i

SIP Revision 

for the

Spokane County, Washington 

Second 10-Year Limited Maintenance Plan

for Carbon Monoxide

Spokane Regional Clean Air Agency

Spokane, Washington

In conjunction with

Air Quality Programs

Washington State Department of Ecology

Olympia, Washington

April 2016
ii

April 2016

Publication and Contact Information

This report is available on Spokane Regional Clean Air Agency’s website, www.SpokaneCleanAir.org.

Contact:

Spokane Regional Clean Air Agency

Attn: Margee Chambers

3104 E. Augusta Avenue

Spokane, WA 99207

Phone: (509) 477-4727 ext. #114

Fax: (509) 477-6828

Email: mchambers@spokanecleanair.org
iii

April 2016

Table of Contents

Publication and Contact Information............................................................................................................ ii

Table of Contents......................................................................................................................................... iii

List of Figures and Tables.............................................................................................................................. v

Figures....................................................................................................................................................... v

Tables........................................................................................................................................................ v

Acronyms and Abbreviations....................................................................................................................... vi

Acknowledgements.................................................................................................................................... viii

Abstract/Executive Summary....................................................................................................................... ix

1.0 Introduction ............................................................................................................................................1

2.0 Background .............................................................................................................................................1

2.1 General and Historical Information ....................................................................................................1

2.2 Planning Direction...............................................................................................................................3

2.3 Spokane CO Maintenance Plan Area ..................................................................................................3

2.4 CO Monitoring Network......................................................................................................................3

3.0 Air Quality Status ....................................................................................................................................4

3.1 Exceedances........................................................................................................................................4

3.2 Second Highest 8-hour Averages........................................................................................................5

3.3 Design Value........................................................................................................................................5

4.0 Existing CO Control Strategies ................................................................................................................6

4.1 Federal Motor Vehicle Emissions Control Program............................................................................6

4.2 Washington State I/M Program..........................................................................................................6

4.3 Oxygenated Fuels................................................................................................................................6

4.4 Administrative Orders.........................................................................................................................7

4.5 Solid Fuel Burning Device Standards...................................................................................................7

5.0 State Measures Not In State Implementation Plan ................................................................................7

6.0 State Implementation Plan Requirements .............................................................................................8

7.0 CO Limited Maintenance Plan.................................................................................................................8

7.1 Attainment Inventory .........................................................................................................................8

7.1.1 Onroad Mobile Sources .............................................................................................................10

7.1.2 Area Sources ..............................................................................................................................11

7.1.3 Nonroad Mobile Sources ...........................................................................................................11

7.1.4 Point Sources .............................................................................................................................12

7.1.5 Changes in Source Category Contributions ...............................................................................12
iv

April 2016

7.2 Maintenance Demonstration............................................................................................................12

7.3 Verification of Continued Attainment ..............................................................................................13

7.3.1 Alternate Method for Verification of Continued Attainment....................................................13

7.4 Contingency Plan...............................................................................................................................14

7.5 Conformity Determinations..............................................................................................................15

7.6 Risk of a Future Violation..................................................................................................................15

7.7 Summary of Maintenance Plan Commitments.................................................................................16

Appendix A. Emission Inventory Details.....................................................................................................17

1 Introduction .........................................................................................................................................17

1.1 Purpose and Background ..............................................................................................................17

1.2 Pollutants and Sources..................................................................................................................17

1.3 Spatial Resolution .........................................................................................................................17

1.4 Temporal Resolution.....................................................................................................................17

2 Statistics Used Throughout the Inventory ...........................................................................................17

2.1 County Demographics...................................................................................................................17

2.2 Meteorological Parameters..........................................................................................................18

3 Base Year 2011 Emissions Estimates ...................................................................................................18

3.1 Point Sources ................................................................................................................................18

3.2 Onroad Mobile Sources ................................................................................................................19

3.3 NONROAD Mobile Sources, Excluding Locomotives and Aircraft.................................................20

3.4 Locomotives..................................................................................................................................21

3.5 Silvicultural Burning (Prescribed Burning) ....................................................................................22

3.6 Agricultural Burning ......................................................................................................................23

3.7 Residential Yard Waste Burning Leaf and Brush...........................................................................24

3.8 Municipal Solid Waste Burning .....................................................................................................25

3.9 Residential Fuel Use, excluding Wood..........................................................................................25

3.10 Residential Wood Combustion ...................................................................................................26

Appendix B. Washington State and SRCAA Rules.......................................................................................28

Appendix C. EPA AirData Carbon Monoxide Data Printouts.......................................................................29

Appendix D. Kaiser Closure Letters.............................................................................................................70

Appendix E. SRCAA Resolution 05-19 Repeal of Motor Fuel Specifications for Oxygenated Gasoline ......72
v

April 2016

List of Figures and Tables 

Figures

Figure 1 Spokane County CO Maintenance Area..........................................................................................2

Figure 2 Second Highest 8-Hour CO History for Spokane.............................................................................5

Figure 3 Spokane CO Area Design Values, 2003-2014..................................................................................6

Figure 4. Spokane CO Emission Categories and Percentages.....................................................................10

Tables

Table 1. Spokane Monitored 8-hour CO Values and Exceedances...............................................................4

Table 2. Source Categories Inventoried for CO Emissions............................................................................9

Table 3. Spokane CO Emissions, (SRTC, adjusted to 2014).........................................................................10

Table 4. On-road CO Emissions, SRTC.........................................................................................................13

Table 5. Spokane Area 2010-2040 Air Quality Conformity Analysis...........................................................15
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April 2016

Acronyms and Abbreviations

ADVMT Average Daily Vehicle Miles Traveled

AIRPACT Air Indicator Report for Public Awareness and Community Tracking

AOP Air Operating Permit issued under Title V of the Clean Air Act

AP-42 or AP42 AP-42, Compilation of Air Pollutant Emission Factors

AQMA Air Quality Maintenance Area

BIA Bureau of Indian Affairs

CAA Clean Air Act

CNG Compressed Natural Gas

CO Carbon monoxide

CO maintenance area Carbon Monoxide Air Quality Maintenance Area 

CRO Central Regional Office of Ecology

DNR Washington State Department of Natural Resources

DOL Washington State Department of Licensing

Ecology Washington State Department of Ecology

EIA Energy Information Administration

EIIP Emission Inventory Improvement Program

EPA Environmental Protection Agency

ERO Eastern Regional Office of Ecology

FTA Federal Transit Administration

HDD50 Heating degree days based on 50 degrees

I/M Washington State Vehicle Inspection and Maintenance Program

lbs. Weight in pounds

LMP Limited Maintenance Plan

LPG Liquefied petroleum gas

mg/m3 milligram per cubic meter

MOA Memorandum of Agreement

MOVES EPA's Motor Vehicle Emission Simulator model version 2010b

MOVES2014 EPA's Motor Vehicle Emission Simulator model version 2014

MSW Municipal Solid Waste

MTP Metropolitan Transportation Plan

MVEB Motor Vehicle Emission Budget

NAA Nonattainment Area

NAAQS National Ambient Air Quality Standard

NONROAD2008 EPA's non-road emissions model version 2008a

NOx Oxides of Nitrogen

NRC2007 Survey conducted by the National Research Center in 2007

NW-AIRQUEST or 

AIRQUEST

Northwest International Air Quality Environmental Science and 

Technology Consortium

OAQPS EPA Office of Air Quality Planning

OBD On Board Diagnostic systems

ODEQ Oregon Department of Environmental Quality
vii

April 2016

OFM Washington State Office of Financial Management

OSPI Washington State Office of the Superintendent of Public Instruction

PM Particulate Matter

ppm parts per million

ppmv parts per million by volume

PSCAA Puget Sound Clean Air Agency 

PSD Prevention of Significant Deterioration 

SCAPCA Spokane County Air Pollution Control Authority1

SIP State Implementation Plan

SRCAA Spokane Regional Clean Air Agency

SRTC Spokane Regional Transportation Council

Title V Title V of the federal Clean Air Act or Air Operating Permit program

tps tons per season

tpy tons per year

USFS U.S. Forest Service

VISUM Transport network and travel demand modeling software

VMT Vehicle Miles Traveled

VOC Volatile Organic Compounds

WAC Washington Administrative Code

WEIRS Ecology's Washington Emissions Inventory Repository System

WSDOT Washington State Department of Transportation

WSU2001 Survey conducted by Washington State University in 2001

 

1

In 2007 the Board of the Spokane County Air Pollution Control Authority (SCAPCA) changed their name to the 

Spokane Regional Clean Air Agency (SRCAA), Resolution #07-15
viii

April 2016

Acknowledgements 

The authors of this report would like to thank the following people for their contribution to this study:

Spokane Regional Clean Air Agency

Margee Chambers

Ron Edgar

Carl Gross

Julie Oliver

Mark Rowe

April Westby

Washington State Department of Ecology

Laurie Hulse-Moyer

Sean Lundblad

Sally Otterson

Mike Ragan

Spokane Regional Transportation Council

Anna Ragaza-Bourassa
ix

April 2016

Abstract/Executive Summary 

The Spokane County Carbon Monoxide Maintenance Area (CO SCMA), which includes the cities of 

Spokane, Spokane Valley and Millwood and surrounding unincorporated areas, has been in compliance 

with the 8-hour carbon monoxide (CO) National Ambient Air Quality Standard (NAAQS) since 1997. The 

U.S. Environmental Protection Agency (EPA) originally classified Spokane as a “moderate plus” 

nonattainment area (NAA) based on monitoring data for 1988 and 1989. Spokane was reclassified to 

“serious” nonattainment due to violations of the standard in 1995. The area has been monitored in 

attainment of the CO 8-hour standard [9 parts per million, by volume (ppmv)] since 1997. With the 

completion and approval of an attainment State Implementation Plan (SIP) and maintenance plan, the 

Spokane County NAA was re-designated to attainment in 2005. The Clean Air Act (CAA) requires that an

area re-designated from nonattainment to maintenance submit two consecutive 10-year plans for 

maintaining compliance with the NAAQS. 

This Spokane CO Plan is submitted by the Spokane Regional Clean Air Agency (SRCAA) for inclusion into 

the Washington SIP and will serve as the second 10-year CO maintenance plan for the CO SCMA. This 

document demonstrates that the Spokane area will be in compliance with the NAAQS for CO through 

2025 and meets EPA requirements for a Limited Maintenance Plan (LMP).

The current NAAQS for CO is 9 ppm for an 8-hour average and 35 ppm for a 1-hour average, not to be 

exceeded more than once per year. The current 8-hour CO design value for the Spokane CO area is 2.3 

ppm based on 2013-2014 data. The Spokane area had a fairly rapid drop in ambient CO levels during the 

first four years of the first maintenance plan, 2005-2008, and consistently low levels through 2014.

Spokane’s design value of 2.3 ppm qualifies for use of the LMP approach in preparing this CO 

maintenance plan. EPA detailed the LMP approach in a memorandum entitled “Limited Maintenance 

Plan Options for Nonclassifiable CO Nonattainment Areas” from Joseph Paisie, Group Leader, Integrated 

Policy and Strategies Group, Office of Air Quality Planning and Standards (OAQPS), dated October 6, 

1995. (LMP Guidance)

According to LMP Guidance, EPA will consider the maintenance demonstration satisfied if the 

monitoring data show the design value is at or below 7.65 parts per million (ppm), or 85 percent of the 

levels of the 8-hour CO NAAQS. The design value must be based on eight consecutive quarters of data.

Another of the requirements for an area to be eligible to use the LMP option is that the control 

measures from the previous maintenance plan remain in the Federally-approved SIP. This plan relies on 

control strategies focused on the Federal Motor Vehicle Emission Control Program, an approved basic 

vehicle Inspection and Maintenance program, and transportation control measures. The control 

measures from the first 10-year CO maintenance plan include:

 Federal Motor Vehicle Emission Control Program – 40 CFR Part 86

 WAC 173-422-031, Vehicle Emission Inspection Schedule

 WAC 173-422-170, Exemptions

 WAC 173-492, Motor Fuel Specifications for Oxygenated Gasoline

 Kaiser Aluminum and Chemical Corporation Administrative Order No. DE 01 AQIS-3285

 Kaiser Aluminum and Chemical Corporation Administrative Order No. DE 01 AQIS-3285, 

Amendment # 1
x

April 2016

The oxygenated fuel program was changed from a control measure to a contingency measure, WAC 173-

492 and SRCAA Regulation section 6.16, in the first 10-year maintenance plan.

In the first 10-year CO maintenance plan it was noted that Kaiser was shut down but there was still a 

possibility that it would reopen in some form. In this 2

nd 10-year LMP SRCAA requests that the Kaiser 

Aluminum and Chemical Corporation orders be removed as the facility has permanently shut down. 

New Mill Capital (NMC) Mead, LLC the company that purchased the former Kaiser Aluminum and 

Chemical Corporation Mead Works facility in Spokane County had notified SRCAA that the facility has 

been permanently shut down and is be dismantled2. See Appendix D.

Onroad mobile sources represent 74%

3

of the total CO emission in Spokane County according to the 

2011 triennial emission inventory. The Spokane Regional Transportation Council (SRTC) Metropolitan 

Transportation Plan (MTP) “Horizon 2040” predicts decreasing CO emission estimates4. This decrease is, 

in part, due to federal automobile emission standards and fleet turnover. Other efforts identified in the 

MTP to improve traffic flow have contributed and continue to contribute to the reductions in pollutants 

from cars and trucks.

EPA will consider the maintenance demonstration satisfied if the monitoring data show the design value 

is at or below 7.65 ppm or 85% of the level of the NAAQS. In addition, when EPA approves a limited 

maintenance plan, the motor vehicle emission budget (MVEB) is considered not constraining for the 

length of the maintenance period. Since the area is in compliance with the standard, no new control 

strategies or new regulations will be necessary. The Spokane area meets the CO standard with existing 

control measures.

Spokane currently has one remaining CO monitor in place to verify compliance with the standard. As 

part of this LMP submission, SRCAA and Ecology request discontinuing the remaining CO monitor and 

replacing it with an alternate strategy to ensure continued compliance with the 8-hour CO NAAQS. The 

proposed approach, described in Section 6.3.1, is similar to those found in the Vancouver, WA and 

Grants Pass, OR, LMPs. This request is being made under 40 CFR 58.14(c) which allows approval of 

requests to discontinue ambient monitors on a case-by-case basis if discontinuance does not 

compromise attainment of the 8-hour CO NAAQS. Pending EPA’s review of the proposed alternate 

strategy, Ecology will continue to maintain the CO monitor.

 

2

Letter dated April 11, 2013 to April Westby, P.E., Air Quality Engineer, Spokane Regional Clean Air Agency from 

Thomas C. Messmer, Vice President – Special Projects, NMC Mead, LLC

3

Originally determined with MOVES 2010a this percentage drops to 69% with the MOVES2014 modeling

4

HORIZON 2040: The Metropolitan Transportation Plan for the Spokane Metropolitan Planning Area, Table 4.16, 

Spokane Regional Transportation Council, December 12, 2013
1

April 2016

1.0 Introduction

Carbon monoxide (CO) is a colorless, odorless gas emitted from combustion processes. Nationally, and 

particularly in urban areas, the majority of CO emissions to ambient air come from mobile sources. CO 

can cause harmful health effects by reducing oxygen delivery to the body's vital organs and tissues. At 

extremely high levels, CO can cause death.

To protect public health EPA first set air quality standards for CO in 1971; an 8-hour primary standard at 

9 parts per million (ppm) and a 1-hour primary standard at 35 ppm. In a review of the standards 

completed in 1985, EPA revoked the secondary standards (for public welfare) due to a lack of evidence 

of adverse effects on public welfare at or near ambient concentrations. The last review of the CO 

NAAQS was completed in 2011 and the EPA chose not to revise the standards at that time.

Areas that have CO levels that are above the standard must develop and carry out plans to reduce CO 

emissions. Areas that previously violated these standards but are now in compliance, must submit plans 

to assure continued compliance.

2.0 Background

2.1 General and Historical Information

In the 1970s EPA designated Spokane as nonattainment for CO because of numerous violations of the 8-

hour CO standard. The number of CO exceedances in Spokane has decreased dramatically since the 

1970s. Still, CO monitoring showed that Spokane continued to violate the CO standard when the 1990 

Amendments to the Clean Air Act (CAA) were enacted on November 15, 1990. The 1990 Amendments 

to the CAA reaffirmed the nonattainment designation of all areas of the country previously designated 

nonattainment for CO. This reaffirmation continued the nonattainment designation of Spokane. EPA 

requested that the state provide recommendations on CO nonattainment area (NAA) boundaries by 

March 15, 1991. The Washington State Department of Ecology (Ecology) coordinated with 

representatives from the City of Spokane, the Spokane Regional Transportation Council (SRTC), the 

Spokane County Air Pollution Control Authority (SCAPCA)5, Spokane County Planning, and the 

Washington State Department of Transportation (WSDOT) on the review of the Spokane boundary. The 

review considered air quality data, traffic, population, density, growth patterns, and the location of 

major industries. As a result, the state recommended, and EPA accepted, the Spokane urban area as 

defined on WSDOT urban area maps as the CO NAA (see Figure 1). This area is also referred to as the 

1980 Federal Aid Urban Area (Ecology, 2001).

 

5

In 2007 the Board of the Spokane County Air Pollution Control Authority (SCAPCA) changed their name to the 

Spokane Regional Clean Air Agency (SRCAA), Resolution #07-15
2

April 2016

Figure 1 Spokane County CO Maintenance Area

In addition, the CO SCMA shown in Figure 1 also shows locations of the currently operating CO monitor

(3rd & Washington), the previous background monitor at Gonzaga University, and the previous 

monitoring sites at the Spokane Club and Hamilton Street. The figure shows the location of the central 

business district, the locations of major roadways, and other features in the SCMA.

The 1990 CAA Amendments required EPA to classify all CO nonattainment areas according to the 

severity of pollution. EPA based a "moderate plus" classification on 1988-89 monitoring data. The 

classification required the state to develop, submit, and implement a plan to attain the CO standard by

December 31, 1995. In the 1995 attainment year, the 8-hour CO standard was exceeded four times at 

the monitor located at the intersection of Third & Washington in Spokane. The CO standard allows only 

one exceedance per year at a monitor. The 1990 CAA Amendments require EPA to reclassify moderate 

CO areas to serious if they have not attained the CO standard by the attainment date. An April 24, 1996 

letter from EPA Region 10 in Seattle informed Ecology that a review of monitoring data confirmed that 

Spokane had not met the CO standard. EPA stated its intention to proceed with rulemaking action in the 

Federal Register to reclassify Spokane from "moderate plus" to "serious" nonattainment (Ecology, 

2001).

As a result of EPA's letter, SCAPCA implemented the contingency measure specified in the moderate 

plus attainment plan. The measure required the maximum allowable oxygenate in wintertime gasoline 

beginning with the 1996-97 CO season. This requirement increased the oxygenate requirement to 3.5 

percent by weight. On July 1, 1996, EPA formally proposed reclassification of the Spokane CO NAA to 

90 E

90 W

290 27

291

195 395

2

290 SPUR 2

291

Airports

Spokane Club

Hamilton Street

Gonzaga University

3rd & Washington

Central Business District

Spokane County Boundary

CO Non-attainment Area

Railroads

Major Roads

0 0.4 0.8 1.6 2.4 3.2Miles Date: Sept, 2004 Prepared by: M. Ma

E.H. Pechan & Associates Inc.
3

April 2016

serious with publication of a proposed rule in the Federal Register (61 FR 33879). Even prior to EPA's 

proposed reclassification, stakeholders in Spokane had raised issues about the location of the CO 

monitor. Recognizing the importance of an informed decision and the need to protect public health 

from unhealthful levels of CO, Ecology, SCAPCA, SRTC and EPA entered into a memorandum of 

agreement (MOA) in January 1997 with a three-fold purpose. The MOA was implemented to: 1) 

provide an opportunity to develop information relevant to the proposed reclassification; 2) to take 

proactive steps directed toward attainment and maintenance of the CO standard; and 3) to prevent 

future exceedances of the standard. The MOA concluded in July 1997 with an interagency review of 

information and control measures developed under the agreement.

On April 13, 1998, EPA reclassified Spokane to serious nonattainment for CO. In September 2001, 

Ecology prepared an attainment plan for the Spokane serious NAA. On November 22, 2004 Ecology 

submitted an additional revision to the attainment plan SIP. EPA announced its proposed approval of 

the Spokane CO attainment plan on March 8, 2005. On May 12, 2005, EPA approved the Spokane 

attainment plan which became effective June 13, 2005. Ecology submitted to EPA on November 29, 

2004 a maintenance plan and request for redesignation of the Spokane CO nonattainment area to 

attainment. June 29, 2005, EPA approved the Spokane CO Maintenance Plan effective August 29, 2005.

The first 10-year CO maintenance plan ended on August 29, 2015. CO concentrations continued to drop 

during the first five years of the maintenance plan, and have leveled off at a point significantly below the 

NAAQS. Section 175A(b) of the CAA requires SRCAA prepare a second 10-year CO maintenance plan to 

ensure that the area will continue to meet the CO NAAQS through 2025. 

This Spokane CO LMP is submitted for inclusion in the Washington SIP and will serve as the second 10-

year CO maintenance plan for the CO SCMA.

2.2 Planning Direction

Spokane qualifies for the LMP option for the second 10-year maintenance plan. EPA’s LMP approach is 

detailed in the EPA guidance Memorandum “Limited Maintenance Plan Option for Nonclassifiable CO 

Nonattainment Areas” from Joseph Paisie of EPA OAQPS dated October 6, 1995. SRCAA and Ecology are 

submitting a LMP to meet the federal requirements for a second 10-year period. A base year inventory 

is required as part of a complete LMP submittal. The base year chosen for this work is 2011. SRCAA 

compiled the base year CO Emissions inventory with assistance from both Ecology and SRTC.

2.3 Spokane CO Maintenance Plan Area

The geographic area of the CO SCMA includes the cities of Spokane, Spokane Valley, Millwood and 

surrounding urban areas as defined by the 1980 Federal Urban Aid Area. See Figure 1.

2.4 CO Monitoring Network

Currently there is one CO monitor operating in Spokane County (3rd & Washington). Monitoring data 

has been gathered for CO in Spokane since the 1970’s at multiple locations. Figure 1 is from the first 10-

year CO maintenance plan and shows the location of four monitors that were in place prior to the 

development of the first 10-year maintenance plan. The Spokane Club monitor was discontinued in 

2003, Hamilton Street monitor was discontinued the end of June 2006 and the Gonzaga special purpose 

monitor ran 1988 t0 2001. Only the 3rd & Washington monitoring location operated from 2005 to 

present. 
4

April 2016

Historically, the highest CO concentrations have been monitored in Spokane’s commercial areas (e.g. 

the central business district and nearby areas shown in Figure 1). In particular, these high 

concentrations have occurred in areas near major intersections. The 3rd & Washington site has been 

determined to experience some of the highest CO concentrations within the NAA. This is based on 

saturation studies carried out in the mid-1990's and subsequent statistical analysis of the monitoring

data (Dames & Moore, 1996; Edgar, 1997, 1998; Ecology, 1997; Guttorp, 1997). From these studies, the 

3rd & Washington site was shown to be a representative location for high CO concentrations in the 

downtown Spokane area. Monitoring site information is in Appendix C.

3.0 Air Quality Status

The current NAAQS for CO is 9 ppm for an 8-hour average and 35 ppm for a 1-hour average, not to be 

exceeded more than once per year over at least two consecutive years. The CO SCMA is currently a 

maintenance area for the 8-hour CO NAAQS. The CO SCMA attained the CO NAAQS based on air quality 

monitoring data from 1997-1998 and has not had an exceedance since. 

3.1 Exceedances

EPA AirData6data shows no exceedances of the 8-hour CO standard since 1997. Table 1 below shows 

the highest 8-hour values for all published AirData data for the years 1995 through 2014 for the Spokane 

area.

Table 1. Spokane Monitored 8-hour CO Values and Exceedances

1st Max 2nd Max # Exceed Year

13.1 11.2 18 1995

10 9 2 1996

7.3 6.5 0 1997

7.7 6.8 0 1998

7.3 5.7 0 1999

6.9 5.6 0 2000

5.3 5.2 0 2001

5.9 5.2 0 2002

5 4.6 0 2003

4.5 4 0 2004

5.2 5.1 0 2005

4.6 4.1 0 2006

3.1 2.9 0 2007

2.7 2.4 0 2008

3 2.8 0 2009

2.3 1.9 0 2010

2.4 2.3 0 2011

2.1 1.9 0 2012

2.4 2.3 0 2013

2.2 1.8 0 2014

 

6

AirData, Access to monitored air quality data from EPA’s Air Quality System (AQS) Data Mart, 

http://www.epa.gov/airdata/index.html
5

April 2016

3.2 Second Highest 8-hour Averages

The CO standard cannot be exceeded more than once per year. The second highest values are used to 

determine compliance. The second highest highs from 1995 through 2014 are shown in Figure 2 below. 

The figure shows that CO values have decreased significantly since the mid 90’s.

Figure 2 Second Highest 8-Hour CO History for Spokane

Monitored attainment has not been due to unusual or extreme occurrences in Spokane‘s weather 

patterns. Conditions that can lead to CO exceedances historically occur in the winter, November 

through February. A prolonged period of high pressure with little mixing usually results in air stagnation 

that can contribute to increased CO concentrations. It has been 18 years since the last exceedance of 

the CO NAAQS. There has been enough variability and stagnant weather conditions during that time 

that could have led to higher CO levels, but CO values continue to decrease.

3.3 Design Value

The design value, or compliance level used to compare against the standard, is the higher of the two 

annual second highs in a two calendar year period. Figure 3 shows the values from 2003 through 2014 

based on EPA AirData. The Spokane AQMA 8-hour average design value is 2.3 ppm based on 2013 and 

2014 data, which is the most recent data available in AirData. The design value for the 1-hour average is 

3.3 ppm. The AirData values for the Spokane sites can be found in Appendix C. The last year that the 

design value was 9 ppm or above was 1997; 1996 was the last year with an exceedance. 

0

2

4

6

8

10

12

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

ppm

Carbon Monoxide

Second Highest 8 Hour Average

CO NAAQS 9ppm 
6

April 2016

Figure 3 Spokane CO Area Design Values, 2003-2014

We are requesting permission to use an alternate method to determine compliance with 8-hour CO 

NAAQS, and are requesting removal of the monitor (see Section 6.3 Verification of Continued 

Attainment.) There are no plans for additional monitoring.

4.0 Existing CO Control Strategies

One of the requirements for an area to be eligible to use the LMP option is that the control measures 

from the previous 10-year maintenance plan remain in the Federally-approved SIP. The control 

measures included in Spokane’s 2005 CO maintenance plan were the Federal Motor Vehicle Emission 

Control Program and the Washington State vehicle emission inspection and maintenance program. 

Additionally, there were some specific orders placing requirements on a major industrial source. 

4.1 Federal Motor Vehicle Emissions Control Program

Spokane’s previous 10-year maintenance plan included the federal motor vehicle standards. EPA 

regulates emissions from mobile sources by setting pollutant specific standards. EPA established 

progressively more stringent emission standards for CO, hydrocarbons, nitrogen oxides, and particulate 

matter.

4.2 Washington State I/M Program

To encourage proper emission related maintenance of motor vehicles the Washington State emission 

inspection and maintenance (I/M) program was implemented in the Spokane Area in 1985. New federal 

and state laws dictated expansion and enhancement of the program. In 1993, the inspection area was 

expanded to include U.S. Postal Service zip codes surrounding the maintenance area that had an impact 

CO levels in Spokane.

4.3 Oxygenated Fuels 

The first CO maintenance demonstration included dropping the existing requirement for winter 

oxygenated fuels requirement. The requirement was dropped after demonstrating the area could

continue to meet the CO standard without the use of oxygenated fuels. In September of 2005 the 

SRCAA Board of Directors repealed Article VI, Section 6.16 Motor Fuel Specifications for Oxygenated 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

ppm

CO Design Values

Spokane , Washington 
7

April 2016

Gasoline. This control measure was changed to a contingency measure in the first 10-year maintenance 

plan. This will not change and oxygenated fuels will remain in consideration as a contingency measure.

This rule is still in the SIP, if needed as a contingency measure. Additionally, ethanol has become a 

regular component of gasoline in Washington State, because the state legislature passed a biofuels bill 

(Engrossed Substitute Senate Bill 6508, March 2006). Much of the gasoline sold in Spokane County has 

10% ethanol, equivalent to 3.5% oxygen content. 

4.4 Administrative Orders

The first CO maintenance plan included considerable analysis on the impact the former Kaiser Aluminum 

and Chemical Corporation’s aluminum reduction plant located in Mead, Washington, north of the City of 

Spokane. At that time it was not known whether the closed facility would remain shut down, or some 

portion of it would reopen. An administrative order and a subsequent amendment to that order were 

issued by the Industrial Section of the Washington State Department of Ecology. Order numbers DE 01 

AQIS-3285 and DE 01 AQIS-3285, Amendment #1 were issued to ensure that the facility did not 

contribute to an exceedance of the CO NAAQS. With the shutdown of the aluminum reduction line at 

the facility, administration of the Air Operating Permit (AOP) was turned over to SRCAA.

In 2013, SRCAA received a letter from the new owners of the facility, NMC Mead, LLC, stating that they 

had permanently shut down the facility and were in the process of dismantling all equipment permitted 

under Air Operating Permit AOP-19 Renewal Permit #1. They would not be renewing the permit and 

requesting that the permit be revoked. Per their request SRCAA voided AOP-19 Renewal #1, Issued 

7/6/09, SRCAA Consolidated Order 09-01, Issued 7/6/09 and all Ecology orders issued for emissions units 

at the facility. A new permit would be required if any facility were to open at that location in the future. 

Most, if not all equipment has been removed and the buildings are demolished. See Appendix D.

SRCAA is requesting that Kaiser Aluminum and Chemical Corporation Administrative Orders No. DE 01 

AQIS-3285 and No. DE 01 AQIS-3285, Amendment #1 be removed from the Spokane, Washington 

portion of the Washington State SIP. 

4.5 Solid Fuel Burning Device Standards

The Spokane CO attainment plan lists Chapter 173-433 WAC Solid Fuel Burning Device Standards and 

SRCAA Article VIII Solid Fuel Burning Device Standards as control measures. However, no reduction in 

CO emissions from the wood stove control program was used in the attainment demonstration. Wood 

stove emission were included in the background concentration, but held constant. All CO reductions

were from transportation related control measures. Neither Ecology’s Chapter 173-433 WAC or SRCAA 

Article VIII is mentioned in the first maintenance plan for the CO SCMA.

When the Chapter 173-433 WAC rule was updated, Ecology removed the CO triggers for solid fuel 

burning devices curtailment arguing that the burn ban program had no significant impact on attainment 

and maintenance of the CO NAAQS. SRCAA’s rule has also been updated to conform to the WAC and 

does not contain a CO trigger value for a burning ban. There was no reduction credit taken for the 

control of solid fuel burning devices in the CO attainment demonstration. Not having these triggers in 

the regulations does not affect the attainment demonstration from the first CO maintenance plan. 

5.0 State Measures Not In State Implementation Plan

Washington State Clean Car Law - In 2005 the Washington State Legislature passed a law (RCW 

70.120A.010) directing Ecology to adopt rules to implement California motor vehicle emission standards. 
8

April 2016

This resulted in following rules: “WAC 173-423-070 Emission standards, warranty, recall and other 

California provisions adopted by reference” and changes to, “WAC 173-423-110 (4) Warranty 

requirements” and “WAC 173-423-120 Recalls”. These rules became effective December 31, 2005, on 

all 2009 and newer model year vehicles. This rule was not part of the first 10-year maintenance plan. 

These additional reductions in CO were not needed to show compliance with the NAAQS but were 

included in the latest CO onroad emissions inventory.

The SIP-approved I/M program with fleet turnover and federal Tier 1, 2, and 3 vehicles are sufficient to 

maintain CO levels consistent with meeting the standard such that no additional control measures are 

necessary.

6.0 State Implementation Plan Requirements

Section 175A(b) of the CAA requires that a nonattainment area that is redesignated as a maintenance 

area submit two consecutive 10-year maintenance plans. EPA approved the first 10-year Spokane CO 

maintenance plan as part of the redesignation request in 2005. The SIP submittal developed under this 

second 10-year LMP will satisfy the Federal Clean Air Act requirements for the Spokane CO maintenance 

area.

7.0 CO Limited Maintenance Plan

The Spokane area is eligible for the LMP approach. This approach simplifies the plan preparation 

process. EPA has allowed areas whose monitored air quality values are at or less than 85% of the CO 

NAAQS to submit a simpler maintenance plan than those areas where CO levels are not as low. On 

October 6, 1995, a guidance memorandum was issued on the Limited Maintenance Plan Option for 

Nonclassifiable CO Nonattainment Areas by Joseph W. Paisie of EPA. This guidance states that an area 

must have a design value less than 85% of the of the 8-hour CO standard (7.65 ppm) to qualify for the

LMP approach. 

The CO SCMA currently has an 8-hour CO design value of 2.3 ppm based on 2013-2014 data. Since the 

design value of the Spokane area is less than 7.65 ppm, the SCMA is eligible for the LMP option. The 

LMP approach does not require future year emission projections or a maintenance demonstration. The

LMP must include an attainment inventory, provision for verification of continued attainment, a 

contingency plan and a statement regarding conformity determinations. Due to the low measured CO 

values in Spokane over the past 18 years, SRCAA does not anticipate that CO levels will approach levels 

that would violate or exceed the 8-hour CO NAAQS.

7.1 Attainment Inventory

SRCAA, Ecology and SRTC updated the attainment emission inventory for the second 10-year Spokane 

LMP. This inventory is consistent with EPA’s most recent guidance on maintenance plan emission 

inventories and is in a “typical winter day” format. The base year for this inventory and the 

maintenance plan starts with a 2011 emissions inventory. For this base year inventory, an area-specific 

total will be given for each source category. 

 Onroad mobile data is for 2015 and was done using MOVES2014 and VISUM for the travel 

demand modeling. This was done to meet the requirement to use the latest mobile emissions 

model. 
9

April 2016

 Point Source emissions are from SRCAA 2014 registration data which has 2013 emissions, the

latest data available. 

 The remaining source categories are based on the Ecology 2011 Triennial Emission Inventory, 

projected to 2014 based on population growth. 

The source categories inventory is shown in Table 2. The inventory includes sources and activities 

county wide and inside the CO SCMA. The SCMA inventory is further broken down to tons per day and 

pounds per day for comparison with the pervious maintenance plan. Estimates are for a winter day. 

Natural emissions, recreational boating and wild fires emissions are set to zero. See Appendix A for 

spatial and temporal adjustments.

Appendix A summarizes the methodologies used in calculating the base year emission inventory. There 

is no future year emission inventory for this second 10-year CO LMP as future emissions estimates are 

not required by a LMP. This is because areas meeting the criteria for a LMP have design values so low 

that EPA considers them at little or no risk of a violation. Future year onroad mobile emissions were 

calculated as part of the verification of continued attainment demonstration. Although forecasted 

future year inventories will not be calculated as part of this submission, the methodologies summarized 

in Appendix A will allow for consistency if future CO winter emission inventories are calculated.

Table 2. Source Categories Inventoried for CO Emissions

Source Category Base Year 2011 Base Year 2014 (2013 point, 2015 

onroad)

County SCMA Tons/day lb/day % lb/day Data Source

Point Sources 229 155.2 0.59 1418 0.46% 2013 SRCAA 

Onroad Mobile Sources 68817 47262.3 106.88 213760 69.37% SRTC 2015

Nonroad Mobile Sources 14939 9458.1 16.42 33760 10.96% 2011 Inventory

Locomotives 250 82.9 0.23 473 0.15% 2011 Inventory

Aircraft 684 684 1.74 3577 1.16% 2011 Inventory

Residential Yard Waste & Trash 

Burning

378 289.3 0.85 1748 0.57% 2011 Inventory

Residential Wood Combustion 9436 7213.9 25.03 51462 16.70% 2011 Inventory

Residential and Commercial Fuel 

Combustion

216 67 0.72 1480 0.48% 2011 Inventory

Commercial Food Preparation 67 61.1 0.17 344 0.11% 2011 Inventory

Misc. 23 17.6 0.05 99 0.03% 2011 Inventory

Open Burning Non-Residential (Ag &

Silvicultural)

510 5 0.01 28 0.01% 2011 Inventory
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April 2016

Table 3 shows the pounds of CO emitted per winter day by source category. The largest category of CO 

emissions by far is onroad mobile sources.

Table 3. Spokane CO Emissions, (SRTC, adjusted to 2014)

Source Category Pounds / winter day

Onroad Mobile Sources 213,760

Area Sources 54,303

Nonroad Mobile Sources 37,221

Point Sources 1,418

Total 306,702

Figure 4 illustrates the dominant contribution mobile sources make to the total CO emitted in winter. 

Onroad mobile sources represent 69% of the total winter CO emissions and area sources represent 18%.

Figure 4. Spokane CO Emission Categories and Percentages

For details on emission calculations for these categories see Appendix A.

By far the largest source of wintertime CO emission is Onroad Mobile sources with 69% of the total. 

Area sources, including residential wood combustion and Nonroad Mobile sources contribute 18% and 

12% of the total CO on a typical winter day, respectively. 

7.1.1 Onroad Mobile Sources

Onroad mobile emissions were 213,760 lbs/winter day in (year) as shown in Table 3. Emissions 

calculations were prepared by the Spokane Regional Transportation Council (SRTC) using MOVES2014 

per EPA’s Policy Guidance on the Use of MOVES2014 for State Implementation Plan Development, 

Transportation Conformity, and Other Purposes, Transportation and Climate Division, Office of 

Transportation and Air Quality, U.S. Environmental Protection Agency, EPA-420-B-14-008, July 2014. 

Onroad Mobile

69.4%

Area Sources

17.9%

Nonroad 

Mobile

12.3%

Point Sources

0.5%

CO Emission Category Percentages
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April 2016

Average Daily Vehicle Miles Traveled (ADVMT) for the Spokane Area is calculated by SRTC using VISUM 

their regional travel demand model. 

Emission rates were generated by MOVES2014. Local data was used for the following input parameters: 

evaluation month, vehicle registration distribution, VMT, vehicle population, inspection and 

maintenance (I/M) program, California vehicle standards, and road type distribution. The parameters 

are described in Appendix A. 

7.1.2 Area Sources

Area sources represent 18% of the total CO emissions. The largest contributor to area source emissions 

is residential wood combustion. 

EPA describes area sources as “facilities or activities whose individual emissions do not qualify them as 

point sources”. Area sources represent numerous facilities or activities that individually release small 

amounts of a given pollutant, but collectively they can release significant amounts of a pollutant. SRCAA 

only reports major sources to Ecology for inclusion in the triennial emissions inventory. Major sources 

emit 100 tons per year or greater of any criteria pollutant or 10 tons per year of any one toxic air 

pollutant or 25 tons of any combination of toxic air pollutants and are required to have an Air Operating 

Permit (AOP). 

CO emissions from smaller sources are mostly from fuel usage. Commercial fuel usage is one of the 

categories in Ecology’s emissions inventory reported as an area source. In addition to commercial fuel 

combustion, residential fuel combustion, residential wood combustion, trash burning and residential 

yard waste burning are included in the area source category. Trash burning is illegal and yard waste 

burning is not allowed in the CO SCMA. Prescribed burning is not generally allowed in the CO SCMA

with some minor exceptions for fire dependent ecosystems. These type of emissions are typically 

estimated by multiplying the activity level by an emission factor in mass per activity or other 

methodologies consistent with EPA’s guidance. Population or numbers of households are used as 

surrogates. 2011 area source emissions were increased by 2.8% based on the population increase 

between 2010 and 20147.

7.1.3 Nonroad Mobile Sources

Emissions from Class I line-haul and switch yard locomotives were estimated using EPA guidance and 

information supplied to Ecology by the railroads. Burlington Northern Santa Fe Railway (BNSF), Union 

Pacific Railroad (UP) and Amtrak were included in the inventory. Class II and III railroads locomotive 

emissions were not inventoried. Class III railroads in Spokane County owned by Washington State 

Department of Transportation (WSDOT) and Spokane County do not operate within the CO SCMA. A 

Class II railroad, Montana Rail Link, operates over BNSF track in Spokane County and in the CO SCMA,

and most of that activity would be included in BNSF’s reporting. 

All other emissions from nonroad mobile emission sources within the CO SCMA were calculated based 

on the latest version of EPA’s nonroad model (NONROAD2008). This includes recreational vehicles, 

recreational boats, agricultural, construction and industrial equipment and lawn and garden equipment. 

There are two airports in the CO SCMA, Spokane International Airport and Felts Field. Spokane 

International is a commercial service airport served by six airlines and two air cargo carriers. It handles 

 

7

U.S. Census Bureau QuickFacts, Population, percent change – April 1, 2010 to July 1, 2014
12

April 2016

the majority of commercial aircraft traffic for the region and is located on the western edge of the CO 

SCMA. Felts Field is a general aviation airport with private aircraft and small charter companies, located 

on the eastern edge of the City of Spokane. The military air base, Fairchild Air Force Base, is outside of 

the CO SCMA to the west of Spokane and is the home of the 92nd Air Refueling Wing of the Air Mobility 

Command Eighteenth Air Force and the 141st Air Refueling Wing of the Washington Air National Guard. 

During the winter there are little or no emissions from boating, agricultural, logging or mining in the CO 

SCMA. Nonroad emissions contributed 12% to the total CO emissions on a typical winter day. Nonroad 

emissions were adjusted from the 2011 to 2014 by 2.8% based on population increase between 2010 

and 20148.

7.1.4 Point Sources

Under EPA’s definition point sources are defined as any stationary source with CO emissions greater 

than or equal to 100 tons per year (tpy). For the inventory, SRCAA included any facility listed as an AOP 

Title V source and are shown in the table as “major” sources. While their emissions were reported to 

Ecology and were reported in the 2011 triennial emission inventory SRCAA’s 2014 registration data,

2013 emissions, was used for this LMP inventory. SRCAA also listed “synthetic minor” sources as point 

sources. This will lead to some double counting of emissions as much of their CO emissions are included 

in the commercial fuel combustion category. While SRCAA has data on smaller sources their emissions 

are again mostly from fuel combustion, boilers, heating and generators.

With the permanent closure of the Kaiser Mead facility point sources make up less than 1% of the CO 

emissions in the CO SCMA.

7.1.5 Changes in Source Category Contributions

In the 2002 emission inventory and in the 2005 10-year maintenance plan there was considerable 

discussion of the Kaiser Aluminum and Chemical Corporation Mead facility. At the time it was not 

known if the facility would ever operate again. In the attainment demonstration inventory Kaiser was 

the largest point source of CO emissions. The facility is now permanently closed and any potential 

emissions are not included in the 2011 EI or considered in out years.

7.2 Maintenance Demonstration

As explained in the EPA 1995 LMP guidance memorandum, the maintenance demonstration 

requirement is considered to be satisfied if the monitoring data show that the area is meeting the air 

quality criteria for limited maintenance area (i.e., the area CO design level is 85% of exceedance level or 

less than or equal to 7.65 ppm) and the area continues to meet this level through the effective date of 

plan approval. The Spokane area has a design value of 2.3 ppm, which is less than 7.65 ppm, the air 

quality criteria value for a limited maintenance area. The LMP guidance memorandum also states, “EPA 

believes if the area begins the maintenance period at or below 85 percent of the exceedance levels, the 

air quality along with the continued applicability of PSD requirements, any control measures already in 

the SIP, and Federal measures9, should provide adequate assurance of maintenance over the 10-year 

maintenance period.” Since the CO SCMA meets these criteria, the maintenance demonstration 

requirement is satisfied.

 

8

U.S. Census Bureau QuickFacts, Population, percent change – April 1, 2010 to July 1, 2014

9

e.g., 40 CFR Part 86 Federal Motor Vehicle Emission Control Program
13

April 2016

7.3 Verification of Continued Attainment

The CO SCMA has been in compliance with the 8-hr CO NAAQS every year since 1997, and was 

redesignated to attainment in 2005 (70 FR 37269). The CO NAAQS has not been exceeded since 1996. 

Design values have been declining over the last ten years as shown in Section 3. SRTC’s Metropolitan 

Transportation Plan Air Quality Conformity Analysis for Spokane County predicts CO emissions well 

below the SIP budget of 558,000 lbs/day. See Table 4 below.

Therefore, direct monitoring for CO concentrations is no longer necessary.

Table 4. On-road CO Emissions, SRTC

CO Second 10-year Limited 

Maintenance Plan VMT and 

Emissions Modeling

2015 2025 2035

Vehicle Miles Traveled (daily) 5,290,060 6,680,072 7,425,315 inside SCMA 

Boundary

CO Emissions (lbs/day) 213,760 109,085 68,004

The EPA’s LMP guidance contains provisions for continued operation of an appropriate EPA approved air 

quality monitoring network to verify continuing attainment with the 8-hour CO NAAQS. To meet this 

provision, for the past two decades, Ecology has been monitoring the SCMA in accordance with 40 CFR 

Part 58. As part of this LMP submission, SRCAA and Ecology request discontinuing the remaining CO 

monitor and replacing it with an alternate strategy to ensure continued compliance with the 8-hour CO 

NAAQS. The proposed approach, described in Section 6.3.1 below, is similar to those found in the 

Vancouver, WA and Grants Pass, OR LMPs. This request is being made under 40 CFR 58.14(c) which 

allows approval of requests to discontinue ambient monitors on a case-by-case basis if discontinuance 

does not compromise attainment of the 8-hour CO NAAQS. Pending EPA’s review of the proposed 

alternate strategy, Ecology will continue to maintain the CO monitor.

7.3.1 Alternate Method for Verification of Continued Attainment

Using the national Triennial Emission Inventory evaluation years and beginning with year 2017, SRCAA 

and Ecology will compare the Spokane County total of the three major categories of CO emissions 

(onroad, nonroad and woodstove combustion) with the 2002 emissions. The 2002 emissions were used 

in the Spokane County attainment plan and first 10-year maintenance plan. The 2002 emissions from 

the first 10-year maintenance plan correspond to a design value for CO of 5.2 ppm. The 2002 emissions 

will be: 

 Used as the baseline for the alternate method of verification of attainment of the CO NAAQS 

(9.0 ppm) and verification that the area continues to meet the LMP qualification threshold (7.65

ppm). 

 Recalculated using current emissions estimation models for each comparison. Onroad and 

nonroad estimates will be prepared using model defaults, as discussed below.

If the inventory (2017, 2020 and 2023) totals are less than or equal to the 2002 CO emissions, then 

continued attainment and qualification under the LMP option threshold is verified. If future triennial 

inventories exceed the 2002 CO emissions, then Ecology will reestablish CO monitoring meeting the 
14

April 2016

requirements of 40 C.F.R. Part 58 to enable EPA to determine if the area continues meet the LMP 

option, to ascertain continued attainment of the CO NAAQS, and to trigger contingency measures if a CO 

NAAQS violation were to occur. 

In order to maintain consistency in comparing 2002 onroad and nonroad emissions inventories to future 

year emission inventories, Ecology will run the models using the national default setting of a current 

version of the accepted model. The use of the national default settings will simplify the process and 

eliminate any bias due to changes in the method of gathering local input data. While the values 

obtained will differ from those in the Triennial Emission Inventory, their trend will be the same and 

proportional. 

A general requirement for LMP areas is that the State determine that the criteria used to qualify for the 

LMP option will continue to be met. As discussed above, SRCAA and Ecology will compare future year 

2017, 2020 and 2023 triennial emissions analysis results to the baseline 2002 CO emissions as part of the 

alternate method for verification of continued attainment and continued eligibility for the LMP option. 

Ecology will submit this information to EPA as part of the monitoring network report submitted to the 

EPA annually pursuant to 40 CFR part 58. The annual network monitoring report will also be available to 

the public for the duration of the 10 year period at:

https://fortress.wa.gov/ecy/publications/UIPages/Home.aspx

7.4 Contingency Plan

Section 175A(d) of the CAA requires that a maintenance plan include contingency provisions if the 

NAAQS is exceeded during the maintenance period. For this 2015 CO LMP, SRCAA is retaining the 

contingency measure provisions approved as part of the first 10-year plan. This first 10-year plan 

included a winter oxygenated fuels requirement as a potential contingency measure and established a 

process to identify and evaluate potential contingency measures other than or in addition to the 

oxygenated fuels requirement. Aside from noting the minor name change from Spokane County Air 

Pollution Control Authority to Spokane Regional Clean Air Agency, SRCAA is making no changes to the 

contingency plan provisions at this time. 

 If triennial emissions exceed 2002 CO emissions, using the method described in the Verification 

of Continued Attainment section 6.3, Ecology will reinstall a CO monitor.

 If a violation is confirmed at the reinstalled monitor, SRCAA will initiate a subcommittee process 

in coordination with SRTC, Ecology and EPA, to identify and evaluate potential contingency 

measures other than or in addition to the winter oxygenated fuel requirements. 

 SRCAA will initiate a subcommittee process no more than 60 days after being notified by Ecology 

that a violation is confirmed. The subcommittee will develop recommended contingency 

measures no more than 120 days after notification of the violation. 

 Within 180 days of notification, the subcommittee will present the contingency measures to 

the SRCAA Board of Directors or other governmental entity with jurisdiction. 

 A public hearing will then be held to consider the recommended contingency measures. 

The necessary contingency measures will be implemented within one year of the date of the CO 

standard violation.
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April 2016

7.5 Conformity Determinations

One way of demonstrating conformity of federal actions is to ensure transportation projects are

consistent with emissions budgets for the maintenance area. The LMP guidance states that the motor 

vehicle emission budget in limited maintenance plan areas may be treated as essentially not 

constraining for the length of the maintenance period, because it is unreasonable to expect the area will 

experience so much growth that a violation of the CO NAAQS will result. Therefore, the regional 

emissions analyses, (i.e., motor vehicle emissions budgets), is not needed. Project conformity 

requirements (i.e., CO hotspot analysis) and consultation will still be in effect for the CO SCMA. SRTC 

will continue to review project conformity and conduct project conformity analysis for the Spokane 

area. Current regional conformity requirements under the 2005 Spokane CO Maintenance Plan will be 

in effect until EPA determines that the conformity demonstration provisions in the second 10-year 

Spokane CO LMP are adequate or until the CO LMP is approved and adopted.

SRTC’s Metropolitan Transportation Plan, Horizon 2040, demonstrates that the CO SCMA is in 

compliance with its regional conformity budget requirements. The CO emissions from the 2010, 2030, 

and 2040 future project conditions are all well below the CO Motor Vehicle Emissions Budget (MVEB) of 

558,000 lbs/day as required by the approved first 10-year CO Maintenance Plan. The projected

emissions decreased by 32% from 2010 to 2020 and remained fairly constant between 2020, 2030, and 

2040 with emissions fluctuating less than 6% between these three points. The decrease in emissions in 

2020 is primarily due to technological advances in vehicles since VMT increased 10% from 2010 to 2020. 

VMT also increased by 14% from 2020 to 2030 and again by 8% from 2030 to 2040. These modest 

increases in VMT should be mitigated by vehicle technology allowing the modeled emissions to stay 

below the MVEB. See Table 5.

Table 5. Spokane Area 2010-2040 Air Quality Conformity Analysis10

2010 2020 2030 2040

Vehicle Trips 1,388,341 1,565,771 1,757,588 1,906,403

Daily VMT11 5,605,587 6,234,532 7,125,611 7,725,018

CO Emissions

(pounds)12 509,667 348,396 367,579 354,843

7.6 Risk of a Future Violation

The Spokane area is at little risk of future violations. Spokane has not exceeded the CO NAAQS since 

1996. The 2013-2014 design value is 2.3 ppm, well below the 8-hour standard of 9 ppm. CO levels have 

been consistently below the 8-hour CO NAAQS for more than ten years. Also, the SRTC Metropolitan 

Transportation Plan for Spokane County concludes that the CO emissions estimates will remain well 

below the original budget in the first 10-year maintenance plan. Onroad mobile sources have 

historically been the largest contributor to CO emissions and represent the majority of the CO emissions 

in the 2011 triennial emissions inventory. Reductions in this source category are predicted for this next 

10-year plan.

 

10 Data from Table 4.16 of the SRTC Horizon 2040 MTP, Horizon 2040 modeling was done with MOVES 2010a.

11 VMT inside the CO Maintenance Area

12 MOVES was used for this analysis
16

April 2016

Because of the efforts of cities and county transportation departments and SRTC to optimize traffic flow 

and federal automobile standards as well as other pollution prevention efforts, it is unlikely that CO 

levels will be problematic for the Spokane area in the future. CO levels have been well below the 

standard for many years, and the design value for the area is also well below the standard. There is very 

little risk that CO levels will increase and threaten air quality in the Spokane Area.

7.7 Summary of Maintenance Plan Commitments

Commitment Responsible Agency

Comparison of future year 2017, 2020 and 2023 CO emissions to 

the baseline 2002 CO emissions

SRCAA (in cooperation with 

Ecology)

Annual reporting to EPA on continued qualification for the LMP 

option in the annual monitoring network report Ecology

Reporting to EPA on continued CO attainment in the annual 

monitoring network report Ecology

Reestablishment of CO monitoring if future year 2017, 2020 and 

2023 CO emissions exceed the baseline 2002 CO emissions

Ecology (in cooperation with 

SRCAA)

Implementation of the contingency measure provisions if the 

Spokane maintenance area violates the CO NAAQS SRCAA
 17

April 2016

Appendix A. Emission Inventory Details

1 Introduction

The following describes the methods and procedures used to develop the Washington State triennial 

inventory as spelled out in the Washington State 2011 County Emissions Inventory. There was some 

variation from the 2011 inventory as related to onroad and point source emission. Area and nonroad 

source emissions based on population were adjusted for population growth between 2010 and 2014 as 

found in the U.S. Census Bureau QuickFacts, Population, percent change. These changes are noted in the 

main LMP document and this Appendix A.

1.1 Purpose and Background

An emissions inventory is part of an overall air quality management program. Emissions inventories are 

used in SIP attainment/maintenance planning, air quality forecasting, other air quality planning and rule 

efforts, public information, point source fee generation, and to meet federal air quality reporting 

requirements. A complete emissions inventory contains emissions from point, area, mobile and biogenic 

sources of air pollution.

This document describes the methods and data sources employed to estimate emissions for base year 

2011. Emissions were estimated for criteria pollutants. Discretion should be used when comparing 

results between different inventory years. What appear to be emissions changes may instead reflect: (1) 

changes in emissions estimation models, methodologies, and /or emission rates, (2) sources and/or 

pollutants included in the inventory, and (3) correction of errors in prior inventories.

1.2 Pollutants and Sources

The inventory includes estimates of the criteria pollutant carbon monoxide (CO).

1.3 Spatial Resolution

The inventory was developed at the county level by Ecology. It was then further refined by SRCAA and 

SRTC. SRCAA used many of the same break downs developed by Pechan13 for the first 10-year 

maintenance plan.

1.4 Temporal Resolution

The inventory was developed for each of the four seasons, and the annual total. Generally, Dec-Feb was 

classified as winter, Mar-May as spring, Jun-Aug as summer and Sep-Nov as fall.

Abbreviations used are tpy (tons per year) and tps (tons per season).

2 Statistics Used Throughout the Inventory

2.1 County Demographics

Emissions estimation methods for many source categories rely on surrogate parameters as indicators of 

activity. Population and housing units are two of the most common. Population for 2011 was available 

through the State Office of Financial Management (OFM). Occupied housing units for 2011 were 

requested from OFM and were provided.

 

13 E.H. Pechan and Associates, Inc., Base and Projection Year CO Emission Inventories for the Spokane 

Nonattainment Area, September 2004, Pechan Report No. 04.08.001/9443.003
 18

April 2016

2.2 Meteorological Parameters

Similar to demographics, meteorological parameters are used to estimate emissions for several source 

categories. Temperature, heating degree days, and rainfall are described here. Daily minimum and 

maximum temperatures and precipitation were obtained from several airports with meteorological 

stations. Monthly averages were calculated from the daily data.

3 Base Year 2011 Emissions Estimates

To estimate emissions, four basic tasks were completed for each source category. The four tasks were: 

1) estimate the activity level, 2) adjust/allocate the activity level (or emissions) temporally and spatially, 

3) determine emission rates per the activity, and 4) estimate emissions. The tasks are described below 

for each source category. Emissions estimates may be found in Section 6 of the maintenance plan.

3.1 Point Sources

Industrial, commercial, or institutional stationary sources which emit criteria and/or hazardous air 

pollutants are called point sources. Major point sources are those with the potential to emit 100 tons 

per year or more of any one criteria pollutant or a combination of criteria pollutants, and/or point 

sources with the potential to emit 10 tons per year or more of any single Hazardous Air Pollutant, or 25 

tons per year or more of a combination of Hazardous Air Pollutants (Section 112, CAA). Point sources

with a potential-to-emit more than those thresholds are included in the Title V Air Operating Permit 

(AOP) program unless a facility voluntarily adopts federally enforceable permit limits that reduce their 

potential-to-emit below the criteria and HAPs thresholds. Facilities that adopt these limits are called 

Synthetic Minor sources.

Local air agencies, Ecology regional offices, and Ecology’s Industrial Section and Nuclear Waste Program 

(regulating authorities) collect emissions data for facilities in their jurisdictions according to state and 

local regulations and air operating permit programs. After data collection, regulating authorities make 

any necessary calculations and perform quality assurance. When the inventories are complete, they 

enter the data into Ecology's Washington Emissions Inventory Repository System (WEIRS).

All Title V sources (major) are included in the point source inventory. Synthetic Minor sources are 

included at the discretion of the regulating authority. SRCAA does not submit Synthetic Minor source 

data at this time.

The inventories provided by the local air agencies are considered the official record for Washington 

State point sources. Ecology submits the data to EPA in accordance with federal reporting requirements 

without significant change. For use in this 2nd 10 year LMP, the data was enhanced in the following ways: 

(1) 2013 emissions estimates were used, (2) annual emissions were seasonally allocated (Section 3.1.2), 

and (3) missing geographic coordinates were added.

3.1.1 Activity Level

Individual facility throughputs and production rates determine the activity level for each facility.

3.1.2 Spatial and Temporal Allocation

Point sources are located by county, address, and coordinates. Point sources are requested to provide 

quarterly throughput percentages. When provided, these schedules were used to allocate emissions to 

the seasons. When not provided, throughput and resulting emissions were assumed uniform throughout 

the year and 25% of the annual total was assigned to each season.
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April 2016

3.1.3 Emission Rates and Estimates

Emissions estimates for each facility are calculated using a variety of emissions estimation methods: 

continuous emissions monitors, stack test data, mass balance, best professional judgment, 

manufacturer’s specifications, speciation profiles, EPA emission factors (e.g., AP-42), and/or other state, 

manufacturer, or research group emission factors. Methods were selected considering permit 

conditions, data availability, and resource constraints.

3.2 Onroad Mobile Sources

Onroad mobile source emissions are those generated by operating vehicles on public roadways. 

Emissions from fuel combustion and evaporation, and brake and tire wear were estimated.

EPA's Motor Vehicle Emission Simulator14 (MOVES2014) was used to calculate emissions. MOVES

combines basic vehicle activity information with information about vehicle and fuel characteristics, 

emissions control programs, meteorological information, and other parameters to estimate emissions. 

The basic activity data are vehicle miles traveled (VMT) and vehicle population. Inventory mode at the 

County-level was used for this 2nd 10 year LMP.

VMT, vehicle population, and a brief description of the MOVES input parameters used to generate the 

emission rates are described below. The MOVES Technical Guidance for SIP inventories and the MOVES 

User’s Guide were used in developing many of the inputs to MOVES.

For use in this 2nd 10 year LMP, the data was enhanced by updating to 2014 input parameters projected 

to 2015.

3.2.1 Vehicle Miles Traveled (VMT)

VMT are used in MOVES to calculate either emissions or emission rates while the vehicle is in motion or 

during short periods of idling. The source of county VMT data used in the Triennial Emissions Inventory 

is the Washington State Department of Transportation (WSDOT) under the national Department of 

Transportation’s Highway Performance Monitoring System (HPMS). HPMS is a system of traffic counts 

collected over several urban and rural sampling areas. WSDOT makes estimates of county VMT by 

roadway (functional) classification using the HPMS data. The WSDOT VMT was used to generate 

emissions for Ecology’s triennial inventory, but it was used to generate emission rates on a per mile 

bases for the LMP inventory. The emission rates were combined with VMT from SRTC’s travel demand 

modeling to estimate emissions for the LMP.

3.2.2 Vehicle Population

Vehicle population is used to calculate either emissions or emission rates while a vehicle is stationary. 

The emissions come from engine starts, extended idling, and some fuel evaporation processes. Vehicles 

are classified by age and type. There are thirteen vehicle types in MOVES within six broader categories: 

cars, motorcycles, light-duty trucks, heavy-duty single unit trucks, heavy-duty combination unit trucks, 

and buses.

Three sources were used to calculate vehicle population. The first was the Washington State 

Department of Licensing (DOL) for 2014. DOL registers non-governmental vehicles annually. Because 

DOL does not register public transit and school buses each year, alternate sources of information were 

obtained. Transit and Intercity bus data came from the Federal Transit Administration (FTA) Annual 

 

14 MOVES2010b was used in the 2011 Triennial Emission Inventory; MOVES2014 was used for this LMP inventory. 
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Report data for 2013 (most recent available). School bus information for 2014 was obtained from the 

Washington State Office of the Superintendent of Public Instruction (OSPI).

3.2.3 MOVES Input Parameters

MOVES includes a default database that summarizes emission relevant information for all counties in 

the United States. Default data may be replaced by local data to improve the estimates. Ecology 

developed local data for many of the parameters in MOVES.

Input parameters were developed that were characteristic of local conditions for each county and 

month. Some of the parameters presented here required local data. For others, EPA guidance 

recommended that local data be used. 

3.3 NONROAD Mobile Sources, Excluding Locomotives and Aircraft

The Nonroad Mobile category includes emissions estimates from gasoline, diesel, compressed natural 

gas (CNG), and liquefied petroleum gas (LPG) fueled equipment. Emissions were estimated using EPA's 

NONROAD2008a model. Equipment types are compiled into 11 categories:

Agricultural Equipment Lawn and Garden Equipment

Airport Service Equipment Logging Equipment

Recreational Marine Vessels Oil Field Equipment

Construction and Mining Equipment Recreational Equipment

Commercial Equipment Railroad Maintenance Equipment

Industrial Equipment

3.3.1 Activity Level and Spatial Allocation

The NONROAD model contains data on statewide equipment types and usage. NONROAD utilizes spatial 

surrogates appropriate for each equipment type to disaggregate state activity levels to individual 

counties. The default surrogates were used for all equipment types except recreational marine vessels. 

The default spatial surrogate for recreational marine vessels is water surface area. This method can 

overestimate recreational boat usage in certain counties due to the large areas of open water in a 

county’s jurisdiction. A new allocation based on county boat registrations was substituted for the 

default. Registrations for 2011 were provided by the Washington Department of Licensing.

3.3.2 Temporal Allocation and Emission Rates

Emissions were generated for the four seasons using the seasonal temporal option in the 

NONROAD2008a model. NONROAD2008a requires user input of seasonal meteorological and fuel 

parameters. The required fuel parameters are gasoline Reid Vapor Pressure (RVP) and oxygen content; 

sulfur contents of different fuels such as gasoline, diesel (land and marine), compressed natural gas 

(CNG) and liquefied petroleum gas (LPG); and if stage II vapor recovery is required. Each is described 

briefly below.

Fuel Sulfur Content: EPA provided diesel sulfur contents with NONROAD2008a (file sulfur.txt). The values 

were 32 ppm and 236 ppm for land and marine diesel, respectively. Gasoline sulfur content was 

assumed to be the same as onroad sulfur content (30 ppm). CNG/LPG was assumed to contain 30 ppm 

sulfur (model template default).
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Gasoline Oxygen Content: Most gasoline in Washington contains 10% ethanol. The corresponding 

oxygen content is 3.5%.

Gasoline Reid Vapor Pressure: RVP values for January, April, July, and October were used to model each 

of the four seasons. The values were the same as those for onroad.

Stage II Gasoline Vapor Recovery: Stage II refueling benefits were not modeled in NONROAD. There are 

stage II requirements on some gasoline stations, but there is no reliable method to estimate the fraction 

of equipment fueled via stage II stations. Furthermore, stage II benefits are small compared to the total 

nonroad inventory. For these reasons, no stage II requirements were modeled in NONROAD.

Meteorological Parameters: NONROAD requires minimum, maximum, and average temperature inputs 

in °F (Section 2.2). Temperatures for January, April, July, and October were used to model each of the 

four seasons. Onroad mobile guidance was used to calculate average temperatures: 

minT + [2/3 * (maxT – minT)]

This equation may result in a temperature that is close to the average daytime temperature when most 

equipment is used.

3.3.3 Emissions Estimates

Total seasonal emissions (tons per season) were generated with the NONROAD2008a model.

3.4 Locomotives

Emissions from Class I line-haul and switch yard locomotives were estimated using EPA guidance and 

other information. U.S. Class I railroads are line-haul freight railroads with operating revenue in excess 

of $250 million or more after adjusting for inflation using the Railroad Freight Price Index ($433.2 million 

in 2011). Two Class I railroads operate in Washington: Burlington Northern Santa Fe Railway (BNSF) and 

Union Pacific Railroad (UP). Amtrak was also included in this inventory. Class II and III railroad 

locomotive emissions were not inventoried. A special Northwest International Air Quality Environmental 

Science and Technology Consortium (NW-AIRQUEST; formerly Northwest Regional Technical Center) 

project conducted by the Oregon Department of Environmental Quality (ODEQ) found that emissions 

from Class 2 and 3 railroad locomotives were a small percentage of total locomotive emissions.

BNSF and UP provided 2011 activity and emissions information. Amtrak provided only activity 

information for 2011.

3.4.1 Activity Level

Activity level is measured in gallons of diesel consumed by locomotives. All of the railroads provided 

2011 fuel use for line haul and switch yard locomotives by county.

3.4.2 Temporal and Spatial Adjustments

Most of the locomotive activity information was obtained by county; therefore, no spatial adjustments 

were necessary.

Locomotives were assumed to operate uniformly year-round per EPA guidance.
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3.4.3 Emission Rates

All railroad companies provided criteria pollutant emissions estimates by county, based on their 

locomotive fleet. 

3.5 Silvicultural Burning (Prescribed Burning)

Silvicultural burning includes logging debris burns and forest health burns. It does not include land 

clearing. Silvicultural burning is conducted by the Department of Natural Resources (DNR), U.S. Forest 

Service (USFS), Bureau of Indian Affairs (BIA), and private industry. DNR permits and tracks all burns, 

except those done by the BIA. Using models developed by the USFS, DNR estimates the tons burned and 

resulting air emissions.

The results from prescribed burning that DNR produced and those that EPA produced were very 

different. Therefore, the Washington emissions inventory data may look very different from the EPA 

data in this category. The BlueSky modeling framework was used to create the EPA data. This framework 

can lead to overestimates of prescribed burn emissions, especially in heavily forested regions (e.g. 

Clallam, Grays Harbor, Lewis, Pacific, and Skamania counties). Prescribed burns in Washington state are 

managed so that only a fraction of the fuels are burned; however, the BlueSky model does not take this 

fully into account and is configured to burn most available fuels within the simulations. There are also 

known over-estimates of duff consumption in prescribed burn simulation software.

3.5.1 Activity Level and Emission Rates

DNR enters information on each permitted burn into the USFS models. The required information 

includes: location, date, ownership, elevation, moisture, species, duff depth, tons of material and/or 

acres, burn type (broadcast, pile, natural). The USFS models calculate fuel consumption and emissions 

for each burn. The emission factors used in the model were developed for the Pacific Northwest by the 

USFS.

DNR provided the entire 2011 burn permit database, which was queried for activity level (in tons 

consumed) and emissions by county and season. The database included PM, PM10, and PM2.5 estimates. 

Broadcast and natural burn particulate emission factors were calculated specifically for each fire. Pile 

burn particulate emissions were estimated using static emission factors. DNR estimated CO and nonmethane hydrocarbons (used as VOC) for most broadcast and natural burns. NOx emissions were 

estimated by Ecology using AP42. VOC and CO emissions were estimated for pile burns by Ecology using 

information from the USFS.

3.5.2 Temporal Adjustments

The date of each burn was included in the DNR burn permit database. Monthly emissions were 

calculated by summing the emissions for all burns occurring in each month.

3.5.3 Spatial Adjustments

No spatial adjustments were necessary. All burns were identified both by county and section-townshiprange.

3.5.4 Emissions Estimates

As stated in Section 3.5.1, emissions were calculated for each burn by date. Seasonal emissions were 

calculated by summing all the burns occurring in the given season.
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3.6 Agricultural Burning

Agricultural burning in Washington is defined as "the burning of vegetative debris from an agricultural 

operation necessary for disease or pest control, necessary for crop propagation and/or crop rotation, or 

where identified as a best management practice by the agricultural burning practices and research task 

force established in RCW [Revised Code of Washington] 70.94.6528 or other authoritative source on 

agricultural practices." All agricultural burning in Washington requires a permit.

3.6.1 Activity Level

The activity level for agricultural burning is the amount of residue burned (consumed). The general 

equation and sources of each parameter are described below.

tons burned = acres burned x fuel loading x fuel consumption factor

Acres or Tons Burned

Department of Ecology Central and Eastern Regional Offices (CRO, ERO)

The Department of Ecology maintains an agricultural burn permit database. The permits are tracked by 

location and date and include other information such as crop type, acreage, and fuel loading estimates, 

or tons burned. Permits issued in 2011 were selected for this inventory.

Local Air Authority Permits

There is very little agricultural burning in western Washington and Spokane County. There were five

permits issued in Spokane County in 2011, a total of 142 acres were burned none within the CO SCMA.

Fuel Loading

Department of Ecology Central and Eastern Regional Offices (CRO, ERO)

The agricultural burn permit database included a loading factor for each burn. The overall average 

loading factor for cereal grain stubble burns was 4.3 tons/acre. This is comparable to the 4 tons/acre 

average found in a special study performed by Air Sciences Incorporated. Air Sciences Incorporated 

performed a field study funded by Ecology, the Washington Association of Wheat Growers, and the US 

EPA-Region 10 to measure emissions and develop emission rates for wheat stubble field burning. The 

loading factor was 0.8 tons/acre higher than the wheat field loading factor of 3.2 tons/acre in AP42 

(adjusted for fuel consumption).

Local Air Authority Permits

Fuel loading factors for burns reported in acres for apple and other orchard trees, Christmas trees, 

daffodils, nursery stock, and limbs/weeds/blackberries were estimated from the Ecology burn permit 

database records (1-2-2009 through 3-26-2012) by calculating the average loading for these crop types. 

The unspecified weed loading in AP4254 was used to estimate loading for potatoes and berries.

Fuel Consumption Factors

The fuel consumption factors developed by Air Sciences Incorporated were used for cereal grains. The 

consumption factor was 0.59 during spring and 0.60 during fall. The consumption factor for all other 

crop types was assumed to be 1.00 due to a lack of any specific information. This assumption will tend 

to overestimate emissions, and may be revisited in the future. 

3.6.2 Emission Rates

Emission rates were taken from EPA's AP42 (PM, VOC, CO, NOX).
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3.6.3 Spatial and Temporal Adjustments

All burn data was available by county and date, so neither spatial nor temporal adjustments were 

necessary.

3.6.4 Emissions Estimates

Emissions estimates were calculated with the equations below.

tons per year (tpy) = (tons consumed) x (pollutant lb/T) x (1 T/2000 lb)

tons per season (tps) = (tons consumed) x (pollutant lb/T) x (1 T/2000 lb) where the tons 

consumed is the amount burned in the given season

3.7 Residential Yard Waste Burning Leaf and Brush

Residential yard waste burning is outdoor burning of vegetative material.

3.7.1 Activity Level and Spatial Allocation

The measure of activity for residential yard waste burning is the amount of material burned. For the 

2011 National Emissions Inventory, leaf and brush are separated into different reporting categories and 

have different criteria pollutant emission factors. In 2001, Washington State University under contract 

to the Idaho Department of Environmental Quality conducted a telephone survey of wood heating and 

outdoor burning habits in Idaho, Oregon and Washington. The survey included questions to estimate the 

fraction of households that burned yard waste and the number of legal size piles (4')15 burned per 

household per year.

In Washington, the survey defined four geographic groups in Washington: 1) incorporated cities, 2) 

unincorporated western WA, 3) unincorporated eastern WA with forest lands, and 4) unincorporated 

eastern WA without forest lands. Each county's incorporated areas were assigned to the first group. 

Unincorporated areas were assigned to one of the last three groups. It was estimated that the weight of 

a legal size pile was approximately 125 lb. The tons of material burned were estimated using the 

following equation:

HH x (fraction burning waste) x (piles/HH) x (lb burned/pile) x (1 T/2000 lb),

where HH = the number of households 

3.7.2 Emission Rates

Criteria and toxic pollutant emission rates for brush and leaf residential yard waste burning were taken 

from the EPA’s Emission Inventory documentation repository for 2011 for the Open Burning Yard Waste 

Leaf and Brush category. Emission rates are given in pounds of pollutant per ton of material burned.

3.7.3 Temporal Allocation

The survey included questions about seasonal burning habits.

3.7.4 Emissions Estimates

Emissions estimates were calculated with the equations below.

tpy = (tons burned) x (pollutant lb/ton) x (ton/2000 lb)

tps = (tpy) x (seasonal fraction)

where: tpy = tons per year, tps = tons per season

 

15 Four (4’) feet was used in the state wide survey SRCAA specifies a maximum 4’ wide by 3’ high. 
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3.8 Municipal Solid Waste Burning

Municipal Solid Waste Burning is outdoor burning of household waste.

3.8.1 Activity Level and Spatial Allocation

The measure of activity for residential trash burning is the amount of material burned. The Washington 

State University telephone survey of wood heating and outdoor burning habits in Idaho, Oregon, and 

Washington described in Section 3.7 above included questions to estimate the fraction of households 

that burned trash. The geographic subgroups, county assignments, and number of households in each 

subgroup were the same as in Section 3.7. 

The amount of trash burned per household was taken from an Emission Inventory Improvement 

Program (EIIP) recommendation. The EIIP reported that 6.75 lb of total refuse were generated per 

household per day. Eighty percent (5.37 lb) of the total is combustible and 50% (3.38 lb) is actually 

consumed when burned.

The tons of material actually consumed were estimated using the following equation:

HH x (fraction of HH burning trash) x (3.38 lb/HH-day) x (365 days) x (1 T/2000 lb),

where: HH = the number of households (Table 2-1)

3.8.2 Emission Rates

Criteria pollutant emission rates for brush and leaf residential yard waste burning were taken from the 

EPA’s Emission Inventory documentation repository for 2011 for the Open Burning MSW category.

Emission rates are given in pounds of pollutant per ton of material consumed.

3.8.3 Temporal Allocation

Trash burning is assumed to be uniform year-round.

3.8.4 Emissions Estimates

Emissions estimates were calculated with the equations below.

tpy = (tons consumed) x (pollutant lb/T) x (1 T/2000 lb)

tps = (tpy) / 4

where: tpy = tons per year, tps = tons per season

3.9 Residential Fuel Use, excluding Wood

Residential fuel use was estimated using EPA’s Residential Fuel consumption tool, modified with 2010 

county level data for WA. The residential non-wood fuels included in this report are distillate oil, natural 

gas, and liquefied petroleum gas (LPG). Residential wood combustion is treated separately in Section 

3.10. Residential coal combustion is not included in the inventory since less than 500 housing units in 

the state use coal as their heating source.

3.9.1 Activity Level

Washington state fuel use for 2010 was obtained from the Energy Information. The state-level volume 

of distillate oil consumed by residential combustion in the U.S. was used to estimate emissions. Energy 

consumption by energy use sector is presented in State Energy Data 2010 Consumption tables published 

by the Energy Information Administration (EIA). Year 2010 consumption data were used as a surrogate 

for 2011 emissions because year 2010 data were the most recent data available when this portion of the 

inventory was prepared.
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3.9.2 Spatial Allocation

State-level consumption was allocated to each county using the Census 2006-2010 American 

Community Survey 5-year Estimates - 2006-2010 Census Detailed Housing Information. These data 

include the number of housing units using a specific type of fuel for residential heating. State energy 

consumption was allocated to each county using the ratio of the number of houses primarily using a 

specific energy source (LPG, distillate oil, Natural gas) in each county to the total number of houses using 

the same source in the state.

3.9.3 Temporal Allocation

Seasonal profiles for this category were taken from temporal files developed for AIRPACT.

3.9.4 Emission Rates

Criteria pollutant emission rates for residential fuel use, excluding wood were taken from the EPA’s 2011 

Emission Inventory documentation and file repository for the residential fuel use category.

3.9.5 Emissions Estimates

Annual and seasonal emissions for each pollutant were calculated as:

tpy = FC x E x (1 T/2000 lb)

tps = tpy x seasonal fraction from temporal profiles

where FC is the amount of fuel used in the given county 

E is the pollutant emission rate in the same units as FC 

3.10 Residential Wood Combustion

Residential wood combustion consists of home heating and recreational use of woodstoves, fireplaces, 

fireplace inserts, and pellet stoves. Other residential wood burning devices were not inventoried.

3.10.1 Activity Level

The measure of activity for residential wood combustion is the amount of wood burned. Residential 

wood combustion activity for each county was estimated using data from one of two residential wood 

combustion surveys. The first survey was conducted by Washington State University in 2001 (WSU2001). 

It divided the state into regions and compiled results for each region. The WSU survey had 749 

completed surveys for WA. The second survey was conducted by the National Research Center in 2007 

(NRC2007). It covered seven geographic areas in the central Puget Sound region and consisted of 1,015 

completed surveys. Both surveys solicited complete information to conduct an inventory. 

The surveys were compared. For all but the eastern WA rangeland counties, the two surveys were 

generally comparable. The NRC2007 survey was newer and included a higher concentration of survey 

responses, so it was used to characterize all counties except those classified as eastern WA rangeland. 

The WSU survey was used for the eastern WA rangeland counties. 

The surveys were used to determine the percentage of households using wood burning devices, the 

fraction of certified stoves and inserts, and the annual amount of wood burned per device for fireplaces, 

woodstoves, inserts, and pellet stoves. Industry data was used to break out certified stoves and inserts 

into catalytic (25%) and non-catalytic (75%).

The usage rates are used in activity level calculations and the fraction of combined inserts and 

woodstoves that were in use. The surveys gathered information on the amount of pellets, firelogs, 

bundles of wood, pickup loads, and cord wood burned. To calculate emissions using emission factors in 
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lb/ton burned, the weight of the wood burned was estimated. Pellets are sold in 40-lb sacks, and fire 

logs were estimated at 8 lb per log.

The weight of a cord of wood varies with moisture content and species type. The most common species 

reported in the survey were fir, alder, and maple. PSCAA estimated the bone dry (zero percent moisture) 

weight of a cord to be 2189 lb. This weight was used for all counties where the NRC2007 survey was 

used in order to keep the amount of wood burned consistent with the wood weight. For the areas using 

the WSU2001 survey, the dry weight was estimated at 2230 lb/cord. This was based on 

recommendations from staff at Ecology, the Department of Natural Resources (DNR), and the US Forest 

Service (USFS).

Bundles of wood and the average of small and large pickup loads were assumed to be approximately 

0.01563 cords and 0.3494 cords, respectively.

3.10.2 Emission Rates

Criteria pollutant emission factors in pounds of pollutant per ton of wood burned were taken from 

version 1 of EPA's 2011 Residential Wood Combustion tool. The emission rates are based on dry (0% 

moisture) wood. The weight of wood burned was expressed as 0% moisture so no adjustments were 

made prior to calculating emissions.

3.10.3 Spatial and Temporal Allocation

Spatial allocation was not necessary since occupied housing units were available by county.

Temporal allocation was based on a relationship between temperature and ambient fine particulate 

concentrations. Analysis of several PM2.5 and meteorological monitoring sites showed a strong linear 

relationship between ambient temperature and ambient fine particulate concentrations at 

temperatures below 50 degrees Fahrenheit. Heating degree days (based on 50 degrees = HDD50) were 

calculated for each day during the NRC2007 survey period (Sept. 2006 - Aug. 2007). The total seasonal 

HDD50 were divided by the annual HDD50 to estimate seasonal fractions.

It is recognized that temperatures vary across the state and seasonal patterns may not be the same 

everywhere. More precise seasonal breakouts may be calculated as needed for specific projects.

3.10.4 Emissions Estimates

Annual and seasonal emissions for each wood burning device were calculated according to the following 

equations:

tpy = (HH) x (usage fraction) x (seasoned tons burned/device-yr) x

(0.8 T dry weight/1 T seasoned weight) x (pollutant lb /T dry weight) x (T/2000 lb)

tps = (tpy) x (seasonal fraction)

Annual emissions for each wood burning device were calculated according to the following equation:

tpy = (OHU) x (usage fraction) x (T burned/device-yr) x (pollutant lb/T) x (T/2000 lb)

where OHU= number of occupied housing units in the geographic area

tps = tpy x (seasonal fraction)
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Appendix B. Washington State and SRCAA Rules

SRCAA Regulations

None (Regulation I, Article VI, Section 6.16 Motor Fuel Specifications for Oxygenated Gasoline was 

repealed 9/1/2005 SRCAA Resolution 05-19) 

Washington State Regulations

Chapter 173-422-031 WAC – Motor Vehicle Emission Inspection Schedule

Chapter 173-422-170 WAC – Exemptions

Chapter 173-423-070 WAC – Emissions standards, warranty, recall and other California provisions 

adopted by reference

Chapter 173-492 WAC – Motor Fuel Specifications for Oxygenated Gasoline

Federal Regulations

40 CFR Part 86 - Federal Motor Vehicle Emission Control Program

Remove the following Administrative Orders:

 Kaiser Aluminum and Chemical Corporation Administrative Order No. DE 01 AQIS-3285

 Kaiser Aluminum and Chemical Corporation Administrative Order No. DE 01 AQIS-3285, 

Amendment # 1
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Appendix C. EPA AirData Carbon Monoxide Data Printouts
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Appendix D. Kaiser Closure Letters
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Appendix E. SRCAA Resolution 05-19 Repeal of Motor Fuel Specifications 

for Oxygenated Gasoline
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