CESO-I

Engineer Pamphlet

1110-1-21

Department of the Army

U.S. Army Corps of Engineers

Washington, DC 20314-1000

EP 1110-1-21

30 October 2000

Engineering and Design

AIR PATHWAY ANALYSIS

FOR THE DESIGN OF

HAZARDOUS, TOXIC, AND

RADIOACTIVE WASTE

(HTRW) REMEDIAL ACTION

PROJECTS

Distribution Restriction Statement

Approved for public release;

distribution is unlimited.
CESO-I

DEPARTMENT OF THE ARMY

U. S. Army Corps of Engineers

Washington, D.C. 20314-1000

EP 1110-1-21

Pamphlet

No. 1110-1-21 30 October 2000

Engineering and Design

AIR PATHWAY ANALYSIS

FOR THE DESIGN OF

HAZARDOUS, TOXIC, AND RADIOACTIVE WASTE

(HTRW) REMEDIAL ACTION PROJECTS

1. Purpose. This Engineer Pamphlet describes Air Pathway Analysis (APA) procedures.

These provide guidance for emission rate and dispersion modeling used to determine public

health impacts of air emissions from HTRW remedial action projects. Using APA results in the

design process for HTRW remedial actions helps to justify need and design requirements for

perimeter air monitoring systems. It also aids in the design of air pollution control equipment and

procedures.

2. Applicability. This pamphlet applies to all USACE commands responsible for the design of

HTRW remedial action projects.

3. References.

a. Executive Order 12580, January 23 1987.

b. 40 Code of Federal Regulations (CFR) 260 through 268, Environmental Protection Agency

(EPA) Regulations Implementing the Resource Conservation and Recovery Act (RCRA).

c. 40 CFR 300 through 3 11, EPA Regulations Implementing the Comprehensive

Environmental Response, Compensations and Liability Act (CERCLA).

d. USACE Engineering Manual (EM) 200-l-4, Risk Assessment Handbook, Human Health

Evaluation.

e. EPA Publication EPA-450/l-89-OOla, Air/Superfund National Technical Guidunce Study

Series, Volume I-Overview of Air Pathway Assessments for Superjimd Sites (revised). National

Technical Information Service (NTIS) Order # PB93 17398.

J: EPA Publ’ica ion t’ EPA-450/l-89-003, Air/Superfund National Technical Guidance Study

Series, Volume III-Estimation of Air Emissions from Cleanup Activities at Superfund Sites.

NTIS Order # PB89180061.

This pamphlet supercedes EP 1110-l-21, dated 15 March 1997.
EP 1110-1-21

30 OCT 00

g. EPA Publication EPA-45 l/R-93-001, Air/Superfund National Technical Guidance Study

Series-Models for Estimating Air Emission Rates From Supe?ftind Remediul Actions. NTIS

Order #PB93 186809.

h. EPA Publication EPA-450/l -9 l-00 1, AirLSuperfund National Technical Guidance Study

Series-Emission Factors for Superfund Remediation Technologies (revised). NTIS Order #

PB91190975.

i. EPA Publication EPA/625/R-92/O 12, Control of Air Emissions from Superfund Sites. NTIS

Order # PB93215614.

,j. EPA Publication EPA-454/R-95-003, Air/Superfund National Technical Guidance Study

Series, Volume V-Procedures for Air Dispersion Modeling at Superfund Sites. NTIS Order #

PB95193124.

k. EPA Publication 9234.2-22FS, ARARS Fact Sheet, Compliance with the Clean Air Act and

Associated Air Quality Requirements. NTIS Order # PB92963282.

1. EPA Publication EPA 45 l/R-96-006, Air Superfund National Technical Guidance Study

Series-Air/Supe$und Guide To Pollutunt Toxicity. NTIS Order # PB96162490.

4. Discussion.

u. Air quality requirements for HTRW remedial action projects are dictated primarily by the

air quality control region (AQCR) in the state where the project is located. Designers are

encouraged to contact the AQCR for requirements for emission rate action levels, emission

controls, and receptor point action levels before starting a project-specific APA.

b. APA is a multi-disciplinary effort, requiring involvement of dispersion modelers,

regulatory specialists, and risk assessors. Solicit input from geotechnical engineers when

estimating emission rates from soil handling operations and from HTRW treatment process

engineers when calculating emission rates from HTRW treatment processes.

c. This EP is to be used to guide the development of in-house APAs and scopes of work for

Architect-Engineer (A-E) developed APAs.

d. Concepts and procedures found in references d through 1 are critical for the development of

APAs. Reference d is available at httn://w3 .environ~~nental.usace.ar~l~~~.~~~il

~infor1~~ation/resoul.ces/risk/risl~~~~ide/risk~~~ide.ht~~~l. References e through 1 can be obtained

from the National Technical Information Service (NTIS) at l-800-553-6847.

2
EP 1110-1-21

30 OCT 00

5. Definitions.

a. Emission Rate. The rate at which contaminants are emitted to the air from point sources

(grams/second) and area sources (grams/second-square meter)

b. Dispersion Modeling. The process of using an air dispersion model and an emission rate to

calculate the concentration of contaminants in the air at a receptor point.

c. Emission Rate Action Level. The regulation or regulatory guideline emission rate for point

source emissions.

d. Receptor Point Action Level. The airborne concentration of a contaminant at the receptor,

which is considered (by regulation, regulatory guideline, or risk assessment practice)

unacceptable for public exposure.

e. Perimeter Air Monitoring Action Level. The airborne concentration of a contaminant to be

monitored at the site perimeter that has been demonstrated through dispersion modeling to be in

compliance with the receptor point action level.

FOR THE COMMANDER:

2 Appendices

APP A-Air Pathway Analysis

Procedure

APP B-Perimeter Air Monitoring

Action Level Development

Major General, USA

Chief of Staff

3
EP 1110-1-21

30 OCT 00

APPENDIX A

AIR PATHWAY ANALYSIS PROCEDURE

Table of Contents

Paragraph Page

A-l. Emission Rate Calculations/Estimation.. ................................................................ A-2

a. Point Sources.. ........................................................................................................................ A-2

b. Area Sources .......................................................................................................................... A-2

A-2. Dispersion Modeling Procedure .............................................................................. A-2

a. Screening Models.. ................................................................................................................. A-2

b. Refined Models.. .................................................................................................................... A-2

c. Meteorological Data Needs.. .................................................................................................. A-3

A-3. Emissions Acceptability .................................................................................. A-3

a. Point Sources.......................................................................................................................... A-3

b. Area Sources .......................................................................................................................... A-3

A-4. Emission Control Requirements ..................................................................... A-4

a. Point Sources.. ........................................................................................................................ A-4

b. Area Sources ........................................................................................................................... A-4

A-5. Air Emission Monitoring Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Figure A-l. Point source APA Summary Flow Chart. .............................................................. A-5

Figure A-2. Area source APA Summary Flow Chart. ............................................................... A-6

A-l
EP 1110-1-21

30 OCT 00

APPENDIX A

AIR PATHWAY ANALYSIS PROCEDURE

A-l. Emission Rate Calculations/Estimations. Develop an emission rate estimate using

project-specific models given in references e,f; g, and h. The emission rate estimate is used to

determine necessary emission control equipment for point sources. It is also used in dispersion

modeling for both point sources and area sources to determine if site emissions comply with

receptor point action levels. EPA’s Office of Air Quality Planning and Standards Technology

Transfer Network (OAQPS-TTN) provides valuable information for estimating and measuring

emissions to the public at l~tt~~:ll~~~y\~.e~~a.rrov/tt~l/chief/.

a. Point Sources. These are stacks and vents on HTRW treatment process equipment.

Contaminants of concern include those present in the environmental medium undergoing

treatment, as well as chemicals used in the treatment process, or by-products of the treatment

process, which may be released to the air. Consult process engineering staff and references,f; g,

and h to calculate emission rates from HTRW treatment process point sources. Be sure to

account for emission control technology if it is included in the design. Pilot-scale treatability

studies and existing full-scale treatment processes, where the processes and contaminants are

similar to the project under design, are valuable sources of information for estimating point

source emission rates.

b. Aren Soz~rces. These are ground level releases to the air over a specified surface area.

Examples of this type of a release on HTRW sites include excavations and associated material

handling activities, stockpiles, landfills, and lagoons. Emissions are calculated using models

specified in referencesA g, and 12. Emission rate modeling results can be made more realistic by

substituting site-specific data (e.g., moisture content, bulk density, particle size distribution, and

chemical and physical properties of the contaminants) for the default values specified in the

models.

A-2. Dispersion Modeling Procedure. Apply a two-tiered approach when performing

dispersion modeling for point sources. Do screening level modeling first, followed by refined

dispersion modeling if the results from the first model exceed receptor point action levels.

Dispersion modeling for area sources needs only to be done with screening level models.

a. Screening Models. TSCREEN or SCREEN3 are good screening level dispersion models

that can be applied to most HTRW remedial action scenarios for both point sources and area

sources. Both models are available to the public at no cost from the EPA’s Support Center for

Regulatory Air Models (SCRAM) web site at I~tt~:ll~~~~~~~~.e~~~~.tro~~/ttn/sc~-~~~~~/.

b. Re$ned Models. Seek professional dispersion modeling support when doing refined

dispersion modeling for point sources when screening level modeling results exceed receptor

point action levels. Professional help is critical for selecting the model, evaluating

A-2
EP 1110-1-21

30 OCT 00

meteorological data, evaluating site-specific model input parameters, and analyzing results.

c. Meteorological Datu Needs. Meteorological data, both from the surface and upper air, are

necessary input to run refined dispersion models. Sources of both types can be found at

htt]o:llwww.epa.gov /ttn/scram/. The meteorological data at this web site are very

comprehensive. The site will likely have data that can be applied to HTRW remedial action

designs at any location. Only on rare occasions will it be necessary to collect site-specific data.

A-3. Emissions Acceptability. Determine if site-specific emissions to the air are acceptable

by comparing modeled emission rates (point sources) and dispersion modeling results to

emission rate action levels (point sources) and receptor point action levels (point sources and

area sources). Seek support from regulatory specialists and risk assessment staff to define sitespecific emission rate and receptor point action levels. In general, emission rate action levels for

point sources will be defined by state regulations or regulatory guidelines. Receptor point action

levels are also influenced heavily by state regulatory guidelines but often times require risk

assessment input because of a lack of state regulatory criteria. It is very important that HTRW

remedial action designers contact the state air quality regulators in the air quality region where

the project is located very early in the design process to arrive at a mutual understanding of

requirements.

n. Point Sources. The following analysis procedure is recommended for point sources.

(1) Review the proposed design to assure that air emission control technology complies

with state-specific air pollution control technology requirements/guidelines for all pollutants

emitted to the air from the point source.

(2) Compare modeled emission rates to emission rate action levels. Adjust control

equipment efficiency, if necessary, to assure compliance with emission rate action levels. Owing

to the variability of most point source emissions on HTRW sites, the efficiency of emission

control equipment is negotiable with most state regulators.

(3) Compare point source dispersion modeling results to receptor point action levels to

assure that point source emissions are acceptable.

6. Area Sources. The following procedure is recommended for area sources.

(1) Compare area source screening level dispersion modeling results to receptor point

action levels. Area source emissions are considered acceptable if screening level results are less

than receptor point action levels.

(2) Include perimeter air monitoring as part of the remedial action design if screening level

dispersion modeling results exceed receptor point action levels. See Appendix B of this

document for development of perimeter air monitoring action levels.

A-3
EP 1110-1-21

30 OCT 00

A-4. Emission Control Requirements.

a. Point Sources. Point source emissions can be controlled. Emission control equipment

should be applied to point sources if required by state regulations or if emission rate action levels

or receptor point action levels are exceeded.

17. Area Sources. Area source emissions are very difficult to control. The most effective way

to control area source emissions is to control the rate of contaminated material handling. The

remedial action project designer should specify handling rate restrictions if screening level

dispersion modeling results for area source emissions exceed receptor point action levels.

Designers may develop other methods to control area source emissions from HTRW sites, but all

methods chosen should be supported by screening level dispersion modeling results exceeding

receptor point action levels.

A-5. Air Emission Monitoring Requirements.

n. Monitor emissions from point sources at the stack to assure that air pollution control

equipment (if used) is working properly or to assure that emission rate modeling assumptions are

correct. Do not attempt to characterize point source emissions using ambient air sampling

methods at the site perimeter or at off-site sampling locations. Daily variability in wind speed

and direction is too great and makes it impossible to characterize point sources at these locations.

b. Monitor emissions from area sources when screening level dispersion modeling results

exceed receptor point action levels. Use ambient air monitoring techniques at the site perimeter

to check the effectiveness of controls and procedures for limiting emissions to the air from the

area source. Specify use of appropriate sampling equipment and analytical methods. See the

Appendix B of this document to develop perimeter air monitoring action levels.

A-4
Apply state required

emission controls.

Skip this step if not

EP 1110-1-21

30 OCT 00

Air Pathway Analysis Process - Point Sources

NO

Figure A-l - Point Source

APA Summary Flow Chart

Use emission rate in

screening level

dispersion model.

comply with receptor stop

Refined Dispersion

comply with receptor

A-5
EP 1110-1-21

30 OCT 00

i

Estimate Emission

Rate

r

Use Emission Rate in

Screening Level

Dispersion Model.

Air Pathway Analysis Process -Area Sources

Figure A-2 -Area Source APA Summary Flow Chart
EP 1110-1-21

30 OCT 00

APPENDIX B

PERIMETER AIR MONITORING ACTION LEVEL DEVELOPMENT

Table of Contents

Paragraph Page

B-l. Area Sources .................................................................................................................. B-2

B-2. Point Sources.. ............................................................................................................... B-2

Figure Page

Figure B-l. Action Level Development Flow Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

B-1
EP 1110-1-21

30 OCT 00

APPENDIX B

PERIMETER AIR MONITORING ACTION LEVEL DEVELOPMENT

B-l. Area Sources. Develop perimeter air monitoring action levels when perimeter air

monitoring is included as part of a remedial action design. The procedure for developing

perimeter air monitoring action levels applies to area sources only. Follow the step by step

procedure described below to calculate these action levels.

a. Use SCREEN 3 to calculate a dilution factor between the site perimeter and the receptor

point location.

b. Multiply the receptor point action level by the SCREEN3 dilution factor to derive the

perimeter air monitoring action level.

c. Monitor for and enforce the perimeter air monitoring action level at the site perimeter.

B-Z. Point Sources. The procedures for developing perimeter air monitoring action levels do

not apply to point sources. Monitor point sources at the stack using emission rate monitoring

techniques to determine compliance with emission rate action levels.

B-2
EP 1110-1-21

30 OCT 00

Perimeter Air Action Level Development

1 Multiply the receptor Point 1

monitoring action level

measureable at

Design monitoring

system

~ Adjust perimeter

monitoring location

closer to the area

I source.

.

--Nod

Figure B-l -Action Level Development Flow Chart

B-3