P.1 

OAR Box 1781 

Prepped by Ollie Stewart 

Document Number: 

26)11-1-18 

Docket Number: 

A-90-37 

Printed 10/29/2008 10:46:19 AM Sheet 26 of 142 
"> 

VA 

89-72.1 

89-72.4 

EXPERIENCE WITH TOP-DOWN BACT POLICY 

CYNTHIA A. SOULE 

CITY PUBLIC SERVICE 

SAN ANTON10/ TEXAS 

\ 

L > 

A IR & WASTE MANAGEMENT 

ASSOCIATIO N 

a> 

SlNCC 1907 

For Presentation a I the 

82nd Annual Meeting & Exhibition 

Anaheim, California 

June 25-30, 1989 

INTRODUCTION 

The determination of Best Available Control Technology 

(BACT) is a major facet of the Prevention of Significant Deterioration (PSD) Program, which came about as a result of the Clean 

Air Act Amendments of 1977. In fact, the Amendments redefined the 

way federal permits were issued for the construction of facilities which have the potential to contribute significantly to air 

pollution. 

The BACT review process remained relatively unchanged from 

its inception until December 1987, when the EPA announced a new 

"Top-Down" review policy for BACT. This policy has been the 

source of confusion and controversy among PSD permit applicants, 

including electric utilities. 

City Public Service, an-electric utility in San Antonio, 

Texas (EPA Region VI), found the policy to be a source of frustration which resulted in months of negotiations with the EPA 

over its PSD permit for a coal-fired power plant. The permit was 

submitted in November, 1987, one month before the Top-Down policy 

was issued. The total permit review required 11 months to com--

plete and the PSD permit was issued on Sept. 30, 1988. As a 

result of the Top-Down policy, some permitted levels for the new 

525-megawatt utility boiler will be better than New Source Performance Standards (NSPS) levels. 

In this paper, the efforts undertaken by CPS in preparing 

its PSD permit are described as well as CPS1 responses to requests for additional information made by EPA Region VI under the 

Top-Down policy. There is also a description of the pollution 

control equipment selected by CPS to meet the permit requirements 

negotiated between CPS and Region VI EPA. 

A description of the new Top-Down policy and some draft 

policy guidelines is provided as well as a discussion of some of 

the controversy surrounding the policy's interpretation. A brief 

discussion of BACT as it is defined and interpreted in the PSD 

regulations is presented first. For a more complete understanding 

of how and why the PSD program developed and an explanation of 

related air quality regulations, an overview of the Clean Air Act 

is provided in the Appendix. 

BEST AVAILABLE CONTROL TECHNOLOGY 

Under the PSD provisions, determinations of best available 

control technology (BACT) are required for the major source being 

permitted. BACT is defined in the PSD regulations at 40 CFR 

52.21 (a)(11) as "an emissions limitation ...based on the maximum 
r" 

89-72.4 89-72.4 

degree of reduction for each pollutant subject to regulation 

under (the) Act which would be emitted from any proposed major 

stationary source or major modification which the Administrator, 

on a case-by-case basis, taking into account energy, environmental and economic impacts, and other costs, determines is 

achievable for such source or modification through application of 

production processes or available methods, systems and techniques..."1 As indicated by the definition, BACT analyses are to 

be made on a case-by-case basis, and source-specific factors such 

as local energy, environmental or economic conditions are to be 

considered. 

BACT is required for all emissions of any pollutant emitted 

above significance levels (see Table IA in Appendix), which 

include criteria, non-criteria and non-regulated (but potentially 

toxic) pollutants. Criteria pollutants are those for which a 

National Ambient Air Quality Standard (NAAQS) has been established. Non-crltcria pollutants are those which are controlled by 

regulation other than NAAQS. Pollutants which are totally nonregulated may also be included in BACT analyses if there are 

regulated pollutants being considered, according to an EPA policy 

directive issued to the regional offices in September 1987, in 

which EPA responded to concerns about air toxic emissions from 

municipal waste incinerators2. 

It is important to note that the legislative language 

mandating the establishment of New Source Performance Standards 

(NSPS) is very similar to the language which defines BACT in the 

PSD regulations. In Section 111 (a) of the Clean Air Act a standard of_ performance selected as NSPS was intended to reflect the 

application of the "best technological system of continuous 

emission reduction" taking into consideration the cost of achieving that emission reduction, and "any nonair quality health and 

environmental impact and energy requirements."3 Thus, the 

standards had to reflect the best demonstrated control practice, 

adequately considering the cost of such control and all variations of operating conditions. Determination of the degree of 

emission reduction achievable was largely based on results of 

emissions tests from well controlled existing sources. 

Historically, the BACT analysis as presented in the permit 

application has been an analysis and comparison of the current 

control technologies available for the particular source being 

permitted. The analysis would first present the level of control, 

option required to meet NSPS generally as the base case. Then 

alternative systems would be described that could achieve compliance with NSPS or better than NSPS and these alternatives 

would be compared to the base case. 

Since BACT control cannot be less stringent than the applicable federal NSPS, no analysis would consider any limit greater 

than NSPS. However, when performance standards were being developed, as stated previously, economic, environmental, and 

energy impacts were each considered for the particular source. 

The best demonstrated control practice, based on emission tests 

of existing facilities, was used as a basis for NSPS. Since 

EPA's development of NSPS standards considered the very elements 

required under the BACT process, meeting NSPS has generally been 

taken to be an adequate demonstration of BACT. This equating of 

BACT with NSPS was specifically eliminated by the Top-Down BACT 

policy. 

LICENSING PROGRAM FOR J.K. SPRUCE 

In late 1986> city Public Service, the municipal electric 

utility which serves the city of San Antonio, Texas and surrounding areas, began intensive environmental assessment work in 

preparation for licensing two 525-megawatt western coal-fired 

power plants. Extensive environmental studies were undertaken in 

order to provide baseline data for preparation of all.necessary 

permits and licenses for the plants. The investigations and 

surveys took over a year to complete and cost in excess of $1 

million. Air permitting costs were about one-third this amount. 

The new plant, called J.K. Spruce, is to be built adjacent 

to four existing power plants - two natural gas and two western 

coal units at Calaveras Lake, approximately 13 miles southeast of 

San Antonio. The existing coal-handling facilities will be 

modified to accommodate the expanded generating capacity which 

would use the same fuel source. The fuel is low sulfur, subbituminous coal from the Powder River Basin in Wyoming. 

A chronology of events in the air permitting process is 

provided in Table I. Permit application preparation, which began 

in January of 1987, involved collection of ambient air quality 

data and climatological data which were to be used in dispersion 

analysis modelling. Additionally, preliminary design information 

relating to emissions from the proposed facility were needed. 

Since permitting necessarily preceded detailed design engineering 

work, initial permitting was conducted on the basis of a 

surrogate facility which very conservatively represented the 

proposed final design. Important design features of the surrogate facility included an estimation of size, fuel burn rate, 

fuel quality, stack height, stack diameter, exact location and 

coal yard design. As final design data became available, the 

conservative nature of the surrogate parameters became obvious. 

Computer dispersion modelling must be performed in order 
89-72.4 

89-72.4 

Table I. Chronology of Events - Air Permitting 

December 1986 

Jan.-Oct. 1987 

Nov. 5, 1987 

Dec. 1, 1987 

March 8, 1988 

March 9, 1988 

April 26, 1988 

May 16, 1988 

July 1, 1988 

July 14, 1988 

Sept. 30, 1988 

Environmental studies begin in support of 

permitting 

Permit application preparation, data collection, 

modelling efforts, meetings with TACB. 

PSD application sent to TACB 

Craig J. Potter memorandum sent to regional 

EPA offices 

EPA informed CPS of need for a more in-depth BAC 

analysis 

CPS began additional BACT studies 

BACT Support Study presented to EPA 

Draft PSD Permit received from TACB 

EPA sent TACB their comments on draft PSD permit 

requesting more BACT information. 

CPS met with EPA to discuss their comments and 

supplied Supplementary BACT Information 

PSD Permit granted by EPA 

to determine compliance of the new source with the NAAQS and PSD 

increment levels. CPS' modelling was performed at maximum 

operating levels in order to determine.impacts based on worst 

case conditions. The modelling methodology was the subject of 

several early meetings with the Texas Air Control Board (TACB) 

and the EPA and those meetings eliminated potential sources of 

modelling problems later in the process. Preliminary modelling 

was performed to determine the area of impact for all pollutants 

emitted in significant quantities. Then, regional emission 

inventories were obtained for these pollutants. 

Project review meetings were held with the TACB several 

times in 1987 to discuss the permitting strategy and the modelling approach. The TACB has partial delegation of the PSD permit 

program but EPA Region VI must approve and issue the final PSD 

permit. The final PSD permit application was submitted in early 

November, 1987 to the TACB, and later to the EPA after it was 

declared administratively complete by the TACB. 

The BACT portion of the PSD permit described the control 

technology for the new units to be the following: fabric filters 

for control of particulate matter, wet limestone scrubber system 

for control of sulfur dioxide, and a combination of combustion 

control techniques and furnace design for control of nitrous 

oxide emissions. A combination of dust collectors and wet suppression would be used for the coal, ash and limestone handling 

systems. Table II describes the alternative technologies which 

were considered for BACT and Table III. provides a description of 

the BACT which was ultimately chosen for the new plant. The 

chosen technologies would meet the New Source Performance Standards (NSPS) for Electric Utility Steam Generating Units built 

after Sept. 1978 which are described in 40 CFR Part 60, Subparts 

A and Da, Subpart Y for Coal Preparation Plants, and Subpart OOO 

for Non-Metallic Mineral Processing Plants. 

The BACT portion of the permit was a conventional analysis 

of the various control alternatives obtained from literature 

data, technical and engineering journals and textbooks, information from boiler and scrubber manufacturers, other PSD permit 

applications and Environmental Impact Statements from other coalfired plants. A review of previously submitted permit applications also helped determine the format and content of the study. 

TOP-DOWN BACT POLICY 

On December 1, 1987, J. Craig Potter, Assistant Administrator for Air and Radiation at the EPA, wrote a memo to all Regional Administrators recommending a new "Top-Down" approach to BACT 

analysis. It was described as "the determination of the sost 
89-72.4 

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89-72.4 

Table II. BACT Control Technologies 

Pollutant Selected BACT 

Control Technology 

Alternatives 

Considered 

Particulates 

Sulfur Dioxide 

Nitrous Oxide 

Carbon Monoxide 

Volatile Organic 

Compounds 

Fabric Filter 

Wet limestone Scrubber 

(FGD) System 

Combustion controls, 

type of boiler 

Table III. 

A/C ratio (Gross) 

No. of bags 

Cloth area 

Gas' flow rate 

Type of bags 

Temperature Min/Max 

Type of cleaning 

Sonic horns 

Type 

Removal efficiency 

Ho. of absorbers 

Manufacturer 

Type 

ControlG 

Electrostatic 

Precipitator 

Spray dryer 

Dual alkali 

Wellman-Lord 

Magnesium oxide 

Fluidized bed 

combustion 

Selective catalytic 

reduction 

Selective non-catalytic reductic 

Flue-gas recirculation 

Water injection 

Reburning 

Design Control Technologies 

FABRIC FILTER 

1.35: 1 

13,440 in 28 compartments 

1,335,398 ft2 

1,805,435 acfm (at 285 F) 

Teflon Finished fiberglass 

235 to 500 F 

Reverse air 

Two per compartment 

SCRUBBER 

Wet limestone scrubber 

70% overall; 90% removal for 

77.8% of flue gas;remaindor 

by-passed for reheat. 

3 (2 in operation, 1 spare) 

BOILER 

Combustion Engineering 

Tangential-fired, dry bottom 

Overfire air, concentric tiring 

stringent control available for a similar or identical source or 

source category", and the demonstration that this level of control is "technically or economically infeasible for the source in 

question."4 If this demonstration is done, the next most stringent level of control would be evaluated until the BACT level 

under consideration "cannot be eliminated by any substantial or 

unique technical, environmental or economic objections."4 The 

memo goes on to state that the approach differs from other analyses in that "it requires the applicant to analyze a control 

technology only if the applicant opposes that level of control; 

the other process required a full analysis of all possible types 

and levels of control above the baseline case."4 

Several draft Guidelines for Top-Down BACT have become 

available through various regional EPA offices. Two of these 

will be described briefly. Draft "Guidelines for Determining 

BACT under the Top-Down Approach" was distributed at an April 14, 

1988 meeting at EPA Region IV offices. Another guideline -

currently being considered by EPA as an appropriate and useful 

interim guidance document is the Northeast States for Coordinated 

Air Use Management (NESCAUM) BACT Guidelines. 

The first step suggested in the Region IV guidelines is to • 

identify the most stringent technically viable control alternatives, with categories of controls being: existing control 

technology (proven in practice or required by a-permit for source 

category), technically feasible alternatives (demonstrated in 

practice on other source categories), innovative control technology (never applied to any source but which could be technically 

applied), and production processes, fuels, and materials that are 

inherently less polluting.5 The NESCAUM Guidelines add that no 

technically feasible alternative should be ruled out and that the 

applicant should not simply review existing controls for the 

source category in question but look at similar categories and 

innovative control technologies.6 

The most stringent control technology "is assumed to be 

BACT, unless the applicant demonstrates via a case specific 

analysis the infeasibility of the control option based on unique 

project specific mitigating factors."5 In justifying a less 

stringent control option, the guidelines suggest that the control 

options be ranked in terms of stringentness, with control options 

most stringent on top, followed by a discussion of the various 

impacts of each control option, including control efficiency, 

economic, environmental and energy impacts. The most stringent 

control alternative is assumed to be BACT unless the applicant 

can demonstrate that it is infeasible.5 The process is continued 

for each level of control until the applicant demonstrates BACT 

for his facility. Examples of unique factors considered 

8 
89-72.4 89-72.4 

appropriate in evaluating the infeasibility of the most stringent 

control option are as follows: technical infeasibility, other 

environmental impacts, energy penalties, and economic impacts. 

The burden of proof for applying a less stringent control 

technology remains in the applicant's "case specific evaluation 

of the control alternatives."

 6 

Due to the many interpretations of the Potter memo, there 

has been confusion as to the correct method for making BACT 

determinations. Some EPA regions apparently are equating BACT 

with Lowest Achievable Emission Rate (LAER) according to a letter 

dated Aug. 17, 1988 to Mr. Donald Clay, EPA's Acting Assistant 

Administrator of Air and Radiation by the law firm of Hunton and 

Williams, representing the Utility Air Regulatory Group (UARG). 

For example, the letter states that Region IX has issued a BACT 

guidance document that adopts a test for determining BACT that 

focuses "almost exclusively on the financial ability of the owner 

or operator", and requires that the most stringent control 

technology - LAER - be installed if the owner or operator has the 

financial ability to pay for it.7 The letter argues that "Where 

the environmental benefits of additional controls are negligible 

but the economic or energy costs are significantly greater than 

other systems of control, the Clean Air Act does not require 

application of the most stringent control system."7 

DEVELOPMENT OF ADDITIONAL BACT STUDIES IN RESPONSE TO EPA 

As a result of CPS' meeting with EPA Region VI in early 

March of 1988, the impact of Potter's Top-Down memo became apparent. The EPA requested greater detail in the BACT analysis 

beginning with better than NSPS levels for control of particulate, sulfur dioxide and nitrous oxides. One particular Western coal-fired plant was mentioned which had been permitted for a 

0.02 lb/MMBTU level for particulate matter and CPS was questioned 

as to why they should not meet this level, rather than the NSPS 

level of 0.03 lb/MMBTU. EPA indicated that they had obtained 

this information from the EPA's BACT/LAER Clearinghouse document, 

which provides recent data on control technology determinations 

and emission limits by source category. 

The Region requested more detailed information on the 

alternative control technologies for sulfur dioxide (S02) and 

nitrous oxide (NOx), such as the rationale for choosing wet versus dry scrubbing. Also, more detail was requested on alternatives for NOx control, specifically selective catalytic reduction 

(SCR) and selective non-catalytic reduction (SNCR), techniques 

which have not found extensive use in coal-fired utility plants 

in the U.S. but which have been used in some cases in Europe and 

Japan. Detailed economic data for additional removal efficiency 

was also requested. 

CPS immediately prepared a supplemental BACT document which 

focused on the economic issues raised by the EPA. The 65-page 

BACT Support Study was completed and submitted to the EPA within 

two months, by the end of April, 1988. The report examined in 

detail the costs for alternative control levels for particulates, 

S02, NOx and carbon monoxide. 

CPS' preferred technology'was used as the base case, then 

compared with alternative and increasingly stringent levels of 

control. This comparison was primarily technical and economic in 

nature, comparing incremental costs for additional control levels 

and representing the results in terms of dollars per ton of pollutant removed on the basis of a 30-year levelized cost calculation. 

Energy penalties and other environmental factors were also 

compared. For example, by using a wet limestone scrubber, fly ash 

can be collected separately and sold as a cement additive. This 

is the current operation at CPS' existing coal-fired plant, and 

it has resulted in savings and royalties to CPS of up to $400,000 

per year. In contrast, a lime spray dryer system would not allow 

separate collection of fly ash and so would result in loss of 

royalty revenues to CPS as well as reguire substantially greater 

landfill construction to accommodate additional waste disposal. 

Another example of environmental factors described was the 

problem with ammonia which is used in SCR and SNCR technologies. 

Emissions of unreacted ammonia can create odor problems and can 

also contaminate fly ash, thus preventing its sale and increasing 

solid waste problems. 

Upon further investigation, CPS discovered that the facility 

which the EPA had pointed out as having the "top" levels of particulate control had actually never been constructed; thus the 

permitted levels for that plant could not be shown to have been 

demonstrated in operation. 

The BACT Support Study differed from the permit application's BACT study in that BACT impacts were evaluated using expected or average conditions. Normally, PSD permitted impacts, 

are based upon a worst case fuel analysis and 100% capacity 

factors. CPS's BACT study results reflected expected or average 

rather than worst case assumptions. The approach of using expected versus worst case conditions created some questions from 

the EPA in that expected emissions from the plant, based upon 

average conditions, would be significantly less than permitted 

conditions which are based upon worst case assumptions. In fact, 

10 
89-72.4 

89-72.4 

expected emissions would be 25 to 30% less than permitted, worst 

case conditions. The worst case levels are those which must be 

proven- to be less than or equal to those required under NSPS. 

A few weeks after the BACT Support Study was submitted, the 

draft PSD permit was written by the TACB and sent out for comments. The EPA officially responded with their comments to the 

TACB on the draft permit on the first of July. The EPA comments 

reiterated the same concerns about the BACT analysis, that there 

was still not sufficient justification for not meeting the "top" 

level of 0.02 lb/MMBTU for particulate matter, nor the better 

than NSPS levels for SO2 and NOx. More information on energy and 

environmental impacts to justify the higher emission limit was 

requested. 

Some aspects of the BACT Support Study previously submitted 

were discussed in the EPA comments, such as marginal versus 

average costs. CPS' position was that the economic comparison 

between the base case and the more stringent control cases should 

be done on an incremental or marginal cost basis. This analysis 

means that removal costs are expressed in terms of additional or 

incremental costs divided by the additional tons removed. This 

incremental cost should then be judged against the base case and 

compared to the environmental benefits which might accrue. However, since CPS was able to demonstrate compelling, noneconomic 

rationales for selecting its chosen control equipment, the issue 

"of marginal versus average costs never became a serious issue. 

Soon after receiving the comments, CPS met with the EPA to 

request further elaboration on the additional information being 

requested. At that meeting, and in a supplementary BACT document 

supplied later, it .was determined that unique operating and 

environmental impacts associated with the preferred technologies 

would be provided as justification for selecting.the preferred 

options. 

Two of the unique factors were that the new unit would be 

designed for speed cycling, a type of operation which causes the 

load to swing daily during certain months of the year, causing 

harsher operating requirements and emission variations which 

baseload units do not encounter. Another factor was that features 

of the new unit would be replicating the technology of an existing station whose operating levels were already documented and 

could be used to determine permitted levels. 

With regard to particulate matter, information from an 

EPA/EPRI conference on particulate control technology was presented on the variability of fabric filter emissions and the 

numerous factors which affect baghouse performance, such as coal 

and ash characteristics. For example, one factor differentiating 

the units being compared was the difference in coal quality. Even 

though the two units both burn coal, one burning a higher BTUvalue coal with lower ash content would demonstrate lower 

emissions. 

The final PSD permit was issued on Sept. 30, 1988, eleven 

months after the application was made. The final permit terms 

resulted in reductions from NSPS levels for sulfur dioxide and 

opacity, but retained NSPS levels for NOx and particulate matter. 

Sulfur dioxide emission levels were reduced from the NSPS level 

of 0.6 lb/MMBTU to 0.5 lb/MMBTU on a 30-day rolling average; 

opacity was reduced from the NSPS level of 20% to 10%. 

CONCLUSION 

As a result of EPA's new Top-Down BACT policy, an extremely 

thorough BACT analysis was performed for a PSD permit for a coalfired power plant in Texas. As a result of intensive research 

and continuous negotiations, the permittee and agency were able 

to reach mutually satisfactory permit levels, some of which resulted in levels more stringent than NSPS for the source due to 

the Top-Down policy. 

Top-down BACT is a new concept which is difficult to address 

because of the lack of unified, specific guidance from the EPA to 

determine the technical feasibility of specific control technologies. Thus, thorough research into the chosen technology and 

rationale for selecting it is recommended prior to PSD application submittal. Early agency contact and negotiations about 

control technologies being considered for the permitted source 

will aid in preparation for the BACT review. In addition, a 

thorough review of the BACT/LAER Clearinghouse document and other 

PSD permits is recommended to determine previously permitted 

levels for similar sources. 

11 
89-72.4 

REFERENCES 

1. Office of the Federal Register, National Archives and Record: 

Administration, Code of Federal Regulations. 40 CFR 52.21 

(a)(11), Washington, D.C. (1987) 

2. Emison, Gerald A., Director, Office of Air Quality Planning 

Standards, Memorandum on Implementation of North County 

Resource Recovery PSD Remand to all Regional Directors, 

(September 25, 1987). 

3. Clean Air Act, Section 111 (a). 

4. Potter, J. Craig, Assistant Administrator for Air and 

Radiation, Environmental Protection Agency, Memorandum on 

Improving New Source (NSR) Review Implementation, to all 

Regional Administrators (December 1, 1987) . 

5. Environmental Protection Agency, "Determining Best Available 

Control Technology (BACT): The "Top-Down" Approach, (marked 

draft), distributed at EPA Region IV offices on April 14, 

1988. 

6. Northeast States for Coordinated Air Use Management 

(NESCAUM), NESCAUM BACT Guideline, October 1988. 

7. Field, Andrea B. et.al., Hunton & Williams, Correspondence 

to Mr. Donald Clay, Acting Assistant Administrator of Air 

and Radiation, U.S.Environmental Protection Agency, (Auqust 

17, 1988). 

NOTE TO EDITORS 

Under the new federal copyright law, 

publication rights to this paper are 

retained by the author(s). 

89-72. 4 

APPENDIX 

OVERVIEW OF CLEAN AIR ACT 

Since it was originally passed in 1955, the Clean Air Act 

(CAA) has been the major regulatory means of protecting human 

health and the environment from sources of air pollution.. The 

act was amended significantly in 1970 and 1977, and is currently 

undergoing major review in Congress. 

The CAA directed EPA to delegate authority to the individual 

states to implement their own programs for air pollution control. 

Each state must demonstrate that its program is equal to or more 

stringent than the federal program before the state can be 

granted final authority. Provisions of the CAA are carried out 

by the EPA through enforcing regulations which include the following: National Ambient Air Quality Standards (NAAQS), Prevention of Significant Deterioration (PSD), Nonattainment (NA) Area 

Regulations and New Source Performance Standards (NSPS) . 

National Ambient Air Quality Standards 

National Ambient Air Quality Standards (NAAQS) are standards 

established by the Clean Air Act to protect public health-and 

welfare. Pollutants for which NAAQS are established are called 

criteria pollutants and include: sulfur dioxide (SO2), nitrogen, 

oxides (NOx), carbon monoxide (CO), ozone, particulate matter 

(smaller than 10 microns in diameter or PM-10) and lead. NAAQS 

standards are based upon scientific information regarding 

identifiable effects on public health or welfare. 

Areas of the country which are in compliance with NAAQS are 

called "attainment" areas and are subject to the Prevention of 

Significant Deterioration (PSD) regulations; areas not in compliance with NAAQS are termed "nonattainment" and are subject to 

a different set of rules (the Emission Offset Interpretative 

Ruling) under which new sources may not be permitted to cause a 

net increase in pollution or create a delay in meeting air quality standards. Designations are made on a pollutant-specific 

basis; thus, for example, an area can be designated attainment 

for carbon monoxide but nonattainment for ozone. 

Prevention of Significant Deterioration 

The purpose 

(PSD) program, fo 

I960, is to prese 

program there are 

ambient pollutant 

pollutants - SO2, 

were set to "prev 

(e.g.baseline) ai 

added to baseline 

of the Prevention of Significant Deterioration 

r which final regulations were issued in August 

rve air quality in attainment areas. Under the 

maximum allowable increases or "increment's" in 

concentrations allowed for three specific 

NOx, and particulate matter. These increments 

ent significant deterioration" in existing 

r quality. In effect, the PSD increment, when 

concentrations, represent new ambient air qual13 
IT 

89-72.4 89-72.4 

Table IA. Significant Emission Rates 

ity standards for PSD areas. Whereas NAAQS limits are applicable 

over the entire U.S. and represent the greatest allowable degree 

of air contamination, the PSD regulations essentially establish 

new ambient standards which are less than or equal to NAAQS and 

which are determined on an area by area basis. 

The PSD permit regulations are triggered by emissions of 

certain pollutants regulated under the Clean Air Act by a new 

source or by a major modification to an existing source. Modifications of major sources are subject to PSD permitting if 

emissions are more than significance levels which are listed in 

Table IA. Major sources include facilities belonging to 28 categories, listed in Table IIA, which have the potential to emit 100 

tons per year of any pollutant regulated under the Clean Air Act. 

Potential to emit means controlled emissions (after pollution 

control equipment) which are based upon the maximum design capacity of the source. Sources not on the list are considered 

"major" if they have emissions of 250 tons per year or more. 

NonAttainment Area 

A major new stationary source or major modification located 

in a nonattainment area must obtain a permit under EPA's Emission 

Offset Interpretative Ruling. This program requires a net air 

quality improvement after the source begins operation. Major new 

sources are subject to review only if they have the potential to 

emit major amounts, generally 100 tons per year or greater of the 

pollutant for which the area is designated nonattainment. Modifications having the potential to increase emissions by greater 

than significance levels are also subject to review. 

Under State New Source Review rules for nonattainment areas, 

the source must comply with the Lowest Achievable Emission Rate 

(LAER) and obtain emission reductions from other existing sources 

that more than offset the increase in emissions from the new 

source. LAER is based on the most stringent emissions rate 

contained in the implementation plan of any state (unless the 

owner can demonstrate that such a limit is unachievable) or the 

most stringent emission limitation achieved in practice by a 

source of the same category. Generally, cost or energy impacts 

are not considered in LAER analyses. 

Hew Source Performance Standards 

The New Source Performance Standards (NSPS) are a set of 

national emission standards for criteria and designated pollutants for various categories of new or modified stationary 

sources. There are over 50 different types of stationary sources -

for which performance standards have been established. 

15 

Pollutant Rate (Ton/year) 

* * 

**. 

** 

* * 

a * 

* * 

** 

* * 

** 

** 

* * 

** 

* * 

** 

* * 

a * 

* * 

* * 

* * 

* a 

a m 

Carbon monoxide 100.0 

Nitrogen oxides 40.0 

Sulfur dioxide 25.0 

Total suspended particulates 25.0 

PM1 0 (Particulate Matter < 10 microns) 15.0 

Ozone (volatile organic compounds) 40.0 

Lead 0.6 

Asbestos 0.007 

Beryllium 0.0004 

Mercury 0.1 

Vinyl chloride 1.0 

Fluorides 3.0 

Sulfuric acid mist 7.0 

Total reduced sulfur (including H2S) 10.0 

Reduced sulfur (including H2S) 10.0 

Hydrogen sulfide 10.0 

Table IIA. Major Stationary Sources 

Fossil-fuel fired steam electric plants of more than 

250 million BTU per hour heat input. 

Coal cleaning plants (with thermal dryers) 

Kraft pulp mills. 

Portland cement plants. 

Primary zinc smelters. 

Iron and steel mill plants. 

Primary aluminum ore reduction plants. 

Primary copper smelters. 

Municipal incinerators capable of discharging more than 250 

tons of refuse per day. 

Hydrofluoric acid, sulfuric acid and nitric acid plants. 

Petroleum refineries. 

Phosphate rock processing plants. 

Coke oven batteries. 

Sulfur recovery plants. 

Carbon black plants. 

Lime plants. 

Furnace process: Primary lead smelters. Fuel conversion 

plants. Sintering plants. 

Secondary metal production facilities. 

Chemical process plants. 

Fossil-fuel boilers of more than 250 million BTU/hr heat input. 

Petroleum storage and transfer facilities with capacity 

exceeding 300,000 barrels. 

Taconite ore processing facilities. 

Glass fiber processing plants. 

Ch_rcoal production facilities. 

16 

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