STATE OF COLORADO
 

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. 

Denver, Colorado 80246-1530 

Phone (303) 692-2000 

Located in Glendale, Colorado 

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

May 11,2011 

James B. Martin 

Laboratory Services Division 

8100 Lowry Blvd. 

Denver, Colorado 80230-6928 

(303) 692-3090 

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: 

Colorado Department 

of Public Health 

and Environment 

co 

l: - :D'~~ C".J = ~o::o c:e ~Cf.'11 ,.... 0::. UJw~

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:) :s 

Pursuant to the provisions ofsection 107(d)(l) ofthe 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 "attainmentlunclassifiable" as applicable for all air quality control regions 

(AQCRs) in Colorado. These recommended designations and underlying technical support were 

originally sent to you on March 18, 2011. Because they were sent prior to Governor 

Hickenlooper's April 11, 2011 letter to you designating me as the official Colorado representative 

for submitting documents to EPA on behalf of the State, we are resubmitting the recommended 

designations and technical support documentation. 

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 attainmentlunclassifiable designations 

for areas lacking representative monitc-f-ing 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. 

Letter to EPA - Colorado Recommended I-Hour S02 Designations May 11,2011 
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, 

U-­

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 

Leller 10 EPA - Colorado Recommended I-Hour 502 Designalions May ll, 20ll 

2 
State of Colorado
 

Technical Support Document
 

for I-Hour Sulfur Dioxide Standard Attainment
 

in Colorado
 

February 18,2011 

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 1. Map of I-Hour Sulfur Dioxide Ambient Air Monitoring Sites 2008-2010 .. .4
 

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

Figure 3. Colorado I-Hour Sulfur Dioxide Ambient Air Concentration Trends (Othel~. ... 5
 

Table 1. 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 Regionsfor i-Hour Sulfitr Dioxide Designations in Colorado 10
 

Colorado Recommended 1-Hour S02 Designations Page 20f10 

Technical Support Document 

February 18, 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 1-hour sulfur dioxide standard. This 

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

with the revised I-hour sulfur dioxide standard. 

Overview 

On June 2, 20 10, the U.S. Environmental Protection Agency (EPA) promulgated a new National 

Ambient Air Quality Standard (NAAQS) for nitrogen dioxide as a 1-hour average. The level was 

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

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

The Air Pollution Control Division (APCD) ofthe 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 2008-20 10 period shows the 3­

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

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 APCDis 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 

attainmentlunclassifiable 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 ofthe two APCD site locations currently in 

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

examined. 

Figure 2 ~resents long term trends for the APCD's CAMP and Welby sites as the 3-year average 

of the 99t percentile daily maximum values, as well as data for a historic APCD site (South 

Adams). [t is evident that ambient I-hour sulfur dioxide levels have decreased dramatically over 

Colorado Recommended I-Hour SOl Designations Page 3 of10 

Technical Support Document 

February 18, 20ll 
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 2001, they do provide information that attainment 

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

Table 1 presents a summary of the 99th percentile data for all these sites, as well as the 3-year 

average calculations. The table also indicates years that are not complete for true data 

assessments, but have been used in this analysis. 

Figure 1. Map of1-Hour Sulfur Dioxide Ambient Air Monitoring Sites 2008-2010 

o PCWldwfW..... r.do 

Colorado Recommended I-Hour S02 Designations Page 4 of10 

Technical Support Document 

February 18. 20ll 
Figure 2. Colorado i-Hour Sulfur Dioxide Ambient Air Concentration Trends (CDPHE) 

100 

Sulfur dioxide (CDPHE sites)
 

3-year average of 99th percentile 1-hour values
 

120 

80 :f~-:;;'-;;;;;;~~S;~~.~i:_~_~_~_~_:;;_;;_;;;_;j.,,;2::01;;0;..;1:..-;.:.;hr:.;,. ;,,;N~AA~Q~S1 ..c 

... 

QI 60 +---------------=-.3110~_---------_j

..

C.
 

III


... 40 NOTE:
 nl
 Partial years onlyfor CAMP for 1999, 2000,
 

2008 and 2009.
 

Q. 

20 

Partial year only for South Adams for 2004. 

a 

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

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

Sulfur dioxide (Colo. Spgs. Utilities sites) 

3-year average of 99th percentile 1-hour values 

120 

100 

l: 

.2 80 

..c 

... 

QI 60

C. 

III

.. ... 40 nl 

Q. 

20 

I 2010 1-hr. NAAQS

--------------------------­ -.. -' -­ .....

- .. - NOTE: 

Partial years onlyfor Colo. Spgs. 

--­ - Uti Iity sites for 200 1. 

a
 

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

Colorado Recommended I-Hour S02 Designations Page 5 of10 

Technical Support Document 

February 18,2011 
Table 1. Colorado 1-Hour Sulfur Dioxide Monitorinf! 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%i1e 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 

Februarv 18. 20ll 
Table 2. Colorado I-Hour Su(fur Dioxide Monitoring 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%ile l-hr. 3-yr. Avg. 99%ile l-hr. 3-yr. Avg. 99%ile l-hr. 3-yr. Avg. 

(ppb) (ppb) (ppb) (ppb) (ppb) (ppb) 

1993 

Year 

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 l-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 502 Designations Page 7 of 10 

Technical Support Document 

Februarv 18, 2011 
Table 3. Recommended l-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 

Desig nation 

State AQCR 01 

Logan County 

Morgan County 

Phillips County 

Sedgwick County 

Washington County 

Yuma County 

AttainmenUUnclassifiable 

State AQCR 02 

Larimer County 

Weld County 

AttainmenUUnclassifiable 

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 AttainmenUUnclassifiable 

EI Paso County 

Park County 

Teller County 

State AQCR 05 

Cheyenne County 

Elbert County 

Kit Carson County 

Lincoln County 

AttainmenUUnclassifiable 

State AQCR 06 AttainmenUUnclassifiable 

Baca County 

Bent County 

Crowley County 

Kiowa County 

Otero County 

Prowers County 

State AQCR 07 

Huerfano County 

Las Animas County 

Pueblo County 

AttainmenUUnclassifiable 

Colorado Recommended I -Hour S02 Designations Page 8 of10 

Technical Support Document 

February 18.2011 
•
 

2010 Colorado Designations for the 1-Hour Sulfur Dioxide NAAQS 

(based on 2007-2009 monitoring data) 

Air Quality Control Regions (AQCR) 

State AQCR 08 

Alamosa County 

Conejos County 

Costilla County 

Mineral County 

Rio Grande County 

Saguache County 

State AQC R 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 

State AQC R 10 

Delta County 

Gunnison County 

Hinsdale County 

Montrose County 

Ouray County 

San Miguel County 

State AQCR 11 

Garfield County 

Mesa County 

Moffat County 

Rio Blanco County 

State AQCR 12 

Eagle County 

Grand County 

Jackson County 

Pitkin County 

Routt County 

Summit County 

State AQCR 13 

Chaffee County 

Custer County 

Fremont County 

Lake County 

Sulfur Dioxide NAAQS 

Designation 

AttainmenUUnclassifiable 

AttainmenUUnclassifiable 

AttainmenUUnclassifiable 

AttainmenUUnclassifiable 

AttainmenUU nclassifiable 

AttainmenUUnclassifiable 

Colorado Recommended I-Hour S02 Designations Page 9 of 10 

Technical Support Document 

February 18,2011 
Figure 4. Map ofAir Quality Control Regionsfor l-Hour Sulfur Dioxide Designations in 

Colorado 

Legend 

<:> S02 Mon1toring Site c::l Colotsdo Air Quality Control Regions 

Cities;Towns 0 Counlies 

AOCR 1 

AOCR 3 

A CR 5 

AOCR 6 

I 

o w 00 _-r::::.-r::::.-_-===-__r.liles 

Colorado Department of Pubnc Health and Err.ironment -Air Pollution Control Dr.;sion 

Cdlorado Recommended I-Hour S02 Designations Page 10 of10 

Technical Support Document 

February 18,2011