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High Level Summary of Meeting with States/Locals/Tribes

May 31, 2012

Introduction

This summary describes ideas and thoughts expressed by states/locals/tribes (SLTs) at the 

May 31 meeting with Environmental Protection Agency (EPA) staff regarding 

implementation of the 2010 primary1-hour sulfur dioxide (SO2) National Ambient Air 

Quality Standard (NAAQS). While the discussion covered many topics, issues related to 

the monitoring costs, a hybrid approach, and realistic timeframes received the most 

attention, with the following general messages:

Many SLTs emphasized the need to deal with real problems and real world 

conditions and, thus, base decisions on monitoring data.

There was strong support for a hybrid approach which allows states flexibility to 

use monitoring or modeling to determine whether areas are meeting or not 

meeting the standard. Furthermore, a threshold should be established to prioritize 

the sources of interest.

Some SLTs urged EPA to consider practicable timelines and pointed out that the 

new SO2 standard is a significant departure (new form, more stringent, etc.) from 

the past. A phased approach is necessary such as was done for NO2 and Pb, and 

overly ambitious timelines on SO2 will force a diversion of resources from other 

programs.

This summary below is organized into three broad topics consistent with the White 

Paper: monitoring, modeling, and implementation. In addition, key subtopics addressed 

are thresholds (monitoring/modeling), actual emissions (modeling), hybrid approach, 

guidance/rulemaking, and timing (implementation). A list of in-person participants is 

attached; there were several additional SLT representatives on the phone.

Limitations

Please note that this is a high level summary, reflecting concepts EPA heard during the 

meeting. It is not intended to be a full transcript or include all topics discussed. As EPA 

moves forward with implementation of the 2010 SO2 NAAQS, the Agency will be 

informed both by concepts contained in this summary as well as concepts not described 

in this summary. Like all of the SO2 implementation-related materials produced by EPA 

to date (e.g., the March 2011 and September 2011 guidance memoranda; the April 12, 

2012 letters to state agencies and tribal representatives; and the May 2012 White Paper) 

this summary does not constitute final or binding agency action. These materials are part 

of an overall work in progress toward developing practicable approaches to implementing 

the SO2 NAAQS that assure expeditious protection of public health. Ultimately, this 

stakeholder outreach process may lead to revised guidance or additional rulemaking. 
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Monitoring

Some SLTs emphasized the need to deal with real problems and real world conditions 

and, thus, base decisions on monitoring.

Some SLTs stated that the monitoring approach worked in the past and, in some cases 

current monitors are adequate. Several SLTs stated that monitors are more cost effective

where there are many sources such as refineries and ports. Some SLTs suggested that 2-3

monitors are sufficient at electricity generating units.

Although it may not be possible to site a monitor at the location of expected maximum 

concentration, some SLTs support the monitoring approach. Some noted that industry has 

been very cooperative in installing monitors. Some SLTs stated that a meteorological 

tower should also be required in each location. Some SLTs also stated that an exit plan 

for monitors is needed; i.e., an incentive is needed that allows for removal of the monitor 

if the monitor is in compliance and source emissions are in compliance.

Many SLTs recognized that cost is a big issue. One SLT stated the cost to site 3 monitors 

around all 2,000 tons per year sources in the state would be $12 million. Another SLT

stated they would need to triple their monitoring network in order to site 3 monitors per 

source. Some SLTs stated that any additional monitors and operation/maintenance need 

to be paid for by the sources. Some SLTs suggested EPA should require sources to pay 

for monitors and operation and maintenance. Some SLTs noted that EPA’s annual 

network review is an opportunity for EPA to identify the need for additional monitors. A

few SLTs stated that a fee rule would not be a good way to fund new monitors. Some 

SLTs noted that the states have experience requiring industry to monitor.

Some SLTs noted that many monitors are not included in EPA’s Air Quality System

(AQS) database. Many sources currently monitor for Prevention of Significant 

Deterioration (and other) purposes and most have at least 2 monitors. Some states have 

agreements with other federal agencies to run SO2 monitors. Some SLTs believe that data 

not publically reported previously may be useful if under state oversight.

Some SLTs stated that if EPA relies on industry monitoring data, then EPA needs to 

develop a monitoring rule which includes guidance regarding the use of these data. Some 

SLTs believe a State would need to review, quality assure, and enter the industry data

into EPA’s AQS. This will take time.

Thresholds

Some SLTs stated that past monitoring data can help define threshold levels. Some also 

stated that stack heights and population may need to be considered beyond just mass 

(tons per year), but that a population-weighted emissions index (and population-based 

factors) is not necessarily helpful. Some SLTs indicated the threshold should be set by 

EPA in order to be more defensible than state by state decisions. 
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Some SLTs generally supported a threshold covering larger sources. A few SLTs

recommended the threshold be combined with a phased program which covers larger 

sources first. 

Some suggested the threshold should be 2,000 - 3,000 tons per year. Some SLTs also 

stated that selecting a threshold is not an easy determination since even small sources can 

cause violations in some cases, such as in complex terrain. Other SLTs stated that 

covering 90% of total SO2 emissions may be the wrong threshold and set the wrong 

precedent for other pollutants. Some SLTs indicated it may be better to base the decision 

on air quality.

Some SLTs noted a threshold could be an incentive for sources to lower emissions. 

Rather than using current emission levels, some SLTs suggested the threshold should be 

based on post-MACT, actual annual emissions, in order to give sources a chance to get 

below the threshold emission level via permit. A few SLTs noted that the threshold is 

critically important for defining areas where additional effort is not needed in order to 

avoid a waste of resources, such as requiring modeling in areas that are very unlikely to 

violate. 

Modeling

Some SLTs stated that modeling should not be used for designations. They indicated that 

modeling results are 2-3 times higher than monitoring. Some SLTs also noted that it is 

difficult to redesignate to attainment through modeling (e.g., where a violation is 

modeled on side of cliff or over water).

Some SLTs stated that many times modeling provides good results and thus it should be 

considered on a case-by-case basis. In contrast, other SLTs stated that the AERMOD 

model overestimates and is not accurate. One SLT stated that EPA needs to update 40

CFR part 51 Appendix W regarding emissions variability.

A small number of SLTs stated it is okay to use modeling to show attainment, but it 

should not be used to designate nonattainment areas. Some of these SLTs were also 

concerned about how an SO2 approach might be applied to other NAAQS pollutants.

Some SLTs suggested EPA guidance is needed on several issues, including the need for 

on-site meteorological data, the number of allowable exceedances, whether cumulative 

modeling including nearby small sources is necessary (one SLT suggested it should not 

be), and how to model multiple sources near each other.

Some SLTs also did not want EPA to require remodeling year after year. They suggested

that continuous emissions monitoring system (CEMS) data would be needed to assure the 

source stays at the permitted level. Some SLTs stated that some permit limits could be 

used to track emissions at non-CEMS sources.
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Some SLTs do not trust modeling. One SLT stated that an SO2 unit with great controls 

still might model nonattainment.

Actual Emissions

Many SLTs stated that there is no need to model maximum emissions since the standard 

is in the form of a percentile. Other SLTs suggested using future permit levels in the 

modeling to reflect expected emission reductions from the Cross-State Air Pollution Rule

and Mercury and Air Toxics Standards.

One SLT suggested that, in implementing a modeling-based approach using actual 

emissions, EPA should allow a statistical approach to source characterization based on a 

distribution of hourly actual emissions values; i.e., an approach that does not assume the 

source operates at the peak hourly value all year.

Some SLTs recommended EPA exempt certain source categories such as infrequently 

used units (e.g., 500 hours per year), emissions from fuel reserve (natural gas units with 

oil reserves), and emergency equipment (e.g., less than 200 hours per year).

Implementation

Several SLTs stated that, if EPA uses modeling to determine attainment, EPA should 

allow states to address any violations through adjusting title V permits as described in the 

White Paper instead of redesignating areas. This has worked in the past in some states.

However, one SLT stated that Prevention of Significant Deterioration permitting is not 

appropriate for this approach since it is rarely triggered for existing sources. One SLT 

suggested instead considering use of the section 111(d) program for addressing sources of 

concern.

Regarding the 110(a)(1) approach, some SLTs felt there was merit to considering this as 

an available option, but not a requirement. They indicated that, while timing it with initial 

infrastructure SIPs would have been impossible, it does offer efficiencies over 

redesignating areas if its scope is properly limited and prioritized to areas where there is 

likely to be a problem. However, one SLT stated that the 110(a) approach flips the 

designation process on its ear by assuming problems in the unclassifiable areas, and a 

monitor should confirm those problems before requiring control measures.

If EPA allows implementation through permitting changes, several SLTs stated that EPA 

should not require SIP revisions for all permit changes. Some SLTs said their title V 

programs give them authority to set NAAQS-based limits without going through a SIP 

process and required the NAAQS to be met before a title V permit could be issued.

Hybrid

There was strong support for a “hybrid” approach which allows states flexibility to use 

monitoring or modeling to determine whether areas are meeting or not meeting the 
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standard. The approach was described as a “Big Box” which includes acceptable methods 

for conducting an air quality assessment and the subsequent actions necessary to protect 

public health. 

Many SLTs supported a hybrid approach where, given a range of sources that must be 

characterized in some way, the States would choose whether to characterize the air 

quality using modeling, monitoring or both based on general EPA guidance. They view 

this approach as flexible, less costly, more efficient course. Some SLTs noted that 

professional judgment is needed in order to determine the number and location of 

monitors to characterize a source (even if it cannot be placed at the location of maximum 

concentration), to consider populated areas, and to not close the door on modeling.

A few SLTs suggested that modeling could serve as an initial screen, and that monitors 

could be deployed in areas that did not screen out based on modeling. The monitoring 

data would then serve as the basis for determining attainment in those areas. Some SLTs 

stated that most sources would pass the modeling test. A few SLTs stated that if modeling

shows very high values (e.g., ten times the standard), then the area should be designated

nonattainment.

Rulemaking or Guidance

Some SLTs stated that the rulemaking is needed. Some SLTs also recognized that it is not 

possible to cover everything in rules or guidance and that professional judgment is 

necessary.

Timing

Some SLTs stated a phased approach may be helpful given resource constraints and the 

time needed to add monitors at larger sources and expand the monitoring network. They 

advised the Agency to not rush these decisions, but to take a more deliberate approach 

such as was done for NO2 and Pb. 

In further urging EPA to consider practicable timelines, some SLTs pointed out that the 

new SO2 standard is a significant departure (new form, more stringent, etc.) from the past 

SO2 standard, and thus time is needed to get it done. Some SLTs stated that, with 

available resources and other pollutants and programs to focus on, a phased approach is 

necessary; further, overly ambitious timelines on SO2 will force a diversion of resources 

from other programs.

Some SLTs noted that time is needed to analyze emissions variability, improve and 

validate AERMOD for low wind speed cases, update Appendix W, collect on-site 

meteorological data, put in additional monitors, determine the modeling threshold value 

based on additional data, and model and revise permits.

Other SLTs suggested the need for a reasonable schedule which would not require a SIP 

in all cases and would allow time for states to decide if modeling or monitoring is best. 

Some SLTs suggested 5 years may be a reasonable timeframe to address modeling, 

controls, rule development, and rule adoption. A few SLTs stated that if modeling is 
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required, it will be a long process. Even with the hybrid approach, some SLTs noted that 

time is needed for EPA to issue guidance/rules to establish that approach. Some SLTs

stated that even if sources pay for monitors it would not be faster, since time is needed for 

modeling to site monitors.

Some SLTs suggested EPA wait 3 years before implementing the 1-hour SO2 NAAQS 

since the SO2 standard is not the drivers for industry (Mercury and Air Toxics Standards

rulemaking is the driver). Some SLTs stated it would be 2015 before states know what 

sources will do with the Cross-State Air Pollution Rule and Mercury and Air Toxics 

Standards and, thus, 2020 is a reasonable date.

Some SLTs did not want timelines for unclassifiable areas, and noted that unclassifiable 

areas historically have had no timeline to show attainment and the Clean Air Act does not 

say what to do with unclassifiable areas. Stakeholders noted that there are many 

unclassifiable areas for other pollutants and asked whether this SO2 action would set a 

precedent that could be a huge resource burden.
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ATTENDEES FOR SO2 NAAQS IMPLEMENTATION STAKEHOLDER MEETING

May 31 - State, Local, and Tribal Government Representatives

Abraczinskas Mike Division of Air Quality, NC Dept. of Environment & Natural Res.

Alteri Sean Kentucky Division for Air Quality

Bacon Leigh State of AL-DEM/Planning Branch Air Division

Bamford Rob State of Nevada

Bates Mike Arkansas Dept. of Envir. Quality

Bergeron Timothy Louisana Dept. of Environmental Quality

Buckler Chuck Division of Air Quality, NC Dept. of Environment & Natural Res.

Calcagni John EPA Region 4

Capp James Georgia EPD

Donald Dahl EPA Region 1

Dowd Michael Virginia Dept. of Environmental Quality

Ferguson Bruce Mississippi Department of Environmental Quality

Glass John SC DHEC BAQ

Hellwig Vince State of Michigan

Hildebrand Susana Texas Commission on Environmental Quality

Hoch Joseph Wisconsin Dept. of Natural Resources

Hodanbosi Bob Ohio EPA

Holman Sheila Division of Air Quality, NC Dept. of Environment & Natural Res.

Hornback John Metro 4/SESARM

Johnson Dan Westar Energy, Inc.

Kaleel Rob Lake Michigan Air Directors Consortium (LADCO)

Kiss Mike Virginia DEQ-Central Office

Klemp David Montana Dept. of Environmental Quality

Ling Michael Environmental Protection Agency

Lloyd Peter Forsyth Co. Office of Environmental Assistance & Protection

Mastro Donna EPA Region 3

McNeill David Utah DEQ

O'Clair Terry NC Dept. of Health

Page Steve Environmental Protection Agency

Pella Theresa Central States Air Resource Agency

Pirolli Richard Connecticut Dept. of Energy & Protection

Post Zarena Texas Commission on Environmental Quality

Ragland Bob Forsyth Co. Office of Environmental Assistance & Protection

Rao Mya Mississippi Department of Environmental Quality

Reece Myra SC DHEC BAQ

Remer Greg State of Nevada

Reynolds Scott SC DHEC BAQ

Schulman Arleen Pennsylvania Department of Environmental Proteciton

Scofield Steve EPA Region 4

Sliwinski Rob NYSDEC
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Summerhays John EPA Region 5

Underhill Jeff Dept. of Envir. Services/State of New Hamp.

Waterson Sara EPA Region 4

Wayland Chet Environmental Protection Agency

Wierman Susan MARAMA