Fugitive Dust from Coal Trains:

Factors Effecting Emissions 

& Estimating PM2.5

Robert Kotchenruther

EPA Region 10

NW-AIRQUEST 2013 
Background

The main reason I looked into this topic was to address a 

public comment EPA received in relation to our federal 

register notice, which proposed approving WA Dept. of 

Ecology’s 2008 baseline emissions inventory (EI) for 

Tacoma. 

The comment came from the Sierra Club and suggested 

the Tacoma 2008 EI was deficient for not discussing or 

accounting for fugitive dust from coal trains in the EI. 

I was asked to see what could be estimated about coal 

train fugitive dust impacts in Tacoma. 
Background

Based on US Coal export data*, coal exports from the 

‘Seattle’ export district (includes Tacoma up through the 

Canadian boarder) were as follows:

So there was some level of coal transported in 2008 (and 

probably through Tacoma).

*http://www.eia.gov/coal/

Year Coal Exported (tons)

2008 30581

2009 365260

2010 3500204

2011 4854451

2012 4746960
Why is this an area of interest now generally?

 There is growing interest from Asian markets in U.S. export coal. 

 Currently there are 7 proposed or existing coal export terminals along the west coast 

 (4 U.S. & 3 Canadian). 

 Coal transport could increase quickly. 

Existing and proposed coal export capacity.

(in millions of tons)

BC Canada 2012 2017 2022

Prince Rupert 0.0 1.5 5.0

N. Vancouver 0.0 2.0 5.0

Roberts Bank 5.0 8.0 15.0

Washington

Cherry Point 0.0 27.5 52.5

Grays Harbor 0.0 0.0 5.0

Longview 0.0 27.5 48.0

Oregon

St. Helens 0.0 5.0 21.0

Boardman 0.0 3.5 8.5

Coos Bay 0.0 0.0 10.0

Totals 5.0 70.0 139.0

(Source: Whiteside et al., 2012)
Coal Transport and Source Location

 The majority of export coal would come from the Powder River Basin (PRB) in MT/WY.

 Based on current pricing, BNSF would be the primary U.S. rail carrier from PRB to PNW.

Rail routes from PRB to proposed U.S. Pacific Northwest Coal Terminals 

Powder River Basin 
Coal Train Frequency Based on Projected Capacity

 The number of coal trains per day on rail routes would significantly increase if these 

terminals are built. 

Proposed coal export capacity and number of projected loaded coal trains per day. 

BC Canada 2022 (106 tons) Loaded trains per day*

Prince Rupert 5.0 0.9

N. Vancouver 5.0 0.9

Roberts Bank 15.0 2.8

Washington

Cherry Point 52.5 9.8

Grays Harbor 5.0 0.9

Longview 48.0 8.9

Oregon

St. Helens 21.0 3.9

Boardman 8.5 1.6

Coos Bay 10.0 1.9

Totals 139.0 25.8

(*assumes 14,750 tons per train, 125 cars per trains; there will be an equal number of empty trains returning to the PRB)
Some Communities will be Impacted More than Others

 Some transit portions have multiple route options, some only one. 

 Every BNSF coal train from the PRB to PNW would go through ‘the funnel’ (Sandpoint – Spokane)

 Three BNSF routes from Spokane to pacific terminals (all would be utilized). 

BNSF – Pacific Northwest Rail Map

‘The funnel’

Sandpoint, ID – Spokane, WA

Three Routes from Spokane to coast

Stevens Pass

Stampede Pass *(empty returns only)

Columbia River Gorge
Community Concerns 

There are a range of community concerns related to 

increased coal train traffic, some of these are:

 Air quality impacts from fugitive coal dust 

 & increased diesel emissions

 Ecological impacts of coal dust

 Derailments

 Longer rail crossing wait times

 Rail infrastructure improvement 

cost burden on local communities

 ‘Nuisance dusting ‘ of coal dust 

on cars/homes

 Rail congestion adverse impacts on current rail 

customers (e.g., container ports, ag shipments) 

 Long term climate impacts
Factors Effecting the Amount of Fugitive Coal Dust from 

Coal Trains. 

Car and load geometry

rail car dimensions 

coal load profile

total exposed surface area of coal

Coal physical properties

coal moisture content

coal size distribution 

Trip specifics 

train speeds throughout route 

load jostling in route 

total journey length 

weather: wind, precipitation, temp

Dust controls

control measure effectiveness and 

percent remaining at end of journey 
Dust control measures

Rail lines have an economic incentive to reduce fugitive coal 

dust ... coal dust in track ballast increases the frequency and 

cost of track maintenance and can lead to derailments. 

In 2010 BNSF and Union Pacific conducted a field evaluation 

of coal dust suppressant technologies. 

 Trackside and train-board aerosol monitors were used.

 1633 coal trains treated with various dust suppressant 

technologies.

>85% dust suppression was achieved with:

Specific load profile guidelines

and

applying a topper agent to loaded coal 

As of October 2011 BNSF’s Coal Loading Rule requires coal 

shippers to use measures achieving > 85% dust suppression. 
Estimating Fugitive Coal Dust Emissions from Coal Trains. 

No clear information about how much coal is lost through fugitive dust in transit. 

Various sources give a range of 0.5% to 3% of total coal transported is lost through fugitive 

dust when there are no dust control measures. 

Wind tunnel experiments (1983) have estimated losses on the order of 0.9 to 1.8% for a 

1100 km journey.
Canadian EI Example 

Canadians EI’s have been using a distance based equation based on a report titled 

“A Study of Fugitive Coal Dust Emissions in Canada” (Cope and Bhattacharyya, 2001). 

The base equation is (for total suspended particulate, TSP):

Emissions Factor (kg/tonne) = 0.1*(0.62*D)0.6

Where 

D = total distance travelled by rail cars (km)

This equation gives 0.5% coal loss over a 1100 km transit, so on the low end of the 0.5 – 3.0% 

uncontrolled coal fugitive dust losses. 

Their recommended equation for TSP estimates yearly emissions including terms for 

precipitation (P), emissions controls (CE), and estimating emissions for only a segment (SD) 

of the total rail trip. 

Emissions Factor (kg/tonne) = 0.1*(0.62*D)0.6 * (365-P)/365 * (SD/D) * (100-CE)/100

Where

D = total distance travelled by rail cars (km)

SD = rail segment estimation emissions for (km)

P = number of days in the year with measureable precipitation (rain and snow)

CE = Control efficiency of any applied dust control measures (%).
Example: Applying Canadian Method to Tacoma 

WRAP and AP-42 recommended a PM2.5 / TSP ratio of 0.15

(Cope and Bhattacharyya used 0.2, from US EPA AP-42 c. 2000)

PM2.5 Emissions Factor = 0.15 * TSP Emissions Factor (kg/tonne)

Example for Tacoma WA using Cope and Bhattacharyya (2001) formula. 

(Emissions Factor (kg/tonne) = 0.1*(0.62*D)0.6 * (365-P)/365 * (SD/D) * (100-CE)/100)

Assumptions: SD = 40 km, D = 2414 km (1500 mi), PM2.5/TSP EF = 0.15

all Seattle export district coal exported through Tacoma 

all projected Cherry Point coal exported through Tacoma

Tacoma nonattainment area estimated coal train fugitive PM2.5 (tons per year)

For comparison, the Ecology Tacoma 2008 SIP EI lists yearly emissions of PM2.5 of:

1199 TPY for Residential wood combustion & 411 TPY for onroad sources

Year Control Efficiency (%) # Precipitation days Coal Exported (tons) Tacoma NAA PM2.5 (TPY)

2008 0 161 30581 0.3

2009 0 146 365260 4.4

2010 0 190 3500204 33.5

2011 85 (3 months) 166 4854451 44.4

2012 85 177 4746960 7.3

2017* 85 168 27500000 44.5

2022* 85 168 52500000 84.9

*projected
Uncertainties with Canadian method: Many, but it does 

give us an estimation method. 

Questions / unknowns / simplifications 

• Some evidence for nonlinear dust loss over journey (more earlier on), but this equation 

assumes linear

• Majority of dust lost may be through ‘dusting events’. Some sections of track may be 

more prone to dusting events based on topography, typical winds, typical train speed, etc.

• Effectiveness of controls may wear off throughout journey, leading to more dust later in 

the journey.

• Does not account for emissions from ‘empty’ return trains (coal residue can emit fugitive 

dust)

• Fugitive dust is directly related to train speed, train speeds make be slower through 

cities(?)

• How variable is the coal size distribution?

• How variable is coal moisture content?

• How important are seasonal effects (winter/summer – temperature / humidity / winds )

• Effects of precipitation are simplified. 

However, for estimating annual emissions the importance of some of the above variability 

may be reduced. 
Other activity around coal train fugitive dust? 

For the Gateway Pacific Terminal at Cherry Point WA

An environmental impact statement (EIS) is being developed under guidelines from the 

National Environmental Policy Act (NEPA) and the State Environmental Policy Act (SEPA).

Air quality is one of many environmental impacts under review. 

Uncertain if this will lead to measurements and/or improved fugitive dust estimates.

The agencies coordinating the EIS are

U.S. Army Corps of Engineers, 

WA State Department of Ecology, and 

Whatcom County 

EIS Timeline:

9/2012 – 1/2013 Public input on scope of EIS

3/2013 EIS scoping summary report issued (summary of comments)

~2014 Issue draft EIS

~2014/2015 Issue final EIS
Other activity around coal train fugitive dust? 

Dan Jaffe (UW Prof.) will conduct a short trackside study based on ‘crowdsource’ funding. 

Duration: 4-6 weeks

Location: North of Seattle (?)

Time: Summer/Fall 2013

Currently proposing to 

measure 

 PM1, 

 PM2.5, 

 PM10, 

 TSP, and

 Met. variables 
Selected References:

BNSF, 2010, Summary of BNSF/UP Super Trial 2010, 

http://www.bnsf.com/customers/pdf/coal-super-trial.pdf

Cope and Bhattacharyya, 2001, A Study of Fugitive Coal Dust Emissions in Canada, An 

Unpublished Report Prepared for the Canadian Council of Ministers of the Environment. 

Cowherd, 2006, Background Document for Revisions to Fine Fraction Ratios Used for AP42 Fugitive Dust Emission Factors, 

http://www.epa.gov/ttn/chief/ap42/ch13/bgdocs/b13s02.pdf

US EPA, 2013, AP-42 Emissions Factors, http://www.epa.gov/ttnchie1/ap42/

Whiteside et al., 2012, Heavy Traffic Ahead: Rail Impacts of Powder River Basin Coal to 

Asia by Way of Pacific Northwest Terminals, http://heavytrafficahead.org/pdf/HeavyTraffic-Ahead-web.pdf
Thank you for 

your attention!