Of
 

John W. Hickenlooper, Governor 

Christopher E. Urbina, MD, MPH 

Executive Director and Chief Medical Officer 

Dedicated to protecting and improving the health and environment of the people of Colorado 

4300 Cherry Creek Dr. S. Laboratory Services Division 

Denver, Colorado 80246-1530 8100 Lowry Blvd. 

Phone (303) 692-2000 Denver, Colorado 80230-6928 Colorado Department Located in Glendale, Colorado (303) 692-3090 of Public Health
 

http://www.cdphe.state.co.us and Environment
 

March 18,2011 

James Martin 

Regional Administrator 

USEPA Region VIII 

1595 Wynkoop Street 

Denver, CO 80202-1129 

RE: 2010 Colorado Designations for I-hour Sulfur Dioxide NAAQS 

Dear Mr. Martin: 

Pursuant to the provisions of section 107(d)(1) of the Clean Air Act, the state of Colorado submits 

to the Environmental Protection Agency the attached area designations for the I-Hour Sulfur 

Dioxide National Ambient Air Quality Standard (NAAQS), as revised on June 2, 2010. Federal law 

requires that the state of Colorado submit the recommended designations for the I-Hour Sulfur 

Dioxide NAAQS to the EPA by June 2, 2011, and this letter provides the designations of 

"attainment" and "attainment/unclassifiable" as applicable for all air quality control regions 

(AQCRs) in Colorado. 

The enclosed technical support document provides a table and map which describes each AQCR 

and its designation and provides supporting analysis. The technical support document makes a 

strong case that these designation recommendations are accurate and supportable for EPA approval. 

The attainment designations for the Denver Metropolitan Area (AQCR 3) are based on actual air 

quality monitoring data for the 2008-2010 time periods. The attainment/unclassifiable designations 

for areas lacking representative monitoring are based on the State's estimation that I-Hour Sulfur 

Dioxide levels in these AQCRs are not out of compliance with the I-Hour Sulfur Dioxide NAAQS. 

RECEIVED 

U.S. EPA R8tllon 8 

RA's Office 

AR 30 l011 

Letter to EPA - Colorado Recommended I-Hour S02 Designations March 18, 2011 
The enclosed area classifications for the 2010 I-Hour Sulfur Dioxide NAAQS were adopted by the 

Colorado Air Quality Control Commission following a public hearing held on March 17, 2011. If 

you have any questions regarding this submittal, please contact Garry Kaufman, Interim 

Administrator for the Air Quality Control Commission, at (303) 692-3478 or Paul Tourangeau, 

Director of the Air Pollution Control Division, at (303) 692-3114. 

Sincerely, 

Christopher E. Urbina, MD, MPH 

Executive Director and Chief Medical Officer 

Colorado Department of Public Health and Environment 

Enclosure 

State of Colorado, Technical Support Document for I-Hour Sulfur Dioxide Standard 

Attainment in Colorado 

Letter to EPA - Colorado Recommended I-Hour S02 Designations March 18, 2011 

2 
State of Colorado
 

Technical Support Document
 

for I-Hour Sulfur Dioxide Standard Attainment
 

in Colorado
 

March 17,2011 

Colorado Department of Public Health and Environment 

Air Pollution Control Division 

4300 Cherry Creek Drive South 

Denver, Colorado 80246 
Contents 

Designation Recommendation 3
 

Overview 3
 

Air Quality Data 3
 

Figure /. Map of /-Hour Sulfur Dioxide Ambient Air Monitoring Sites 2008-20/0 4
 

Figure 2. Colorado I-Hour Sulfur Dioxide Ambient Air Concentration Trends (CDPHE) 5
 

Figure 3. Colorado I-Hour Sulfur Dioxide Ambient Air Concentration Trends (Other) 5
 

Table I. Colorado I-Hour Sulfur Dioxide Monitoring Data Summary (CDPHE) 6
 

Table 2. Colorado I-Hour Sulfur Dioxide Monitoring Data Summary (Other) 7
 

Summary Conclusions 7
 

Table 3. Recommended I-Hour Sulfur Dioxide Designations by Areafor Colorado 8
 

Figure 4. Map ofAir Quality Control Regions for I-Hour Sulfur Dioxide Designations in Colorado 10
 

Colorado Recommended 1-Hour S02 Designations Page 2 of10 

Technical Support Document 

March 17, 2011 
Colorado Analysis for I-Hour Sulfur Dioxide Attainment 

Designation Recommendation 

The State recommends that the entire state of Colorado be designated as attainment or 

attainmentlunclassifiable for the 2010 revised I-hour sulfur dioxide standard. This 

reconunendation is based on monitoring information that indicates the region is in compliance 

with the revised I-hour sulfur dioxide standard. 

Overview 

On June 2, 2010, the U.S. Environmental Protection Agency (EPA) promulgated a new National 

Ambient Air Quality Standard (NAAQS) for sulfur dioxide as a I-hour average. The level was 

set at 75 ppb as the 3-year average ofthe 99th percentile I-hour daily maximum values. States are 

required to submit area designation reconunendations to EPA by June 2,2011. 

The Air Pollution Control Division (APCD) of the Colorado Department of Public Health and 

Environment (CDPHE) currently operates two sulfur dioxide analyzers in Colorado, both in the 

Denver metropolitan area. All sulfur dioxide monitoring for the 2008-2010 period shows the 3­

year averages ofthe 99th percentile I-hour daily maximum values to be below the level ofthe 

NAAQS. There are no other known monitoring sites for sulfur dioxide in Colorado that are 

currently in operation and meet EPA quality assurance criteria. Thus, the APCD is proposing that 

Colorado be designated as attainment or attainmentlunclassifiable for the entire state (excluding 

tribal lands over which the APCD has no jurisdiction). 

The EPA requires states base their designation recommendations on monitoring data results from 

the most current complete three year period. The following analysis discusses air quality data as 

necessary to demonstrate that Colorado should be designated as attainment or 

attainmentllinclassifiable for the new I-hour sulfur dioxide NAAQS. It must also be noted that 

this attainment demonstration applies only to non-tribal lands over which the State of Colorado 

has direct air quality jurisdiction. 

Air Quality Data 

The air quality analysis looked at all known monitoring sites for the I-hour sulfur dioxide 

standard in Colorado for 2008 through 2010. A map of the two APCD site locations currently in 

operation in Colorado (CAMP and Welby) is presented in Figure 1. Other historic sites were also 

examined. 

Colorado Recommended I-Hour S02 Designations Page 3 of10 

Technical Support Document 

March 17, 2011 
Figure 2 ~resents l.ong t~rm tre~ds for the APCD's CAMP and Wel,by s~tes as the ~~y~ar average 

of the 991 percentIle daily maximum values, as well as data for a histone APeD sJte (Sottth 

Adams). It is evident that ambient I-hour sulfur dioxide levels have decreased dl'amaticalfy ()ver 

time and are now well below the level of the new I-hour NAAQS. Much of thIS decrease is 

likely due to emissions reductions in major stationary sources and reduced sulfur levels in diesel 

fuels. 

Figure 3 presents trends from some historic sites that were operated by Colorado Springs 

Utilities. While these sites ended operation in 200 I, they do provide information that attainment 

of the new I-hour NAAQS is likely in other areas of Colorado. 

_Tables I & 2 present a summar)~ of the_99th percentile data for all these sites, as well as the 3­

year average calculations. These tables also indicate years that are not complete for true data 

assessments, but have been used in this analysis. 

Figure 1. Map ofI-Hour Sulfur Dioxide Ambient Air Monitoring Sites 2008-2010 

Colorado Recommended I-Hour S02 Designations Page 4 of10 

Technical Support Document 

March 17, 2011 
Figure 2. Colorado l-Hour Sulfur Dioxide Ambient Air Concentration Trends (CDPHE) 

Sulfur dioxide (CDPHE sites)
 

3-year average of 99th percentile i-hour values 

120 

100 

NOTE: 

Partial years only for CAMP for 1999, 2000, 

2008 and 2009. 

Partial year only for South Adams for 2004. 

20 

40 

60 +--------------.:~~=--------------j

c 

o 

cu 

C. 

III 

.... 

III 

Q. 

.c 

O--'------'-----'---'-----'------'---------'-----'---'--------'----'---------'-----'------'--------'--...L..-...­

...-Welby 08-001-3001 _CAMP 08-031-0002 ~South Adams 08-001-0007 

Figure 3. Colorado l-Hour Sulfur Dioxide Ambient Air Concentration Trends (Other) 

Sulfur dioxide (Colo. Spgs. Utilities sites) 

3-year average of 99th percentile i-hour values 

120 

100 

c 

.9 80 

.c 

cu 60

C. 

III 

.... 40 III 

Q. 

20 

I 2010 1-hr. NAAQS

--------------------------­

.4'-~ t ;<::: -. NOTE: 

Partial years only for Colo. Spgs. 

--­ - Utility sites for 2001. 

~CSU-Nixon 08-041-6001_CSU-Pulpit Rock 08-041-6004 -+-CSU-Colo. College 08-041-0011 

Colorado Recommended 1-Hour S02 Designations Page 5 of10 

Technical Support Document 

March 17, 2011 
Table 1. Colorado 1-Hour Sulfur Dioxide Monitorin/! Data Summary (CDPHE) 

Year 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 

2010 

Welby
 

AQS# 08-001-3001
 

99%ile I-hr. 

(ppb) 

92 

76 

100 

71 

94 

69 

81 

56 

75 

78 

58 

46 

43 

37 

27 

28 

33 

38 

New Standard: 

3-yr. Avg. 

(ppb) 

89 

82 

88 

78 

81 

69 

71 

70 

70 

61 

49 

42 

36 

31 

29 

33 

CDPHE-APCD sites
 

CAMP
 

AQS# 08-031-0002
 

99%ile I-hr. 

(ppb) 

117 

107 

95 

101 

78 

79 

67 * 

78 * 

71 

68 

57 

33 

34 

31 

33 

46 * 

35 * 

39 

3-yr. Avg. 

(ppb) 

106 

101 

91 

86 

75 

75 

72 

72 

65 

53 

41 

33 

33 

37 

38 

40 

3-yr. Avg. of I-hr. 99th percentile =75 ppb 

South Adams
 

AQS# 08-001-0007
 

99%i1e I-hr. 3-yr. Avg.
 

(ppb) (ppb)
 

69 

64 

36 56 

32 * 44 

NOTE: * 1999,2000,2008,2009 are incomplete years for CAMP 

* 2004 is an incomplete year for South Adams 

Colorado Recommended I-Hour S02 Designations Page 6 of10 

Technical Support Document 

March 17, 2011 
Table 2. Colorado I-Hour Sulfur Dioxide Monitorinf( Data Summary (Other) 

Colorado Springs Utilities sites 

CSU-Nixon CSU-Pulpit Rock CSU-Colo. College 

AQS# 08-041-6001 AQS# 08-041-6004 AQS# 08-041-6011 

99%i1e i-hr. 3-yr. Avg. 99%ile i-hr. 3-yr. Avg. 99%ile i-hr. 3-yr. Avg. 

Year (ppb) (ppb) (ppb) (ppb) (ppb) (ppb) 

1993 58 27 46 

1994 51 28 60 

1995 53 54 24 26 52 53 

1996 45 50 25 26 54 55 

1997 55 51 15 21 27 44 

1998 43 48 22 21 54 45 

1999 55 51 17 18 56 46 

2000 39 46 23 21 60 57 

2001 39 * 44 19 * 20 49 * 55 

(shut down) (shut down) (shut down) 

New Standard: 3-yr. Avg. of i-hr. 99th percentile =75 ppb 

NOTE: * 2001 is an incomplete year for CSU-Nixon, CSU-Pulpit Rock, CSU-Colo. College 

Summary Conclusions 

The data and analysis presented provide documentation and compelling evidence supporting a 

finding that Colorado should be designated as attainment or attainmentlunclassifiable for the 

2010 I-hour sulfur dioxide NAAQS. It is important to note that only areas over which Colorado 

has direct air quality jurisdiction are included in this attainment attainmentlunclassifiable finding 

and recommendation. The Southern Ute Indian Tribe, and the Southern Ute Indian Tribe/State of 

Colorado Environmental Commission, as well as the Ute Mountain Ute Indian Tribe, are distinct 

nations or entities and consequently such Tribal lands are specifically excluded from this 

designation recommendation. 

Table 3 provides a complete listing of the recommended designations, by area. Figure 4 provides 

a map of the Air Quality Control Regions for the I-hour sulfur dioxide designations in Colorado. 

These recommendations are based on current monitoring information that indicates compliance 

with the revised standard. 

Colorado Recommended I-Hour S02 Designations Page 7 of 10 

Technical Support Document 

March 17.2011 
Table 3. Recommended I-Hour Sulfur Dioxide Designations by Area/or Colorado 

2010 Colorado Designations for the 1-Hour Sulfur Dioxide NAAQS 

(based on 2007-2009 monitoring data) 

Air Quality Control Regions (AQCR) Sulfur Dioxide NAAQS 

Designation 

State AQCR 01 

Logan County 

Morgan County 

Phillips County 

Sedgwick County 

Washington County 

Yuma County 

AttainmentiUnciassifiable 

State AQCR 02 

Larimer County 

Weld County 

AttainmentiUnclassifiable 

State AQCR 03 

Adams County 

Arapahoe County 

Boulder County (including the portion of Rocky Mountain 

National Park therein) 

Broomfield County 

Clear Creek County 

Denver County 

Douglas County 

Jefferson County 

Gilpin County 

Attainment 

State AQCR 04 AttainmentiUnclassifiable 

EI Paso County 

Park County 

Teller County 

State AQCR 05 

Cheyenne County 

Elbert County 

Kit Carson County 

Lincoln County 

AttainmentiUnclassifiable 

State AQCR 06 AttainmentiU nclassifiable 

Baca County 

Bent County 

Crowley County 

Kiowa County 

Otero County 

Prowers County 

State AQCR 07 

Huerfano County 

Las Animas County 

Pueblo County 

Attainment/Unclassifiable 

Colorado Recommended 1-Hour S02 Designations Page 8 of10 

Technical Support Document 

March 17, 2011 
2010 Colorado Designations for the 1-Hour Sulfur Dioxide NAAQS 

(based on 2007-2009 monitoring data) 

Air Quality Control Regions (AQCR) Sulfur Dioxide NAAQS 

Designation 

State AQCR 08 

Alamosa County 

Conejos County 

Costilla County 

Mineral County 

Rio Grande County 

Saguache County 

Atta inmentlUnclassifiable 

State AQCR 09 

Archuleta County (part) excluding Southern Ute Indian Tribe 

(SUIT) lands 

Dolores County 

La Plata County (part) excluding SUIT and Ute Mountain Ute 

Tribe lands 

Montezuma County (part) excluding SUIT and Ute Mountain 

Ute Tribe lands 

San Juan County 

AttainmentlUnciassifiable 

State AQCR 10 

Delta County 

Gunnison County 

Hinsdale County 

Montrose County 

Ouray County 

San Miguel County 

AttainmentlUnciassifiable 

State AQCR 11 

Garfield County 

Mesa County 

Moffat County 

Rio Blanco County 

AttainmentlUnclassifiable 

State AQCR 12 AttainmentlUnciassifiable 

Eagle County 

Grand County 

Jackson County 

Pitkin County 

Routt County 

Summit County 

State AQCR 13 AttainmentlUnciassifiable 

Chaffee County 

Custer County 

Fremont County 

Lake County 

Colorado Recommended I-Hour S02 Designations Page 9 of10 

Technical Support Document 

March 17, 2011 
Figure 4. Map 0/Air Quality Control Regions/or I-Hour Sulfur Dioxide Designations in 

Colorado 

S02 Monitoring Site c:l Colorado Air auality Comrol Regions 

CitiesfTowns 0 Counties 

AQCR 1 

A CR 5 

AQCR 6 

Colorado Oepartmem of Puhlrc Health and E",;ronment . Air Pollution Control or,;sion 

Legend 

(;) 

Colorado Recommended I-Hour S02 Designations Page 10 of10 

Technical Support Document 

March 17, 2011