## APPENDIX C Haul Road Workgroup FindingsMEMORANDUMUNITED STATES ENVIRONMENTAL PROTECTION AGENCY RESEARCH TRIANGLE PARK. NC 2n11


### March 2, 2012

SUBJECT: Haul Road Workgroup Final Report Submission to 

### EPA-OAQPS FROM: Tyler Fox,

# Lead~r-7**~ J~**  Air Quality Modeling Group, C439-0l TO: Regional Office Modeling Contacts OFFICE OF AIR QUALITY PLANNING AND STANDAROS



### The challenge ofmodeling the emissions and associated air 

### quality impacts ofhaul roads has 

### been a particularly vexing problem for the dispersion modeling community. There is a large degree ofuncertainty in the magnitude ofthese fugitive dust emissions and subsequently in the modeled estimates at near-source receptor locations. At the 2009 Regional, State, and Local Modelers' Workshop, EPA held an intemctive session on best modeling pmctices ofhaul roads that was chaired by Randy Robinson, USEPA Region 

### 5, and Mick Daye, USEPA Region 7 to 

### open up a constructive dialog throughout the regulatory dispersion modeling community on the challenges ofcharacterizing and appropriately addressing the haul road fugitive emissions in a compliance demonstration project. Following this 2009 Workshop, the Haul Road Workgroup was formed with a collection offederal, state, and local government dispersion modelers. The goal ofthis Workgroup was to examine and better understand haul road characterization issues and recommend a modeling methodology back to the broader dispersion modeling community. The Workgroup decided to focus on the air 

### quality modeling aspects and not address the fugitive dust emissions factor issues. A 

### report out ofthe Haul Road Workgroup was presented at the 2010 Regional, State, and Local Modelers' Workshop. Along with discussion amongst the regulatory dispersion modelers in attendance at the 2010 Workshop, feedback and comments were solicited and accepted on the recommendations ofthe Workgroup throughout 2010 and the first halfof2011. An

### update presentation on the Workgroup was given at the 2011 Regional, State, and Local 

### Modelers' Workshop with the subsequent release ofa draft version ofthe Haul Road Workgroup Final Report during the fall of2011.

RacycJed/Recyclable •Prfnled will! Vegelllbl& on Based Inks on 100% Re<:ycled Paper (40% POSiconsumer)

### Attached to this letter is the Haul Road Workgroup Final Report that provides a "best practices guide" for modeling ofhaul road fugitive emissions in the AERMOD modeling system. This final report is being shared with the entire dispersion modeling community prior to the 1Oth Conference on Air Quality Models to promote broader consideration and facilitate further comment. Please send this report to your state, local and tribal agency modelers so that they can provide review and comment, as appropriate. The recommendations presented are not an endorsement by the USEPA as the definitive methodology for characterizing and addressing fugitive dust emissions from haul roads but should be considered a best practice approach based on the broad involvement ofthe co-regulating community in the development ofthis recommendation. We would like to 

### give special recognition to the initiative and labors ofRandy Robinson and Mick Daye in spearheading this initiative in 2009, chairing the Haul Road Workgroup, and developing this final 

### report. We would also like to thank all ofthe federal, state, and local government dispersion modelers that participated in the Workgroup and assisted in the drafting ofthe final report presented in the attachment.

Attachment: Robinson and Daye December 6, 2011 memorandum with Haul Roads Workgroup Final Report included as an attached documentUNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGIONS 77 WEST JACKSON BOUlEVARD CHICAGO, ll60604-3590 

# DEC 

# .·e 2Dif**~. ~y**  TOTHEATTENTJON OF: 

## MEMORANDUM SUBJECT: FROM: TO: Haul Road 

### Workgroup Final Report**~ ~·~**  

### Randy Robinson. EPA Region

# ~- ·' ' '" 

# _·Fl.--'-. Mick 

### Daye, EPA Region 7 

# {M

# £**~** Tyler

### Fox.**~der.** AirQuality

### ModelingGrolip George Bridgers, Clearinghouse 

### Coordinator, AirQuality 

### Mo¢1ing Group
The purpose ofthis memorandum is to I:I'anSmit**~~** 

### attached haul 

### road modeling ftnal 

### report to 

### theAir Quality

### Modeling 

### Group. The report represents the collective 

### efforts ofthe Haul Road Wodcgroup, which was fonned 

### following. the

### 2009 

### Regional/StateiLocal Modeling Workshop. The purpose ofthe**wo~group**

## was to**id~tify'and** 

### recommend a technically 

### supportable approach

## for modeling haul road re-entrained dust. · 

### The attached document

## cOntains a summary of

### the possible 

### options formodeling fugitive· road dust, a descripti9Il of

### the sensitivity modeling**c~** 

### by 

### the 

### workgroup. and a tiered set 

### ofrecommendations 

### for mOdeling haul road fugitiveemissions. The other attachment contains selected.slides from thehaul road presentation at the 2010 Regional/State/Local modeling 

### workshop. The·

### Workgroup 

### requests Air Quality 

### Modeling 

### Group review and distribution ofthe 

### recommencfa.tions document 

### to the modeling 

### community.**~** 

### you and please contact us if

### you have 

### any questions orrequire additional 

### iofonnation.

## Haul Road Workgroup Recommendations November 2011 Workgroup Charge

- The Haul Road Workgroup was formally established shortly after the May 2009 Regional/State/Local Workshop. The purpose ofthe workgroup is to identify and recommend a technically supportable approach for modeling haul road re-entrained dust. While emission factors are a critical part ofany roadway modeling exercise, this workgroup felt that emissions were outside our scope and did not engage in a review or evaluation ofavailable fugitive dust emission factors. Based on modeling work and field study/journal article review, the following represents a recommendation for an approach to characterizing haul road fugitive emissions in AERMOD. Source Characterization

- The model to be used for modeling haul road fugitive dust emissions is AERMOD. There are several ways haul road fugitive dust emissions can be characterized in AERMOD, including area source, volume source, and series ofpoint sources. A line source algorithm is being developed but is not currently available. Each approach has advantages and disadvantages. The workgroup has considered each approach and a summary ofthe strengths and weaknesses is presented below. Area source advantages:

• Can place receptors in ambient air contained within the area source • Easy to replicate dimensions ofroadway in X and Y coordinates • Avoids the need to determine Sigma Y values (Sigma Z values are optional) • Can utilize a Sigma Z value ifdesired, to reflect an initial, well-mixed plume • Area sources explicitly simulate a uniform emission density across the roadway, which may be more realistic in some respects than other approaches. Area source disadvantages:

• Area source in AERMOD does not have the meander algorithm • Run times are generally longer than other approaches Volume source advantages:

• Volume source in AERMOD contains meander algorithm • Conceptually, a volume source mimics an initial, well-mixed plume • Potentially faster run time than area source

1Volume source disadvantages:

• Concentrations are not calculated in a volume source exclusion zone o Exclusion zone is the region ( (2.15 x Sigma Y) 

### + 1 meter)) from the center ofthe volume. Point Source with downwash advantages:

• Precludes the need to establish Sigma values; handled internally by downwash • Conceptually, consistent with well-mixed plume • Can place receptors anywhere within roadway • Can be used for buildings near roadways Point source with downwash disadvantages:

• Downwash algorithm in AERMOD does not contain meander for receptors within the wake • Technique would be new to modeling community • Additional assumptions required, including building (truck) size, stacktemp, velocity, height. • Potential issues with BPIP used in this technique 

### Sensitivity analysis Early in the process, the workgroup conducted an AERMOD sensitivity analysis to examine changes in haul road characterization inputs using volume and area source techniques. Limited, preliminary point source technique sensitivity runs were also conducted. Details ofthe sensitivity analyses are available at http://www.cleanairinfo.com/regionalstatelocalmode

### Iingworkshop/archive/20 1 0/Docume nts/Presentations/RSL20I0 HauiRoads.pdf. The following summarizes the setup and general conclusions. Analysis setup:
• Used AERMOD Version 09292 • 1year ofmeteorological data (variety oflocations) • N-S and E-W crisscrossing road segments. Each 500m long, 1Om wide. • Flat Terrain • Receptor Grids- Cartesian and Polar; beginning as near as possible to the volume sources. 1 meter from edge ofarea source. No receptors within source. • Unit emission rate • Evaluated range ofvalues for top ofplume height, Sigma Z, Sigma Y, and release height. • Modeled using Adjacent Volume, Alternate Volume, and Area source representations. 

### 2• Calculated results for annual ave, peak 1-hr, 8th H 1-hr, peak 24-hr, gth H 24-hr • Point source modeling examined single vs multiple stacks and varying stack parameters.
General Conclusions:

• Increasing release height (and related Sigma Z) led to lower concentrations. • Increasing Sigma Y for alternate and adjacent volume sources lowered concentrations. • For area source- increasing X dimension lowered concentrations at lower release heights (i.e., Om and 0.5m). It had little impact at higher release heights (i.e, 1.5m and 3m). • For area source- adding a Sigma Z lowered concentrations for surface release heights, but generally increased concentrations at higher release heights • For volume runs, adjacent gives higher concentrations than alternate. • Point Source- limited, preliminary modeling shows some sensitivity to stack height and velocity • On-site meteorological data model runs showed same trends as with National Weather Service data, although concentrations were higher with on-site data.


### Model/Monitor Comparison The workgroup was interested in locating field data to facilitate our review ofhaul road dispersion characteristics. Finding field data relevant to our task was difficult. While there are numerous field studies relevant to haul roads, the vast majority deal with monitoring designed to evaluate haul road emissions rather than dispersion characteristics. An evaluation conducted by OAQPS in 2006 examined haul road emissions from the Cordero Rojo Mine in Eastern Wyoming. The modeling looked at volume and area source configurations in AERMOD. The study, while limited, showed volume source characterizations performing slightly better than area source when compared to monitored PMl0 data. The analysis was primarily designed to examine the impact ofthe meander algorithms. This is significant because the volume source approach incorporates meander while the area source approach does not. The difference in model performance was attributed to area source over-estimates due to lack of meander upwind dispersion. Details ofthe Cordero Rojo Mine evaluation results can be found at http://www.awma.org/events/confs/AQMODELS06/Session%204/4- Roger%20Brode.pdf.



### 3

### Haul Road Recommendations Definitions During the workgroup discussions and sensitivity modeling work, the following definitions were used; "VH" means vehicle height**[~3m** for typical haul trucks;**~1Om** for large mining trucks] "VW" means vehicle width**[~3m** for typical haul trucks; -lOrn for large mining trucks] "VL" means vehicle length**[~I**Om for typical haul trucks; -20m for large mining trucks] These definitions and associated dimensions were useful to the group as we discussed the various methods and developed the inputs to be used in the sensitivity modeling. They should not be treated as default values and/or used in place ofsite specific dimensions available for individual modeling demonstrations. General Recommendation The following represents a general recommendation for modeling ofhaul road emissions. The recommendation is not meant to be prescriptive; local conditions and specific information may lead to an alternative approach. However, the workgroup feels that the recommendation presented below is reasonable, can be technically supported, and provides a level ofconservativeness given the large amount ofuncertainty associated with characterizing and simulating dispersion offugitive emissions resulting from haul road traffic. Concentrations must be calculated in areas that are considered ambient air. 1

• Volume Source- Recommend for all haul roads, except for cases where ambient air receptors are within the volume's exclusion zone (i.e., ( (2.15 x Sigma Y) 

### + 1 meter)) from the center ofthe volume.
Rationale: Volume source contains the meander algorithm. Conceptually fits the physical parameters associated with well-mixed plume. Limited model/monitor comparison study information supports volume source Recommended Volume Source Configuration:

o Adjacent Volume Source

1Ambient Air is defined at 40 CFRPart SO.l(e) and further clarified in a December 19, 1980 from Douglas Costle to SenatorJennings Randolph. See http://www.epa.gov/scramOOl!guidance/mch/ama4.txt 

### 4o Top ofPlume Height2

- 1.7 x VH o Volume Source Release Height- 0.5 x Top ofPlume height o Width ofPlume- VW + 6m for single lane roadways 

### I Road Width+ 6m for two lane roadways3• o Initial Sigma Z- Top ofPlume 

### I 2.15 AERMOD User's Guide, Table 3-1 for use when modeling multiple volumes. o Initial Sigma Y- Width ofPlume 

### I 2.15 AERMOD User's Guide, Table 3-1 o Emissions input as g/s

• The 1.7 factor in the Top ofPlume Height equation above is supported by information in a 2005 Atmospheric Environment paper by Gillies, et. al, entitled Effect ofVehicle Characteristics on Unpaved Road Dust Emissions. • The Width ofPlume value is based on a conservative adaptation ofmonitor placement guidance from EPA's 1992 document, Guideline for Modeling Carbon Monoxide from Roadway Intersections. In that document, it is recommended that monitors not be placed nearer than 3 meters from the roadway edge to account for vehicle turbulence. Two-lane roadways are for cases with heavy two-way traffic where the combined plume needs to be approximated. Agencies may need to consider traffic counts, vehicle width, road width, and the amount oftwo-way traffic, in order to determine whether the roadway is best represented using single-lane or two-lane assumptions. While the workgroup's sensitivity analysis indicates increased volume source width leads to decreased concentrations, our group didn't specifically examine single-lane versus two-lane roadways. One option is to model two-lane roadways as two, single-lane volume sources. • For cases where ambient air receptors fall within the volume source exclusion zone, a conservative volume source approach would be to reduce the width ofplume dimensions enough so thatthe ambient air receptors are not inside the exclusion zone. Additionally, a mix ofarea sources and volume sources may adequately allow for consideration ofall ambient air receptors. 

### Area Source- Recommended for haul roads where ambient air receptors are located within source dimensions. Rationale: Volume source doesn't allow placement ofreceptors within exclusion zone. Area source can calculate concentrations at receptors within source. Area source can simulate volume source with use ofsimilar release height and Sigma Z parameters.

2 Gillies, J.A., V. Etyemezian, H. Kuhns, D. Nikolic, D.A. Gillete, 2005. Effect ofVehicle Characteristics on Unpaved Road Dust Emissions. Atmospheric Environment, 39,2341-2347 3 EPA. 1992. Guideline for Modeling Carbon Monoxide From Roadway Intersections. EPA-454/R-92- 005. http://www.epa.gov/scramOOI/guidance/guide/coguide.pdf 

### 5Recommended Area Source Configuration

o Length

- length ofroadway segment (Aspect ratio in AERMOD extended to 100:1 before warning is issued. See Model Change Bulletin #3, Miscellaneous item 

### # 1 0) o Width- VW + 6m for single lane 

### I Road Width+ 6m for two-lane (same comment as for volume, two single-lanes is an option) o Top ofplume height -1.7 x VH o Release height- 0.5 x top ofplume height o Sigma Z- Top ofPlume height 

### I 2.15 o Emissions input as g/s/m2 

### Point Source- The workgroup is not forwarding any point source recommendation at this time. There are potential benefits to this approach, however, more study is needed.


### FutureEfforts The workgroup understands that efforts are underway on a line source algorithm to be included in AERMOD. The time frame for completion ofthis work may be within the next couple years. A new line source algorithm would likely supplantthe need to model haul road fugitive dust emissions using either volume, area, orpoint sources. Point source modeling offugitive roadway emissions has some potential benefits, as noted earlier in this paper. One example is the ability to consider the influence offacility structures located near roadways when simulating the roadway fugitive dust in AERMOD. The Haul Road Workgroup supports further study ofthis approach. More field studies examining initial plume dimensions are encouraged. The effects of vehicle speed on the initial plume dimensions is an area that should be investigated when, or if, more field studies are conducted.



### 6

### References Brode, R.W., Improved Algorithms for Modeling Impacts Near Roadways. MACTEC Federal Programs, Inc. A&WMA Specialty Conference, Denver, CO, April2006 EPA. 1992. Guideline for Modeling Carbon Monoxide From Roadway Intersections. EPA-454/R-92-005. http://www.epa.gov/scramOOI/guidance/guide/coguide.pdf EPA. 1994. Modeling Fugitive Dust Impacts from Surface Coal Mining OperationsPhase II. EPA-454/R-94-025 Eskridge, R. E., Thompson, R.S., 1982, Experimental and Theoretical Study ofthe Wake • ofa Block-Shaped Vehicle in a Shear-Free Boundary Flow. Atmospheric Environment, 16,2821-2836 Fitz, D. R., 2001. Measurements ofPM10 and PM2.5 Emission Factors from Paved Roads in California. ContractNo. 98-723. California Air Resources Board, Monitoring and Laboratory Division Gillies, J.A., V. Etyemezian, H. Kuhns, D. Nikolic, D.A. Gillete, 2005. Effect ofVehicle Characteristics on Unpaved Road Dust Emissions. Atmospheric Environment, 39,2341- 2347. Guideline on Air Quality Models, US Environmental Protection Agency, 40 CFR Part 51, Appendix W, November 9, 2005. Heinerikson, A., Goodman, A., Anderson, K., Analysis ofHaul road Emission Test Data for Determining Dispersion Modeling Parameters. Trinity Consultants. Reed, W. R., Performance Evaluation ofa Dust-dispersion Model for Haul Trucks. National Institute for Occupational Safety and Health, Pittsburgh Research Lab. User's Guide for the AMS/EPA Regulatory Model- AERMOD, US Environmental Protection Agency, EPA-454/B-03-001, September 2004. Westbrook, J.A., Sullivan, P.S., Fugitive Dust Modeling with AERMOD for PMlO Emissions from a Municipal Waste Landfill. Williams, D.S., Manoj, K.S., Ross, J., Particulate Matter Emission by a Vehicle Running on Unpaved Road. 2008. Atmospheric Environment, 42, 3899-3905.



### 7

### Select Slides from May 2010 Regional/State/Local Workshop Presentation 

# SensitivityAnalysis Work

111 

### Used AERMOD Version 09292 111 

### 1 year of meteorological data (variety of locations) 111 

### N-S and E-W crisscrossing road segments. Each 500m long, 10m wide. • Flat Terrain • Receptor Grids
- Cartesian and Polar; beginning as near as possible to the volume sources. 1 meterfrom edge of area source. No receptors within source.



# Cont.

• Unit emission rate 111 

### Evaluated range ofvalues for top of plume height, Sigma Z, Sigma Y, and release height. 11 

### Modeled using Adjacent Volume, Alternate Volume, and Area source representations. • Calculated results for annual ave, peak 1hr, Sth 

### H 1hr, peak 24hr, Sth 

### H 24hr,

1

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# Matrix ofValues for Analysis

Top of Plume Height I 

### 2.15 10m/2.15 16m/2.15 Top of Plume Height /2



### 2

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### 5 5

# j 

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Raloaso Holght (m)

Area Source -1ST01 H_BOTH

Changing Releaae Height NoSigmaZ

10 X Dlmonsl<>n (m)



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### 5m 

### I Sigma Z - 4.65/ Sigma V - 4.65**·~** ,..,___ Oft ......,...,."iil 

### MAX. CONCENTRATION- 89 ug/m3 72 3 Case Study 7m Top of Plume /10m Plume Width 8th High 24-hourAva.

Scenarios

Adjacentvs Altemala 1-hrAverage Results

W**~** U m M U M V**~** Scenario



### 8Hhl ftrizxrlal =**4.~** Volume Source

Dlctlllot(mt1tr0) llnlceFe!gUSOII- MOEQ

a•tinct (mtin) llnlceFerguson- MDEQ

9

# Haul Road as Point Sources**~** 

### RanAERMOD using pointsourcesto represent haul road**~** 

### Flatterrain • Assume buildingwith dimensionsof3mx 3m x 1Om -oriented along roadway. • Locate pointateach comerof building- 384 total stacks. • 1 g/s emissions distributed among stacks



# Continued
... • Stack height= 1.5m and 3.5m • Temperature=ambient • Velocity= .001 m/s • Diameter= 0.5m • Receptors- cart. - start 11 mfrom centerof road at25 m resolution plus 10 degreepolar at250mat 50 m resolution

10POINT SOURCE WITH DOWNW ASH 

### Annual Average tack Ht.- 1 .5m I Dlam. - 0.5m I Ambient T I Vel. - 0.001

Casestuctr 7m Top of Plune /10m Plune Wclh 8th Hgh24-hou' Ave.

I Scemrios



### 11

# General Conclusions for SensitivityAnalysis Runs**~** 

### Increasing RH (release height)always led to lower concentrations.**~** 

### Increasing Sigma Yforalt. andadj. volume sources lowered concentrations.**~** 

### Forarea source- increasingX dimension lowered concentrations at0 and 0.5 RH, at 1.5 and 3m RH, had little impact on concentrations.**~** 

### Forarea source- adding a sigma z lowered concentrations forO RHs, but usually increased concentrations at 1.5 and 3.5 RHs, mixed results for 0.5mRH.



# Cont.

11 

### Forvolume runs, adjacentgives higher concentrationsthan alternate. 11 

### PointSource-limited modeling shows sensitivityto stack height; little sensitivityto stackdiameter. a On-site metdata runs showedsametrends as NWS, although concentrations higherwith on-site.

12