Technical Support Document

State of Iowa Regional Haze Submittal

Prepared by:

Chrissy Wolfersberger

Environmental Protection Specialist

United States Environmental Protection Agency, Region 7

February 2012

Table of Contents 

I. Summary of EPA’s action Page 3

II. Iowa’s regional haze rulemaking Page 3

III. Regional haze plan requirements Page 3

a. Affected Class I areas Page

i. Northern Midwest Class I areas

ii. Arkansas and Missouri Class I areas

iii. South Dakota Class I areas

b. Reasonable progress goals Page

c. Long term strategy Page

i. Consultation with other States Page

1. Missouri and Arkansas

2. South Dakota

3. Oklahoma

4. Minnesota

5. Michigan

d. Best Available Retrofit Technology (BART) Page

i. BART eligible sources Page

ii. BART subject sources Page

1. Q/d screening

2. Model plant screening

3. CAMx screening

4. Holcim, ADM-Clinton, and Equistar

5. BART for particulate matter 

e. Monitoring strategy Page

f. Emissions inventory Page

g. Periodic SIP revisions and five year progress report Page

h. Consultation with Federal Land Managers (FLMs) Page
2

List of Figures

Figure 1 Map of the 156 mandatory Class I federal areas

Figure 2 Areas within 300 km of a Class I area

Figure 3 Geographical area of Regional Planning Organizations

Figure 4 Distribution of the 2002 Iowa NH3 emission inventory by source category

Figure 5 Distribution of the 2002 Iowa VOC emission inventory by source category

List of Tables 

Table 1 Percent contribution of Iowa, Minnesota, and Michigan to visibility impairment at 

the Northern Midwest Class I areas, 20% worst days

Table 2 Iowa’s absolute contribution to visibility impairment, Northern Midwest Class I 

areas

Table 3 Estimated 2018 level of visibility impairment in the absence of all Iowa emissions 

sources

Table 4 Facilities with BART-eligible units in the State of Iowa

Table 5 Nearest Class I area & Q/d values for non-EGU BART-eligible sources

Table 6 Non-EGU BART-eligible facilities significantly below Q/d screening tests

Table 7 Description of the IDNR BaseK cumulative modeling scenarios

Table 8 Scenario k2002ia36b0v2r1: Class I area maximum impacts

Table 9 Scenario k2002ia36b0v2r2: Class I area maximum impacts

Table 10 Scenario k2002ia12b0v2r2: Class I area maximum impacts

Table 11 2002 Iowa emissions summary

Table 12 2018 Iowa projected emissions summary
3

I. Summary of EPA’s Action

The Environmental Protection Agency (EPA) is proposing a limited approval of a revision to the 

Iowa State Implementation Plan (SIP) submitted by the State of Iowa in March 2008 that 

addresses regional haze for the first implementation period. This revision addresses the 

requirements of the Clean Air Act (CAA or “Act”) and the EPA’s rules that require States to 

prevent any future and remedy any existing anthropogenic impairment of visibility in mandatory 

Class I areas caused by emissions of air pollutants from numerous sources located over a wide 

geographic area (also referred to as the “regional haze program”). States are required to assure 

reasonable progress toward the national goal of achieving natural visibility conditions in Class I 

areas. 

EPA is proposing a limited approval of this SIP revision to implement the regional haze 

requirements for Iowa on the basis that the revision, as a whole, strengthens the Iowa SIP. In a 

separate action, on December 30, 2011, EPA previously proposed a limited disapproval of the 

Iowa regional haze SIP because of deficiencies in the State’s regional haze SIP arising from the 

remand by the U.S. Court of Appeals for the District of Columbia (D.C. Circuit) to EPA of the 

Clean Air Interstate Rule (CAIR). In that rulemaking, EPA proposed a Federal Implementation 

Plan (FIP) to replace reliance on the CAIR requirements in Iowa’s SIP with reliance on the 

Cross-State Air Pollution Rule (Transport Rule) as an alternative to BART. 

II. Iowa’s Regional Haze rulemaking

On May 1, 2007, the Iowa Environmental Protection Commission adopted revisions to 567 Iowa 

Administrative Code 22.9 related to regional haze. These rules became effective on June 27, 

2007. The Iowa Department of Natural Resources (IDNR) requested that EPA approve these 

changes into the federally-approved SIP in a letter dated March 7, 2008. 

The State documented in its SIP the legal authority that the Iowa Environmental Protection 

Commission has for adopting rules related to regional haze (appendix 2.1 of the SIP). 

Opportunity for public comment on the Iowa regional haze SIP was advertised in the Des 

Moines Register on December 26, 2007, and the full SIP was posted on IDNR’s website. A 

public hearing was held on January 30, 2008 at the IDNR office in Urbandale, IA, with the 

public comment period open through January 31, 2008. Iowa received comments from three 

organizations: USDA Forest Service, National Park Service, and EPA Region 7. See appendix 

2.1 of the SIP for full comments and responses. 

EPA believes that the State has met the requirements of the CAA sections 110(l) and 110(a)(2) 

which require that the State adopt a SIP after reasonable notice and public hearing. EPA also 

believes that the State has met the requirements of the specific procedural requirements for SIP 

revisions promulgated at 40 CFR Part 51, subpart F. 

III. Regional Haze SIP requirements

a. Affected Federal Class I areas (40 CFR 51.308 (d))

States are required to identify each Class I area located within the State and each Class I 

area located outside the State which is affected by emissions from within the State. 
4

Produced by NPS Air Resources Division October 2002

National Park Service

U.S. Department of the Interior

Areas within 300km of Class I Units

/

Roosevelt Campobello Intl. Park

FWS Class I

USFS Class I

Alaska Hawaii NPS Class I

US Virgin Islands

Puerto Rico

0 250 500 1,000

Author: KLD Km

Figure 1: Map of the 156 mandatory Class I federal areas.

There are no Class I areas hosted by the State of Iowa, and no portion of land within the 

State of Iowa is within 300 kilometers (km) of a Class I area. States that host Class I 

areas are required to estimate the baseline, natural and current visibility conditions of 

those Class I areas. Iowa does not host a Class I area, therefore, it is not required to 

estimate these metrics.

Figure 2: 

Areas 

within 

300 km of 

a Class I 

area. 

Iowa is 

the only 

state 

whose 

border 

does not 

intersect 

a 300 km 

buffer 

zone. 
5

The State of Iowa participated in the planning efforts of the Central Regional Air 

Planning Association (CENRAP) which is affiliated with the Central States Air Resource 

Agencies (CENSARA). This RPO includes nine states - Nebraska, Iowa, Oklahoma, 

Texas, Minnesota, Iowa, Missouri, Arkansas, and Louisiana. CENRAP and its 

contractors provided air quality modeling to the States to help them determine whether 

sources located within the State can be reasonably expected to cause or contribute to 

visibility impairment in a Class I area. The modeling conducted relied on baseline year 

(2002) and future planning year (2018) emissions inventories that were prepared with 

participation from each of the CENRAP states. States relied on these inventories to 

develop control strategies to meet the visibility improvement goals of the regional haze 

rule and to develop their State Implementation Plans (SIPs). 

Figure 3: Geographical area of Regional Planning Organizations

The State of Iowa relied upon the regional modeling work performed by CENRAP for 

determining the impact that sources within the State might have on Class I areas in the 

region and beyond. The modeling was based on PM Source Apportionment Technology 

(PSAT) for the Comprehensive Air Quality Model with extensions (CAMx) 

photochemical model. A detailed description of this modeling can be found in Appendix 

7 of the SIP. 

The following Class I areas were evaluated for contribution by the State of Iowa:

• Boundary Waters Canoe Area, Minnesota (BOWA)

• Voyageurs National Park, Minnesota (VOYA)

• Seney Wilderness Area, Michigan (SENE)

• Isle Royale National Park, Michigan (ISLE)
6

• Hercules Glades Wilderness Area, Missouri (HEGL)

• Mingo Wilderness Area, Missouri (MING)

• Caney Creek Wilderness, Arkansas (CACR)

• Upper Buffalo Wilderness, Arkansas (UPBU)

• Badlands National Park, South Dakota (BADL)

• Wind Cave National Park, South Dakota (WICA)

i. Northern Midwest Class I areas: Boundary Waters, Voyageurs, Seney, and 

Isle Royale

According to the CENRAP PSAT results, the combined effect of all Iowa 

emissions upon the total modeled visibility impairment at the four Northern 

Midwest Class I areas is approximately 4-5% in both 2002 and 2018. The data 

were calculated in accordance with the new IMPROVE equation1 and are 

representative of those days which yielded the worst 20% visibility conditions. A 

detailed description of the source apportionment methods utilized by CENRAP is 

available in Appendix 7.1 of the SIP. 

Table 1: Percent contribution of Iowa, Minnesota, and Michigan to visibility 

impairment at the Northern Midwest Class I areas, 20% worst days

Iowa Minnesota Michigan

2002 2018 2002 2018 2002 2018

Boundary Waters 3.7 3.9 25.6 28.5 2.3 2.7

Voyagers 3.8 4.0 29.1 30.4 1.4 1.6

Isle Royale 4.5 4.9 11.5 12.5 11.1 12.8

Seney 4.2 4.8 3.9 4.4 9.6 12.7

The PSAT results provided above are in terms of percentages of total visibility 

impairment. The State of Iowa found them useful for determining the proportion 

of the State’s contribution in relation to the total modeled visibility impairment at 

a Class I area. However, characterizing visibility impairment using just 

percentages can fail to identify the magnitude of the contribution. For example, 

Iowa’s percent contributions increase between 2002 and 2018, but the actual light 

extinction values decrease between the same years. 

Table 2: Iowa’s absolute contribution to visibility impairment, Northern 

Midwest Class I areas

Worst 20% Days

Modeled Extinction (Mm-1)

Iowa Class I Area Total

2002 2018 2002 2018

Boundary Waters 2.39 2.08 64.87 53.44

Voyagers 2.60 1.97 56.45 48.84

Isle Royale 3.23 3.02 71.40 61.26

Seney 4.54 3.95 107.92 82.00

 1 Interagency Monitoring of Protected Visual Environments (IMPROVE)
7

Iowa’s contributions to visibility impairment, as calculated through light 

extinction using the new IMPROVE equation, are provided in Table 2. The total 

modeled visibility impairment for each Class I area are also shown in the table. 

Iowa emissions sources cumulatively contribute only 2.2 - 4.5 Mm-1 of the 56 -

107 Mm-1 total modeled visibility impairment at the Northern Midwest Class I 

areas in 2002. Together, Iowa’s percentage and absolute contributions describe 

the impacts emissions sources in Iowa may have upon nearby Class I areas. The 

State determined that when considered collectively, the data in Tables 1 and 2 

show that Iowa sources were responsible for a minimal contribution to visibility 

impairment at the Northern Midwest Class I areas and that control of emissions of 

these sources offer little in terms of potential visibility improvement.

An alternative means of assessing Iowa’s contribution to visibility impairment can 

be conducted through implementation of the dv metric. As shown by Table 3, 

visibility improvements resulting from the elimination of all Iowa sources yield 

impacts below 0.5 dv. 

Table 3: Estimated 2018 level of visibility impairment in the absence of all 

Iowa emissions sources

2018 Worst 

20% (dv)

2018 Worst 20% 

Less Iowa’s 

Contribution (dv)

Iowa’s Visibility 

Impacts (dv)

Boundary Waters 18.5 18.1 0.4

Voyagers 17.7 17.4 0.3

Isle Royale 19.6 19.2 0.4

Seney 22.2 21.8 0.4

ii. Arkansas and Missouri Class I areas: Caney Creek, Upper Buffalo, Mingo, 

Hercules Glades

Iowa’s contributions to the Arkansas and Missouri Class I areas (HEGL, UPBU, 

CACR, MING) in terms of percentage contribution to visibility extension were 

less than to the Northern Midwest Class I areas. PSAT analysis showed that Iowa

sources contributed approximately 1.6-2.7% to the total visibility extinction on 

the 20% worst visibility days in 2018 at these Class I areas.

iii. South Dakota Class I areas: Badlands and Wind Cave

The PSAT analysis showed that Iowa sources contributed approximately 1.6% to 

the total visibility extinction on the 20% worst visibility days in 2018 at the 

Badlands and approximately 1.2% to the total visibility extinction on the 20% 

worst visibility days in 2018 at the Wind Cave National Park, a contribution 

which the State determined to be insignificant.
8

b. Reasonable progress goals (RPG): 40 CFR 51.308(d)(1)

The RHR requires States and Tribes to establish a Reasonable Progress Goal (RPG) for 

each Class I area within the state. The RPG is measured in deciviews and is to provide for 

reasonable progress towards achieving natural visibility conditions during the first 

implementation period (through 2018). RPGs should represent an improvement in 

visibility for the most impaired days, and ensure no degradation in visibility on the least 

impaired days.

Iowa does not have a Class I area within the state and therefore is not required to 

establish a RPG. States hosting Class I areas have established RPGs, and have made 

assessments regarding whether emission reductions are needed from sources in Iowa in 

order to meet their RPG. 

c. Long-Term Strategy: 40 CFR 51.308(d)(3)(iii)

States are required to submit a long-term strategy (LTS) that addresses visibility 

impairment for each Class I area, inside and outside the State, which may be affected by 

the State’s emissions. If emissions from the State are reasonably anticipated to contribute 

to visibility impairment in Class I areas in other States, the State is required to consult 

with other State(s) to develop coordinated emission management strategies. In the case 

where multiple State(s) cause or contribute to impairment of the same Class I area, States 

are required to obtain their share of the emission reductions needed to meet the 

reasonable progress goal for the Class I area. 

In developing its LTS, the State should consider:

• the anticipated net effect on visibility due to projected changes in point, area, and 

mobile source emissions over the period addressed by the LTS;

• measures to mitigate the impacts of construction activities;

• source retirement and replacement schedules;

• smoke management techniques for agricultural and forestry management; and

• enforceability of emissions limitations and control measures. 

The emissions inventory for Iowa projects changes to point, area, and mobile source 

inventories by the end of the first implementation period resulting from population 

growth, industrial, energy and natural resources development, land management, and air 

pollution control. Iowa considered the minor and major nonattainment new source review 

programs (NNSR), prevention of significant deterioration permits (PSD), CAIR, the 

heavy duty highway diesel rule, the clean air non-road diesel rule, other on-road and nonroad mobile source programs, operating permits, pertinent new source performance 

standards (NSPS), national emissions standards for hazardous air pollutants (NESHAP), 

associated maximum achievable control technology (MACT) standards, and Integrated 

Planning Model (IPM)

2 results in developing its long-term strategy. 

In a separate notice proposing limited disapproval of the regional haze SIPs of a number 

of States, including Iowa, EPA noted that these States relied on the trading programs of 

 2

 http://www.epa.gov/airmarkets/progsregs/epa-ipm/index.html
9

CAIR to satisfy the BART requirement and the requirement for a LTS sufficient to 

achieve the State-adopted reasonable progress goals. (76 FR 82219, December 30, 

2011). In that notice, we proposed a limited disapproval of Iowa’s LTS insofar as it 

relied on CAIR. For that reason, we are not taking action on that aspect of the long-term

strategy in this notice. 

In order to mitigate the impact of construction activities, Iowa’s rule on fugitive dust (567 

IAC 23.3(2)“c”) states that reasonable precautions shall be taken to prevent the discharge 

of visible emissions of airborne dust beyond the lot line of the property from which the 

emissions originated. Iowa also requires minor NSR permits for aggregate processing 

plants, concrete batch plants, and asphalt plants. Portable aggregate, concrete, or asphalt 

plants must notify the IDNR 30 days before transferring the equipment to a new location 

to allow for review of the emissions impacts on national ambient air quality standards 

(NAAQS). The IDNR would notify the portable plant if there are potential adverse 

impacts on the NAAQS. A more stringent emission standard and the installation of 

additional control equipment would be required if the relocation would prevent the 

attainment or maintenance of the NAAQS. Iowa determined that no additional measures 

were needed to mitigate the impacts of construction activities, and EPA agrees with this 

determination. 

Iowa demonstrated that source retirement and replacement schedules were taken into 

account, to the extent possible, when developing inputs for the IPM that was used in the 

CENRAP modeling analysis. 

Iowa does not have a smoke management program at this time. Iowa notes that the 

CENRAP PSAT modeling indicates that fires in Iowa do not significantly contribute to 

visibility impairment in Class I Federal areas and, therefore, believes that a smoke 

management program is not needed for purposes of visibility improvement at this time. 

i. Consultation with other States 

1. Missouri and Arkansas

Iowa participated with the central consultation group, a subset of the 

CENRAP. This group was coordinated by the States of Missouri and 

Arkansas. Other participants included Ohio, Indiana, Illinois, Oklahoma, 

Texas, Kentucky, Tennessee, FLMs, other RPOs, and tribes. In a letter 

dated July 23, 2007 (sent by the State of Arkansas and found in Appendix 

10 to the SIP), the central consultation group determined that additional 

reductions beyond existing and proposed controls, through both state and 

federal requirements, would not be necessary from the State of Iowa in 

order for the uniform rate of progress to be met at each of the Class I areas 

in the States of Missouri and Arkansas (HEGL, MING, CACR, and the 

UPBU). 

2. South Dakota

Iowa communicated directly with the State of South Dakota, via letters 

dated May 31, 2007 and June 18, 2007 (provided in Appendix 10 to the 
10

SIP) regarding visibility impacts at the Badlands and Wind Cave National 

Parks. The State of South Dakota asked the State of Iowa for any analysis 

that it conducted to determine the impacts, if any, sources in Iowa may 

have on the South Dakota Class I areas. The State of Iowa responded that 

source PSAT analysis was available on the CENRAP website titled 

“PSAT Viz Tool 27-April 2007.” The State of Iowa explained the analysis 

showed that sources in the State contributed approximately 1.6% to the 

total visibility extinction on the 20% worst visibility days in 2018 at the 

Badlands and approximately 1.2% to the total visibility extinction on the 

20% worst visibility days in 2018 at the Wind Cave National Park and as 

such was insignificant. The State of Iowa did not receive a response or 

request for additional information from the State of South Dakota. 

3. Oklahoma

The State of Iowa also communicated directly with the State of Oklahoma 

regarding potential visibility impacts of Iowa sources on the Wichita 

Mountains Wildlife Refuge. In a letter dated February 25, 2008 (provided 

in Appendix 10 to the SIP), the State of Oklahoma invited states that had a 

projected contribution of at least 1 Mm-1 visibility impact in 2018 at 

WIMO to participate in its consultation process. The letter goes on to 

determine that, after evaluating 2018 modeling projections for the 20% 

worst visibility days at the Class I area, anthropogenic emissions from the 

sources in the State of Iowa were not reasonably anticipated to contribute 

to visibility impairment at the WIMO and that the State of Oklahoma was 

not requesting that the State of Iowa consider additional emission 

reductions.

4. Minnesota

In addition to participation in the CENRAP regional planning process, the 

SIP indicates that Iowa also participated in the Midwest Class I area 

consultation group, coordinated by the States of Minnesota and Michigan, 

which included participation from the States of Illinois, Indiana, Michigan, 

Ohio, and Wisconsin, as well as Tribal lands in the five States that are part 

of the Midwest Planning Organization (MRPO). The states that comprise 

the CENRAP, the states that comprise the MRPO, the EPA, the FLMs and 

the State of North Dakota participated in the Midwest Class I area 

consultation group.

The State of Minnesota determined that the State of Iowa (among other 

states), via a letter dated September 19, 2007, was a significant contributor 

to visibility impairment at VOYA and BOWA. Attachments provided with 

the letter indicated that the State of Minnesota utilized Lake Michigan Air

Directors Consortium (LADCO) trajectory analysis and CENRAP PSAT 

analysis (for baseline years) to determine if a state contributed 5% or more 

to visibility impairment at the two Minnesota Class I areas. A contribution 

of 5% was considered by the State of Minnesota to be significant. The 
11

LADCO trajectory analysis estimated contributions from emissions from 

the State of Iowa to be approximately 7.4% at BOWA and approximately 

10.2% at VOYA. The CENRAP PSAT modeling estimated contributions 

from emissions from the State of Iowa to be approximately 3.5% at 

BOWA and approximately 3.8% at VOYA. 

In its letter, the State of Minnesota asked the State of Iowa to “...evaluate 

further reductions of SO2 from electric generating units (EGU) in order to 

reduce SO2 emissions by 2018 to a rate that is more comparable to the rate 

projected for 2018 for Minnesota, approximately 0.25 lbs/MMBtu.” The 

State of Minnesota also asked the State of Iowa to make a commitment to 

review, by 2013, the potential emission reductions that could be gained 

from control of industrial, commercial, and institutional (ICI) boilers and 

other point sources (such as reciprocating engines and turbines). 

The State of Iowa responded to the State of Minnesota via letter dated 

November 1, 2007, communicating that it would not commit to evaluate 

further reductions of SO2 from EGUs because the State was participating 

in CAIR and because the State of Iowa had concerns with the State of 

Minnesota’s interpretations of the LADCO/Minnesota four-factor analysis 

for reasonable progress. The State of Minnesota used some information 

from its four-factor analysis as an appendix to its request letter. The State 

of Iowa considered the State of Minnesota’s cost per dv improvement 

($/dv) figures, in a range of approximately $3 billion/dv to $3.3 billion/dv, 

to be unreasonable for SO2 control beyond CAIR for EGUs in the State of 

Iowa. The State of Iowa also considered the State of Minnesota’s $/dv 

figures, in a range of approximately $2.8 billion/dv to $3.4 billion/dv, to 

be unreasonable for control of ICIs. Iowa explained that a similar 

argument could be made for reciprocating engines and combustion 

engines.

The State of Iowa also questioned the State of Minnesota’s use of the 

LADCO trajectory analysis to determine significance of emissions from 

surrounding states because the trajectory analysis was based upon 

theoretical air flow and did not account for chemical reactions in the 

atmosphere, which CENRAP PSAT modeling did. Because the CENRAP 

PSAT modeling indicated that emissions from the State of Iowa contribute 

less than 5% to impairment at Minnesota-hosted Class I areas, the State of 

Iowa did not consider emissions from sources within its boundaries to be 

significant (using the State of Minnesota’s significance threshold of 5%). 

Iowa determined that additional controls were unsupported at this first 

stage of the regional haze rule, because Minnesota did not request that 

controls be installed on specific sources; did not provide justification on 

how such controls would lead to visibility improvement at the Minnesota 

Class I areas; did not provide documentation or otherwise consult with 
12

Iowa regarding any specific visibility improvement at the Minnesota Class 

I areas which would result from controlling Iowa sources; and because of 

the cost and visibility issues mentioned above. However, on page 38 of the 

SIP, the State of Iowa does commit to continued consultation with 

Minnesota in the future on issues involving regional haze as requested and 

warranted. 

5. Michigan

The State of Michigan wrote the State of Iowa a letter, dated October 26, 

2007, stating that it was not asking other states to reduce emissions for 

purpose of meeting the requirements of the RHR. 

In summary, Iowa developed an emissions inventory for 2018 which considered

projected changes in point, area, and mobile source emissions, including source 

retirement and replacements; has a program in place to mitigate the impacts of 

construction activities; and considered a smoke management program. These programs 

are fully enforceable and provide for the mitigation of new source impacts through new 

source permitting programs. 

Iowa also consulted with the States which may be impacted by Iowa sources, directly and 

through the RPO process. EPA proposes to find that Iowa met the consultation 

requirements of 40 CFR 51.308 (d)(1)(iv).

Iowa ultimately determined that no controls beyond those existing or on the way would 

be needed in order for Iowa to address its share of emission reductions for other states’ 

reasonable progress goals. EPA agrees with this determination, and proposes to find that

Iowa has adequately addressed the LTS requirements of 40 CFR 51.308(d)(3).

d. BART: 40 CFR 51.308 (e)

Section 169A of the CAA directs States to evaluate the use of retrofit controls at certain 

larger, often uncontrolled, older stationary sources in order to address visibility impacts 

from these sources. Specifically, the CAA requires that certain categories of existing 

stationary sources built between 1962 and 1977 procure, install, and operate the “best 

available retrofit technology”, or BART, as determined by the State.3 States are directed 

to conduct BART determinations for the sources that cause or contribute to any visibility 

impairment in a Class I area.

 3 The set of “major stationary sources” potentially subject to BART are listed in CAA section 169A(g)(7). The 26 source 

categories are: (1) Fossil-fuel fired steam electric plants of more than 250 million British thermal units per hour heat input, 

(2) Coal cleaning plants (thermal dryers), (3) Kraft pulp mills, (4) Portland cement plants, (5) Primary zinc smelters, (6) Iron 

and steel mill plants, (7) Primary aluminum ore reduction plants, (8) Primary copper smelters, (9) Municipal incinerators 

capable of charging more than 250 tons of refuse per day, (10) Hydrofluoric, sulfuric, and nitric acid plants, (11) Petroleum 

refineries, (12) Lime plants, (13) Phosphate rock processing plants, (14) Coke oven batteries, (15) Sulfur recovery plants, 

(16) Carbon black plants (furnace process), (17) Primary lead smelters, (18) Fuel conversion plants, (19) Sintering plants, 

(20) Secondary metal production facilities, (21) Chemical process plants, (22) Fossil-fuel boilers of more than 250 million 

British thermal units per hour heat input, (23) Petroleum storage and transfer facilities with a capacity exceeding 300,000 

barrels, (24) Taconite ore processing facilities, (25) Glass fiber processing plants, and (26) Charcoal production facilities.
13

On July 6, 2005, EPA published the Guidelines for BART Determinations under the 

RHR to assist states in determining which of their sources should be subject to the BART

requirements and determining appropriate emissions limits for each BART-subject 

source. 

In the BART determination process, States must address all significant visibility 

impairing pollutants. The most significant visibility impairing pollutants are SO2, NOx, 

and PM. As indicated by the BART Guidelines, a State should use its best judgment in 

determining whether VOCs, ammonia (NH3) or ammonia compounds impair visibility in 

particular Class I areas4. Iowa conducted a quantitative analysis of emissions inventory 

data to show that Iowa point source NH3 and VOC emissions do not cause or contribute 

to any visibility impairment in any Class I area, as described below.

Figure 4: Distribution of the 2002 Iowa NH3 emission inventory by source category. 

Point sources include all Iowa facilities, BART and non-BART.

 4 Appendix Y of 40 C.F.R. Part 51- States should exercise judgment in deciding whether the following pollutants impair 

visibility in an area :( 4) Volatile organic compounds (VOC), and (5) Ammonia and ammonia compounds. A State should use 

its best judgment in deciding whether VOC or ammonia emissions from a source are likely to have an impact on visibility in 

an area. Certain types of VOC emissions, for example, are more likely to form secondary organic aerosols than others. 

Similarly, controlling ammonia emissions in some areas may not have a significant impact on visibility. A State need not 

provide a formal showing of an individual decision that a source of VOC or ammonia emissions is not subject to BART 

review. Because air quality modeling may not be feasible for individual sources of VOC or ammonia, a state should also 

exercise its judgment in assessing the degree of visibility impacts due to emissions of VOC and emissions of ammonia or 

ammonia compounds. A state should fully document the basis for judging that a VOC or ammonia source merits BART 

review, including its assessment of the source's contribution to visibility impairment.

2002 Iowa NH3 Emissions (tons per year)

259640, 98%

57, 0%

3366, 1%

2863, 1%

Onroad Nonroad Point Area
14

A simple scale analysis demonstrates that point source emissions of NH3 and VOC are 

insignificant in comparison to other sources and source types. Summing all (not just 

BART-eligible sources) 2002 Iowa point source NH3 emissions yields an emission rate of 

3366 tpy. Area source emissions are approximately seventy-seven times higher, at 

~260,000 tpy (Figure 4). VOC emissions from Iowa’s BART-eligible sources comprise 

only 4% of the total (anthropogenic plus biogenic) 2002 VOC inventory (

Figure 5) and are considered insignificant in terms of visibility impacts. Therefore point 

source NH3 and VOC emissions were not evaluated for visibility impacts.

Figure 5: Distribution of the 2002 Iowa VOC emission inventory by source category.

To further support this conclusion, the State utilized CENRAP-performed PSAT 

modeling sensitivity analyses. These analyses demonstrated that anthropogenic emissions 

of VOC and NH3 did not significantly impair visibility at the Class I areas in the 

CENRAP or MRPO regions. Thus, although emissions inventories were developed for 

NH3 and VOC, and applicable federal VOC reductions were incorporated into Iowa’s 

regional haze analyses, Iowa did not evaluate NH3 and VOC emissions sources for 

potential controls under BART or for its LTS. Due to the limited improvement sourcespecific controls would have on visibility improvement at Class I areas in the CENRAP 

or MRPO regions, EPA agrees with this determination. 

In making a BART determination for a fossil fuel-fired generating plant with a total 

generating capacity in excess of 750 megawatts, a State must use the approach set forth in 

the BART Guidelines. The BART Guidelines provide five steps toward identifying 

BART control for these EGUs.

• Identify all available retrofit control technologies;

• Eliminate technically infeasible control technologies;

• Evaluate the control effectiveness of remaining control technologies;

• Evaluate impacts and document the results;

• Evaluate visibility impact.

2002 Iowa VOC Emissions (tons per year)

70494, 11%

61455, 10%

73522, 12%

386174, 60%

16824.28418, 3%

22332, 4%

Onroad

Nonroad

Area

Biogenics

Point: BART

Point: Non-BART
15

i. BART-eligible sources

For an emission source to be identified as BART-eligible, the State used these 

criteria from the BART Guidelines:

• One or more emissions units at the facility fit within one of the 26 categories 

listed in the BART Guidelines;

• The emission unit was in existence on August 7, 1977 and began operation at 

some point on or after August 7, 1962; and

• The limited potential emissions from all emission units identified in the 

previous two bullets were 250 tons or more per year of any of these 

visibility-impairing pollutants: SO2, NOx, or PM10.

To identify the sources that met the criteria above, Iowa performed a multi-step 

search and analysis including requiring sources to self identify as BART-eligible 

by rule (Iowa Administrative Code 567-22.9 Special Requirements for Visibility 

Protection) on a form supplied by the State (BART Eligibility Certification Form 

#542-8125). The State reviewed all in-house permitting, Title V databases and the 

submitted forms to determine if a source met the criteria explained above. This 

process is outlined in detail in Appendix 9 of the SIP. The twenty seven BARTeligible facilities are listed in Table 4. EPA proposes to find that Iowa 

appropriately identified the BART-eligible units in the State.

Table 4: Facilities with BART-eligible units in the State of Iowa

Source Category Company Name Facility 

Number BART Emission Units

Fossil Fuel-fired 

Steam Electric Plant 

Individually Greater 

than 250 

MMBtu/hour

Cedar Falls Utilities 07-02-005 Unit #7 (EU10, 1A)

Central Iowa Power 

Cooperative (CIPCO) – Summit 

Lake Station

88-01-004 Combustion turbines (EU1, 

EU1G, EU2, EU2G)

Central Iowa Power 

Cooperative (CIPCO) – Fair 

Station

70-08-003 Unit #2 (EU2 & EU 2G)

City of Ames – Steam Electric 

Plant

85-01-006 Boiler #7 (EU2)

Interstate Power and Light –

Burlington

29-01-013 Main plant boiler

Interstate Power and Light –

Lansing

03-03-001 Boiler #4 Sixteen units total. 

Interstate Power and Light –

ML Kapp

23-01-014 Boiler #2. Six units total. 

Interstate Power and Light –

Prairie Creek

57-01-042 Boiler #4. Fourteen units total. 

MidAmerican Energy Company 

– Council Bluffs

78-01-026 Boiler #3 (EU003)

MidAmerican Energy Company 

– Neal North

97-04-010 Boiler #1-3 (EU001-EU003)
16

MidAmerican Energy Company 

– Neal South

97-04-011 Boiler #4 (EU003)

Muscatine Power and Water 70-01-011 Boiler #8

Pella Municipal Power Plant 63-02-005 Boilers #6-8

Chemical Process 

Plant

Equistar Chemicals 23-01-004 301 emission units

Koch Nitrogen Company 94-01-005 Ammonia vapor flares and 

primary reformer/auxiliary 

boiler. 8 units total.

Monsanto Company Muscatine 70-01-008 Boilers #5-7. 57 emission units 

total. 

Terra Nitrogen Port Neal Comp 97-01-030 Boiler B & auxiliary boiler

Petroleum Storage 

and Transfer Units 

with a Total Storage

BP – Bettendorf Terminal 82-02-024 Truck loading

BP – Des Moines Terminal 77-01-158 Truck loading

Portland Cement 

Plant

Holcim (US) Inc. 17-01-009 109 emission units

Fossil Fuel-fired 

Boiler

ADM 23-01-006 #7 & 8 boilers. These boilers 

will permanently shut down by 

9/13/08.

Iron and Steel Mills

Bloomfield Foundry, Inc 26-01-001 18 emission units

Griffin Pipe Products Co. 78-01-012 10 emission units

John Deere Foundry Waterloo 07-01-010 37 emission units

Keokuk Steel Casings, A 

Matrix Metals Company LLC

56-01-025 67 emission units

The Dexter Company 51-01-005 Tumblers 5 & 6

Secondary Metal 

Production

Alcoa, Inc. 82-01-002 Hot line mill. 87 emissions 

units total. 

ii. BART-subject sources

Of the twenty seven BART-eligible facilities, thirteen are fossil-fuel fired EGUs, 

and as such, are subject to CAIR for NOx and SO2. As noted in EPA’s separate 

notice proposing revisions to the regional haze rule (76 FR 82219, December 30, 

2011) a number of States, including Iowa, relied on CAIR to satisfy the BART 

requirements for SO2 and NOX, in accordance with 40 CFR 51.308(e)(4). Prior to 

the CAIR remand, the State’s reliance on CAIR to satisfy BART for NOX and 

SO2 for affected CAIR EGUs was approvable and in accordance with 40 CFR 

51.308(e)(4). As explained above, we are not proposing to take action in today’s 

rulemaking on issues associated with Iowa’s reliance on CAIR in its regional haze 

SIP, including BART for SO2 and NOx for EGUs. The PM BART evaluation for 

these EGU sources is described in section V.F.2 below. 

Iowa used three screening approaches to determine if the fourteen non-EGU 

sources identified in table 4 were subject to BART:
17

• Q/d (with "Q" being allowable emissions, in tons per year, and "d" 

representing the distance in km to the nearest Class I area, multiplied by a 

prescribed constant);

5

• a variety of assessments using CAMx photochemical model (a regional scale 

model); and 

• an emissions inventory analysis. 

The RHR established thresholds defining the terms “cause” and “contribute”. A 

source is said to “cause” visibility impairment if its impact is equal to or greater 

than 1.0 dv at any Class I area. A source is said to “contribute” to visibility 

impairment if its impacts are equal to or greater than 0.5 dv at any Class I area. 

Although the RHR affords States the opportunity to adopt a more stringent 

deminimis threshold, the State of Iowa chose not to do so. However, for its three 

step BART-subject screening analyses, the State did utilize a threshold that 

considered the number of days a source’s impact was equal to or greater than 0.5 

dv. The State chose seven days for this threshold. 6 The State’s “Variegated 

Protocol in Support of Best Available Retrofit Technology Determinations - May 

2006” explains that if the State were to find no maximum delta-deciview (ddv) 

values greater than 0.5 dv from any of the three screening methods, it would 

provide a state-wide exemption of the BART-eligible sources involved in the 

given scenario. Should initial cumulative modeling quantify ddv impacts 

exceeding 0.5 dv, the state would refine its analyses. For each BART-eligible 

source, information regarding Q/d analyses, CALPUFF model plant evaluation, 

and CAMx results were assembled and utilized in a weight-of evidence approach 

in the final subject-to-BART determination. If a unit was not clearly identifiable 

as either BART-subject or exempt from the BART determination process, the 

State provided case-by-case discussion.

1. Q/d screening

Table 5 lists each of the fourteen non-EGU BART-eligible sources 

analyzed for Q/d estimates, where “Q” is the sum of NOx, SO2 and PM10

emissions (PM2.5 direct emission estimates were not available at the time 

of the calculations were performed by the State) and “d” is the distance 

between the source and the nearest Class I area in km. The Q/d estimates 

were completed using both actual and potential emissions and were 

multiplied by three different constants (20 as prescribed by the State of 

North Carolina, 10 and 5). Iowa used a 1.0 threshold as its Q/d screening 

threshold. Note that potential emissions include only BART-eligible units 

 5 The method, originally developed by the North Carolina Department of Environment and Natural Resources, is a tool to eliminate distant, 

insignificant emission sources from ambient assessments submitted under the Prevention of Significant Deterioration (PSD) program. The Q/d 

method determines a source to be insignificant if the allowable emissions in tons per year (Q) divided by a constant times the distance in kilometers 

(d) is greater than a value of 1. For example, North Carolina uses a constant of 20, which was determined empirically. Therefore, a source could be 

considered insignificant if its emissions divided by 20 times its distance, in km, from the nearest Class I area is less than 1. For this application, for 

determining exemption from BART, the combined emissions of S02, NOx , and PM2.5 of a BART-eligible unit could be divided by 20 times the 

distance to the nearest Class I area. If that quotient is less than 1, the source would not be subject to BART. If a source is not found to be exempt 

under this approach, the CALPUFF screening analysis could still be used for an exemption determination. Page 25196 of 69 FR 25183. 6 This is discussed on pages 3 and 11 of the state’s “Variegated Protocol in Support of Best Available Retrofit Technology Determinations”.
18

while actual emissions represent facility wide totals, thus in certain cases 

actual emissions may exceed potentials.

Based on the six Q/d calculations the state categorized each of the fourteen 

non-EGU BART-eligible sources into three categories: 1) those sources 

that clearly exceed the 1.0 threshold, 2) sources well below the 1.0 

threshold and 3) those sources with mixed results. Table 5 shows that only 

ADM-Clinton and Holcim, Inc. exceed the 1.0 threshold in nearly each of 

the six Q/d calculations.

Table 5: Nearest Class I area & Q/d values for non-EGU BART-eligible sources

Facility Name

Nearest 

Class I

Distan

ce 

(km)

BART Units Potential Emissions (tpy) Facility Wide Actual Emissions (tpy)

SO2 NOx PM10 Q/20d Q/10d Q/5d SO2 NOx PM10 Q/20d Q/10d

Q/5

d

Equistar 

Chemical

MING

531.2 3,883 3,433 258 0.71 1.43 2.85 1 728 52 0.07 0.15 0.29

Koch Nitrogen 

Company

BOWA

615.4 40 1,399 23 0.12 0.24 0.48 0 442 20 0.04 0.08 0.15

MonsantoMuscatineMING

486.8 430 168 81 0.07 0.14 0.28 465 192 8 0.07 0.14 0.27

Terra NitrogenPort NealBADL

487.6 1 916 325 0.13 0.25 0.51 1 461 33 0.05 0.10 0.20

BP-Bettendorf MING 499.9 0 0 0 0.00 0.00 0.00 0 0 0 0.00 0.00 0.00

BP-Des Moines HEGL 547.0 0 0 0 0.00 0.00 0.00 0 0 0 0.00 0.00 0.00

Holcim, Inc. BOWA 527.0 28,715 4,738 1,000 3.27 6.54 13.07 3,826 2,813 190 0.65 1.30 2.59

ADM-Clinton MING 531.9 6,051 2,117 507 0.82 1.63 3.26 6,479 5,003 1,272 1.20 2.40 4.80

Bloomfield 

Foundry, Inc.

HEGL

448.8 136 68 605 0.09 0.18 0.36 1 0 22 0.00 0.01 0.01

Griffin Pipe 

Products 

HEGL

563.6 190 235 211 0.06 0.11 0.23 2 88 111 0.02 0.04 0.07

John Deere 

FoundryWaterloo

BOWA

588.8 0 0 285 0.02 0.05 0.10 9 21 99 0.01 0.02 0.04

Keokuk Steel 

Casing

MING

392.0 11 72 554 0.08 0.16 0.32 4 9 67 0.01 0.02 0.04

The Dexter 

Company

MING

468.9 0 0 541 0.06 0.12 0.23 29 3 112 0.02 0.03 0.06

Alcoa, Inc. MING 501.8 15 400 1,092 0.15 0.30 0.60 2 137 209 0.03 0.07 0.14

A majority of the non-EGU facilities were well below the 1.0 screening 

threshold in all six Q/d tests. Eleven facilities, listed in Table 6, yield Q/d 

values well below 1.0 at even the most stringent potential to emit Q/5d 

evaluation. The State subsequently determined that these sources were 

unlikely to be considered subject to BART. Iowa indicates, on page 13 of 

Appendix 9 to the SIP, that this conclusion is further supported through 

evaluation of the Q/d values using facility-wide actual emissions. The 

actual emission Q/5d values average 0.09, with the upper limit at 

Monsanto Company Muscatine of only 0.27. The State determined that 
19

these low values suggested any emission reductions would be insignificant

at the nearest Class I area to the source. 

Table 6: Non-EGU BART-eligible facilities 

significantly below all Q/d screening tests

Koch Nitrogen Company

Monsanto- Muscatine

Terra Nitrogen-Port Neal

BP-Bettendorf 

BP-Des Moines 

Bloomfield Foundry, Inc.

Griffin Pipe Products 

John Deere Foundry-Waterloo

Keokuk Steel Casing

The Dexter Company 

Alcoa, Inc.

Equistar Chemical is the only facility listed in Table 5 above where results 

are not clear cut. Considering potential emissions, the Q/20d value is 0.71 

with Q/10d and Q/5d exceeding 1.0. Actual emissions reveal that the most 

conservative value, Q/5d, remains well below 1.0 at 0.29. Equistar 

Chemical reported facility wide SO2 emissions in 2002 at one tpy, with 

NOx emissions of 728 tpy. As shown in Table 5, the nearest Class I area 

receptor is located at Mingo, at a distance of approximately 531 km. The 

transport distance in combination with low actual emissions produced the 

low Q/d value for Equistar Chemical. Under these circumstances, Equistar 

Chemical is unlikely to be subject to BART. However, the State 

considered results from additional analyses, described below, before 

making any BART exemptions based solely on Q/d calculations.

2. Model plant screening

The BART Guidelines indicate that when determining if a source is 

BART-subject, CALPUFF, or other appropriate models, can be used to 

determine if an individual source is anticipated to cause or contribute to 

impairment of visibility in Class I areas7

. The State explains in Appendix 

9 to the SIP, and in its Variegated Protocol, that because each BARTeligible unit located within the State was an average of 516 km (with a 

minimum of 392 km) away from the nearest Class I area, it experienced 

difficulties using the CALPUFF model to determine if a unit was BARTsubject. Because of the potential to over-predict single source impacts 

when the source is located long-range distances from the nearest Class I 

 7 CALPUFF is a multi-layer, multi-species non-steady-state puff dispersion model that simulates the effects of time- and 

space-varying meteorological conditions on pollution transport, transformation and removal. CALPUFF can be applied on 

scales of tens to hundreds of kilometers. It includes algorithms for subgrid scale effects (such as terrain impingement), as 

well as longer range effects (such as pollutant removal due to wet scavenging and dry deposition, chemical transformation, 

and visibility effects of particulate matter concentrations). http://www.epa.gov/ttn/scram/dispersion_prefrec.htm#calpuff
20

area, the State has flexibility to utilize other methods to determine singlesource impacts at Class I areas. The State did use CALPUFF as the 

modeling tool for its model plant approach described in more detail below.

In the BART Guidelines, EPA describes a modified approach, using 

model plants based on representative sources sharing certain 

characteristics that the States may use to simplify the BART determination 

process either to exempt (individually or as a group) those small sources 

that are not reasonably anticipated to cause or contribute to visibility 

impairment, or to identify those large sources that clearly should be 

subject to BART review. The BART guidelines indicate that States could 

use the CALPUFF model to estimate levels of visibility impairment 

associated with different combinations of emissions and distances to the 

nearest Class I area. In carrying out this approach, the State could then 

reflect groupings of specific types of sources with important common 

characteristics, such as emissions, stack heights and plume characteristics, 

and develop "composite model plants." Based on CALPUFF analyses of 

these model plants, a State may find that certain types of sources are 

clearly reasonably anticipated to cause or contribute to visibility 

impairment. Conversely, representative plant analyses may show that 

certain types of sources are not reasonably anticipated to cause or 

contribute to visibility impairment. Based on the modeling results, a State 

could exempt from BART all sources that emit less than a certain amount 

per year and that are located a certain distance from the nearest Class I 

area. 

For the model plant analysis, the State utilized combined (SO2 and NOx) 

emission rates of 5,000 tpy and 3,000 tpy per source. A detailed 

description of the State’s model plant approach and any deviations from 

the EPA recommended approach is provided in Section 5.2 of Appendix 9 

to the SIP. 

It should be noted that the State utilized visibility assessment Method 68

, 

and therefore had to utilize Class I area specific natural background 

conditions. The State chose to use the following Class I areas based on 

their distance from Iowa sources: BADL, BOWA, VOYA, MING, HEGL, 

ISLE and SENE. Natural background concentrations were extracted from 

the EPA’s Guidance for Estimating Natural Visibility Conditions under 

the Regional Haze Program.

9

During the State’s analyses, each model plant simulation required fourteen 

iterations: two natural background scenarios across seven Class I areas. 

 8 Monthly f(RH) (increase in the aerosol scattering coefficient with relative humidity) adjustment factors were applied 

directly to the background and modeled sulfate and nitrate concentrations, as recommended in the BART guidelines.

9 http://www.epa.gov/ttn/oarpg/t1/memoranda/rh_envcurhr_gd.pdf
21

Results for each Class I area assessment were tabulated and ranked 

individually. Both maximum and 98th percentile values were considered 

when determining the levels at which emissions may cause (dv impacts 

greater than or equal to 1.0) or contribute (dv impacts greater than or equal 

to 0.5) to visibility impairment.

The analyses were completed considering the 2002-2004 base years. For 

each year, the model was run using both the emission scenario where the 

model plant emits 2,500 tpy of SO2, 2,500 tpy of NOx (or 5,000 tpy 

combined), and 50 tpy of PM2.5 and the emissions scenario where the 

model plant emits 1,500 tpy of SO2 and NOx each (or 3,000 tpy 

combined), and 50 tpy of PM2.5. For each scenario, impacts were 

compared against annually averaged natural background conditions and 

against the 20 percent best natural background conditions. The State 

counted the number of days in which dv impacts greater than or equal to 

0.5 dv were produced. When evaluating the 98th percentile, the State 

utilized a maximum of seven days of dv impacts exceeding 0.5 dv as a 

threshold. The State also looked at the maximum dv impacts at each of the 

seven Class I areas.

The results of the analysis (given on page 28 and 29 of Appendix 9 to the 

SIP) showed that the model plant, with 5,000 tpy of NOx and SO2

combined (and 50 tpy of PM2.5) did not yield any dv impacts greater than 

0.5 dv at the 98th percentile as compared against annually averaged 

natural background conditions. In the years 2002 and 2003, a maximum of 

5 days exceed the 0.5 dv impact threshold, occurring at the BADL, likely 

due to utilization of the cleaner western natural background conditions10. 

During 2004, six days exceed the 0.5 dv impact threshold. The remaining 

six Class I area evaluations yield counts less than or equal to five days 

with impacts greater than 0.5 dv. Considering individual daily maximum 

impacts, 2002 values remain near the 0.5 dv level; slightly higher 

maximum impacts occur in 2003. In 2004 maximum impacts were 

consistently above 1.0 dv. When compared against the 20 percent best 

natural background conditions, each year, for each site, had more than 

seven days with maximum impacts exceeding 0.5 dv. As expected, 

maximum individual daily impacts show a corresponding increase versus 

annually averaged natural background conditions. 

The results of the model plant analysis with 3,000 tpy of NOx and SO2

combined (and 50 tpy of PM2.5) showed that the 98th percentile is never 

exceeded, regardless of the natural background scenario. Additionally, at 

3,000 tpy NOx and SO2 maximum impacts for the years 2002 and 2003, as 

compared against annually averaged natural background conditions, do 

 10 Annual average natural background concentrations are not strictly Class I area specific. Alternatively, sites are assigned 

one of two datasets: Eastern or Western. Of the seven Class I areas examined within the Iowa domain, all are considered 

Eastern sites with the exception of the Badlands. Page 23 of Appendix 9 to the SIP.
22

not exceed 0.5 dv. The year 2004 does produce impacts above 0.5 dv. Two 

days above 0.5 dv are modeled for the BADL, and one day above 0.5 dv 

are shown for the remaining Class I areas. Consulting the 20% best natural 

background conditions, maximum daily impacts remain below 0.5 dv for 

all but SENE in 2002. In 2003, impacts greater than 0.5 dv are found for 

each site, but occur on no more than two days. Again, 2004 stands out as 

producing the highest impacts, but the impacts do not exceed the 98th 

percentile.

Based upon the above results, the State concluded that any BART-eligible 

source that emitted less than 3,000 tpy of combined NOx, SO2 and PM2.5

would likely be exempt from being BART-subject. At the 3,000 tpy level, 

evaluation against the stringent 20% best natural background conditions 

yields no more than five days with dv impacts exceeding 0.5 dv. Utilizing 

the emissions data (provided in Table 5 above), the State determined that 

eleven of the fourteen non-EGU BART-eligible sources would remain 

well below the 3,000 tpy combined potential to emit. These happen to be 

the same facilities already identified in Table 6 as being below the Q/d 

screening thresholds. 

3. CAMx screening

As a final tool in the BART-subject screening process, the State utilized 

the CAMx regional modeling system to model cumulative impacts across 

all BART-eligible sources at Class I areas. As set forth in the BART 

guidelines, a State may consider exempting all its BART-eligible sources

by conducting analyses that show that all of the emissions from BARTeligible sources in the State, taken together, are not reasonably anticipated 

to cause or contribute visibility impairment. To make such a showing, a 

State could use CALPUFF or another appropriate dispersion model to 

evaluate the impacts of individual sources on downwind Class I areas, 

aggregating those impacts to determine the collective contribution from all

BART-eligible sources in the State. A State with a sufficiently large 

number of BART-eligible sources could also make such a showing using a 

photochemical grid model.

11 The EPA determined that the option of 

allowing a State to demonstrate that the full group of BART-eligible 

sources in the State does not contribute to visibility impairment would, by 

default, satisfy an individual source contribution assessment. As 

previously discussed the State had concerns with the use of CALPUFF so 

it elected to use the photochemical model CAMx to model cumulative 

impacts of all BART-eligible sources across Class I areas. 

 11 For regional haze applications, regional scale modeling typically involves use of a photochemical grid model that is 

capable of simulating aerosol chemistry, transport, and deposition of airborne pollutants, including particulate matter and 

ozone. Regional scale air quality models are generally applied for geographic scales ranging from a multistate to the 

continental scale. Because of the design and intended applications of grid models, they may not be appropriate for BART 

assessments, so States should consult with the appropriate EPA Regional Office prior to carrying out any such modeling.
23

For its CAMx analysis the State used 2002 as the base year due to the 

availability of model-ready emission inventories and the associated 

baseline established by one-atmosphere modeling efforts under the RHR. 

A 36 km domain (from LADCO) provided the fundamental horizontal 

structure. The impacts of a finer resolution 12 km grid were also assessed. 

The meteorological data driving the CAMx system was derived from the 

State’s 2002 MM5v363 36/12 km simulation (discussed in greater detail in 

Appendix 9 of the SIP). The LADCO 2002 Base J and Base K emissions 

inventories12 were used to populate the model. Similar to the Q/d analysis, 

the State utilized a 0.5 dv impact as screening a threshold of the CAMx 

modeling results.

For all cumulative CAMx modeling scenarios, the scenario design 

involved zeroing the actual point source emissions of BART-eligible 

sources on a facility-wide basis. In zeroing BART-eligible facility 

emissions, emphasis was placed upon the elevated point source emissions. 

Point source emissions are divided between two file types in the LADCO 

CAMx modeling system: elevated point and low point. Elevated point 

sources were identified in the emissions modeling stage through 

implementation of an idealized plume rise calculation. Using each stack’s 

specific characteristics, a representative plume rise calculation was 

performed. Stacks yielding a plume rise exceeding a user supplied 

threshold were assigned to the elevated stack file; all other units were 

placed in the low point file and treated as an area source. Low point source 

file modification required complex emissions modeling (while actual low 

point emission rates are expected to be negligible). Focusing upon the 

elevated point sources allowed a scenario to be constructed using a simple 

post processor. Therefore, the State utilized modeling scenarios that were 

capable of zeroing elevated stack emissions. The effectiveness of this 

method is briefly discussed in section 6.4.1 of Appendix 9 to the SIP. 

Again, resolutions included 36 and 12 kilometers. The BART-eligible 

source list included distinctions for CAIR versus non-CAIR units (in lieu 

of CAIR as BART).

Table 7: Description of the IDNR BaseK cumulative modeling scenarios

Scenario Resolution 

(km)

BART Source Emissions Processing Description

K2002ia36b0v2r1 36 All BART source emissions were zeroed out (both EGU and non-EGU 

facilities). Only elevated point source emissions were zeroed (low point 

emissions were not modified). Emissions were removed facility-wide 

(not just BART units). The LADCO LAMB (low, area, mobile, 

biogenic) emissions files were not modified. 

K2002ia36b0v2r2 36 Similar to K2002ia36b0v2r1, except only non-EGU BART emissions 

were zeroed. (Again, only elevated point source units were impacted, 

 12 http://www.ladco.org/reports/rpo/emissions/
24

with emissions zeroed facility-wide.) As above, the LADCO LAMB files 

were used. 

K2002ia36b0v2r2 12 The same emissions scenario as K2002ia36b0v2r2 was implemented 

within a 12 km grid through flexi-nesting of the emissions data. 12 km 

meteorological data was processed independent of the 36 km grid (i.e. 

the meteorological data was not flexi-nested). 

As outlined in Table 7, scenario k2002ia36b0v2R1 eliminated all elevated 

point source emissions from both EGU and non-EGU BART-eligible 

sources. Maximum values are provided in Table 8 below. Impacts ranged 

between 2.23 ddv at the BADL and 3.17 ddv at SENE under annually 

averaged natural background conditions. The number of days registering 

an impact greater than or equal to 0.5 ddv ranged between 22 at the BADL 

and 47 at the SENE. As expected, the impacts increased when compared 

against the 20% best natural background conditions, ranging from 2.79 

ddv at the BADL to 4.41 ddv at the SENE with the number of days 

registering an impact greater than or equal to 0.5 ddv between 28 at the 

BADL and 73 at MING. Based on these results, the State concluded that 

in the absence of CAIR, Iowa BART-eligible sources would not be 

eligible for cumulative exclusion from being subject to BART.

Table 8: Scenario k2002ia36b0v2r1: Class I area maximum impacts

Site

Annual Average Natural 

Background

20% Best Natural 

Background

Maximum 

DDV

Number of Days 

DDVs ≥0.5

Maximum 

DDV

Number of Days 

DDVs ≥0.5

BADL 2.23 22 2.79 28

BOWA 2.97 41 4.16 53

HEGL 2.65 36 3.72 71

ISLE 2.70 41 3.72 56

MING 2.34 40 3.32 73

SENE 3.17 47 4.41 63

VOYA 2.40 33 3.41 49

Tabular results from scenario k2002ia36b0v2r2, the scenario with only 

non-EGU emissions modified, are shown in Table 9. In contrast to 

scenario k200ia36b0v2r1, where impacts greater than 0.5 ddv are common 

and frequent, only three of the seven sites registered impacts above 0.5 

ddv: BOWA, ISLE, and SENE (when considering annual average natural 

background). In terms of frequency, BOWA and SENE each registered 

one day with an impact greater than 0.5 ddv. ISLE registered two days 

with a ddv greater than or equal to 0.5. The maximum impacts predicted 

under annually averaged natural background conditions ranged from 0.15 

ddv at the BADL to 0.64 ddv at the ISLE. 
25

The evaluation conducted against the 20% best natural background 

conditions showed that six of the seven Class I areas registered impacts 

greater than 0.5 ddv. The BADL was the only Class I area under the 0.5 

ddv threshold. ISLE again exhibited the highest impact, at 0.92 ddv, with 

the other five Class I areas at or above 0.53 ddv. The BADL is the only 

area which did not register an increase in the frequency of ddv impacts 

greater than 0.5 dv when evaluated against the 20% best natural 

background conditions, while ISLE exhibited the most variability, with a 

four day increase. All other areas demonstrate only moderate variability, 

with one or two additional daily impacts greater than 0.5 ddv.

Table 9: Scenario k2002ia36b0v2r2: Class I area maximum impacts

Site

Annual Average Natural 

Background

20% Best Natural 

Background

Maximum 

DDV

Number of Days 

DDVs ≥0.5

Maximum 

DDV

Number of Days 

DDVs ≥0.5

BADL 0.15 0 0.20 0

BOWA 0.62 1 0.91 3

HEGL 0.38 0 0.57 1

ISLE 0.64 2 0.92 6

MING 0.41 0 0.60 1

SENE 0.58 1 0.85 3

VOYA 0.36 0 0.53 2

Table 9 provides the cumulative visibility impacts upon nearby Class I 

areas from all non-EGU BART-eligible sources. If one considers natural 

background conditions and maximum impacts, a 0.64 ddv is produced 

(ISLE). However, a maximum of only two days are of concern. If one 

considers the 20% best natural background conditions, the maximum 

impact increases to 0.92 ddv (ISLE), with the frequency of impacts 

increasing to six days. 

In a third run of the model, modeling run k2002ia12b0v2r2, the State 

utilized a 12 km grid in place of the 36 km grid. Differences between the 

12 and 36 km results (provided in Table 10 with parentheses; positive 

values indicate the 12 km grid generated greater visibility impacts) 

exhibited no pattern. Both increases and decreases in visibility impacts are 

found among the sites. Assessment of the annually averaged natural 

background conditions shows the largest change in visibility impacts 

occurs at VOYA, with impacts increasing 0.17 ddv, from 0.36 to 0.53 ddv. 

Alternatively, the impacts at SENE are reduced 0.15 dv, from 0.58 to 0.43 

dv. The number of days with impacts at or above 0.5 dv fluctuates by no 

more than one day. As expected, a similar result is produced under the 

20% best natural background conditions. Considering 20% best natural 

conditions, the 12 km grid increased the visibility impacts at VOYA by 

0.25 dv, while impacts at SENE were reduced by 0.21 dv. The number of 
26

days in which the 12 km results pushed the impacts above the 0.5 ddv 

threshold (versus 36 km data) changed by no more than two days. Given 

the increased sensitivity of the 20% best natural background conditions to 

changes in concentrations, the variability is expected.

Table 10: Scenario k2002ia12b0v2r2: Class I area maximum impacts

Values in parentheses indicate the differences as compared to the 36 km results. 

Calculated as (k2002ia12b0v2r2 - k2002ia36b0v2r2)

Site

Annual Average Natural 

Background

20% Best Natural Background

Maximum

DDV

Number of Days 

DDVs ≥0.5

Maximum 

DDV

Number of Days 

DDVs ≥0.5

BADL 0.24 (0.09) 0 (0) 0.30 (0.10) 0 (0)

BOWA 0.63 (0.01) 1 (0) 0.93 (0.02) 2 (-1)

HEGL 0.52 (0.14) 1 (1) 0.76 (0.19) 3 (2)

ISLE 0.62 (-0.02) 2 (0) 0.90 (-0.02) 5 (-1)

MING 0.34 (-0.07) 0 (0) 0.50 (-0.10) 1 (0)

SENE 0.43 (-0.15) 0 (-1) 0.64 (-0.21) 2 (-1)

VOYA 0.53 (0.17) 1 (1) 0.78 (0.25) 2 (0)

In general, the variability encountered through comparison of the 12 km 

grid was well within expectations. While ddv changes up to 0.25 dv were 

shown (VOYA), such a change required only a modest modification in 

species concentrations. The number of days in which ddv impacts greater 

than or equal to 0.5 dv occurred showed only minor fluctuations (at most 

two days at HEGL). The results suggested the 12 km simulations lead to 

more active chemistry, as expected, but major anomalies between the 12 

and 36 km results are not created. In summary, considering a 12 km grid, 

emissions from non-EGU BART-eligible sources and natural background 

conditions, the maximum impact modeled is 0.63 ddv (BOWA) with a 

maximum of only two days above the 0.5 ddv threshold (ISLE). Under the 

20% best natural background conditions, the maximum impact increases 

to 0.93 ddv (BOWA), and the maximum frequency of impacts greater than 

0.5dv is five days (ISLE). Because there were impacts greater than the 0.5

dv threshold, the State could not provide a blanket exemption for all nonEGU BART-eligible sources considering just the results of the CAMx 

modeling. The State did not consider these analyses to be definitive so it 

considered actual emissions of visibility impairing pollutants from the 

sources evaluated in the modeling. Because eleven of the non-EGU 

BART-eligible sources (the same eleven as previously identified in Table 

6) comprise approximately 11% (2,547 tpy of SO2, NOx and PM) of the 

total of actual emissions (22,911 tpy of SO2, NOx and PM) from all 

fourteen non-EGU BART-eligible sources, the State determined that these 

eleven sources were unlikely to play a significant role in the cumulative 

modeled visibility impacts.
27

Although Iowa did not strictly follow the Guidelines for exempting a 

source, specifically with respect to modeling a BART-eligible source 

using maximum actual emissions, we believe that Iowa’s alternative

analysis should result in an acceptable conclusion to exempt these eleven

sources for the following reasons. First, Iowa’s analysis used both actual 

emissions on a facility-wide basis and potential emissions for the BART 

eligible units. When looking at the actual emissions facility-wide, for 

many of the sources, it was clear that had the maximum actual emissions 

been modeled using CALPUFF, the results would indicate minimal 

visibility impacts. This was apparent when comparing the modeled plant 

analysis emission inputs with the actual emissions. In almost all cases the 

sum of the actual emissions of visibility impairing emissions were 

significantly less than those used in the model plant analysis. The same is 

also true when looking at the potential emissions for many of these 

sources. Given that most of these non-EGU units do not have continuous 

emission monitoring systems (CEMS) that can be used for an accurate 

calculation of actual maximum 24-hour emission rate, using both the 

actual annual emissions facility-wide and potential emissions for the 

BART-eligible units gives us confidence that these sources can be 

excluded as BART sources. Second, the Q/d analysis Iowa used provided 

a good indication of those sources where additional analysis might be 

warranted. Although we have not specifically relied on the Q/d analysis 

for our approval of BART exemptions, we do believe it was informative 

and the use of Q/5d is fairly conservative for this type of an analysis. We 

believe that the State reasonably demonstrated that the eleven non-EGU 

BART-eligible sources (listed in table 6) are not BART-subject. 

4. Holcim, ADM-Clinton, and Equistar

Because the State’s multi-step analyses demonstrated that eleven of the 

fourteen non-EGU BART-eligible sources (listed in Table 6) were not 

BART-subject, the remaining discussion of this section will focus on the 

three remaining non-EGU BART-eligible units that could not be easily 

exempted based on the thresholds established by the State: Holcim, 

ADM-Clinton, and Equistar.

Equistar Chemical’s potential and actual emissions are dominated by 

VOCs, not SO2, NOx or PM. While potential emissions of SO2 and NOx

exceed the 5,000 tpy model plant threshold, the actual emissions are far 

below the 3,000 tpy threshold – 729 tons per year of NOx and SO2

combined. As such, the State determined that Equistar Chemical would 

not contribute impacts exceeding 0.5 dv, and was therefore not BARTsubject. EPA agrees with this determination.

Both Holcim and ADM-Clinton fail the Q/d and CALPUFF model plant 

analyses. Almost all Q/d metrics exceed the 1.0 significance level, while 

SO2 and NOx emissions (potentials and actual emissions) exceed both the 
28

3,000 and 5,000 tpy scenarios examined with the CALPUFF model plant 

application. The State decided to look at both ADM-Clinton and Holcim 

on a case-by-case basis. 

As mentioned above, the State found the uncertainties of using the 

CALPUFF modeling system for determining single source visibility 

impacts from sources far removed from Class I areas very challenging. 

The State decided to use an alternative process, scaling the cumulative 

modeling impacts according to emission rates. The State utilized the 

maximum dv impacts from the most relevant CAMx modeling scenario 

(k2002ia12b0v2r2), at the most stringent 20% best natural background 

conditions, a value of 0.93 dv to scale actual SO2, NOx and PM emissions 

for both sources. The State zeroed out the actual SO2, NOx and PM 

emissions in the following scenario. If Holcim’s SO2, NOx and PM 

emissions account for 6,828 tpy of the 22,911 tpy total non-EGU BARTeligible sources’ SO2, NOx and PM emissions, Holcim’s would account 

for 30% of the emissions. If ADM-Clinton’s SO2, NOx and PM emissions 

account for 12,755 tpy of the 22,911 tpy total non-EGU BART-eligible 

sources’ SO2, NOx and PM emissions, ADM-Clinton would account for 

56% of the emissions. The State then scaled the visibility impact 

attributable to Holcim and ADM-Clinton. If the maximum visibility 

impact from all non-EGU BART-eligible sources was figured to be 0.93 

dv, and Holcim was found to contribute approximately 30% to that 

impairment, it could be estimated that Holcim would contribute 

approximately 0.28 dv visibility impairment (below the 0.5 dv threshold). 

Using the same method, ADM-Clinton was found to contribute 

approximately 56% to the maximum visibility impairment, or 

approximately 0.52 dv, above the 0.5 dv threshold. The State found that 

this additional information supported a determination that Holcim did not 

cause or contribute to visibility impairment at any Class I area, and was 

not BART-subject, however, the same determination for ADM-Clinton 

could not be made according to this analysis. 

EPA believes the State's approach to the photochemical modeling analysis 

does not fully account for the non-linear aspects of photochemical 

modeling and does not fully acknowledge that modeled impacts will not 

necessarily be directly proportional to the modeled emissions. However, 

EPA believes it is unlikely that Holcim will have visibility impacts on a 

Class I area greater than 0.5 dv for the following reasons. First, all 

modeled sources, including Holcim, are located a significant distance from 

any Class I area, with Holcim being 527 km from the nearest Class I area.

Second, the modeling inputs showed that emissions from Holcim 

constituted only 30 percent of total emissions from the modeled sources. 

Third, the maximum modeled impacts from this group of sources at any 

Class I area using average natural background conditions is 0.64 dv with 

at most 2 days of impacts over 0.5 dv. Fourth, looking at all the maximum 
29

modeled impacts at all seven Class I areas shows an average maximum 

impact of 0.44 dv, indicating that no single source is likely the cause for 

the majority of impacts at any single Class I area. Finally, ADM-Clinton 

represents 56 percent of the visibility impairing emissions of the modeled 

sources and this source's BART eligible units have been permanently shut 

down, thus EPA anticipates impacts from the remaining group of sources 

would have less than a 0.5 dv impact. Based on these factors, EPA 

believes that State adequately demonstrated that Holcim does not cause or 

contribute to visibility impairment in any Class I areas, and therefore is 

not subject to BART.

As discussed previously, ADM-Clinton could not be screened out with 

any of the three analyses described above. However, at the time the State 

drafted the SIP, ADM-Clinton was going through a PSD permitting 

activity to construct new boilers. In the permit for the new boilers (Permit 

05-A-314), ADM-Clinton was required to shut down boilers 1-14 no later 

than 180 days after the startup of the new boilers.13 This includes the two 

BART-eligible boilers, numbers 7 and 8. We have confirmed with the 

State that these boilers have indeed shut down. In the PSD permit for the 

new boilers that replaced boilers 7 and 8, the facility was required to 

install and operate a baghouse, selective non-catalytic reduction, and 

limestone injection flue gas desulfurization on the new boiler units (three 

coal burning and two natural gas; five in total). The construction permit 

limited the emissions of the replacement boiler units through an annual 

cap applicable across all five new units. SO2 emissions are not to exceed 

3,629 tpy and NOx emissions are not to exceed 1,445 tpy. These limits 

represent best available control technology (BACT) emission rates as 

required under the PSD program.14 Because the BART-eligible boilers 

were permanently shut down pursuant to an enforceable PSD permit, and 

the replacement boilers satisfy BACT, the State concluded that ADMClinton was not subject to BART. EPA agrees with this determination.

5. EGU BART evaluation for PM

Although Iowa presumed that CAIR satisfied SO2 and NOx BART for 

EGUs, Iowa was still required to evaluate each BART-subject EGU for 

PM BART. There is no PM presumptive emission rate for EGUs with a 

capacity of 750 MW or greater. The State again relied on its CALPUFF 

model plant analysis for analyzing EGU PM emissions. Model year 2004 

was selected in order to generate maximum impacts (the State’s analysis 

showed that 2004 data generated impacts that exceeded 2002 and 2003 

data). Two scenarios were completed, using emission rates of 10,000 and 

5,000 tpy of PM. No NOx or SO2 emissions were modeled. The model 

plant configuration was modified to reflect idealized EGU stack 

 13 https://aqbweb.iowadnr.gov/data/23/2301006/05A314P.pdf 14 The applicable State permit numbers are 05-A-313-P, 05-A-314- P, 05-A-315-P for the coal-fired boilers, and 05-A-316-P, 

05-A-317-P for the natural gas fired boilers.
30

parameters, obtained from the EPA’s CALPUFF Analysis in Support of 

the June 2005 changes to the RHR. Graphical results are given on page 46 

of Appendix 9 to the SIP. 

No impacts above 0.5 dv were observed at any Class I area under annually 

averaged natural background conditions with PM emissions of 10,000 tpy. 

Under the 20% best natural background conditions no impacts exceeding 

the 98th percentile occur. Reducing the emissions to 5,000 tpy, no impacts 

above 0.5 dv were produced under annually averaged background 

conditions or 20% best natural background conditions. In terms of scale, 

Iowa’s largest PM10 source (an EGU that is not BART-eligible) emits 

3,174 tpy (based on a facility-wide value), approximately 36.5% below the 

emission rate which yielded no visibility impacts. Based upon these results 

the State concluded, and the EPA agrees, that PM emissions from BARTeligible EGUs in the State of Iowa would not cause or contribute to 

visibility impairment at any nearby Class I areas, and are therefore not 

subject to BART for PM.

e. Monitoring strategy: 40 CFR 51.308 (d)(4)

Because it does not host a Class I area, Iowa is not required to develop a monitoring 

strategy for measuring, characterizing, and reporting regional haze impairment that is 

representative of Class I areas within the State. However, Iowa is required to establish 

procedures by which monitoring data and other information is used to determine the 

contribution of emissions from within the State to regional haze impairment at Class I 

areas outside of the State. 

There are two IMPROVE monitoring protocol sites (sites that are not managed directly 

by IMPROVE (a federal program), but by the operating agency) which are operated in 

the State. One is located at Lake Viking State Park in southwestern Iowa, and the second 

is located at Lake Sugema Wildlife Management Area in southeastern Iowa. The 

monitors began operation in June 2002. Descriptions of these monitoring sites and 

methods for data validation can be found in Chapter 6 of the State’s Regional Haze SIP.

The State has provided a commitment in Chapter 6 of the SIP to maintain the IMPROVE 

protocol monitoring sites contingent upon continued national funding.

Data from IMPROVE protocol monitors is analyzed by a national laboratory (funded via 

an interagency agreement between the EPA and the National Park Service) and uploaded 

by the laboratory into two publicly available databases at 

http://vista.cira.colostate.edu/improve and http://vista.cira.colostate.edu/views/ . Any 

supplemental monitoring data from additional monitoring equipment at each site is 

publicly available at http://www.epa.gov/ttn/airs/airsaqs.

EPA believes the State’s commitment to utilize data from these sites, or any other EPAapproved monitoring network location, to characterize and model conditions within the 

state and to compare visibility conditions in the state to visibility impairment at Class I 
31

areas hosted by other states, and proposes that Iowa has satisfied the requirements of 40 

CFR 51.308(d)(4). 

f. Emissions inventory: 40 CFR 51.308 (d)(4)(v)

Iowa provided an inventory of emissions of pollutants that are reasonably anticipated to 

cause or contribute to visibility impairment in any Class I area: VOCs, NOx, SO2, PM2.5, 

PM10 and NH3. As required, the inventory includes emissions for a baseline year (2002), 

the most recent year for which data are available, and estimates of future year (2018) 

projected emissions along with a commitment to update the inventory periodically.

The 2002 point source inventory was derived from the 2002 National Emission Inventory 

(NEI). 15 All other source category emission inventories were developed by CENRAP 

and its contractors as part of the development of a baseline inventory for the 2002 

modeling inventory.

16 A summary of the 2002 baseline emissions inventory can be found 

in Chapter 7 of the SIP. Methodologies for the development of the 2002 emissions 

inventories can be found in appendix 7.1 of the SIP.

To estimate the 2018 future year emissions, the State grew the 2002 emissions using the 

Economic Growth Analysis System (EGAS) 5, MOBILE 6 and NONROAD vehicle 

emissions software. The State also used the IPM to forecast EGU emissions.

As shown in Table 12, the State made a modification to the estimated 2018 SO2

emissions for the point source EGU source category. In tables 7 and 8, the 2002 and 

2018 point source EGU SO2 emissions are 135,833 and 160,733 tons per year (tpy), 

respectively. The State was concerned with the accuracy of the 2018 (160,733 tpy) 

value. CENRAP utilized the “RPO version 2.1.9” IPM (referred to as IPM v2.1.9) 

predictions to generate the 2018 BaseG scenario, in which total Iowa EGU SO2 emissions 

were forecast to be approximately 147,305 tpy. 17 During review of the CENRAP 

BaseE2 modeling, errors were identified in the 2018 Iowa EGU emissions. Among the 

errors, certain EGU emissions were overestimated when a growth methodology was 

applied twice, once with EGAS and then again within IPM. Following error 

identification, corrections were submitted for inclusion in the BaseF (and subsequent 

BaseG) modeling scenarios. After the corrections, 2018 EGU SO2 emissions totaled 

151,354 tpy. Thus, the State believed the value of 160,733 tpy provided through the 

emissions inventory report developed by a CENRAP contractor to be inaccurate.18 The

State found that the corrected EGU SO2 emissions estimate of 151,354 tpy for 2018 is 

conservative, given updated results from IPM version 3.0 (discussed in Chapter 11 of the 

SIP) and Iowa’s participation in CAIR.

 15 http://www.epa.gov/ttn/chief/net/2002inventory.html 16 http://www.cenrap.org/html/projects.php 17 The CENRAP modeling emissions inventory consists of several distinct datasets: the 2002 basecase for model 

performance evaluation, 2002 typical, 2018 basecase, and the 2018 control strategy scenario. The inventory was refined 

through several rounds of CENRAP workgroup review and revision, beginning with the initial BaseA version and 

culminating in the BaseG inventory.

18 The “Consolidation of Emissions Inventories”- Pechan Report No. 05.03.002/9500.003
32

The EPA believes the 2002 and 2018 statewide emissions inventories and the State’s 

method for developing the 2018 emissions inventory for Iowa meets the requirements of 

40 CFR 51.308(d)(4)(v) of the Regional Haze Rule.

Table 11: 2002 Iowa emissions summary (tons per year)

VOC NOx PM 2.5 PM 10 NH3 SO2

Ammonia 0 0 0 0 258,915 0

Area 106,712 6,782 11,540 12,182 6.560 3,184

Area Fire 1,120 138 4,681 4,893 0 160

Fugitive Dust 0 0 38,666 193,331 0 0

Off road 63,694 92,595 8,904 9,707 79 9,037

On road 87,392 120,621 1,747 2,373 3,064 3,200

Point EGU 1,075 81,761 4,527 9,424 0 135,833

Point Fire 545 33 594 700 48 35

Point NonEGU 41,184 35,812 7,651 17495 3,317 51,836

Road dust 0 0 19,525 127,882 0 0

Wildfire 5 29 218 224 0 8

Biogenic 408,291 25,732

TOTAL 710,018 363,503 98,053 378,211 271,983 203,293

Table 12: 2018 Iowa projected emissions summary (tons per year)

VOC NOx PM 2.5 PM 10 NH3 SO2

Ammonia 0 0 0 0 302,012 0

Area 127,849 7,476 10,677 11,510 13,304 3,224

Area Fire 1,120 138 4,681 4,893 0 160

Fugitive Dust 0 0 40,608 203,044 0 0

Off road 37,143 60,210 5,582 6,088 101 220

On road 36,404 33,975 708 708 4,225 400

Point EGU 1,802 65,629 9,578 11,232 713 151,354

Point Fire 547 33 596 702 49 36

Point NonEGU 56,714 40,964 10,151 21,737 5,763 42,862

Road dust 0 0 17,712 114,889 0 0

Wildfire 5 29 218 224 0 8

Biogenic 408,291 25,732

TOTAL 669,875 234,186 100,511 375,027 326,167 198,264

g. Periodic SIP revisions and five year progress report: 40 CFR 51.308 (f)-(h)

Iowa acknowledged the requirement under 40 CFR 51.308 (f) to submit periodic progress 

reports and regional haze SIP revisions, with the first report due by July 31, 2018, and 

revisions due every ten years thereafter. Iowa committed to meeting this requirement.

Iowa also acknowledged the requirement under 40 CFR 51.308 (g) to submit a progress 

report in the form of a SIP revision every five years following this initial SIP submittal. 

Iowa committed to submitting the required five year SIP revision by December 17, 2012.
33

However, EPA has since advised that five year SIPs are not due until five years after this 

initial SIP is submitted, meaning that Iowa’s five year progress SIP is not due until March 

2013. 

The report will evaluate the progress made towards the RPGs for each mandatory Class I 

area which may be affected by emissions from Iowa sources. Iowa committed to 

addressing all the requirements of 40 CFR 51.308 (g), including a review of the changes 

in the emission inventory, a review of the periodic reporting requirements, and a 

determination of whether additional action is needed according to 40 CFR51.308(h). 

Depending on the findings of the five-year progress report, Iowa commits to taking one 

of the following actions:

• Iowa determines that the existing SIP requires no further substantive revision in

order to achieve established goals. Iowa provides the Administrator a negative 

declaration that further revision of the SIP is not needed at this time.

• Iowa determines that the existing SIP may be inadequate to ensure reasonable

progress due to emissions from other states which participated in the regional

planning process. Iowa provides notification to the Administrator and the states

that participated in regional planning. Iowa collaborates with states through the

regional planning process to address the SIP’s deficiencies.

• Iowa determines that the current SIP may be inadequate to ensure reasonable

progress due to emissions from another country. Iowa provides notification, along 

with available information, to the Administrator.

• Iowa determines that the existing SIP is inadequate to ensure reasonable progress 

due to emissions within the State of Iowa. Iowa will revise its SIP to address the 

plan’s deficiencies.

h. Consultation with Federal Land Managers: 40 CFR 51.308(i)

40 CFR 51.308 (i) requires that States identify in writing to the FLMs the title of the 

official to which any FLM can submit recommendations. Iowa has met this requirement 

by identifying Catharine Fitzsimmons, Air Quality Bureau Chief as the cognizant official 

at IDNR concerning regional haze. 

States are also required to provide the FLMs an opportunity for consultation, in person 

and at least 60 days prior to holding any public hearing on the SIP (or its revision).

Consultations should include the opportunity for the FLMs to discuss their assessment of 

impairment of visibility in any Class I area; and recommendations on the development of 

the RPG and on the development and implementation of strategies to address visibility 

impairment. 

Iowa met this consultation requirement by sending the draft SIP to the FLMs on 

November 26, 2007, and notifying the FLMs of the public hearing on January 30, 2008. 

40 CFR 51.308(i)(3) requires that States provide a description of how they addressed any

comments provided by the FLMs. Iowa has provided this in appendix 2.1 of the SIP. EPA 

believes that Iowa adequately responded to the comments received from the FLMs. 
34

Finally, regional haze SIPs must provide procedures for continuing consultation between 

the State and FLMs on the implementation of 40 CFR 51.308, including development and 

review of SIP revisions and 5-year progress reports, and on the implementation of other 

programs having the potential to contribute to impairment of visibility in Class I areas. 

Iowa has committed to continuing to coordinate and consult with the FLMs during the 

development of future progress reports and plan revisions, as well as during the 

implementation of programs having the potential to contribute to visibility impairment in 

the mandatory Class I Federal areas. 

Iowa currently notifies the appropriate FLM in writing of proposed major source or major 

modifications that may affect a Class I area and requires applicants to submit ambient

impact assessments for Class I areas consistent with the Prevention of Significant 

Deterioration (PSD) regulatory requirements for the review of impacts on Class I areas, 

and plans to continue his practice in the future.

Iowa plans to continue to utilize the RPOs as the primary mechanism for consultation 

with the FLMs. Should the RPO structure disappear, Iowa has committed to meeting 

these consultation requirements. 

We propose that Iowa has satisfied the requirements of 40 CFR 51.308 (i).