Date of Adoption: February 14, 2001.

Purpose: To demonstrate to the United States Environmental Protection Agency (EPA). The future maintenance of the carbon monoxide national ambient air quality standard in the Yakima carbon monoxide nonattainment area and request attainment status.

Statutory Authority for Adoption: Federal Clean Air Act Amendments (FCAAA) of 1990, Section 110.

Adopted under notice filed as WSR 00-24-075 on December 4, 2000.

Number of Sections Adopted in Order to Comply with Federal Statute: New 0, Amended 0, Repealed 0; Federal Rules or Standards: New 0, Amended 0, Repealed 0; or Recently Enacted State Statutes: New 0, Amended 0, Repealed 0.

Number of Sections Adopted at Request of a Nongovernmental Entity: New 0, Amended 0, Repealed 0.

Number of Sections Adopted on the Agency's Own Initiative: New 0, Amended 0, Repealed 0.

Number of Sections Adopted in Order to Clarify, Streamline, or Reform Agency Procedures: New 0, Amended 0, Repealed 0.

Number of Sections Adopted Using Negotiated Rule Making: New 0, Amended 0, Repealed 0; Pilot Rule Making: New 0, Amended 0, Repealed 0; or Other Alternative Rule Making: New 0, Amended 0, Repealed 0. Effective Date of Rule: May 1, 2001.

February 16, 2001

Les Ornelas

Air Pollution Control Officer

Prepared by:

     Yakima Regional Clean Air Authority

     Washington State Department of Ecology, Air Quality Program

     City of Yakima, WA, Public Works Department

Adopted for local use and recommended to the State of Washington, Department of Ecology for the State Implementation Plan this 14th day of Feb., 2001 by the Board of Directors, Yakima Regional Clean Air Authority, Yakima, Washington. The Board of Directors requests the U.S. Environmental Protection Agency, Region 10 to grant attainment status for the Yakima Carbon Monoxide Nonattainment Area.

Thomas W. Gasseling Chairperson
Jessie S. Palacios Member	Dale A. Olsen Member
John Puccinelli Member	_________________ Member

State Adoption

Adopted by the State of Washington, Department of Ecology at a State adoption hearing conducted at Yakima, WA on _________ __, ____, and recommended to the U.S. Environmental Protection Agency, Region 10 for inclusion in the State Implementation Plan and the granting of attainment status for the Yakima Carbon Monoxide Nonattainment Area.

__________________ Designated Representative for the Governor

_____________ Date

Federal Approval

Approved for inclusion in the State Implementation Plan and attainment status granted.

___________________ Environmental Protection Agency, Region 10

_____________ Date

Table of Contents
		Content	Page No.
1.0		Summary		7
2.0		General and Historical Information		9
	2.1	Planning Direction		9
	2.2	Location		10
	2.3	Air Quality Status		11
	2.4	CO Monitoring		12
	2.5	Design Value		13
	2.6	Planning Area		13
	2.7	Existing Control Strategies		14
	2.8	Past Emissions Inventories		16
3.0		Risk of a Future Violation		18
	3.1	Growth Potential		18
	3.2	Potential for Dramatic Change		20
	3.3	Major Population or Source Distribution Changes		20
	3.4	Impacts from Outside the Nonattainment Area		20
	3.5	Reliance on Unproven Control Measures		21
	3.6	Strength of Past Contingency Measures		21
	3.7	Meteorological and CO Monitor Data Analysis		21
4.0		State Implementation Plan (SIP) Requirements		23
	4.1	Summary of Previous SIP Submittals		23
	4.2	Demonstration of Attainment		23
	4.3	Adequacy of the Monitoring Network		23
	4.4	Permanent and Enforceable Emission Reductions		23
	4.5	Transportation Conformity		24
	4.6	Section 110 and Part D Requirements		24
5.0		Air Quality Maintenance Plan		25
	5.1	Maintenance Plan Emission Inventory		25
	5.2	Maintenance Demonstration		26
	5.3	Monitoring Network		27
	5.4	Verification of Continued Attainment		27
	5.5	Control Measures		27
	5.6	Contingency Plan and Measures		27
	5.7	Mitigation Measures		30
	5.8	Additional Measures		31
	5.9	Transportation Emission Budgets		31
Appendices 1
	A	Bibliography		A - 1
	B	Technical Analysis Protocol		B - 1
	C	Inventory Preparation and Quality Assurance Plan		C - 1
	D	Maps		D - 1
	E	Legal Description of the Yakima CO Nonattainment Area		E - 1
	F	Five Highest Annual CO Concentrations		F - 1
	G	Analysis of Meteorological Conditions for the Five Days Per Year with the Highest CO Monitor Values		G - 1
	H	Yakima Carbon Monoxide Nonattainment Area Maintenance Plan Emission Inventory		H - 1
	I	City of Yakima, Washington Evaluation of Mobile Source Carbon Monoxide Emissions in the Yakima CBD and Review Comments		I - 1
	J	Historical CO Information		J - 1
	K	City of Yakima, Washington Adopted Resolution No. 2000 - 115		K - 1
	L	List of Contributors
Tables 2
	Table 1.0 - 1, Base Year Emissions Inventory Summary			7
	Table 2.32 - 1, Information about CO Monitor Values			12
	> 8 Hr. NAAQS Since Jan. 1, 1988
	Table 2.8 - 1, 1992 CO NAA Emissions Inventory Summary			17
	Table 3.11 - 1, Summary of Local Growth Statistics			19
	Table 5.1 - 1, 1999 Limited Maintenance Plan Inventory			26
	Summary of Actual Emissions
	Table 5.62 - 1, Modeling Estimates for Peak Afternoon			29
	Hour Traffic Conditions in the Central Business District

1.0 Summary

This is a limited maintenance plan which describes the maintenance of the carbon monoxide (CO) national ambient air quality standards (NAAQS) in the Yakima CO Nonattainment Area (NAA). A limited maintenance plan is a less extensive plan than a full maintenance plan because past CO monitor values have demonstrated that the chances of an exceedance of the NAAQS are much lower. This plan fulfills the Federal Clean Air Act requirements, and it is recommended to the U.S. Environmental Protection Agency (EPA), Region 10 for inclusion in the state implementation plan (SIP) with a request that this nonclassifiable CO NAA be granted attainment status. The SIP is the federally-enforceable plan which identifies how the state and local authorities will attain or maintain the NAAQS for CO.

The plan includes an analysis of weather and CO monitoring records which indicate that the highest CO levels occur during weekdays in the months of Dec. and Jan. during winter inversion periods. The CO monitoring data also shows that Yakima has attained the CO NAAQS since 1988 and both the average and peak CO levels are declining.

A limited maintenance plan is required to include only the an emissions inventory for the base year which is 1999. Table 1.0 - 1 summarizes the base year emissions inventory for the NAA.

2.0 General and Historical Information

2.01

Plan Preparation - This limited maintenance plan was developed by the Yakima Region Clean Air Authority (YRCAA) after consulting with the Washington State Department of Ecology, Air Quality Program (ECY); and the City of Yakima, Public Works Department (City PWD). In addition information needed for the plan was provided by numerous business, industry, and government representatives and interested citizens. The people who participated in this planning process are listed in Appendix L.

2.02

Disclaimer - During the planning process the past and current CO emissions from several industries within and close to the CO NAA were evaluated, and some of this information was used in this plan. It is not the purpose of this plan or intent of the agencies preparing the plan to make value judgements about the social and economic contributions of these industries to the community or to suggest future management actions for the companies. The emissions from these industries are only listed to show to their contributions to the total CO emissions in the CO NAA.

2.1 Planning Direction

2.11

EPA Direction - Because Yakima is a nonclassifiable CO NAA with a design value below 7.65 ppm, YRCAA can submit a limited maintenance plan.3 A full maintenance plan is not required because this area has achieved air quality levels well below the NAAQS without using control measures required for nonattainment areas with worse air quality. A limited maintenance plan does not require any of the following elements to demonstrate future maintenance of the air quality:

•	Modeling to project future CO emission changes with different control strategies;
•	Future CO inventories for the NAA; or
•	Additional control measures to reduce CO emissions which are adopted at the time the plan is submitted for SIP adoption.

2.12

Local Direction - The Board of Directors for the YRCAA approved the preparation of a limited maintenance plan for the Yakima CO NAA on May 10, 2000.4 This plan is being prepared according to the direction in the documents listed in Appendix A. A copy of the approved Technical Analysis Protocol (TAP) is in Appendix B, and the Inventory Preparation and Quality Assurance Plan is in Appendix C.

2.13	Effective Date - Except for the City of Yakima Resolution No. 2000 - 115 in Appendix K which is currently effective, this limited maintenance plan will be effective for local use on May 1, 2001.

2.14	Plan Duration - This plan is effective for ten years following the date of redesignation to attainment status for the Yakima CO NAA by EPA, Region 10 unless modified or rescinded by an appropriate authority.5

2.2 Location

The NAA is located in Central Washington State in Yakima County. It is 6.4 square miles in size, and the Cities of Yakima and Union Gap, and Yakima County are the local governmental jurisdictions. The NAA is a mix of established residential, commercial, and industrial properties. The area is bisected by major arterial streets which bring traffic from many parts of the Pacific Northwest into the NAA. Vehicle traffic is a major contributor to the CO air pollution.

The original CO NAA was fourteen square blocks in downtown Yakima bounded by Front, D, Third, and Walnut Streets.⁶ When the expanded and current NAA boundary was submitted to EPA on March 15, 1991, the largest source category in the CO emissions inventory was on-road mobile sources.^{7 8} The new boundary location was determined by analyzing traffic data for the downtown area and drawing a boundary that enclosed the majority of the emissions from these mobile sources.⁹

Appendix D contains maps showing the CO NAA, PM₁₀ NAA, and the Wood Smoke Control Zone (WSCZ). Appendix E has the legal description for the CO NAA.

2.3 Air Quality Status

The NAAQS for CO is not more than one exceedance per year of an eight-hour average of 9 ppm.¹⁰ The second non-overlapping exceedance in a year at a monitoring site is a violation of the NAAQS. CO monitors normally measure concentrations to the nearest 0.1 ppm. The EPA rounding convention for CO is values > 9.5 ppm exceed the CO NAAQS.¹¹

2.31

Air Quality History - From 1978 - 1986 Yakima experienced 25 non-overlapping exceedances of the eight-hour standard. These exceedances put the area in nonattainment status. There were three or four exceedances of the NAAQS in 1987, and the last violation of the NAAQS occurred on December 21, 1987 with a value of 11 ppm12. Under the 1990 Federal Clean Air Act amendments, all CO nonattainment areas continued in nonattainment status. If an area did not violate the NAAQS in 1988 and 1989, the area could not be classified according to the degree of severity of nonattainment as required by the 1990 amendments.13 These nonclassified areas still remain as nonattainment areas and are subject to SIP requirements.

2.32

Recent Air Quality Trends - Since Jan. 1, 1988 the standard has been attained, and 1988 is the year of attainment. During this period there have been no violations of the NAAQS, three exceedances, and one exceptional event that was recognized by EPA. The details about these events are summarized in Table 2.32 - 1.

Date	Monitor		Comments
	ppm	Location
Dec. 23, '88	10.1	Jade Tree	Exceedance
Dec. 19, '91	11.6	Jade Tree	Exceedance. Overlapping exceedance on Dec. 20, '91.
Dec. 21, '92	9.6	Jade Tree	Exceedance.
Jan. 18, '94	9.4	Jade Tree	Not an exceedance because the value is rounded to 9 ppm.
Feb. 7, '96	12.4 10.5	Jade Tree	Two non-overlapping events. Accepted by EPA, Region 10 as an exceptional event on March 6, 1998.14
Jan. 10, '97	9.4	Courthouse	Not an exceedance because the value is rounded to 9 ppm.

Yakima is currently attaining the NAAQS for CO, and the annual high and average CO monitor values are dropping. Appendix J - 2 has a graph showing the CO monitor values since 1986.

2.4 CO Monitoring

The Yakima CO monitor was located at the County Courthouse on the east side of North 1st Street from 1979 to 1989. After a saturation study, the monitor was moved in 1990 to the Jade Tree Restaurant on the south side of East Yakima Avenue. The Jade Tree Restaurant values were representative of the highest maximum concentrations in the NAA.¹⁵ Another CO saturation study done between December 1994 and March 1995 determined that the East Yakima Avenue corridor and the Jade Tree site had higher concentrations, and the monitor should remain at this site.¹⁶

During the winter of 1996 - 1997 the Jade Tree building was severely damaged by large snowstorms. This resulted in the deactivation of the monitor, the condemnation of the building, and the eventual building demolition. Later in 1997 the monitor was moved back to the Courthouse location. Because past studies had shown the Courthouse was not the optimal location for a CO monitor for downtown Yakima, a limited CO saturation study was done by ECY during February 1999. The results of the study were inconclusive for selecting a CO monitoring site, and a report was never published.¹⁷

During 1999 the Yakima County Courthouse CO monitor recorded 8512 hours with valid data and 97% of the data was determined to be valid.¹⁸ Because the NAA is small in size, Yakima has never had more than one operational CO monitor.

2.5 Design Value

Appendix F shows the five highest readings during each of the last four years. The greater of the second highest CO monitor values during 1998 and 1999 was 5.1 ppm, and this is the current CO design value.¹⁹ This value qualifies for a limited maintenance plan because it is less than 7.65 ppm or 85% of the CO NAAQS.²⁰ The 1988 - 1989 design value was 8.9 ppm.

2.6 Planning Area

The maintenance plan, emission modeling, and emission inventories are limited to the geographic limits of the NAA as shown in Appendix D - 1. EPA has determined that a stationary source that emits < 5,000 tons per year (TPY) of CO through stacks is not likely to produce concentrations in excess of the CO NAAQS,²¹ and there are no sources in the CO NAA or within two miles of the boundary which have CO emissions > 5,000 TPY. Therefore, the CO emissions from Boise Cascade are listed for information only, and other sources are not included in the plan or the inventory.

Any control or contingency strategies which are included in the plan will be designed for optimum effectiveness with an adequate safety margin for the monitored CO values to remain below 85% of the CO NAAQS. The geographic area subject to a strategy may be larger than the NAA depending on the nature of the measure.

2.7 Existing Control Strategies

The following control strategies exist and were used to reduce CO emissions in the NAA. Except for the voluntary programs in Subsection 2.74, these control strategies are all permanent and enforceable emission reductions:

2.71	Federal Requirements - Tier 1 Federal Motor Vehicle Emissions Standards for gasoline powered vehicles.22
2.72	State Requirements

•	Commute trip reduction programs by six employers within the CO NAA and and six additional employers in the City of Yakima but outside of the NAA.23 24
•	Most of the state requirements included in the Washington Administrative Code (WAC) are also local requirements. The state and local citations are shown in Subsection 2.73.

2.73

Local Requirements - The following are local regulations which were included in Restated Regulation I and adopted into the SIP.25 26 These regulations were included in the SIP as PM10 controls and are applicable to areas larger than the CO NAA. However, they also exert some control on CO emissions. They are also included in the new Regulation 1 which was filed for SIP adoption on August 22, 2000.27

•	Prohibition of outdoor and agricultural burning in the NAA;28 29 30

•	Prohibition of the installation of uncertified wood stoves;31 32 33
•	Prohibition of the use of pre-existing uncertified wood stoves during the first stage of an impaired air quality event unless it is the sole source of heat for a living area.34 35 36 A first stage impaired air quality event will be declared when the PM10 values reach 60 µg/m3 or the CO values reach 8 ppm; and37 38 39
•	Prohibition of the use of all wood stoves during a second stage of an impaired air quality event or an alert or higher stage of an air pollution episode except sole sources of heating for living areas, and the compliance patrols required by the SIP.40 41 42 43

2.74	Voluntary Programs.

•	Wood stove buy back programs in 1993 and 1994 removed 58 uncertified wood stoves from the WSCZ that surrounds the NAA. An estimated 34 of these stoves were in the NAA;
•	The recently completed 2000 wood stove rebate program removed 52 uncertified stoves from homes in the WSCZ. Thirty-six of these stoves were in the PM10 NAA and two were in the CO NAA44; and

•	Transit service offered by the City of Yakima.

2.8 Past Emissions Inventories

EPA determined that nonclassified areas are required to submit an emissions inventory.⁴⁵ This was submitted to EPA in March 1994 for the base year of 1992,⁴⁶ but EPA, Region 10 deferred action on this inventory until a maintenance plan was submitted. In December 1997 YRCAA submitted a CO emissions inventory update for 1996,⁴⁷ but this inventory was never approved by ECY or submitted to EPA. The 1992 inventory estimated the CO emissions as shown in Table 2.8 - 1.⁴⁸

3.0 Risk of a Future Violation

There are a number of factors that can be reviewed to evaluate the potential for future violations of the NAAQS for CO in the Yakima area. The following data is provided to assist in evaluating the possible risk of a future violation of the standard and the imposition of a new nonattainment classification.

3.1 Growth Potential

3.11

Growth Projections - The NAA is a mix of urban area zoning classifications varying from Single-Family Residential (R1) to Heavy Industrial (M2)50, and it has few large tracts of vacant land for new multiple housing units or large commercial developments. Most of the future growth is expected to occur from the conversion of existing single-family houses to multiple-family dwellings or small commercial buildings, or new construction on currently vacant lots in areas where the proposed changes are permitted by the zoning. The projected planning statistics and growth rates for the CO NAA, two cities within and adjacent to the NAA, and Yakima County are summarized in Table 3.1 - 1.51 52

3.12

Growth Data Interpretation - The population and housing unit growth rates for the NAA are consistent with those projected for the Cities of Yakima and Union Gap and other parts of the state, and offer no evidence that these growth rates will increase CO emission significantly. The VMT growth rate is almost twice the population growth rate which could indicate out-year increasing vehicle CO emissions. However, this is a situation that has been seen in other VMT projections made with traffic models where the predicted future VMTs growth rates are greater than the resulting future growth rates.

3.2 Potential for Dramatic Change

There is little potential for changes in the source mix for the CO emissions within the NAA. A dramatic change in this emissions inventory would have to be triggered by large increases in VMT or the construction of a major source emitting CO within the nonattainment area. If the projected VMT growth rates do happen and they are combined with a persistent winter inversion, higher CO levels could be expected. Based on four seasons of weather and CO monitor values, the analysis in Appendix J - 1 shows that 1% of the maximum daily CO monitor values between Nov. 1st and Feb. 29th are expected to be > 7.6 ppm. The Board and YRCAA consider this an acceptable level of risk for this plan.

3.3 Major Population or Source Distribution Changes

No major changes are expected in the spatial distribution of emissions in the NAA. Most of the industrial growth is occurring south and west of the NAA or in the area of the Valley Mall at the very southern extremity of the area. This growth could influence VMT inside and around the NAA. Large commercial projects which could generate additional VMT within or adjacent to the CO NAA will be requested to do CO hot spot modeling and analysis during the SEPA review and permitting process.

3.4 Impacts from Outside the NAA

Vehicle traffic originating outside the NAA is the main source that could affect CO emissions within the NAA. The emissions from these vehicles is included in the emissions modeling after they enter the area.

In the past Boise Cascade has proposed closing the plywood plant, but the current plans are for the plant to remain operational. A closure of all or part of the operations of this company would reduce the total CO emissions in the Greater Yakima Area. Because the winter prevailing winds are from the west and the Boise Cascade mill site is on the east side of the NAA, the net emissions change in the NAA would be small.

3.5 Reliance on Unproven Control Measures

The YRCAA is relying upon control measure cited in Section 2.7 that have been in place for a number of years and have effectively reduced CO emissions. The amount of reduction from each of these controls is unknown. Since past CO emissions inventories have indicated the largest amount of CO was from on-road mobile sources, it is reasonable to assume that the federal motor vehicle program emission standards have been the most effective in attaining the CO NAAQS.

3.6 Strength of Past Contingency Measures

Because this is a nonclassified area, contingency measures were not required in prior CO SIP submittals and none were included.

3.7 Meteorological and CO Monitor Data Analysis

An evaluation of historical National Weather Service data from the Yakima Airport and CO emission levels for the two monitor sites was done.

3.71

Analysis and Findings - High CO values normally occur between November 1st and February 29th during an atmospheric inversion with poor ventilation and normal winter temperatures. An analysis of the meteorological conditions for the five days per year with the highest CO monitor values from 1996 through 1999 documented in Appendix G determined the following:

•	The highest CO values occurred on days with temperatures in normal ranges. The average temperature for high value days was only 3°F lower than the seasonal average for 1996 through 1999;
•	None of the highest values occurred on days with an average temperature < 15°F, and nine of the nineteen highest values occurred with an average temperature > 32°F;
•	90% of the highest readings occurred on weekdays;
•	The highest 8 hr. values tended to occur either between 8 AM and 5 PM or at night between 10 PM and 2 AM;
•	75% of the highest readings were two or three day events;
•	75% of them occurred in the month of January; and
•	The average wind speed was lower than the seasonal average wind speed, and there were long periods during the day with winds > 4 mph.

Another analysis documented in Appendix J - 1 looked at the occurrence of CO monitor values > 4.0 ppm and found the following:

•	1% of the maximum daily 8 hour CO monitor values during the season were > 7.6 ppm, and the seasonal range for these values was between 0 and 3%. These values all occurred during severe winter weather in Jan. 1997; and
•	4% of the maximum daily 8 hour monitor values during the season were > 6.0 ppm.

These findings generally agree with the atmospheric conditions for high CO concentrations in the City of Spokane. Both Yakima and Spokane, WA have similar winter climatic conditions, and both cities have large areas in a valley bottom which traps cold air and concentrates CO levels during winter inversions.

3.72	Analysis Conclusions - The analysis of winter CO values and weather conditions documented in Appendices F, G, and J lead to the following conclusions about when high CO values are most likely to occur:

•	The higher monitor values are strongly influenced by weekday vehicle traffic and and to a lesser extent building heating emissions during inversion periods;
•	They occur on weekdays during a winter inversion periods in December or January;
•	They have rapidly rising CO monitor values, last for two or three days, and then drop quickly; and
•	The probability of CO values > 7.65 ppm occurring in future years should diminish because of continuing vehicle replacements with lower emission rates and the completion of the optimized intersection mitigation measure described in Subsection 5.71 and Appendix I.

Appendix I contains some emission inventory and weather information that is slightly different than the plan and the other appendices. When differences are found in weather and emission inventory information, the reader should use the information in the plan and other appendices.

4.0 State Implementation Plan (SIP) Requirements

4.1 Summary of Previous SIP Submittals

Restated Regulation I of 1995 was adopted into the SIP⁵⁴, and the newly adopted Regulation 1 was submitted to ECY for SIP adoption on August 22, 2000.⁵⁵ The only existing CO SIP submittal for Yakima is in Section 4.6.2.CO.1 approved by EPA on Sep. 14, 1981. This submittal predicted attainment of the CO NAAQS in 1982.⁵⁶ This did not happen.

Because Yakima is a not classified area under the 1990 Federal Clean Air Act Amendments, no SIP submittals were required.

4.2 Demonstration of Attainment

The data in Appendix F, and the narratives in Sections 2.3 and 2.5 show that 1998 and 1999 had no CO NAAQS exceedances or violations, and the CO NAAQS has been attained since 1986.

4.3 Adequacy of the Monitoring Network

See Sections 2.4 and 5.3 for discussions on past CO monitoring and the network.

4.4 Permanent and Enforceable Emission Reductions

The existing permanent and enforceable emission controls are listed in Section 2.7, and they will all remain in effect. The actual contribution of each control in the CO NAA is not known, but the federal motor vehicle emission standards have made the greatest reduction. The CO air quality contingency measure described in Subsection 5.62 has a companion City of Yakima adopted resolution in Appendix K.

The optimized intersection mitigation measure described in Subsection 5.71 is a permanent capital investment by the City of Yakima.

4.5 Transportation Conformity

Yakima is subject to transportation conformity by YVCOG and has been complying with the state and federal conformity regulations since they were adopted. Under the CO limited maintenance plan directions, regional conformity analysis on the metropolitan transportation plan and transportation improvement program is no longer necessary because there is no limit on motor vehicle emissions and thus no way to receive a negative conformity determination. Individual transportation projects must still continue to have a conformity analysis and receive a positive determination to obtain project approval. The project level analysis will continue to be done by the project sponsor in accordance with the existing state and federal requirements for planning and modeling.⁵⁷ YVCOG will work with the effected jurisdictions and interested parties to develop an evaluation criteria and process to meet the transportation conformity requirements.

The metropolitan transportation planning organizations with ozone and CO NAAs have agreed that Yakima can qualify for the minimum guaranteed allocation of congestion mitigation and air quality (CMAQ) funds when the YRCAA Board approves and submits either a Yakima CO or PM₁₀ maintenance plan to ECY which includes transportation elements.⁵⁸

4.6 Section 110 and Part D Requirements

The only applicable requirement is state transportation conformity regulations. While EPA has yet to approve the State of Washington regulations, EPA has determined that states are still bound by the federal regulation, and the absence of an EPA approval does not constitute an obstacle to redesignation.

EPA has approved the new source review rule in WAC 173-400-110 dated Aug. 20, 1993,⁵⁹ and the local rule in Restated Restated Regulation 1, Section 4.02, dated Dec. 15, 1995 ⁶⁰.

5.0 Air Quality Maintenance Plan

     The following sections document the planned strategies for maintaining the CO monitor values below the NAAQS and the 7.65 ppm level prior to being granted attainment status.

    
5.1 Maintenance Plan Emission Inventory

An annual and a typical winter day CO maintenance plan emission inventories was constructed for 1999 consistent with the EPA limited maintenance plan direction. 1999 was selected for the base year for this inventory because this is the base year for the traffic modeling done by YVCOG. These inventories also will fulfill the EPA requirement for a three year emissions inventory in the NAA.

The 1992 inventory was used as a reference for constructing the 1999 attainment inventory. However, major changes have occurred in residential home heating and the traffic modeling between the inventories. The 1999 inventory replaces the 1992 and 1996 CO NAA emissions inventories. Therefore, no comparisons with the previous inventories are necessary. The maintenance plan inventory including the inventory calculations, documentation, and quality control evaluations are in Appendix H. The inventory preparation and quality assurance plan is in Appendix C.

The inventory is limited to the CO NAA, and there is one air operating permit point source within the NAA. However, this source is only a major source for VOC emissions⁶¹, and the small level of CO emissions from the source are treated as an area source emission. The CO emissions from Boise Cascade are listed for information because they were included in previous CO NAA inventories, but they are not included in the inventory totals. Table 5.1 - 1 summarizes the maintenance plan inventory.

The EPA direction for limited maintenance plans assumes that the CO emissions are at a low enough level, that even with future growth or unfavorable winter weather, a violation of the NAAQS will not occur. This is the expected situation in Yakima. Therefore, no modeling was done to construct out-year emissions inventories.

5.3 Monitoring Network

Because the NAA is small in size, and the one CO monitor has been acceptable, there is no need for a second monitor. ECY is currently working to relocate the CO monitor to a site on East Yakima Ave., but the specific location has not been finalized. In order to have continuous monitoring during the CO season, the monitor relocation needs to be done between March 1st and Oct. 1st of any year, or to continue the operation of the Courthouse monitor until a second CO monitor is fully installed, tested, and certified at the new site. After that the Courthouse monitor can be deactivated and the equipment returned to ECY. YRCAA and ECY plan to periodically review the adequacy of the monitor location. There are no current plans for a CO saturation study. However, ECY and YRCAA recognize the need for one and plan to schedule one for a future winter season.

5.4 Verification of Continued Attainment

YRCAA will annually review the monitored air quality data and assumptions supporting the plan to verify the continued attainment of the CO NAAQS. Every three years starting in 2003 for the year 2002, YRCAA and ECY will review the maintenance plan inventory and the factors used to construct the inventory to determine if there has been a significant change in CO emissions.⁶⁴. If a significant change in CO emission levels is found, an emissions update will be prepared and submitted to EPA, Region 10.

Saturation studies will be scheduled and conducted as needed to evaluate the configuration of the monitoring network and the spatial changes in CO concentrations.

5.5 Control Measures

The control measures listed in Section 2.7 will all remain effective. No additional control measures are planned for this limited maintenance plan.

5.6 Contingency Plan and Measures

This plan contains one contingency measure described in the following subsections.

5.61

Rationale for Selection of a Contingency Measure - All past CO NAA emissions inventories have identified on-road, gasoline-powered vehicles as the largest source of CO in both the annual and typical winter day inventories. In addition, outdoor burning is prohibited in the NAA except for certain specific types of fires permitted by YRCAA, and the emission trend for home wood heating is declining. The analysis and conclusions in Section 3.7 show that the primary contingency measure for this plan needs to quickly stop rapidly rising winter CO emissions before the 7.65 ppm level is reached, but only needs to be implemented for short periods during the winter.

The CO NAA has 63 signalized traffic intersections, and the central business district within the NAA has 40 fixed-time traffic signals. These signals in the central business district are using old technology and do not optimize traffic movement. Converting all or part of these traffic signals to an alternative timing sequence by installing new technology has a great potential to move traffic more efficiently and reduce CO emissions. The City PWD has studied the traffic movement in the central business district, and it is documented in Appendix I.

Activation of an alternate traffic signalization program during a CO episode at levels > 5.5 ppm as described in Subsection 5.62 to reduce vehicle emissions on the major downtown arterial streets which lasts one to five days could make a significant difference in preventing a monitor value > 7.65 ppm. This should rapidly reduce the emission rate for the greatest single source category in the NAA. An alternate traffic signal program to control potentially very high values which is used an average of 6% of the time during a winter CO season should be much more acceptable to the public than other control measures.

5.62

CO Air Quality Contingency Measure - This plan includes in Appendix I an episodic CO air quality contingency measure which will change the timing on 40 signals in the central business district to favor the traffic on arterial streets and delay the lower traffic volumes on the cross streets during periods of predicted higher CO monitor values. This measure would move more traffic with less total delays and lower emissions, and give a high probability of stopping rising CO values. Traffic modeling using SYNCHRO 4.0 produced estimates for the afternoon peak traffic volumes and vehicle CO emissions which are shown in Table 5.62 - 1.65

It is the decision of YRCAA to have the appropriate rules adopted before submitting the maintenance plan. Therefore, the City of Yakima Resolution No. 2000 - 115 for the CO air quality contingency measure is included in Appendix K. The YVCOG will include this contingency measure as an amendment to the State Transportation Implementation Plan (TIP).

5.63	Implementation of the Contingency Measure - The CO air quality contingency measure will be activated by the YRCAA from the 8 hour CO values at the local monitor that are posted on the ECY state air quality website under the following conditions:

•	After local adoption of the limited maintenance plan - CO monitor values > 5.5 ppm and the monitor data indicates that the values are rising; or
•	After EPA, Region 10 grants CO attainment status - CO monitor values > 7.0 ppm and the monitor data indicates that the values are rising.

It is expected that these conditions will exist one to three times each winter, and the duration of this contingency measure will be no longer than the next Saturday morning following the activation of the measure. Because activation of this contingency measure is intended for a short duration, the public should not significantly change their driving patterns to avoid the extended intersection delays on the local streets.

The City PWD has written detailed instructions for the procedures to convert the timing of the signals in the central business district to implement this contingency.⁶⁸

5.64

Continuing Use of the Contingency Measure - During and after the completion of the optimized intersection system mitigation measure described in Subsection 5.71, it will still be possible to convert the traffic signal system to the CO air quality contingency system to stop rising high CO values using the activation system identified in Subsection 5.63.

5.7 Mitigation Measures

The plan includes two non-enforceable mitigation measures which will reduce CO levels in addition to the existing control and contingency measures.

5.71

Optimized Intersection Mitigation Measure - The long term solution for more efficient traffic and pedestrian movement and CO emission reductions in the central business district is the installation of new traffic signal controls, detection and communication equipment, and the construction of left turn lanes at some intersections. This optimized intersection mitigation system is planned to be done by the City of Yakima over a several year period as funds become available, and it is documented in Appendix I. Part of the funding was granted from the Washington State Department of Transportation, and CMAQ funds are expected to be the other major source for the project. Table 5.62 - 1 shows the expected CO emissions reductions from the existing conditions.69

5.72

Public Information Mitigation Measure - YRCAA is using news releases and interviews through the print, radio, and television media to inform the public of rising PM10 and/or CO levels, and to request voluntary reductions in outdoor and agricultural burning, wood stove use, and trip reductions to prevent an exceedance of the PM10 or CO NAAQS. These media releases will continue to the extent that funds are available. No estimates have been made of the effectiveness of this mitigation measure.

5.8 Additional Measures

If the control, contingency, and mitigation measures discussed in Sections 5.5, 5.6, and 5.7 are not successful in preventing a future violation of the CO NAAQS, the plan and SIP will be amended to incorporate additional measures and rules as needed.

5.9 Transportation Emission Budgets

Under a limited maintenance plan future emissions are not calculated and regional analysis of transportation plans and programs is not required. Therefore, no transportation emission budgets are developed.

     ¹ Appendices A through J and L are considered part of this limited maintenance plan, but they were not filed with the Code Reviser for publication in the State Register. Appendix K is an adopted resolution and part of this plan.

     ² Does not include tables in the appendices.

     ³ Paisie, Oct. 6, 1995.

     ⁴ Board Meeting Minutes, May 10, 2000, Pg. 2.

     ⁵ Calcagni, Sep. 8, 1992, Pg. 7.

     ⁶ Approved WA SIPS, Sec. 4.6.2CO.1, Sep. 9, 1981.

     ⁷ Carbon Monoxide Emissions Inventory for the Yakima Carbon Monoxide Nonattainment Area, Mar. 1, 1994, Pgs. 2 & 4.

     ⁸ Williams, Mar. 24, 1994.

     ⁹ Silva, Aug. 22, 2000.

     ¹⁰ 40 CFR 50.8 (a)(1), Jul. 1, 1999.

     ¹¹ 40 CFR 50.8(d), Jul. 1, 1999.

     ¹² EPA AIRS Data, Dec. 1987.

     ¹³ 40 CFR 81.348, Jul. 1, 1998.

     ¹⁴ Frankel, Anita by Bonnie Thie, Mar. 6, 1998.

     ¹⁵ Schweiss and Miller, Nov. 1985.

     ¹⁶ Bennett and Miller, Sep. 1996, Pg. 7.

     ¹⁷ Billings, Aug. 24, 2000.

     ¹⁸ Rauh, Apr. 2000, Pg. 11.

     ¹⁹ Laxton, Jun. 18, 1990, Pg. 2.

     ²⁰ Paisie, Oct. 6, 1995.

     ²¹ Laxton, May 13, Pg. 2.

     ²² 40 CFR Part 86, Jul. 1, 1998.

     ²³ RCW 70.94.531, undated.

     ²⁴ Webster, Aug. 8, 2000.

     ²⁵ Federal Register, Vol. 63, No. 21, Feb. 2, 1998, Pg. 5269->5272.

     ²⁶ Approved WA SIPS, Sec. 3.YC.

     ²⁷ Ornelas, Aug. 22, 2000.

     ²⁸ Restated Reg. I, Sub. 5.03B, Pg. 5-3.

     ²⁹ Regulation 1, Sub. 3.03C1d, Pg. 3-12.

     ³⁰ WAC 173-425-040 (1), Pg. 4.

     ³¹ Restated Reg. I, Sub. 9.04A, Pg. 9-1.

     ³² Regulation 1, Sub. 3.04C4, Pg. 3-35.

     ³³ WAC 173-433-100, Pgs. 3 & 4.

     ³⁴ Restated Reg. I, Sub. 9.05A2, Pg. 9-3.

     ³⁵ Regulation 1, Table 3.05 - 2, Pg. 3-38.

     ³⁶ WAC 173-433-150, Pgs. 7 & 8.

     ³⁷ Restated Reg. I, Sub. 9.05A2, Pg. 9-3.

     ³⁸ Regulation 1, Table 3.05 - 1, Pg. 3-37.

     ³⁹ WAC 173-433-140 (1)(b), Pg. 6.

     ⁴⁰ Restated Reg. I, Sub. 9.05A3, Pg. 9-3.

     ⁴¹ Regulation 1, Table 3.05-2, Pg. 3-38.

     ⁴² WAC 173-433-150, Pgs. 7 & 8.

     ⁴³ SIP Supp. For PM₁₀ in Yakima, WA, Nov. '91, Pg. 9.

     ⁴⁴ Ornelas, Nov. 14, 2000, Pg. 2.

     ⁴⁵ Calcagni, Sep. 4, 1992, Pg. 8.

     ⁴⁶ Williams, Mar. 4, 1994.

     ⁴⁷ Carbon Monoxide Emissions Inventory Update - 1996 for the Yakima Nonattainment Area, Dec. 1997.

     ⁴⁸ Carbon Monoxide Emissions Inventory for the Yakima Carbon Monoxide Nonattainment Area, Mar. 1, 1994, Pg. 4.

     ⁴⁹ Carbon Monoxide Emissions Inventory for the Yakima Carbon Monoxide Nonattainment Area, Mar. 1, 1994, Pg. 7.

     ⁵⁰ Yakima Co. GIS Dep't., Jul. 17, 2000.

     ⁵¹ Davenport, Aug. 24, 2000.

     ⁵² Webster, Apr. 4, 2000.

     ⁵³ RTP/MTP, Dec. 1999.

     ⁵⁴ Federal Register, Feb/ 2. 1998, Pg. 5269 ->5272.

     ⁵⁵ Ornelas, Aug. 22, 2000.

     ⁵⁶ Approved WA SIPS, Section 4.6.2CO.1, Sep. 9, 1981.

     ⁵⁷ WAC 173-420-100, Aug. 25, 1995, Pg. 9.

     ⁵⁸ Wyrick, Jun. 2000.

     ⁵⁹ Approved WA SIPS, Sec. 2.2.

     ⁶⁰ Approved WA SIPS, Sec. 3.YC.

     ⁶¹ Stansel, Jul. 6, 2000.

     ⁶² Yakima CO NAA Maint. Plan Emissions Inventory, Nov. 2000, Pg. C - 4.

     ⁶³ Sandberg, May 22, 2000.

     ⁶⁴ Calcagni, Sep. 4, 1992, Pg. 11.

     ⁶⁵ City of Yakima, Washington Evaluation of Mobile Source Carbon Monoxide Emissions in the Yakima CBD, Sep. 8, 2000, Pg. 2.

     ⁶⁶ Gardner, Sep. 11, 2000.

     ⁶⁷ Davenport, Sep. 21, 2000.

     ⁶⁸ Traffic Signal Program Instructions to Provide a Response to a Critical Carbon Monoxide Event, Oct. 1, 2000.

     ⁶⁹ City of Yakima, Washington Evaluation of Mobile Source Carbon Monoxide Emissions in the Yakima CBD, Sep. 8, 2000, Pg. 2.

     WHEREAS, the Yakima Valley is subject to winter seasonal temperature inversions which can create poor air quality conditions, sometimes resulting in periods of elevated Carbon Monoxide levels due primarily to vehicle traffic; and

     WHEREAS, rising CO values during temperature inversions may be reduced by implementation a temporary and alternate signal timing plan, referred to as the "Yakima CO Air Quality Contingency Measure" which reduces vehicle idling on major arterial streets in the Yakima CBD; now, therefore,

This alternative plan serves as the Yakima Transportation Contingency Measure (TCM) as required by the Federal Highway Administration and Environmental Protection Agency and by Section 176(c) of the Clean Air Act (CAA) [42 U.S.C. §7509]. Conformance of the TCM with the Washington State Implementation Plan (SIP) is required by Chapter 173-420 WAC.

Section 2: The Department of Ecology Carbon Monoxide monitoring device will be used to determine when an air quality advisory period is in effect which requires implementation for the TCM. The following thresholds will be used:

1.	A Carbon Monoxide (CO) reading of greater than 5.5 parts per million (PPM), averaged over an 8-hour period until the Yakima CO Limited Maintenance Plan is approved by the Washington Department of Ecology and the Environmental Protection Agency grants attainment status for CO in Yakima;
2.	A Carbon Monoxide (CO) reading of greater than 7.0 parts per million (PPM), averaged over an 8-hour period after the Environmental Protection Agency grants attainment status for CO in Yakima.

Section 3: If the threshold values described in Section 2 above are observed on or after 5:00 PM on a Friday, implementation of the TCM will be deferred 48 hours (until 5:00 PM, Sunday), pending a threshold reading at that time.

Section 4: Yakima Regional Clean Air Authority will provide notice to the City of Yakima Department of Public Works that an air quality advisory event is in effect. The Yakima Regional Clean Air Authority will provide public notice that an air quality advisory event is in effect and the CO Air Quality Contingency Measure is in effect for the Yakima CBD.

Section 5: The City of Yakima Public Works Department will respond with implementation of the TCM within 4 hours of the notice given by the Clean Air Authority. The TCM will be in effect until air quality conditions are below the threshold values in Section 2 above.

     ADOPTED BY THE CITY COUNCIL this 19th day of September, 2000.

S/ MARY PLACE Mary Place, Mayor

ATTEST:

     /S/ KAREN S. ROBERTS, CMC

     City Clerk

Reviser's note: The brackets and enclosed material in the text of the above section occurred in the copy filed by the agency and appear in the Register pursuant to the requirements of RCW 34.08.040.

Reviser's note: The typographical errors in the above material occurred in the copy filed by the Yakima Regional Clean Air Authority and appear in the Register pursuant to the requirements of RCW 34.08.040.

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