPROVE Particulate Sampler
November 2001
2-157
-------
Visibility in Mondatory Federal Class I Areas (1994-1998): A Report to Congress
an annual basis over a five-year period. The contributions from sulfates are lower in the autumn and
winter and higher in the spring and summer. Nitrate contributions were just 9 percent in the summer
but rose to 26 percent in the winter. The contributions from organic carbon rose from 13 percent in the
spring to 22 percent in the autumn. Annually, elemental carbon and crustal material contributions were
near 9. and 7 percent.
Figure WA-11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinction at the Snoqualmie Pass site from 1994 to 1998. While the total
annual aerosol light extinction ranged from 28 to 34 Mm-1, there was no statistically significant trend
in the total light extinction coefficients. The annual light extinctions for sulfates, organic carbon, ele-
mental carbon, and crustal material showed no significant trends over this time period.
D Organic Carbon
1998
Crustal Material
Figure WA-1 1. Contributions to Calculated Annual Aerosol Light Extinction from 1994-1998
for the Snoqualmie Pass IMPROVE Particulate Sampler
Washington State Summary
The calculated annual average aerosol extinction coefficients at Washington's IMPROVE monitor-
ing sites are presented in Table WA— 1. Both sites showed similar rankings for contributions of the
species to light extinction: sulfate, followed by organic carbon, nitrate, elemental carbon, and lastly
crustal material.
The two sites are located only 60 miles apart, but the calculated visibility at the Mount Rainier site
was considerably more impaired than that at Snoqualmie Pass. The calculated aerosol light extinction
coefficient was 30 percent higher at Mount Rainier. The major species responsible for the difference in
2-158
November 2001
-------
(ndividuaf Areas—Wasfifngton
light extinction coefficients was .sulfate. The ambient average sulfate concentrations at both sites were
similar at Mount Rainier and Snoqualmie Pass (1.2 and 1.1 u,g/m3) for the years 1994 through 1998.
However, the sulfate extinction coefficient at Snoqualmie Pass was much lower than the one at Mount
Rainier because the average relative humidity adjustment factor was lower at Snoqualmie Pass (4.86)
than at Mount Rainier (6.40). Since the relative humidity correction factor (presented in Appendix C) is
30 percent higher at Mount Rainier than at Snoqualmie Pass, the average sulfate extinction coefficient
was notably higher at Mount Rainier even though ambient concentrations were similar at both sites.
Table WA-1. Washington Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Mount Rainier NP
Snoqualmie Pass
Calculated Total
Aerosol Extinction
Coefficient (Mm-1)
40.1
31.1
Pollutant Extinction Coefficient (Mm-1)
Sulfate
23.3
16.3
Nitrate
3.4
. 4.4
Organic
Carbon
8.1
5.4
Elemental
Carbon
3.2
2.9
Crustal
Material
2.1
2.0
November 2001
2-159
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
24. WEST VIRGINIA
Figure WV-1 shows the Dolly Sods and Otter Creek Wilderness Areas, West Virginia's mandatory
Federal Class I areas covered by the Regional Haze Rule. An IMPROVE particulate sampler (39.11°N,
79.17°W, elevation 3800 feet) is located near the Dolly Sods area and has been operating since
September 1991.
Wheeling
Dolly Sods IMPROVE Monitor
Otter Creek Wilderness
Dolly Sods Wilderness
0
50
S3"85
miles
100
Figure WV-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Site
in West Virginia
Dolly Sods Wilderness Area
The Dolly Sods IMPROVE particulate sampler began reporting data in September of 1991. Figure
WV—2 presents the calculated visibility indices for selected data sets from 1992 through 1998. The fig-
ure shows that the visibility index for the most-impaired days remained near 31 deciviews (VR 11
miles). There was no statistically significant trend in visibility. However, the visibility indices on the
mid-range days decreased from 22 to 30 deciviews (VR from 22 to 30 miles), with a significant trend
toward improved visibility. The indices on the least-impaired days remained near 16 deciviews (VR 50
miles), with no significant trend in visibility.
Figure WV-3 shows the seasonal averages for the calculated visibility indices from 1992 through
1998. Coarse mass measurements were not available at this site until August 26, 1992, so Figure WV-3
does not include a point for spring 1992. Interested readers can view the data for other species at
http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi. Similar to observations at the Shenandoah site
(Virginia), the indices for summer were on average 7 deciviews higher than the autumn, winter, and
2-160
November 2001
-------
Individual Areas—Wesf Virginia
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure WV-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1992-1998 for the Dolly Sods IMPROVE Particulate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-Spring -•-Summer -A-Autumn
-Winter
Figure WV-3. Seasonal Deciview Averages from 1992-1998 for the
Dolly Sods IMPROVE Particulate Sampler
November 2001
2-161
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate Organic
5% Carbon
10%
Sulfate
78%
Elemental
Carbon
4%
Crustal
Material
3%
Figure WV-4. Contribution to Calculated
Annual Aerosol Light Extinction from
1994-1998 for the Dolly Sods IMPROVE
Particulate Sampler
spring values. The visibility indices for the winter
and spring showed no statistically significant trends
over the seven-year period. Statistically significant
trends were noted for the summer and autumn; their
visibility conditions improved by 2 and 3 deciviews
over the seven-year period.
Figure WV-4 presents a chart showing the cal-
culated fractional contribution to Dolly Sods' light
extinction by each aerosol species on an annual
basis. Figure WV—5 shows the same information for
the four seasons. These five pie charts show that the
largest contributors to light extinction were sulfate
particles. Sulfate particles were responsible for 66 to
86 percent of the light extinction at the Dolly Sods
site, averaging 78 percent on an annual basis over a
five-year period. The contributions from sulfates
were lower in the winter and higher in the summer.
Nitrate contributions were just 3 percent in the sum-
Nitrate Organic
QO/O Carbon
12%
Sulfate
73%
Elemental
Carbon
5%
Crustal
Material
4%
Nitrate
3%
Sulfate
86%
Elemental
Carbon
2%
Crustal
Material
2%
Spring
Nitrate Organic
6% Carbon
12%
Sulfate
73%
Elemental
Carbon
6%
Crustal
Material
3%
Summer
Organic
Nitrate Carbon
9% 14% Elemental
Carbon
7%
Crustal
Material
4%
Sulfate
66%
Autumn Winter
Figure WV-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Dolly Sods IMPROVE Particulate Sampler
2-162
November 2001
-------
Individual Areas—Wesf Virginia
mer but rose to 9 percent during the winter. The contributions from organic carbon, elemental carbon,
and crustal material were near 10, 4, and 3 percent year-round.
Figure WV-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinction at the Dolly Sods site from 1992 to 1998. The total annual
aerosol light extinction decreased from 120 to 90 Mm-1, with a statistically significant trend indicating
improved visibility. The statistically significant drop in sulfate species light extinction (30 Mm"1) was
responsible for the improvements in aerosol light extinction over this seven-year period. The annual
light extinction for organic carbon, elemental carbon, and crustal material showed no significant trends
over this time period.
I^HJ
120 -
7E
§, mn -
o
"•g
.E 80 -
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HI
4-1
0> 60
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O 4U
1
<^U
I^Jtwf-Wjjflift-'te^tyL'.. ,• -'-'^.''y-^ '.'-'':''*" ~s$~:' -'* >,---'• ••-X"*^'^;'
™..k^ - • -. ~VUf^'.',.^-*~^^^*.'^^^,*!^*£*!**.-.r-lr^*~ms***-:~~:«™-*'-..,
*• ' — . - - —- - ...— . ' -' ~ .
*• -' ' - >•'•'"-' ' :,.::-.:• -
— • : — — — — ___
'-, -. -- »« i-1-: ^-»7^*''«tr,i^i^.;/>dii'-4i43;J!!^?I>-t^a»1 ,'.,•; ->.•(,,.•.• 1:';!-sn-,;i-,;1 *jft«.. V--
^^" »•• ''"" •-;•• •'' ."Si*^*^ra:&-tW:''--!-;j;»iM-^rt»-«T7:-^-?-7«' —;--—- J--,-r%t-:-
r -
mm
^
^B
— -
^m
—
^m
n i i i i i t i i i i
1988 1989 1990 1991 1992 1993 1994 1995
Year
U Sulfate Q Nitrate D Organic Carbon D Elemental Carbon
1996 1997 1998
• Crustal Material
Figure WV-6. Contributions to Calculated Annual Aerosol Light Extinction from 1992-1998
for the Dolly Sods IMPROVE Particulate Sampler
November 2001
2-163
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
25. WYOMING
Figure WY—1 shows Wyoming's national parks (Grand Tetons and Yellowstone) and wilderness
areas (Bridger, Fitzpatrick, North Absaroka, Teton, and Washakie) designated as mandatory Federal
Class I areas covered by the Regional Haze Rule. They are all located in the central western and north-
western portion of the State. IMPROVE particulate samplers are located near the Bridger Wilderness
Area (monitor at 42.95°N, 109.75°W, elevation 6000 feet) and in Yellowstone National Park (44.56°N,
110.39°W, elevation 6300 feet). Both samplers have been operating since 1988. An IMPROVE protocol
particulate sampler located at Brooklyn Lake (41.33°N, 106.30°W, elevation 10300 feet) within the
Medicine Bow/Routt National Forest has been operating since September 1993 but is located in the
southeast portion of the state. This is outside of the mandatory Federal Class I areas and will therefore
not be discussed in this report. In addition, the. State of Wyoming has designated the Savage Run
Wilderness Area as a Wyoming Class I Area, although this area remains a Federal Class II area, not
covered by the Regional Haze Rule.
Yellowstone
National Park"
Teton
Wilderness
Grand Teton
National Park
North Absaroka Wilderness
Yellowstone
IMPROVE Monitor
Washakie Wilderness
Fitzpatrick Wilderness
Bridger Wilderness
1 Casper
Bridger
IMPROVE Monitor
Cheyenne
100
200
miles
Figure WY-1. Mandatory Federal Class I Areas and IMPROVE Monitoring Sites in Wyoming
Bridger Wilderness Area
The Bridger Wilderness IMPROVE particulate samplers started reporting data in March of 1988.
Figure WY—2 presents the calculated visibility indices for selected data sets from 1988 through 1998.
The figure shows that the visibility index for the most-impaired days ranged from 10 to 13 deciviews
(VR 90 to 65 miles). The visibility indices on the mid-range days remained near 7.6 deciviews (VR 115
miles). The indices on the least-impaired days remained near the average of 4.3 deciviews (VR 160
miles). The index sets for the most-impaired, mid-range, and least-impaired days all showed no statisti-
cally significant trends in visibility.
2-164
November 2001
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Individual Areas—Wyoming
14
12
> 10
o
0)
a
°
_c
>.
£ 6
jo
'55
-"Most-Impaired
•-if.
• Mid-Range
Least-Impaired
4-
4-
4-
4-
4-
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure WY-2. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Bridger IMPROVE Participate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
Year
1998
-Spring
-Summer
-Autumn
-Winter
Figure WY-3. Seasonal Deciview Averages from 1988-1998 for the
Bridger IMPROVE Particulate Sampler
November 2001
2-165
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Organic
Carbon
29%
Nitrate
7%
Elemental
Carbon
9%
Crustal
Material
18%
Sulfate
37%
Figure WY-4. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Bridger IMPROVE Particulate Sampler
Figure WY-3 shows the seasonal averages for the
calculated visibility indices from 1988 through 1998.
The indices for winter were, on average, 2.5 deciviews
lower than the values for the other three seasons. The
visibility index sets for all four seasons showed no statis-
tically significant trends over the eleven-year period.
Figure WY-4 presents a chart showing the calculated
fractional contribution to Bridger's light extinction by
each aerosol species on an annual basis. Figure WY-5
shows the same information for the four seasons. These
five pie charts show that the largest contributors to light
extinction were sulfate particles and organic carbon.
Sulfate particles were responsible for 29 to 46 percent of
the light extinction at the Bridger Wilderness site, aver-
aging 37 percent on an annual basis over a five-year
period. The contributions from sulfates were lower in the
Organic
Carbon
22%
Elemental
Carbon
7%
Nitrate
7%
Crustal
Material
18%
Sulfate
46%
Spring
Elemental
Carbon
9%
Organic
Carbon
39%
Crustal
Material
18%
Nitrate
5%
Sulfate
29%
Summer
Organic
Carbon
31%
Nitrate
7%
Elemental
Carbon
10%
Crustal
Material
17%
Sulfate
35%
Autumn
Organic
Carbon
21%
Nitrate
13%
Elemental
Carbon
8%
Crustal
Material
21%
Sulfate
37%
Winter
Figure WY-5. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Bridger IMPROVE Particulate Sampler
2-166
November 2001
-------
Individual Areas—Wyoming
summer and higher in the spring. The contributions from organic carbon rose from 21 percent in the
winter and spring to 39 percent in the.summer. Nitrate contributions were just 5 percent in the summer
but rose to 13 percent in the winter. Annually, elemental carbon and crustal material contributions were
near 9 and 18 percent.
Figure WY-6 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinction at the Bridger.Wilderness site from 1988 to 1998. The total
annual aerosol light extinction ranged from 10 to 14 Mm-1, indicating no statistically significant trend
in light extinction coefficients. The annual light extinction for .sulfates, organic carbon, elemental car-
bon, and crustal material showed no significant trends over this time period.
* • v . • " .> •.•';''" .'it .'.'• •.. iVY* ~-~ a * ' - • ra
-i—'• —i— —i— —r
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
DSulfate H Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure WY-6. Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998
for the Bridger IMPROVE Particulate Sampler
Yellowstone National Park
The Yellowstone IMPROVE particulate sampler started reporting data in March of 1988. Figures
WY-7, WY-8, and WY-11 all show considerably higher values in 1988 than in other years. During the
summer of 1988, nearly half of Yellowstone's 2.2 million acres burned in eight major wild fires. In
order to capture the behavior outside this anomalous year, the trends in this section will be evaluated
only for the years 1989 through 1998. Figure WY-7 presents the calculated visibility indices for select-
ed data sets from 1988 through 1998. The figure shows that the visibility index for the most-impaired
days (1989-1998) dropped from 14 to 12 deciviews (VR from 60 to 75 miles), but the trend was not
statistically significant. The visibility indices on the mid-range days remained near 9 deciviews (VR
100 miles), indicating no significant trend"in visibility. The indices on the least-impaired days.
November 2001
2-167
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
iiiiUHeiiyii la.!, iii iiit ncuMCiduiiUUflMBmiKi
iSillSIS
^^
Most-Impaired
Least-Impaired
• 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure WY-7. Yearly Deciview Averages for Most-Impaired, Mid-Range, and Least-Impaired
Days from 1988-1998 for the Yellowstone IMPROVE Particulate Sampler
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
-^-Spring -B-Summer -A-Autumn -•-Winter
Figure WY-8. Seasonal Deciview Averages from 1988-1998 for the
Yellowstone IMPROVE Particulate Sampler
2-168
November 2001
-------
Individual Areas—Wyoming
Elemental
Carbon
9%
Organic
Carbon
36%
Nitrate
7%
Crustal
Material
19%
Sulfate
29%
Figure WY-9. Contribution to
Calculated Annual Aerosol Light
Extinction from 1994-1998 for the
Yellowstone IMPROVE Particulate
Sampler
decreased from 6.7 to 4.3 deciviews (VR 125 to 160
miles) and showed a statistically significant trend toward
improved visibility.
Figure WY-8 shows the seasonal averages for the cal-
culated visibility indices from 1988 through 1998. Since
CIRA reported no winter 1997 data, no value is reported
for winter 1997 in Figure WY-8. Interested readers can
view the ambient concentration data at
http://improve.cnl.ucdavis.edu/cgi-bin/SSDisplay.cgi. The
average seasonal indices for the summer were approxi-
mately 2 deciviews higher than those for the spring and
autumn (except in 1993, 1997, and 1998). The spring and
autumn values were approximately 3 deciviews higher
than those for the winter. The visibility indices for the
winter dropped 3 deciviews over the ten-year period, indi-
cating significant trends toward improved visibility. The
Organic
Carbon
26%
Nitrate
8%
Elemental
Carbon
8%
Crustal
Material
20%
Sulfate
38%
Organic
Carbon
42%
Elemental
Carbon
9%
Spring
Nitrate
5%
Summer
Crustal
Material
20%
Sulfate
24%
Organic
Carbon
37%
Elemental
Carbon
10%
Nitrate
7%
Autumn
Crustal
Material
19%
Sulfate
27%
Organic
Carbon
32%
Nitrate
12%
Elemental
Carbon
9%
Crustal
Material
14%
Sulfate
-33%
Winter
Figure WY-10. Contribution to Calculated Seasonal Aerosol Light Extinction
from 1994-1998 for the Yellowstone IMPROVE Particulate Sampler
November 2001
2-169
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
spring, summer, and autumn indices showed no statistically significant trends toward improved visibili-
ty between 1989 and 1998.
Figure WY-9 presents a chart showing the calculated fractional contribution to Yellowstone's light
extinction by each aerosol species on an annual basis. Figure WY-10 shows the same information for
the four seasons. These five pie charts show that the largest contributors to light extinction were organ-
ic carbon and sulfate particles. The contributions from organic carbon rose from 26 percent in the
spring to 42 percent in the summer, averaging 36 percent on an annual basis over a five-year period.
Sulfate was responsible for 24 to 38 percent of the light extinction at the Yellowstone site, averaging 29
percent on an annual basis over a five-year period. The contributions from sulfates were lower in the
summer and autumn and higher in the winter and spring. Nitrate contributions were near 5 percent in
the summer but rose to 12 percent hi the winter. Annually, elemental carbon and crustal material contri-
butions were near 9 and 19 percent.
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
@ Sulfate 01 Nitrate D Organic Carbon D Elemental Carbon • Crustal Material
Figure WY-11.
Contributions to Calculated Annual Aerosol Light Extinction from 1988-1998
for the Yellowstone IMPROVE Particulate Sampler
Figure WY—11 shows the calculated contributions of each of the aerosol mass components to the
annual average aerosol light extinctions at the Ifellowstone site from 1988 to 1998. The high light
extinction attributed to organic and elemental carbons in 1988 resulted from the major wildfires. From
1989 to 1998, the total annual aerosol light extinctions dropped from 17 to 13 Mm-1, with a statistically
significant trend toward lower total light extinction coefficients. The annual light extinctions for sul-
fates, organic carbon, and elemental carbon showed no significant trends over this time period.
However, the annual light extinction coefficients for crustal material decreased 3 Mm-1, indicating sta-
tistically significant trends toward lower light extinction coefficients for that species and lower ambient
concentrations.
2-170
November 2001
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Individual Areas—Wyoming
Wyoming State Summary
The calculated annual average aerosol extinction coefficients at Wyoming's IMPROVE monitoring
sites are presented in Table WY—1. The sites are located 115 miles apart. The total aerosol extinction
coefficients at both sites were within 20 percent of one another, indicating similar annual visibility con-
ditions at both sites. The extinction coefficients for the individual species were also similar at both
sites. Both sites also showed similar rankings for contributions of the species to light extinction: sul-
fate, followed by organic carbon, crustal material, elemental carbon, and lastly nitrate. The same rank-
ings were observed for the Arizona, Colorado, and Texas sites in Tables AZ—1, CO-1, and TX—1.
Table WY-1. Wyoming Calculated Total Extinction Coefficients from 1994-1998
IMPROVE Site
Bridger Wilderness
Yellowstone NP
Calculated Total
Aerosol Extinction
Coefficient (Mar1)
12.0
14.3
Pollutant Extinction Coefficient (Mm"1)
Sulfate
4.4
4.1
Nitrate
0.9
1.0
Organic
Carbon
3.6
5.1
Elemental
Carbon
1.0
1.3
Crustal
Material
2.1
2.8
November 2001
2-171
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-------
National and Regional Discussions of Visibility
3. National and Regional Discussions of Visibility
A. Introduction
This chapter presents visibility data from all of the sites in a series of national maps. The first sec-
tion presents the subsets of data from the least-impaired, most-impaired, and mid-range days. The maps
show the average visibility indices for these data subsets from 1994 through 1998 and also show the
statistically significant trends at the sites over the entire operational periods of the particulate samplers.
The second section examines the concentrations of the five pollutant species found in fine particu-
late matter: sulfates, nitrates, organic carbon, elemental carbon, and soil and crustal material. National
maps show the concentrations of these species, the percentages of the fine particulate matter that they
constitute, the light extinction coefficients calculated from these species, and the percentages of the
visibility impairment attributable to these species.
The final section of this chapter compares and contrasts visibility impairment in the East and West.
Mean values for the regions are calculated by averaging the calculated light extinction coefficients
from the sites. Likely causes are also presented to explain some of the annual and seasonal differences
between Eastern and Western measurements of the five particulate matter components.
November 2001
3-1
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
B. National Visibility
Trends for Least-Impaired Days
Figure 3-1 shows the annual average visibility indices for the least-impaired, or "best," days from
1994 through 1998 at the IMPROVE monitoring locations. The indices range from 3.9 deciviews
(VR 165 miles) at the Jarbidge Wilderness Area (NV) to 19.2 deciviews (VR 36 miles) at the Sipsey
Wilderness Area (AL). Other high deciview values were observed in the Southeast and mid-Atlantic
states.
Denali NP, Alaska
Figure 3-1. Annual Average Visibility Indices for Least-Impaired Days from 1994-1998
3-2
November 2001
-------
National and Regional Discussions of Visibility
Figure 3-2 illustrates which IMPROVE sites showed statistically significant trends in visibility on
their least-impaired days during their operational periods. Six monitors showed improvements in visi-
bility on the least-impaired days, and three showed declines in the visibility on the least-impaired days.
Only 2 of the 13 sites in eastern states showed improving trends on the least-impaired days, and only 4
of the 32 sites in western states showed improving trends on the least-impaired days. The western sites.
showing improvement could not be grouped spatially, and the western sites showing declines were
found in both Washington State and along the southwestern U.S. border.
Trend in Visual Range
(Least-Impaired Days)
No Significant Change
^Decline
Denali NP, Alaska
Figure 3-2. IMPROVE Sites Showing Statistically Significant Trends in Visibility
on Least-Impaired Days
November 2001
3-3
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Trends for Mid-Range Days
Figure 3—3 presents the annual average visibility indices for the mid-range days from 1994
through 1998 at the IMPROVE monitoring sites. The indices range from 6.3 deciviews (VR 130
miles) at Denali National Park (AK) to 25.2 deciviews (VR 20 miles) at Mammoth Cave National
Park (KY). Other high deciview values were observed in the Southeast, mid-Atlantic region, and four
California sites.
Denali NP, Alaska
Figure 3-3. Annual Average Visibility Indices for Mid-Range Days from 1994-1998
3-4
November 2001
-------
National and Regional Discussions of Visibility
Figure ?>-4 shows which IMPROVE sites showed statistically significant trends in visibility on their
mid-range days during their operational periods. None of the sites showed declining visibility on the
mid-range days. Four of the 13 eastern sites showed improvements in visibility on the mid-range days,
but only four of the 32 western sites showed statistically significant improvements in the calculated vis-
ibility. Four of the 8 sites showing improved visibility on mid-range days also showed improvement on
the least-impaired days (Figures 3-2 and 3-4).
Trend in Visual Range
(Mid-Range Days)
Denali NP, Alaska
4^ Improve
1 No Significant Change
Figure 3-4. IMPROVE Sites Showing Statistically Significant Trends in Visibility
on Mid-Range Days
November 2001
3-5
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Trends for Most-Impaired Days
The annual average visibility indices for the most-impaired days at the IMPROVE sites are present-
ed in Figure 3-5. The indices represent data collected between 1994 and 1998. Denali National Park
(AK) had the lowest index at 10.4 deciviews (VR 85 miles) for the most-impaired days, and Mammoth
Cave National Park (KY) had the highest index at 32.1 deciviews (VR 10 miles). The ten sites with the
highest indices for the most-impaired days were the ten located in the Southeast and mid-Atlantic
states. They had visibility indices greater than 27 deciviews (VR less than 16 miles).
Denali NP, Alaska
Figure 3-5. Annual Average Visibility Indices for Most-Impaired Days from 1994-1998
3-6
November 2001
-------
National and Regional Discussions of Visibility
Figure 3-6 shows which IMPROVE sites showed statistically significant trends in visibility on their
most-impaired days during their operational periods. The visibility on the most-impaired days did not
decline at any of the sites. Only one of the 13 eastern sites (Mammoth Cave, KY) showed statistically
significant improvements in the calculated visibility on the most-impaired days. Only 5 of the 32 west-
ern sites showed improvements on these days, four of the sites located in California. Only the Pinnacles
site in California showed statistically significant improvements on the least-impaired, mid-range, and
most-impaired days (Figures 3-2, 3-4, and 3-6).
Denali NP, Alaska
Trend in Visual Range
(Most-Impaired Days)
^Improve
• No Significant Change
^Decline
Figure 3-6. IMPROVE Sites Showing Statistically Significant Trends in Visibility
on Most-Impaired Days
November 2001
3-7
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
C. Contributors to Visibility Impairment
This section presents a series of four national maps associated with each pollutant: (1) annual aver-
age concentration ((ig/m3), (2) average annual contribution to the particulate fine mass (percent), (3)
average annual calculated light extinction for the pollutant (Mm"1), and (4) average annual contribution
to the calculated aerosol light extinction coefficient (percent). The data presented show the averages for
the years from 1994 through 1998.
Sulfate
Table 1-1 reported that the natural sources of sulfate particulate matter include sea spray and the
oxidation of sulfur gases emitted by volcanoes, oceans, wetlands, and wildfires. The oxidized sulfur
gases combine with ammonia (emitted from motor vehicles, animal husbandry, sewage treatment, land
fertilizers, and wild animals) to form fine particulate matter. The major manmade source of sulfate par-
ticulate matter is fossil fuel combustion.
Figure 3-7 shows the average sulfate concentrations at the IMPROVE monitoring sites between
1994 and 1998. The figure shows that the sulfate concentrations were greater than 2.5 jJ-g/m3 at all
locations in the eastern states except for the Boundary Waters site (MN). The average sulfate levels
were below 2.5 fXg/m3 at all locations in the western states except for the Big Bend site (TX).
""0.5
Denali NP, Alaska
Figure 3-7. Average Annual Sulfate PM Concentrations at IMPROVE Monitoring Sites
from 1994-1998
3-8
November 2001
-------
National and Regional Discussions of Visibility
To better understand the causes of elevated sulfate levels (and reduced visibility) during recent years
in Big Bend National Park (TX), the EPA and the National Park Service funded the Big Bend Regional
Aerosol and Visibility Observational Study in 1999 (NFS, 1999). The study aims to identify and quanti-
fy the specific emission sources, emission types (e.g., petroleum refineries, fossil fuel power plants,
urban areas), and source regions (by state and country) that contribute to the degraded visibility in the
park.
Figure 3-8 presents the average contribution of sulfate particulate matter to the total PM2 5 levels at
the IMPROVE monitoring locations from 1994 to 1998. All of the sites located in the eastern states
except Boundary Waters Canoe Area (MN) showed average sulfate contributions greater than 50 per-
cent and averaged 57 percent. The sulfate contributions from the 33 western sites were all less than 48
percent and averaged just 31 percent. Since the manmade SO2 emissions in states east of the
Mississippi River were more than three times greater than those west of the Mississippi (E. H. Pechan
and Associates, 1994), the higher sulfate observations in the East were not unexpected.
Denali NP, Alaska
Figure 3-8. Average Annual Contributions of Sulfate PM to Total PM2 5 Levels at
IMPROVE Monitoring Sites from 1994-1998
November 2001
3-9
-------
Visibility in Mandatory Federal Class I Areas-(1994-1998): A Report to Congress
The high average sulfate concentrations in the eastern states lead to high average sulfate extinction
coefficients calculated for those sites (Figure 3-9). In eastern states, the calculated annual average sul-
fate extinction coefficients were as high as 101 Mm"1 (Mammoth Cave National Park, KY) and as low
as 18 Mm"1 (Boundary Waters. Canoe Area, MN). The average sulfate extinction coefficient was 61
Mm"1 in eastern states and 9 Mm"1 in western states. Some of the difference between the average sul-
fate extinction at eastern and western IMPROVE monitoring locations was because the extinction coef-
ficients are calculated as a function of average relative humidity (Appendix C). Relative humidities
near the western monitors were often considerably lower than those in eastern states. (See Section 3.D,
Regional Pollutants for additional supporting data.) In western states, the calculated annual average
sulfate extinction coefficients ranged from 3 Mm"1 (Jarbidge Wilderness Area, NV) to 25 Mm"1
(Redwood National Park, CA).
Denali NP, Alaska
Figure 3-9. Average Annual Sulfate Extinction Coefficients at IMPROVE Monitoring Sites
from 1994-1998
3-10
November 2001
-------
National and Regional Discussions of Visibility
Figure 3-10 shows the average annual contributions of sulfate particulate matter to the calculated
aerosol light extinction coefficients for the IMPROVE sites from 1994 to 1998. The contributions
ranged from 23 percent at San Gorgonio Wilderness Area (CA) to 78 percent at Mammoth Cave
National Park (KY) and Dolly Sods Wilderness Area (WV). The average was 47 percent for all sites.
The eleven highest contributions occurred in eastern states and the lowest contribution from any eastern
monitor was 52 percent; Since the annual average relative humidity is higher in the East and sulfate
concentrations are higher in the East (Figure 3-7), the spatial distribution of Figure 3—10, showing
higher percentages in the East,, was not unexpected.
Denali NP, Alaska
Figure 3-10. Average Annual Contributions of Sulfate PM to Calculated Aerosol Light
Extinctions at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-11
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Nitrate
Table 1-1 listed the oxidation of NOX emissions as the major natural source of nitrate particulate
matter. The natural sources of NOX include soils, wildfires, and lightning. Oxidized nitrate gases com-
bine with ammonia (emitted from motor vehicles, animal husbandry, sewage treatment, land fertilizers,
and wild animals) to form particulate matter. Manmade sources of NOX include motor vehicle exhaust,
prescribed burning, and other fossil fuel combustion processes.
Figure 3-11 presents the annual nitrate concentrations averaged for the period from 1994 through
1998. In the eastern states, the annual average nitrate concentrations ranged from 0.3 |ig/m3 in Acadia
(ME) to 1.6 |ig/m3 in Washington (DC). The average was 0.7 (J-g/m3 among all the eastern sites. The
average nitrate concentrations in western states ranged from 0.05 (ig/m3 in Denali National Park (AK)
to 2.6 jJ-g/m3 in San Gorgonio Wilderness Area (CA). The average was 0.4 p,g/m3 among all the western
sites. The highest nitrate levels (0.8 to 2.6 J-ig/m3) in the western states were observed at southern
California monitoring stations (Pinnacles, Point Reyes, San Gorgonio, and Sequoia).
— 0.1
Denali NP, Alaska
Figure 3-11. Average Annual Nitrate PM Concentrations at IMPROVE Monitoring Sites
from 1994-1998
3-12
November 2001
-------
Nafional and Regional Discussions of Visibility
The annual nitrate concentrations at the rural southern California sites were still considerably lower
than those measured at urban and suburban sites in southern California in 1993 and 1995
(Christoforou, et al. 2000; South Coast Air Quality Management District, 1997). For example, in 1993,
the South Coast Air Quality Management District reported annual average nitrate concentrations
between 2.3 and 9.7 |J.g/m3 at four urban and suburban sites. The site measuring 9.7 |lg/m3 nitrate in
1993 (Rubidoux, CA) is located just 35 miles west of the San Gorgonio IMPROVE site, which meas-
ured 3.7 (J,g/m3 as its 1993 annual average nitrate concentration.
Figure 3—12 presents the average contribution of nitrate particulate matter to the total PM2 5 levels
at the IMPROVE monitoring locations from 1994 through 1998. At sites in the eastern states, the
nitrate contributions ranged from 3 percent at the Great Smoky Mountains National Park (TN) to 14
percent at Boundary Waters Canoe Area (MN). The average was 7 percent. The percent contribution of
nitrate at Boundary Waters Canoe Area is perceived as high because the total fine mass and sulfate fine
mass at this site averaged just 4.4 and 1.8 |ig/m3, while the other eastern sites averaged 10 (_ig PM2 s/m3
and 5.6 |ig sulfate/m3. The highest nitrate contributions in western states occurred at Point Reyes (21
percent) and San Gorgonio (36 percent), both near major metropolitan areas in California. The average
nitrate contribution to PM2 5 among the monitoring stations in the western states was 9 percent.
Denali NP, Alaska
Figure 3-12. Average Annual Contributions of Nitrate PM to Total PM2 5 Levels
at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-13
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Figure 3-13 shows the calculated annual average nitrate extinction coefficients for the period from
1994 through 1998. In the eastern states, the extinction coefficients from nitrate ranged from 3 Mm"1 in
Acadia National Park (ME) and Great Smoky Mountains National Park to 16 Mm"1 at the Washington
(DC) site. In the western states, the calculated extinction coefficients for nitrate ranged from 0.5 Mm"1
for Denali National Park (AK) to 17 Mm"1 for San Gorgonio Wilderness Area (CA). The average was 3
Mm"1 for all western sites. When comparing Figures 3-11 and 3-13, readers may note that the relative
differences between the desert sites and the less arid sites are higher for the light extinction figure. This
behavior can be attributed to the low relative humidity in the desert areas, which prevents water
droplets from-joining the particulate aerosols and efficiently obscuring visibility.
~~~0.5
Denali NP, Alaska
Figure 3-13. Average Annual Nitrate Extinction Coefficients at IMPROVE Monitoring Sites
from 1994-1998
3-14
November 2001
-------
National and Regional Discussi'ons of Visibility
Figure 3-14 shows the average contributions of nitrate particulate matter to the calculated aerosol
light extinction coefficients for the IMPROVE sites from 1994 to 1998. In eastern states, .the nitrate
contributions to light extinction ranged from 3 percent at Great Smoky Mountains National Park (TN)
to 18 percent at Boundary Waters Canoe Area (MN). The average was 9 percent for all 13 sites. The
nitrate contribution to light extinction in western states averaged 11 percent. In western states, the
nitrate contributions to light extinction were lowest at Big Bend National Park (TX), 5 percent, and
remained below 20 percent for all but four sites. The four western sites with nitrate contributions over
20 percent were all located in California: Sequoia (22 percent), Pinnacles (21 percent), Point Reyes (25
percent), and San Gorgonio (39 percent).
Denali NP, Alaska
Figure 3-14. Average Annual Contributions of Nitrate PM to Calculated Aerosol Light
Extinctions at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-15
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
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3-16
November 2001
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National and Regional Discussions of Visibility
Organic Carbon
Table 1-1 reported major natural sources of organic carbon particulate matter to be wildfires and
the oxidation of hydrocarbons emitted by vegetation. Daily measurements from the "Ybsemite and
Glacier National Park IMPROVE monitoring locations between 1994 and 1998 confirmed that organic
carbon concentrations rose significantly during major wildfire events (National Interagency Fire
Center, 1998). Manmade sources of organic carbon particulate matter include open burning, wood
burning, prescribed burning, cooking, motor vehicle exhaust, incineration, tire wear, and the oxidation
of hydrocarbons emitted from motor vehicles, open burning, wood burning, prescribed burning, fuel
storage and transport, and solvent usage.
Figure 3-15 was constructed from satellite imagery and represents the level of photosynthetic activ-
ity in the vegetation during July 1988 (Los et al., 1994). The Normalized Difference Vegetation Index
represents the green leaf density of vegetation, with higher numbers indicating greater photosynthetic
activity. Figure 3-15 is presented here to illustrate vegetation growth in the 48 contiguous states. The
figure clearly shows more vegetation growth in July 1988 in the East, along the Pacific Coast, and in
Idaho and western Montana than in other parts of the United States.
Normalized Difference
Vegetation Index (July 1998)
• 0.7
a 0.2
a o
Figure 3-15. Level of Photosynthetic Activity in Vegetation during July 1988
November 2001
3-17
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report fo Congress
Figure 3—16 presents the annual average concentrations of organic carbon particulate matter at the
IMPROVE monitoring sites for the period from 1994 through 1998. The organic carbon concentrations
range from 0.6 fig/m3 at Denali National Park (AK) to 3.9 |ig/m3 at the National Mall in Washington
(DC). Higher concentrations of organic carbon were observed in the Southeast and near Sequoia and
Yosemite National Parks than at other rural sites. The major natural sources of organic carbon emis-
sions are wildfires and the atmospheric oxidation of hydrocarbons emitted from vegetation (Table 1-1).
Therefore, organic carbon concentrations would be expected to be higher closer to these activities (i.e.,
where growing seasons are longer) and lower in areas with slower vegetation growth (yellow areas in
Figure 3-15). When vegetation grows more slowly, less is available to burn in wildfires, and prescribed
burns over several decades. Besides Denali National Park, the sites with annual average organic carbon
concentrations less than 0.9 |0,g/m3 were all located in the arid Four Corners area of the Southwest
(Bryce Canyon and Canyonlands, UT; Grand Canyon, AZ; and Mesa Verde, Weminuche, and Great
Sand Dunes, CO).
*0,S
Denafi NP, Alaska
Figure 3-16. Average Annual Organic Carbon PM Concentrations at IMPROVE Monitoring
Sites from 1994-1998
3-18
November 2001
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National and Regional Discussions of Visibility
Figure 3-17 presents the average contribution of organic carbon particulate matter to the total
PM2 5 levels at the IMPROVE sites from 1994 through 1998. The lowest percent contributions from
organic carbon (between 20 and 25 percent) were observed at mid-latitude eastern sites (Mammoth
Cave, KY; Dolly Sods, WV; Shenandoah, VA; and Brigantine, NJ) and the three monitors closest to the
Mexican border (Chiricahua, AZ; Guadalupe Mountains, TX; and Big Bend, TX). The highest percent
contributions from organic carbon (40 to 55 percent) were found at the monitors in the northwestern
sites in Alaska, Washington, Montana, Oregon, Wyoming, and northern California.
Denali NP, Alaska
Figure 3-17. Average Annual Contributions of Organic Carbon PM to Total PM2 5 Levels
at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-19
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Figure 3-18 shows the annual average organic carbon extinctioji coefficients for the period from
1994 through 1998. The lowest light extinction coefficients (from 2.3 to 3.6 Mm"1) for organic carbon
were observed at Denali National Park, AK and the sites in the Four Corners area of the Southwest
(Bryce Canyon and Canyonlands, UT; Grand Canyon, AZ; and Mesa Verde, Weminuche, and Great
Sand Dunes, CO). The annual average organic carbon concentrations at all seven of these sites were
below 0.9 fig/m3. The highest light extinction coefficients for organic carbon (from 10.5 to 16 Mm"1)
were at Sequoia National Park (CA), Washington (DC), and the mandatory Federal Class I areas in the
southeastern states of Kentucky, Tennessee, Alabama, Georgia, and Florida.
Denali NP, Alaska
Figure 3-18. Average Annual Organic Carbon Extinction Coefficients
at IMPROVE Monitoring Sites from 1994-1998
3-20
November 2001
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National and Regional Discussions of Visibility
Figure 3-19 shows the average contributions of organic carbon particulate matter to the calculated
aerosol light extinction coefficients for the IMPROVE sites from 1994 to 1998. The lowest percent con-
tribution from organic carbon (9 percent) occurred at the Mammoth Cave National Park (KY) monitor
site, the site that showed the highest total visibility impairment on the least-impaired, most-impaired,
and mid-range days (Figures 3-1, 3-3, and 3-5). The highest percent contributions from organic carbon
(30 to 38 percent) were observed at seven sites in the Northwest: Glacier National Park (MT), Crater
Lake National Park (OR), Yellowstone National Park (WY), Lassen Volcanic and Yosemite National
Parks (CA), and Great Basin National Park and Jarbidge Wilderness Area (NV).
Denali NP, Alaska
Figure 3-19. Average Annual Contributions of Organic Carbon PM to Calculated Aerosol
Light Extinctions at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-21
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Elemental Carbon
Table 1—1 reported wildfires as the natural source of elemental carbon particulate matter and motor
vehicle exhaust, wood burning, prescribed fires, and cooking as the manmade sources of elemental car-
bon particulate matter.
Figure 3—20 presents the annual average concentrations of elemental carbon particulate matter at
the IMPROVE sites for the period from 1994 through 1998. The lowest average concentration of ele-
mental carbon (0.09 (ig/m3) was observed at Denali National Park, AK. The highest concentrations
(0.35 to 0.60 |ig/m3) at rural sites were observed at Glacier National Park (MT), three sites in southern
California (Pinnacles, Sequoia, and San Gorgonio), the mid-Atlantic sites (Brigantine, Dolly Sods, and
Shenandoah), and the sites in the Southeast (Mammoth Cave, Upper Buffalo, Great Smoky Mountains,
Sipsey, Okefenokee, and Chassahowitzka). In addition, the concentration observed at the urban
Washington (DC) site was 1.24 [ig/m3, more than double any of the other readings.
0.2
u.
-------
National and Regional Discussions of Visibility
Figure 3-21 presents the average contribution of elemental carbon particulate matter to the total
PM2 5 levels at the IMPROVE monitoring locations from 1994 through 1998: The two sites in Texas
(Big Bend and Guadalupe Mountains National Parks) had the lowest percent contribution (3 percent)
from elemental carbon to the total PM2.s concentrations. The highest percent contributions (8 to 9 per-
•cent) from elemental carbon occurred at Washington (DC) and four sites in the Northwest: Mount
Rainier National Park and Snoqualmie Pass (WA)> Glacier National Park (MT), and Crater Lake
National Park (OR).
Denali NP, Alaska
Figure 3-21. Average Annual Contributions of Elemental Carbon PM to Total PM2.s Levels
at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-23
-------
r
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Figure 3-22 shows the calculated annual average elemental carbon extinction coefficients for the
period from 1994 through 1998. The lowest average extinction coefficient for elemental carbon (0.92
Mm"1) was observed at Denali National Park (AK). The highest coefficients (3.5 to 6.0 Mm"1) at rural
sites were observed at Glacier National Park (MT), three sites in southern California (Pinnacles,
Sequoia, and San Gorgonio), the mid-Atlantic sites (Brigantine, Dolly Sods, and Shenandoah), and the
sites in the Southeast (Mammoth Cave, Upper Buffalo, Great Smoky Mountains, Sipsey, Okefenokee,
and Chassahowitzka). In addition, the coefficient calculated at the urban Washington (DC) site was 12.4
Mm"1, more than double any of the other light extinction coefficients calculated for elemental carbon.
"""0.9
Denali NP, Alaska
Figure 3-22. Average Annual Elemental Carbon Extinction Coefficients
at IMPROVE Monitoring Sites from 1994-1998
3-24
November 2001
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National and Regional Discussions of Visibifify
Figure 3-23 shows the average contributions of elemental carbon particulate matter to the calculat-
ed aerosol light extinction coefficients for the IMPROVE sites from 1994 to 1998. The lowest percent-
age contributions from elemental carbon occured at California's two coastal sites, Redwood National
Park (2 percent) and Point Reyes National Seashore (3 percent). Values at other sites ranged from 4
percent at several eastern sites up to 16 percent at Crater Lake National Park (OR).
"10
Denali NP, Alaska
Figure 3-23. Average Annual Contributions of Elemental Carbon PM to Calculated Aerosol
Light Extinctions at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-25
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Soil and Crustal Material
Soil data in the IMPROVE network reflect measurements of various components emitted from soil
emission activities: aluminum, silicon, calcium, titanium, and iron, and their calculated oxides. The soil
data are independent of the soil types, such as sediment, sandstone, or limestone and are measured and
calculated for the fraction of particulate matter less than 2.5 microns in aerodynamic diameter.
In the IMPROVE calculations, processes emitting earthen particles (e.g., mining and quarrying
activities, construction, agriculture, and fugitive road dust) also contribute to the coarse mass fraction
(particles larger than 2.5 microns but smaller than 10 microns) of particulate matter. Therefore, the soil
data are combined with the coarse mass fraction to describe crastal material. Since smaller particles
impair visibility to a greater extent than larger particles (on a mass basis), the fine soil and coarse mass
concentrations are not weighted equally when calculating light extinction from crustal material (see
Appendix C for the calculation method).
Table 1-1 reports two natural emissions sources of crustal material in the PM2-5 range: wind ero-
sion and the re-entrainment of deposited particles. Manmade sources of crustal material include fugi-
tive dust from paved and unpaved roads, agricultural operations, construction and demolition, forestry,
mining and quarrying activities, and some industrial processes (e.g., stone cutting and finishing).
Figure 3-24 presents the annual average concentrations of fine soil particulate matter at the
IMPROVE sites for the period from 1994 through 1998. The highest fine soil concentrations (1.3 to
1.65 (Ig/m3) were observed at the Sequoia National Park site (CA) and the two monitors in Texas: Big
Bend and Guadalupe Mountains National Parks. The lowest fine soil concentrations (0.15 to 0.30
|J,g/m3) were observed at Denali National Park (AK) and six additional monitor sites: Mount Rainier
and Snoqualmie Pass (WA), Three Sisters (OR), Point Reyes and Redwood (CA), and Acadia (ME).
The data trends suggest a general observation that sites near major bodies of water may tend to have
lower annual average fine soil concentrations than sites further inland. Since fewer emission sources of
fine soil are spatially available near coastal sites (i.e., less land mass near the coast), this observation is
not unexpected.
Figure 3—25 presents the average contribution of fine soil particulate matter to the total PM2.s levels
at the IMPROVE monitoring locations from 1994 through 1998. The highest percent contributions of
fine soil (18 to 32 percent) occurred at the 19 sites in Wyoming, Nevada, Utah, Colorado, Arizona,
New Mexico, and Texas. The lowest annual fine soil contributions (4 to 5 percent) were at Point Reyes
National Seashore (CA) and the eastern sites from Tennessee northward: Great Smoky Mountains
(TN), Mammoth Cave (KY), Dolly Sods (WV), Shenandoah (VA), Washington (DC), Brigantine (NJ),
Lye Brook (VT), and Acadia (ME). The fine soil represents only a small fraction of the total PM2 5 at
the eastern sites because the annual average sulfate concentrations were high at these sites.
3-26
November 2001
-------
National and Regional Discussions of Visibility
•0.2
Denali NP, Alaska
Figure 3-24. Average Annual Fine Soil PM Concentrations at IMPROVE Monitoring Sites
from 1994-1998
'13
H
Denali NP, Alaska
Figure 3-25. Average Annual Contributions of Fine Soil PM to Total PM2>5 Levels
at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-27
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
The crustal material extinction coefficients are calculated from both the fine soil and the coarse
mass measurements. Since the ratio of coarse mass to fine soil for the annually averaged data ranged
from 4.3 at Mesa Verde National Park (CO) up to 42 at Point Reyes National Seashore (CA), the fine
soil component represented less than 20 percent of the crustal material concentration on an annual
basis. The highest ratios (17 to 42) of coarse mass to fine soil were observed at the sites closest to the
coast: Pinnacles, Point Reyes, and Redwood (CA), Acadia (ME), and Brigantine (NJ). The high con-
centrations of coarse mass at these sites may be due to sea spray, which is composed primarily of parti-
cles greater than 2.5 but less than 10 microns in aerodynamic diameter (USEPA, 1997a).
Figure 3-26 shows the annual average crustal material extinction coefficients for the period from
1994 through 1998. Lassen Volcanic (CA) and Denali (AK) monitoring sites,showed the lowest extinc-
tion coefficients with values near 1.9 Mm"1. The highest crustal material extinction coefficients were
observed at the Sequoia site (CA, 8.1 Mm"1) and the Brigantine site (NJ, 8.2 Mm"1).
Denali NP, Alaska
Figure 3-26. Average Annual Crustal Material Extinction Coefficients
at IMPROVE Monitoring Sites from 1994-1998
3-28
November 2001
-------
National and Regional Discussions of Visibility
Figure 3-27 shows the average contributions of crustal material particulate matter to the calculated
aerosol light extinction coefficients for the IMPROVE sites from 1994 to 1998. Crustal material was
responsible for only 3 percent of the aerosol light extinction coefficient at the Sipsey (AL), Mammoth
Cave (KY), Dolly Sods (WV), and Shenandoah (VA) sites. Crustal material was responsible for 16 to
31 percent of the aerosol light extinction coefficients at Denali National Park (AK), Crater Lake
National Park (OR), Sequoia National Park (CA), and all nineteen monitoring locations in Wyoming,
Nevada, Utah, Colorado, Arizona, New Mexico, and Texas.
•19
Denali NP, Alaska
Figure 3-27. Average Annual Contributions of Crustal Material PM to Calculated Aerosol
Light Extinctions at IMPROVE Monitoring Sites from 1994-1998
November 2001
3-29
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Visibility in Mandatory Federal Class 1 Areas (1994-1998): A Report to Congress
D. Regional Pollutants
From the discussions in the previous section, it is readily apparent that pollutants affect the monitor
readings differently hi the various regions of the continental United States. Figure 3-28 presents the
mandatory Federal Class I areas and the IMPROVE monitoring sites divided into a western region
(greater than 100°W) and an eastern region (less than 100°W), with Alaska lying in the western region.
Thirteen sites are located in the East and 33 in the West. Since the calculated annual aerosol light
extinction coefficient at the urban Washington (DC) (not a mandatory Federal Class I area) site was
within one standard deviation (28 Mm"1) of the average for all eastern sites, it was included in the
analysis as an eastern site.
Rodwood** ,
Dolly.Sbds-jlf,// ^Wa?
••'-,•• ShenandoanGi
Chassahowitzka'Kfei,,;,,' j
I,
Figure 3-28. Mandatory Federal Class I Areas and IMPROVE Participate Matter Samplers
Divided into Western and Eastern Regions
3-30
November 2001
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National and Regional Discussions of Visibility
Table 3-1 presents the light extinction coefficients for the East and West as averages from all of the
sites within the region. The calculated total aerosol extinction coefficients represent the sum of the
extinction coefficients for the five pollutant species: sulfate, nitrate, organic carbon, elemental carbon,
and crustal material. The aerosol extinction coefficients, as well as the extinction coefficients for the
individual species, are presented on annual and seasonal bases.
Table 3-1. Average Calculated Total Light Extinction Coefficients from 1994-1998
Season
Annual
Spring
Summer
Autumn
Winter
Region
East
West
East
West
East
West
East
West
East
West
Calculated Total
Aerosol Extinction
CoefficientJMm"1)
87
22
72
22
138
27
83
22
59
•16
Pollutant Extinction Coefficient (Mm )
Sulfate
61.4
8.6
48.3
8.9
108.1
10.6
57.4
7.8
36.2
5.4
Nitrate
6.8
2.9
5.9
3.1
7.6
2.4
7.1
2.6
6.3
3.4
Organic
Carbon
10.0
5.2
8.8
4.4
12.8 .
6.9
9.7
5.9
8.6
3.3
Elemental
Carbon
4.8
2.0
4.4
1.7
4.5
2.2
5.2
2.3
5.0
1.7
Crustal
Material
4.2
3.6
4.5
4.0
5.2
4.6
3.8
3.5
3.2
2.4
On an annual basis, the eastern sites showed calculated total aerosol extinction coefficients 4 times
higher than those at the western sites. This ratio between East and West varied from 3.3 times higher in
the spring to 5.1 times higher in the summer season. The lowest average light extinction coefficients
were calculated for the winter in both eastern and western regions. The highest average aerosol light
extinction coefficients occurred during the summer in both regions.
Table 3-1 shows that the sulfate light extinction coefficients were also highest in the summer and
lowest in the winter in both East and West. These seasonal trends are consistent with known sulfate
aerosol chemistry principles. On an annual basis, the eastern region showed sulfate light extinction
coefficients 7.1 times higher than the western region. The sulfate ratio between East and West varied
from near 5.4 in the spring to 10.2 in the summer season. One reason for the large difference in sulfate
extinction between East and West is that sulfur dioxide emissions in the East were 3 times higher than
those in the West (E. H. Pechan and Associates, 1994).
The difference in sulfate extinctions between East and West can also be partially attributed to the
higher relative humidities in the East compared to the West. On an annual basis, the sulfate and nitrate
adjustment factor for relative humidity averaged 3.7 in the East (equivalent to 86 percent relative
humidity) and 2.6 in the West (equivalent to 79 percent relative humidity). To illustrate how this affects
the calculated visibility, an ambient concentration of 1.0 (ig/m3 of sulfate would contribute 11.1 Mm"1
to the light extinction coefficient in the East but only 7.8 Mm"1 to the average western site.
November 2001
3-31
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
The annual nitrate extinction coefficients in Table 3-1 were 2.3 times higher for the East than for
the West. In both East and West, the nitrate extinction coefficients were highest in the winter and lowest
in the summer, consistent with the chemical equilibrium calculations for nitrate aerosol formation
(Matsumoto and Tanaka, 1996). The nitrate ratio between East and West was lowest during the winter at
1.9 and rose to 3.2 in the summer.
The annual organic carbon extinction coefficients in Table 3-1 were 1.9 times higher for the East
than for the West. One source of organic carbon is the oxidation of hydrocarbons released by vegeta-
tion. The highest organic carbon extinction coefficients were observed in both East and West in the
summer, the season when vegetation growth is rapid. In both regions, the lowest organic carbon extinc-
tion coefficients were found during the whiter, when vegetation growth is slowest. These observations
are consistent with the findings of Goldstein, et al. (1996) that biogenic emissions of certain hydrocar-
bons from vegetation exceeded manmade emissions during the summer, while manmade emissions
dominated during the whiter seasons.
The organic carbon ratio between East and West was lowest in the autumn and highest in the winter
(Table 3—1). Western states conducted more than 40 percent of their prescribed burning activities in the
autumn, whereas eastern states conducted more than 40 percent in the winter (Ward et al. 1993). Since
fires are a source of organic carbon and prescribed burning often takes place near mandatory Federal
Class I areas, this activity may be partly responsible for the low organic carbon ratio between East and
West in the autumn (1.6) and the high ratio in the winter (2.6).
Elemental carbon ratios between the East and West were also highest in the winter. Since vegetation
burning (both prescribed burning and wildfires) produces elemental carbon and often occurs near
mandatory Federal Class I areas, this activity may be partly responsible for the high winter ratio
between East and West. (Eastern prescribed burning is predominantly a winter activity.)
On an annual basis, the elemental carbon extinction coefficients in Table 3-1 were 2.4 times higher
for the East than the West. The higher elemental carbon extinction coefficients in the East were calcu-
lated in autumn and winter-as high as 20 Mm"1 in Washington (DC)-and the lower coefficients in the
spring and summer. In the West, the higher coefficients were calculated in the summer and autumn (as
high as 10 Mm"1 at Sequoia National Park, CA), and the lower coefficients during winter and spring.
The extinction coefficients for crustal material showed less variation between East and West than
the other four components. Table 3-1 shows that the crustal material in the East was only 17 percent
higher than crustal material in the West on an annual basis, and the percentage did not change consider-
ably from one season to the next. In the East, crustal material was responsible for 5 percent of the
annual aerosol light extinction coefficient, less impairment than the other four components. However,
in the West, 16 percent of the annual aerosol extinction coefficient was attributed to crustal material.
Only 9 and 13 percent were attributed to elemental carbon and nitrates in the west.
3-32
November 2001
-------
References
4. References
Air Resource Specialists. (1992). Interagency Monitoring of Protected Visual Environments
(IMPROVE) (vol. 1. No. 1) [Newsletter]. Fort Collins, CO.
Arnold, J. (2000). Personal Communication with K. Walsh (SAIC). U.S. National Park Service, Lassen
Volcanic National Park, CA. April.
Bowman, C. (2000). Personal Communication with K.Walsh (SAIC). U.S. National Park Service,
Grand Canyon National Park, AZ. March.
Bunch, F. (2000). Personal Communication with K. Walsh (SAIC). U.S. National Park Service, Great
Sand Dunes National Park, CO. April.
Christoforou, C. S., Salmon, L.G., Cass, G. R. (2000). Trends in Fine Particle Concentrations and
Chemical Composition in Southern California. Journal of the Air and Waste Management
Association, 50(1), 43.
E. H. Pechan and Associates. (1994). National PM Study: OPPE Particulate Programs Implementation
Evaluation System. Springfield, VA.
Goldstein, A.H., et al. (1996). Emissions of Ethene, Propene, and 1-butene by a Midlatitude Forest.
Journal of Geophysical Research, 101(D4): 9149-9157.
Kendall, M. G. and Gibbons, J. D. (1990). Rank Correlation Methods. (5th ed.). New York: Oxford
University Press.
Los, S. O., et al. (1994). A Global 1 by 1 Degree NDVI Data Set for Climate Studies Derived from the
GIMMS Continental NDVT Data. International Journal of Remote Sensing, 15(17), 3943-3518.
Matsumoto, K and Tanaka, H. (1996). Formation and Dissociation of Atmospheric Particulate Nitrate
and Chloride: An Approach Based on Phase Equilibrium. Atmospheric Environment, 30(4),
639-648.
National Interagency Fire Center. (1998). National Park Service Fire Management Data [CD-ROM].
Boise, ID.
NFS. (1999). Big Bend Regional Aerosol and Visibility Observational Study.
Online: http://www.aqd.nps.gov/ard/bravo/index.htm
Regional Haze Regulations, Final Rule. (1999). Federal Register, 64 (126), 35714-35774.
Sisler, IF. (1996). Spatial and Seasonal Patterns and Long Term Variability of the Composition of the
Haze in the United States: An Analysis of Data from the IMPROVE Network. Fort Collins, CO:
Cooperative Institute for Research in the Atmosphere.
November 2001
4-1
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
South Coast Air Quality Management District. (1997). Air Quality Management Plan [Appendix 5].
Online: http://www.aqmd.gov/aqmp/97aqmp
U. S. Department of Energy [USDOE]. (1984). Atmospheric Science and Power Production. DOE/TIC-
27061. Oak Ridge, TN: Office of Scientific and Technical Information.
U. S. Environmental Protection Agency [USEPA]. (1993). Effects of the 1990 Clean Air Act
Amendments on Visibility in Class I Areas: An EPA Report to Congress. EPA-452/R-93-014.
Washington, DC: U. S. Government Printing Office.
USEPA. (1997a). Conceptual Model [Prepared by the Science and Technology Support Work Group
under the Particulate Matter and Regional Haze Implementation Programs]. Available online:
http://www.epa.gov/ttn/faca/stissu.html
USEPA. (1997b). National Air Pollution Emission Trends, 1900-1996. EPA-454-R-97-001. Washington,
DC : U. S. Government Printing Office.
USEPA. (1998). National Air Quality and Emission Trends Report, 1997. EPA-454/R-98-016.
Washington, DC: U. S. Government Printing Office.
Ward, D. E., et al. (1993). An Inventory of Particulate Matter and Air Toxic Emissions from Prescribed
Fires in the U.S.A. for 1989. Proceedings of the Air and Waste Management Association 1993
Annual Meeting and Exhibition. Denver, CO.
4-2
November 2001
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Appendfx A
Appendix A
List of 156 Mandatory Federal Class I Areas Where Visibility is an Important Value
(As Listed in 40 CFR 81)
1
State
Alabama
Alaska
Arizona
Arkansas
California
-
Name of Area
Sipsey Wilderness Area
Bering Sea Wilderness Area
Denali National Park (formerly 'Ml McKinley National Park)
Simeonof Wilderness Area
Tuxedni Wilderness Area
Chiricahua National Monument
Chiricahua Wilderness Area
Galiuro Wilderness Area •
Grand Canyon National Park
Mazatzal Wilderness Area
Mount Baldy Wilderness Area
Petrified Forest National Park
Pine Mountain Wilderness Area
Saguaro National Monument Wilderness Area
Sierra Ancha Wilderness Area
Superstition Wilderness Area
Sycamore Canyon Wilderness Area
Caney Creek Wilderness Area
Upper Buffalo Wilderness Area
Agua Tibia Wilderness Area
Caribou Wilderness Area
Cucamonga Wilderness Area
Desolation Wilderness Area
Dome Land Wilderness Area
Emigrant Wilderness Area
Hoover Wilderness Area
John Muir Wilderness Area
Joshua Tree National Park Wilderness Area
Kaiser Wilderness Area
Kings Canyon National Park
Lassen Volcanic National Park
Lava Beds National Monument Wilderness Area
Marble Mountain Wilderness Area
Minarets Wilderness Area
Mokelumne Wilderness Area
Pinnacles National Monument Wilderness Area
Point Reyes National Seashore Wilderness Area
Redwood National Park
San Gabriel Wilderness Area
San Gorgonio Wilderness Area
San Jacinto Wilderness Area
San Rafael Wilderness Area
Acreage
12,646
41,113
1,949,493
25,141
6,402
9,440
18,000
52,717
1,176,913
205,137
6,975
93,493
20,061
71,400
20,850
124,117
47,757
14,344
9,912
15,934
19,080
9,022
63,469
93,781
104,311
47,916
484,673
429,690
36,300
22,500
459,994
105,800
28,640
213,743
109,484
50,400
12,952
25,370
27,792
36,137
56,722
37,980
20,564
142,722
Federal Land
Manager
USDI-FWS
USDI-NPS
USDI-FWS
USDI-FWS
USDI-NPS
USDA-FS
USDA-FS
USDI-NPS
USDA-FS
USDA-FS
USDI-NPS
USDA-FS
USDI-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
. USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS.
USDY-FS
USDA-FS
USDI-NPS
USDI-BLM
USDA-FS
USDI-NPS
USDI-NPS
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDI-NP
USDI-NPS
USDI-NPS
USDA-FS
USDA-FS
USDI-BLM
USDA-FS
USDA-FS
November 2001
A-1
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
State
California (cont.)
Colorado
Florida
Georgia
Hawaii
Idaho
Kentucky
Louisiana
Maine
Michigan
Minnesota
Missouri
Name of Area
Sequoia National Park
South Warner Wilderness Area
Thousand Lakes Wilderness Area
Ventana Wilderness Area
Yolla Bolly-Middle Eel Wilderness Area
Yosemite National Park
Black Canyon of the Gunnison National Park Wilderness Area
Eagles Nest Wilderness Area
Flat Tops Wilderness Area
Great Sand Dunes National Monument Wilderness Area
La Garita Wilderness Area
Maroon Bells-Snowmass Wilderness Area
Mesa Verde National Park
Mount Zirkel Wilderness Area
Rawah Wilderness Area
Rocky Mountain National Park
Weminuche Wilderness Area
West Elk Wilderness Area
Chassahowitzka National Wildlife Refuge Wilderness Area
Everglades National Park
St. Marks Wilderness Area
Cohutta Wilderness Area
Okefenokee National Wildlife Refuge Wilderness Area
Wolf Island Wilderness Area
Haleakala National Park
Hawaii Volcanoes National Park
Craters of the Moon National Monument Wilderness Area1
Hells Canyon Wilderness Area
Sawtooth Wilderness Area
Selway-Bitterroot Wilderness Area2
Yellowstone National Park3
Mammoth Cave National Park
Breton Wilderness Area
Acadia National Park
Moosehorn National Wildlife Refuge Wilderness Area
Edmunds Unit
Baring Unit
Isle Royale National Park
Seney Wilderness Area
Boundary Waters Canoe Area Wilderness Area
Voyageurs National Park
Hercules-Glades Wilderness Area
Mingo Wilderness Area
386,642
68,507
1.5,695
95,152
111,841
42,000
759,172
11,180
133,910
235,230
33,450
48,486
71,060
51,488
72,472
26,674
263,138
400,907
61,412
23,360
1,397,429
17,745
33,776
343,850
5,126
27,208
217,029
43,243 '
83,800
216,383
988,770
31,488
51,303
5,000
37,503
7,501
2,706
4,680
542,428
25,150
747,840
114,964
12,315
8,000
Federal Land
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDI-BLM
USDI-NPS
USDI-NPS
USDA-FS
USDA-FS
USDI-NPS
USDA-FS
USDA-FS
USDI-NPS
USDA-FS
USDA-FS
USDI-NPS
USDA-FS
USDA-FS
USDI-FWS
USDI-NPS
USDI-FWS
USDA-FS
USDI-FWS
USDI-FWS
USDI-NPS
USDI-NPS
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDI-NPS
USDI-NPS
USDI-FWS
USDI-NPS
USDI-FWS
USDI-FWS
USDI-FWS
USDI-NPS
USDI-FWS
USDA-FS
USDI-NPS
USDA-FS
USDI-FWS
A-2
November 2001
-------
Appencfoc A
Vkmtana
Nevada
New Hampshire
New Jersey
New Mexico
North Carolina
North Dakota
Oklahoma
Oregon
Name of Area
Anaconda-Pintlar Wilderness Area
Bob Marshall Wilderness Area
Cabinet Mountains Wilderness Area
Gates of the Mountains Wilderness Area
Glacier National Park
Medicine Lake Wilderness Area
Mission Mountain Wilderness Area
Red Rock Lakes Wilderness Area
Scapegoat Wilderness Area
Selway-Bitterroot Wilderness Area4
U. L. Bend Wilderness Area
Yellowstone National Park5
Jarbidge Wilderness Area
Great Gulf Wilderness Area
Presidential Range-Dry River Wilderness Area
Brigantine Wilderness Area-Edwin B. Forsythe National Wildlife
Refuge
Bandelier Wilderness
Bosque del Apache Wilderness Area
Carlsbad Caverns National Park
Gila Wilderness Area
Pecos Wilderness Area
Salt Creek Wilderness Area
San Pedro Parks Wilderness Area
Wheeler Peak Wilderness Area
White Mountain Wilderness Area
.Great Smoky Mountains National Park6
Joyce Kilmer-Slickrock Wilderness Area7
Linville Gorge Wilderness Area
Shining Rock Wilderness Area
Swanquarter Wilderness Area
Lostwood Wilderness Area
Theodore Roosevelt National Park
Wichita Mountains Wilderness Area
Crater Lake National Park
Diamond Peak Wilderness Area
Eagle Cap Wilderness Area
Gearhart Mountain Wilderness Area
Hells Canyon Wilderness Area8
Kalmiopsis Wilderness Area
Mountain Lakes Wilderness Area
Mount Hood Wilderness Area
Mount Jefferson Wilderness Area
Mount Washington Wilderness Area
Strawberry Mountain Wilderness Area
Three Sisters Wilderness Area
Acreage
950,000
94,272
28,562
1,012,599
11,366
73,877
32,350
239,295
251,930
20,890
167,624
64,667
5,552
20,000
6,603
23,267
80,850,
46,435
433,690
167,416
8,500
41,132
6,027
31,171
273,551
10,201
7,575
13,350
9,000
5,557
69,675
8,900
160,290
36,637
293,476
18,709
108,433
22,700
76,900
23,071
14,160
100,208
46,116
33,003
199,902
Federal Land
Manager
USDA-FS
USDA-FS
USDA-FS
USDI-NPS
USDI-FWS
USDA-FS
USDI-FWS
USDA-FS
USDA-FS
USDI-FWS
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDI-FWS
USDI-NPS
USDI-FWS
USDI-NPS
USDA-FS
USDA-FS
USDI-FWS
USDA-FS
USDA-FS
USDA-FS
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDI-FWS
USDI-FWS
USDI-NPS
USDI-FWS
USDA-NPS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDI-BLM
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
November 2001
A-3
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
State
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virgin Islands
Virginia
Washington
West Virginia
Wyoming
New Brunswick,
Canada
Name of Area
Cape Remain National Wildlife Refuge Wilderness Area
Badlands National Park Wilderness Area
Wind Cave National Park
Great Smoky Mountains National Park6
Joyce Kilmer-Slickrock Wilderness Area7
Big Bend National Park
Guadalupe Mountains National Park
Arches National Park
Bryce Canyon National Park
Canyonlands National Park
Capitol Reef National Park
Zion National Park
Lye Brook Wilderness Area
Virgin Islands National Park
James River Face Wilderness Area
Shenandoah National Park
Alpine Lakes Wilderness Area
Glacier Peak Wilderness Area
Goat Rocks Wilderness Area
Mount Adams Wilderness Area
Mount Rainer National Park
North Cascades National Park
Olympic National Park
Pasayten Wilderness Area
Dolly Sods Wilderness Area
Otter Creek Wilderness Area
Bridger Wilderness Area
Fitzpatrick Wilderness Area
Grand Teton National Park
North Absaroka Wilderness Area
Teton Wilderness Area
Washakie Wilderness Area
Yellowstone National Park9
Roosevelt Campobello International Park
Acreage
28,000
64,250
28,060
241,207
3,832
708,118
76,292
65,098
35,832
337,570
221,896
142,462
12,430
12,295
8,703
190,535
303,508
464,258
82,680
32,356
235,239
503,277
892,578
505,524
10,215
20,000
392,160
191,103
305,504
351,104
557,311
686,584
2,020,625
2,721
Federal Land
USDI-FWS
USDI-NPS
USDI-NPS
USDI-NPS
USDA-FS
USDI-NPS
USDI-NPS
USDI-NPS
USDI-NPS
USDI-NPS
USDI-NPS
USDI-NPS
USDA-FS
USDI-NPS
USDA-FS
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDI-NPS
USDI-NPS
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDA-FS
USDI-NPS
USDA-FS
USDA-FS
USDA-FS
USDI-NPS
see note 10
A-4
November 2001
-------
Appendix A
Table Notes:
1 Hells Canyon Wilderness Area, 192,700 acres overall, of which 108,900 acres are in Oregon and 83,800 acres are in
Idaho.
2 Selway Bitterroot Wilderness Area, 1,240,700 acres overall, of which 988,700 acres are in Idaho and 251,930 acres
are in Montana.
3 Yellowstone National Park, 2,219,737 acres overall, of which 2,020,625 acres are in Wyoming, 167,624 acres are in
Montana, and 31,488 acres are in Idaho.
4 Selway-Bitterroot Wilderness Area, 1,240,700 acres overall, of which 988,770 acres are in Idaho and 251,930 acres
are in Montana.
5 Yellowstone National Park, 2,219,737 acres overall, of which 2,020,625 acres are in Wyoming, 167,624 acres are in
Montana, and 31,488 acres are in Idaho.
6 Great Smoky Mountains National Park, 514,758 acres overall, of which 273,551 acres are in North Carolina, and
241,207 acres are in Tennessee.
7 Joyce Kilmer-Slickrock Wilderness Area, 14,033 acres overall, of which 10,201 acres are in North Carolina, and 3,832
acres are in Tennessee.
8 Hells Canyon Wilderness Area, 192,700 acres overall, of which 108,900 acres are in Oregon, and 83,800 acres are hi
Idaho.
9 Yellowstone National Park, 2,219,737 acres overall, of which 2,020,625 acres are in Wyoming, 167,624 acres are in
Montana, and 31,488 acres are in Idaho.
10 Chairman, RCIP Commission.
Abbreviations Used in Table:
USDI-NPS: U.S. Department of Interior, National Park Service
USDA-FS: U.S. Department of Agriculture, Forest Service
USDI-FWS: U.S. Department of Interior, Fish and Wildlife Service
USDI-BLM: U.S. Department of Interior, Bureau of Land Management
November 2001
A-5
-------
-------
Appendix B
Appendix B
Explanation of Method for Creating Summary Data
from Raw IMPROVE Data
The summary data used in this report were provided by the Cooperative Institute for Research in
the Atmosphere (CIRA) at Colorado State University. Raw data samples (measurements of particulate
matter mass and its constituents) were collected on Wednesdays and Saturdays, and CIRA constructed
the annual and seasonal summary data using the following timeframes:
1. Annual data for Year X cover the period from March in year X through February in year X+l.
2. Spring data cover the period from March through May.
3. Summer data cover the period from June through August.
4. Autumn data cover the period from September through November.
5. Winter data for Year X cover the period from December in year X through February in year
X+l.
To calculate the seasonal (annual) summary data, the steps below were followed:
1. The daily species concentrations (sulfate, nitrate, organic carbon, elemental carbon, soil, and
coarse mass) were first each averaged for the entire season (year) and reported in units of ug/m3.
This process yielded average seasonal (annual) concentrations for the species.1
2. The average seasonal (annual) concentrations for each species were multiplied by the seasonal
(annual) f(RH) factor for that site and the species-specific light extinction factor (see Appendix
C) to calculate the reported seasonal (annual) light extinction coefficients for each species.
3. The reported seasonal (annual) light extinction coefficients for the species-were summed to give
the total seasonal (annual) aerosol light extinction coefficient (bAer).
4. The seasonal (annual) light extinction coefficient for each species was divided by the total sea-
sonal (annual) aerosol light extinction coefficient to calculate the seasonal (annual) contribution
of the species to the total aerosol light extinction coefficient (expressed as percentages in Chapter
2's pie charts). These percentages often did not match the number calculated by averaging the
percent contributions to light extinction coefficients of the species on the individual days. 2
5. The deciview index (in deciviews) was calculated from the total seasonal (annual) aerosol light
extinction coefficient bAer (in Mm-1) by the following formula:
deciview index =10 /«[(bAer+bRay)/10]
where bRay represented the Rayleigh light extinction coefficient (10 Mm-1 at 1.8 km elevation).
Each year's data was sorted into three groups based on the cumulative frequency of occurrence of
PM2 5: lowest fine mass days, 0 to 20 percent; median fine mass days, 40 to 60 percent; and highest
fine mass days, 80 to 100 percent. Each group was then labeled by its midpoint (e.g., 10th, 50th, 90th
percentiles). After sorting each group's average concentrations of PM2 5 and selecting the associated
principal aerosol species, scattering and/or absorption of each species, reconstructed light extinction
and deciview are calculated.
November 2001
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Note that the sorting is based on fine mass concentrations and ignores coarse mass concentrations.
Also, the result is not necessarily the same as the rankings for visibility impairment. Due to lack of
other data, the 10th, 50th, and 90th percentiles were assigned as the least-impaired, mid-range, and
most-impaired days in this report.
Footnote:
1 On June 1, 1996, the sampling technique at all IMPROVE particulate samplers was altered. Glycerine was added to
the denuders and resulted in nitrate measurements approximately 40 percent lower than earlier values. In order to assess vis-
ibility trends, a fixed nitrate concentration was chosen for all of the years of data at each site. The fixed measurement was
based on the average nitrate value measured between 1997 and 1999, while the glycerine was added to the denuders.
Therefore, this report does not discuss temporal trends in nitrate concentrations.
2 At sites where visibility impairment is much greater in one season, this averaging method sometimes results in the
annual species contributions being skewed toward the season with greater impairment.
B-2
November 2001
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Appendix C
Appendix C
Methodology for Calculating Light Extinction from Monitored Aerosol Mass Data
Under the IMPROVE visibility monitoring program, particulate matter samples are collected at
each monitoring site (see Figure C-l) twice a week (the sampling frequency will change to one sample
every three days beginning in the year 2000). Each sample is collected over a 24-hour period on special
teflon, nylon, and quartz filters. The filters are weighed and analyzed according to specific protocols to
determine the total mass of particulate matter collected, and to determine the portion of the total mass
that can be attributed to specific components of PM (e.g., sulfate, nitrate, organic carbon, elemental
carbon, and crustal material). Quality assurance procedures are followed for filter handling, chemical
analysis, and raw data reporting.
Point *"'- " "•(- ...... ......... ~;~? - *i-one Pear r,, ...... • ...... ,
—H^—Great Basin / / „ *RockyMtn
.. ' - s -«« ----
"jjrCanydnlands
' Wpminuche
Garden if
San GofgoRBEbXVji^n^7,/j; Petrified Forest ;
«,~~~l ~*^*..^,^.~2
! •*»!
Figure C-l. Locations of IMPROVE Particulate Matter Samplers Operating Continuously from
1994-1998 (Green Shaded Areas Represent Mandatory Federal Class I Areas)
A separate data record is established for each 24-hour sampling period for each site. This data
record includes levels of total PM10 mass, PM2.5 mass, mass for each PM2.5 component (each
expressed in nanograms per cubic meter, or ng/m3), and the uncertainty associated with the measure-
ments.1 Associated light extinction levels are calculated using a standard methodology, hereafter
November 2001
C-l
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
referred to as the IMPROVE methodology. The methodology for calculating light extinction (expressed
in inverse megameters, or Mm-1) from speciated PM data has been developed and refined by scientists
with the IMPROVE monitoring program.
Total light extinction is expressed as the sum of the following components:
• Light scattering due to particles—caused by both fine and coarse particulate matter. Scattering is
the largest contributor to total light extinction in most locations.
• Light absorption due to particles—caused exclusively by carbon-containing particles.
• Light scattering due to natural gases—also known as Rayleigh scattering, or the scattering of light
due to the gases (e.g. nitrogen and oxygen molecules) that make up clear sky. Rayleigh scattering is
assumed to account for 10 Mm-1 at 1.8 kilometers elevation above sea level.
• Light absorption due to gases—caused primarily by nitrogen dioxide (NO2). Assumed to be negligi-
ble in rural Class I areas.
The IMPROVE methodology calculates light extinction attributable to each of the five main com-
ponents of PM2.s and to coarse PM by multiplying the mass of each component by the light scattering
coefficient for that component (or, in the case of elemental carbon, the light absorption coefficient).
The scattering coefficients for sulfate, nitrate, organic carbon, fine soil, and coarse PM are 3, 3, 4, 1,
and 0.6 m2/g. The standard light absorption coefficient for elemental carbon is 10 m2/g. The current
IMPROVE methodology for calculating light extinction (in Mm-1) from aerosol mass is described by
the following equation:
Total Light Extinction = [sulfate mass] x [3 m2/g] x f(RH)
+ [nitrate mass] x [3 m2/g] x f(RH)
+ [organic carbon mass] x [4 m2/g]
+ [elemental carbon mass] x [10 m?/g]
+ [fine soil]-x [1 m2/g]
+ [coarse mass] x [0.6 m2/g]
+ Rayleigh scattering, or 10 Mm-1
where f(RH) is a relative humidity adjustment factor to account for the water uptake by some particles.
Footnote:
1 During the 1990s, scientists discovered that the IMPROVE Module A filter size was insufficient to capture accurate
measurements of high sulfur concentrations. Therefore, the filter sizes were increased and the measurements rose. Since
this study examined trends back to 1988, the measurements in this study reflect the sulfate ion measurements from the
IMPROVE Module B filter to avoid this change in Module A sample collection.
C-2
November 2001
-------
Appendix C
d>
24
22
20
18
16
=L 14
12
10
£
'•&
3
1
0)
DC
0% 10% 20% ,30% 40% 50% 60% 70% 80% 90% 100%
Relative Humidity (%)
Figure C-2. Relative Humidity Adjustment Factor, f(RH), used to Calculate Light Extinction
Because sulfate and nitrate particles take on water from the atmosphere and become more efficient
at scattering light under humid conditions, the IMPROVE methodology for calculating light extinction
multiplies sulfate and nitrate mass by a relative humidity adjustment factor, f(RH), which varies with
the average relative humidity at the site. Figure C-2, derived from analyses of parallel humidity moni-
toring at a number of IMPROVE sites, illustrates how the relative humidity adjustment factor increases
with higher relative humidity values.
To date, hourly humidity values in excess of 98% have been disregarded in calculating average
f(RH) values since it is likely that such readings occur during precipitation events. Table C-l lists the
relative humidities used for calculations at each IMPROVE Monitoring site.
The inverse distance units used to describe light extinction coefficients are difficult to interpret as
humanly perceptible changes in visibility. Therefore, the deciview haze index (dv) was developed and is
calculated directly from the total light extinction coefficient (bext expressed in Mm-1):
Jv=101n(bext/10Mm-i)
The deciview scale is nearly zero for a pristine atmosphere (dv equals zero for Rayleigh scattering
at approximately 1.8 km elevation), and each deciview change corresponds to a small but perceptible
scenic change that is observed under either clean or polluted conditions. Like the decibel scale for
sound, similar changes in deciviews are perceived as equal. This report includes many trends expressed
as deciview changes. Each deciview decrease approximates a perceptible improvement in visibility.
November 2001
C-3
-------
Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Table C-l. Relative Humidity Adjustment Factors by Season for Each IMPROVE Site
Code
ACAD
BADL
BAND
BIBE
BOWA
BRCA
BRID
BRIG
CANY
CHAS
CHIR
CRLA
DENA
DOSO
GLAC
GRBA
GRCA
GRSA
GRSM
GUMO
INGA
JARB
LAVO
LOPE
LYBR
State
ME
SD
NM
TX
MN
UT
WY
NJ
UT
FL
AZ
OR
AK
\VV
MT
NV
AZ
CO
TN
TX
AZ
NV
CA
UT
VT
Site Name
Acadia NP
Badlands NM
BandelierNM'
Big Bend NP
Boundary Waters CA
Bryce Canyon NP
Bridget WA
Brigantine Div. of EB
Forsythe NWR
Canyonlands NP
Chassahowitzka NWR
Chiricahua NM
Crater Lake NP
Denali NP
Dolly Sods WA
Glacier NP
Great Basin NP
Grand Canyon NP
Great Sand Dunes NM
Great Smoky Mtns NP
Guadalupe Mtns NP
Indian Garden
Jarbidge WA
Lassen Volcanic NP
Lone Peak WA
Lye Brook WA
Elevation
(Feet)
420
2,493
6,500
3,500
1,700
7,997
8,000
50
5,950
10
5,400
6,500
2,100
3,800
3,200
6,800
7,100
8,200
2,700
5,400
3,800
6,200
5,900
6,200
3,250
Latitude
(Degrees)
44.3833
43.7500
35.7833
29.3000
47.9500
37.6167
42.9500
39.4667
38.4500
28.7500
32.0167
42.8833
63.7333
39.1000
48.5000
39.00003
36.0667
37.7333
35.6333
31.8500
36.0667
41.8833
40.5333
40.4500
43.1667
Longitude
(Degrees)
68.2667
101.9333
106.2667
103.1833
91.5167
112.1667
109.7500
74.4500
109.8167
82.5667
109.3500
122.1333
148.9667
79.4333
113.9833
114.2000
112.1500
105.5000
83.9167
104.8167
112.1333
115.4167
121.5667
111.7000
73.0000
f(RH)
Spring
3.18
2.63
1.68
1.46
2.53
3.68
2.32
4.02
1.52
3.76
1.39
2.92
2.25
3.33
3.92
1.75
1.72
4.26
2.68
1.55
1.69
2.15
2.45
2.00
2.58
Summer
3.35
2.54
1.75
1.62
3.13
2.16
1.63
4.17
1.24
4.27
1.81
2.27
2.65
3.63
3.41
1.39
1.42
1.70
3.40
1.83
1.27
1.77 .
4.08
1.50
3.96
Autumn
3.83
2.36
1.80
1.78
3.91
1.92
2.16
3.20
1.64
4.5.3
1.65
2.11
3.65
3.49
4.09
1.71
1.68
2.02
3.31
" 1.94
1.57
1.82
1.81
2.07
4.28
Winter
3.54
2.63
2.15
1.76
3.63
2.40
2.44
2.89
2.34
3.75
2.20
3.10
3.01
4.41
4.49
2.02
2.59
2.11
3.64
•2.04
2.38
1.95
2.52
2.85
3.09
C-4
November 2001
-------
Appendix C
Table C-1. Relative Humidify Adjustment Factors by Season for Each IMPROVE Site (continued)
Code
MACA
MEVE
MOOS
MORA
MOZI
OKEF
PEFO
FINN
PORE
REDW
ROMA
ROMO
SAGO
SEQU
SHEN
SHRO
SIPS
SNPA
THSI
TONT
UPBU
WASH
WEMI
YELL
YOSE
State
KY
CO
ME
WA
CO
GA
AZ
CA
CA
CA
SC
CO
CA
CA
VA
NC
AL
WA
OR
AZ
AR
DC
CO
WY
CA
Site Name
Mammoth Cave NP
Mesa Verde NP
Moosehorn NWR
Mount Rainier NP
Mount Zirkel WA
Okefenokee NWR
Petrified Forest NP
Pinnacles NM
Point Reyes NS
Redwood NP
Cape Romain NWR
Rocky Mountain NP
San Gorgonio WA
Sequoia NP
Shenandoah NP
Shining Rock WA
Sipsey WA
Snoqualmie Pass
Three Sisters WA
Tonto NM
Upper Buffalo WA
DC National Mall
Weminuche WA
Yellowstone NP
Yosemite NP
Elevation
(Feet)
750
7,210
130
1,430
10,557
50
5,500
1,040
125
760
8
7,900
5,618
1,800
3,600
5,290
600
3,600
2,850
2,600
2,300
30
9,050
7,744
5,300
Latitude
(Degrees)
37.2167
37.2000
45.1167
46.7500
40.5500
30.7333
35.0731
36.4833
38.1167
41.5500
32.9400
40.3833
34.2000
36.4989
38.5500
35.3933
34.3333
47.4167
44.2833
33.6500
35.8333
38.8833
37.6500
44.5500
37.7000
Longitude
(Degrees)
86.0667
108.4833
67.2833
122.1167
106.7000
82.1167
109.7739
121.1667
122.9000
124,0833
79.6600
105.5667
116.9167
118.8239
78.4000
82.7764
87.3333
121.4167
122.0500
111.1000
93.2167
77.5000
107.8000
110.4000
119.7000
f(RH)
Spring
3.34
1.57
3.18
6.01
2.37
3.92
1.47
2.81
4.11
8.27
3.92
2.15
2.58
2.51
3.10
3.31
3.16
4.45
4.83
1.32
3.01
2.69
4.85
2.50
2.51
Summer
6.82
1.61
3.35
4.86
1.32
4.97
1.51
2.09
5.50
5.84
4.97
1.96
1.56
1.37
4.45
5.06
5.43
3.33
3.03
1.32
3.46
3.01
1.61
2.16
1.37
Autumn
4.81
1.71
3.83
7.36
2.02
5.34
1.72
2.11
3.65
8.50
5.34
1.84
1.72
1.80 '
3.80
3.26
4.70
5.37
4.80
1.27
2.97
3.14
2.15
2.01
1.80
Winter
3.42
2.52
3.54
7.40
2.42
4.28
2.37
2.83
3.49
6.41
4.28
1.70
2.96
3.17
3.77
3.56
3.58
6.30
6.98
1.76
3.30
2.59
2.34
1.97
3.16
CA Canoe Area
NM National Monument
NP National Park
NWR National Wildlife Refuge
WA Wilderness Area
November 2001
C-5
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Appendix O
Appendix D
Theil Method to Determine Statistically Significant Trends
A simple least-squares technique can be used to analyze any time series of data to determine if the
overall trend is positive, negative, or zero. A positive slope indicates a trend toward higher values and a
negative slope indicates a decreasing 'trend. However, air quality data examined over multiple years may
show considerable fluctuations from one year to the next (Figure D-l). The negative slope calculated
for the seven data points in Figure D-l might indicate overall improved visibility due to air quality
improvements. Therefore, the Theil method was employed in this report to indicate whether or not the
observed trends were statistically significant.
16.0
1988
1994
Figure D-l. Sample Data to Illustrate Theil Method
The Theil method utilizes a nonparametric regression technique to determine statistically signifi-
cant trends. The method is further referenced in the National Air Quality Trends Report (EPA, 1997).
All possible pairs of data points (i.e., years) are evaluated to determine whether the visibility index
increases, decreases, or remains constant across each pair. Table D-l displays these combinations for
the sample data contained in Figure D-l. For each data pair, values of-1, 0, and +1 are assigned for
data that decreases, remains constant, and increases. The assigned values for all pairs are then summed
to calculate the S value. The S value is simply a calculated statistic used to determine whether the data
exhibit a statistically significant trend. The sample data have an S value of-13.
November 2001
D-l
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Visibility in Mandatory Federal Class I Areas (1994-1998): A Report to Congress
Table D-1. Calculating S Value for Sample Data.
Star-ting
Data Point
1988
1988
1988
1988
1988
1988
1989
1989
1989
1989
1989
1990
1990
1990
1990
1991
1991
1991
1992
1992
1993
Ending
Data Point
1989
1990
1991
1992
1993
1994
1990
1991
1992
1993
1994
1991
1992
1993
1994
1992
1993
1994
1993
1994
1994
Direction
(Increase/Decrease/
Remain Constant)
Decrease
Decrease
Decrease
Decrease
Decrease
Decrease
Increase
Decrease
Increase
Decrease
Decrease
Decrease
Decrease
Decrease
Decrease
Increase
Increase
Decrease
Decrease
Decrease
Decrease
Assigned Value
-1
-1
-1
-1
-1
-1
+1
-1
+1
-1
-1
-1
-1
-1
-1
+1
+1
-1
-1
-1 -
-1
TOTAL (S value for 7 data points) -13
With seven data points, the possible S values range from -21 to +21. For decreasing data sets (i.e.,
S values less than zero), Figure D-2 shows the probabilities that an S value will be below a certain
number for randomly fluctuating data sets. The cumulative probabilities are calculated from the numer-
ical arrays of Kendall's Tau statistics (Kendall, 1990). Reading from Figure D-2, an S value of-13 for
seven data points corresponds to a 3 percent cumulative probability. In other words, a randomly fluctu-
ating data set would yield an S value between -21 and -13 in only 3 percent of the cases. If the negative
signs of the S values along the ordinate axis in Figure D-2 are made positive, the same graph can be
used to determine the probability of increasing trend.
^ m previous reports (e.g., EPA, 1997), EPA has chosen a 5 percent cumulative probability as the sig-
nificance criterion to be applied for-trend evaluations. If the cumulative probability of a data event is
less than 5 percent, then the trend is considered statistically significant. The same criterion was used in
D-2
November 2001
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Appendix D
5 Points
6 Points
7 Points
8 Points
— 9 Points
- 10 Points
11 Points
-30
5% Significance
Criterion
Figure D-2. Probability of Decreasing Trend in a Random Data Series (Kendall's Tau statistic)
this report to determine statistically significant trends of the data sets. The S values were calculated, the
cumulative probabilities were determined from Kendall's Tau statistics, and any probabilities less than
or equal to 5 percent were considered to indicate statistically significant trends.
November 2001
D-3
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TECHNICAL REPORT DATA
(Please read instructions on reverse before completing)
1. REPORT NO.
EPA-452/R-01-008
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Visibility in Mandatory Federal Class I Areas (1994-1998)
A Report to Congress
5. REPORT DATE
November 2001
6. PERFORMING ORGANIZATION CODE
OAQPS/AQSSD/IPSG
7. AUTHOR(S)
Science Applications International Corporation
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Strategies & Standards Division
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D-98-113
12. SPONSORING AGENCY NAME AND ADDRESS
Same as Above
13. TYPE OF REPORT AND PERIOD COVERED
Report to Congress 1994-1998
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This Report to Congress on visibility is an assessment of actual progress and improvement in visibility
conditions in mandatory Federal Class I areas. Under section 169 of the Clean Air Act (CAA; as amended
in 1990), the Environmental Protection Agency (EPA) must issue a report to Congress estimating the visibility
improvement that could be expected in Class I areas due to implementation of the 1990 CAA Amendments.
The EPA first issued this report in October 1993. The CAA also requires that every 5 years thereafter, EPA
shall provide Congress with an assessment of actual progress and improvement in visibility in Class I areas
in the form of a written report with copies to appropriate Congressional committees. This report is intended
to satisfy that requirement and assesses visibility improvement over the period 1994-1998. Visibility conditions
at forty-five monitor locations were calculated based on particulate matter concentrations for the period from
1994 through 1998. Visibility conditions showed statistically significant improvements at six sites on the
least-impaired days and five sites on the most-impaired days. They also showed declines at three sites on
the least-impaired days but no sites on the most-impaired days.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Report to Congress; Visibility; Class I Areas;
Regional Haze; IMPROVE; Particulate Matter;
Visual Range; Deciview
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report)
Unclassified
21. NO. OF PAGES
256
20. SECURITY CLASS (Page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EDITION IS OBSOLETE
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U.S. Environmental Protection Agency
Office of Air Qualify Planning and Standards
Research Triangle Park, NC 27711
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