Reply to Attn Of: AWT-107 

MEMORANDUM 

DATE: November 18, 2009 

SUBJECT: Technical Support Document for the Vancouver Portion of the PortlandVancouver (Pdx/Van) Air Quality Maintenance Area, 8-hour Ozone Section 

110(a)(1) Maintenance Plan. 

FROM: Krishna Viswanathan, Environmental Scientist 

TO: Docket EPA-R10-OAR-2007-0112 

TABLE OF CONTENTS

I. Purpose 

II. Background 

III. Review of the Maintenance Plan 

IV. Evaluation 

V. Conclusion 

VI. Recommended Agency Action 

I. Purpose 

This technical support document (TSD) provides information supporting EPA’s proposed action 

to approve the State of Washington’s January 17, 2007 request to approve the Section 110(a)(1) 

Ozone Maintenance Plan and supporting rules. The submittals are specifically for the Vancouver 

portion of the Portland-Vancouver (Pdx/Van) Air Quality Maintenance Area (AQMA). The 

Section 110(a)(1) Maintenance Plans for this area demonstrates how the State of Washington 

will maintain compliance with the 1997 8-hour Ozone National Ambient Air Quality Standards 

(NAAQS). 

On May 22, 2007, EPA received a request from the Oregon Department of Environmental 

Quality (ODEQ), to approve a SIP revision pertaining to the Maintenance Plan for the Portland 

Portion of the Pdx/Van AQMA, and the Salem Keizer Area Transportation Study Air Quality 

Area (SKATS AQA), under section 110 of the CAA. That submission by the ODEQ will be 

acted upon concurrently with this action as they both pertain to the Pdx/Van Air Quality 

Maintenance Area. 

The 110(a)(1) Maintenance Plan for this area meets the Clean Air Act (CAA) requirements and 

demonstrates that the Vancouver portion of the Pdx/Van AQMA will be able to remain in 
2

attainment for 1997 and 2008 Ozone NAAQS through 2015. Based on my review, I am 

recommending full approval of the proposed Maintenance Plan and implementing regulations. 

II. Background 

Ground-level ozone is not emitted directly by sources. Rather, emissions of volatile organic 

compounds (VOCs) and nitrogen oxides (NOx) react in the presence of sunlight to form groundlevel ozone. The air pollutants, VOCs and NOx, are referred to as precursors of ozone. The 

Clean Air Act (CAA) establishes a process for air quality management through the attainment 

and maintenance of the NAAQS. 

On March 3, 1978 (43 FR 8961), the Portland-Vancouver (Pdx/Van) Interstate Area consisting 

of the southern portions of Clark County, Washington and portions of Multnomah, Clackamas, 

and Washington Counties in Oregon, was designated an ozone nonattainment area under the 

1977 Clean Air Act. The Interstate designation was warranted as the Portland, OregonVancouver, Washington Interstate Urban Area shares a common air shed and common air quality 

problems.1 On November 15, 1990, the CAA was amended (42 U.S.C 7401-7671(q)) and 

Section 107(d)(1)(C) provided that designations occurred by operation of law for areas that had 

been designated nonattainment before enactment of the amendments. In the 1990 amendments, 

the Pdx/Van Interstate nonattainment area was classified as a marginal 1-hour ozone 

nonattainment area (Section 181(a)(1) of the CAA). 

On May 19, 1997, EPA redesignated the Pdx/Van Interstate Nonattainment Area to attainment 

for the 1-hour ozone air quality standard and approved a Maintenance Plan (62 FR 27204). On 

July 18, 1997, EPA revised the ozone NAAQS and established a new standard of 0.08 ppm 

averaged over eight hours and temporarily vacated the 1-hour standard. No violations of the 

1997 8-hour ozone standards have been reported in this AQMA.2 

In 2002, EPA began the process to designate areas under the 1997 8-hour ozone standard. On 

April 30, 2004 (69 FR 23858), EPA designated and classified areas for the 8-hour ozone 

NAAQS. The Carus Site ozone monitor shows the highest reading in the area with a 2005-2007 

design value of 0.065 ppm; the area remains in attainment with the 1997 8-hour ozone NAAQS. 

EPA’s Phase 1 Implementation Rule for the 8-hour ozone standard was published on April 30, 

2004 (69 FR 23951, 23998). 40 CFR 51.905 sets forth requirements for anti-backsliding 

purposes for areas designated attainment for the 8 hour standard. These provisions require such 

areas to submit a 10 year Maintenance Plan under section 110(a)(1) of the CAA, if they were 

also a nonattainment or an attainment/unclassifiable area with a section 175A Maintenance Plan, 

under the ozone standard. The Maintenance Plan needs to demonstrate that the area will maintain 

the standard for 10 years after designation in accordance with section 110(a)(1) of the CAA. 

EPA specified that even though the 1-hour ozone standard had been revoked, the 1-hour ozone 

NAAQS designations and classification statuses were retained as of the effective date of 

designation for the 8-hour NAAQS, for purposes of anti-backsliding regulations (40 CFR 

51.905). Anti-backsliding regulations apply even after revocation of the 1-hour ozone NAAQS. 

 

1

 Letter from Clark L. Gaulding, Chief Air Programs Branch, US EPA Region 10 to Peter Hildebrandt, Assistant Director, Office 

of Air Programs, State of Washington, dated June 12, 1978. 2

 The last exceedance of the 1-hour ozone standard at the Carus Site in Portland occurred in 1998 when the 1-hour ozone standard

was temporarily revoked so the 1-hour ozone contingency plan was not triggered.
3

On December 22, 2006, the U.S. Court of Appeals for the District of Columbia Circuit vacated 

EPA’s Phase 1 Implementation Rule for the 8-hour Ozone Standard (69 FR 23951, April 30, 

2004). On June 8, 2007, in South Coast Air Quality Management Dist. v. EPA, Docket No. 04-

1201, in response to several petitions for rehearing, the DC Circuit clarified that the Phase 1 Rule 

was vacated only with regard to those parts of the rule that had been successfully challenged – 

the Phase 1 Rule provisions related to classifications for areas currently classified under subpart 

2 of Title I, Part D of the CAA. The June 8 decision reaffirmed the December 22, 2006, decision 

that EPA had improperly failed to retain measures required for areas that were previously 

designated nonattainment for the 1-hour standard and the anti-backsliding provisions of the 

regulations. That decision does not affect EPA’s ability to act on this submission. 

On January 17, 2007, the Washington State Department of Ecology (Ecology) submitted for 

approval under section 110 of the CAA a revised 8-hour ozone Maintenance Plan for the 

Vancouver Portion of the Portland-Vancouver AQMA. This Plan was developed by the 

Southwest Clean Air Agency (SWCAA) with collaboration from ODEQ and Ecology. 

Throughout this document the submitting agency is referred to as Ecology, recognizing that air 

quality management in this area is shared between Ecology and the SWCAA. 

The Plan demonstrates how Ecology intends to maintain the 1997 and 2008 8-hour ozone 

NAAQS. The proposed Maintenance Plan contains a base-year inventory for 2002 and 

demonstrates that emissions will not be greater than the base year in 2015. The proposed 

Maintenance Plan indicates the Plan’s progress will be tracked and identifies measures that 

would be available to promptly correct any NAAQS violation. Ecology’s SIP submittal meets the 

CAA requirements for SIP submittals under CAA Section 110(a)(1). Additionally, Ecology’s 

submittal also meets the requirements of CAA 110(l) and CAA 193. 

III. Review of the Maintenance Plan 

A. What are the components of a section 110(a)(1) 8-hour ozone Maintenance Plan? 

CAA Section 110(a)(1) requires states to submit plans to EPA which provide for the 

implementation, maintenance and enforcement of NAAQS standards in each air quality control 

region with the state. On May 20, 2005, EPA issued guidance that applies to areas that are 

designated as unclassifiable/attainment for the 8-hour ozone standard. The purpose of that 

document is to provide guidance on the maintenance requirements in section 110(a)(1) of the 

CAA, and provide guidance to the states in the development of a SIP. It indentifies five 

components of an 8-hour ozone Maintenance Plan: 

1. Attainment Inventory – The attainment inventory should be based on actual “typical summer 

day” emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx) for a 10-year 

maintenance period. For purposes of an attainment emissions inventory, the state must choose 

any one of the three years on which the 8-hour ozone attainment designation was based. As 

many areas are already required to develop an inventory for the 2002 under EPA’s Consolidated 

Emissions Reporting Rule (67 FR 39602), EPA recommends that areas use that year as the 

attainment emission inventory base year for the section 110(a)(1) Maintenance Plan. 

2. Maintenance Demonstration – The submission should demonstrate how the area will remain 

in compliance with the 8-hour ozone standard for a period of 10 years following the effective 
4

date of designation as unclassifiable/attainment. If the effective date of the area’s designation for 

the 8-hour NAAQS was June 15, 2004, the Maintenance Plan must project attainment for 2014 

or beyond. 

A typical method that areas have used to demonstrate that an area will maintain the 1-hour 

standard has been to use the attainment inventory and to show that future emissions of ozone 

precursors will not exceed those levels. However, in areas where transport of precursor 

emissions from an area outside a jurisdiction is a factor to ozone levels, more sophisticated 

analysis using dispersion models may be required to demonstrate maintenance of the standard. 

3. Ambient Air Quality Monitoring - The state should continue to operate air quality monitors 

in accordance with 40 CFR Part 58 to verify maintenance of the 8-hour ozone standard. 

4. Contingency Plan – The state should develop measures so that in the event of a violation of 

the 8-hour ozone NAAQS, the measures can be implemented as expeditiously as practicable after 

the violation. 

5. Verification of Continued Attainment – The state should indicate how it intends on tracking 

the progress of the Maintenance Plan. This is necessary because emissions projections for the 

maintenance demonstration depend on assumptions of point, area, and mobile source growth. 

B. How has the state addressed the components of a section 110(a)(1) 8-hour ozone 

Maintenance Plan? 

1. Attainment Inventory – Ecology has provided a comprehensive and current emissions 

inventory for VOCs, NOx, and CO, using 2002 as a base year. The effective year of the 8-hour 

ozone initial designation was 2004; Ecology projected emissions for 10 years or beyond from the 

effective date of the initial designation. Consequently, Ecology developed an emissions 

inventory for ozone precursors for the year 2002 and 2015. In the Maintenance Plan, Ecology 

included information on anthropogenic and biogenic sources of ozone precursors, VOCs and 

NOx (e.g., “Point sources,” “On-road sources,” “Nonroad sources”, “biogenic sources”, and 

“area sources”). The tables below show the VOCs, NOx, and CO attainment emissions inventory 

for 2002. 
5

Table 1: Vancouver Area 2002 Attainment Inventories (lb/day) 

 Vancouver-Area 2002 Attainment Inventory

 Typical Summer Day, lb/day

 (Clark County)

2002 2002 2002

 Source Type VOC NOx CO

AREA 18,014 665 3,912

BIOGENIC 79,417 965

NONROAD 15,374 23,222 228,078

ON-ROAD 38,315 50,495 397,983

POINT 3,572 6,089 3,803

Total 154,692 81,436 633,776

Figure 1 

Vancouver Area 

2002 VOC Attainment Inventory

AREA

12%

BIOGENIC

51%

ON-ROAD

25%

POINT

2%

NONROAD

10%

AREA BIOGENIC NONROAD ON-ROAD POINT

Vancouver Area 

2002 NOx Attainment Inventory

ON-ROAD

62%

BIOGENIC

1%

NONROAD

29%

AREA

POINT 1%

7%

AREA BIOGENIC NONROAD ON-ROAD POINT

Vancouver Area

2002 CO Attainment Inventory

ON-ROAD

62%

BIOGENIC

0% POINT

1%

AREA

1%

NONROAD

36%

AREA BIOGENIC NONROAD ON-ROAD POINT

The 2002 Consolidated Emissions Reporting Rule (CERR) emissions data submitted by Ecology 

and SWCAA to EPA’s National Emission Inventory (NEI) were used as the basis for the 2002 

attainment year inventory. The Technical Appendices submitted with Ecology’s Maintenance 

Plan contain more detailed information for each sector of the emission inventories. 

The Technical Appendices submitted with Ecology’s Maintenance Plan contain more detailed 

information for each sector on the emissions inventories. Emissions for all source categories 

were calculated following EPA guidance and are properly documented in the Appendix 3 of the 

proposed Maintenance Plan. This component of the Maintenance Plan meets the requirements 

for attainment inventories under Section 110(a)(1) of the CAA. 

2. Maintenance Demonstration – The proposed Maintenance Plan must demonstrate 

maintenance to 2014 or beyond, as the effective date of designations for this area for the 8 hour 

ozone NAAQS is 2004. This proposed Maintenance Plan meets this criterion by projecting 

emissions to 2015. 

Ecology developed two different growth scenarios for major industrial (point) sources. The first 

growth scenario (called “2015 Projection”) reflects the 2002 estimate of actual industrial 

emissions, increased by regional employment projections for that sector. The second growth 

scenario (called “2015 Maintenance Demonstration”) represents a very conservative estimate of 

possible future year emissions and is used in maintenance demonstration for the Maintenance 

Plan. The 2015 Maintenance Demonstration reflects maximum “legally allowable” emission 

levels currently permitted for existing industry, plus the emissions growth allowance 

reestablished for new industry growth. It is to be noted that the approved Maintenance Plan for 

this area (62 FR 27204) included an industrial emissions growth allowance. The current plan 

continues to use this approach to manage industrial emissions growth and these growth 
6

allowances were included in the 2015 ozone maintenance demonstrations. The growth allowance 

for point sources amounts to 411 tons VOC and 1,313 tons of NOx in the Vancouver, 

Washington portion of the Portland-Vancouver AQMA. Section 4.2.2.1 of this Maintenance 

Plan, Requirements for New Sources in a Maintenance Plan Area, explains how the growth 

allowance will be allocated to industrial facilities. 

Although Table 3 indicates that the total future emissions are projected to decrease during the 

10-year maintenance period, it is important to note that the formation of ozone is dependent on a 

number of variables which cannot be estimated by emissions growth and reduction calculations 

alone. Other variables include weather and the transport of ozone precursors from areas outside 

of the State of Washington. As the Pdx/Van Interstate Urban Area shares a common airshed and 

common air quality problems3

, examining the effects of transport of Ozone precursors from the 

Portland side of the AQMA is necessary. In order to demonstrate continued maintenance, a state 

may utilize more sophisticated tools such as dispersion modeling; the State of Washington did 

use modeling to assess the comprehensive impacts of growth through 2015 on air quality. 

Figure 2 

Vancouver 2002 and 2015 Emission projections used for Maintenance Demonstration in 

lbs/day

Vancouver Area VOC Emissions

0

100,000

200,000

Lbs per day

POINT 3,572 3,780 9,682

ON-ROAD 38,315 16,026 16,026

NONROAD 15,374 9,339 9,339

BIOGENIC 79,417 79,417 79,417

AREA 18,014 21,860 21,860

2002 Actual 2015 Growth Projection 2015 Maintenance 

Demonstration

Vancouver Area NOx Emissions

0

40,000

80,000

120,000

Lbs per day

POINT 6,089 6,197 22,965

ON-ROAD 50,495 19,482 19,482

NONROAD 23,222 15,183 15,183

BIOGENIC 965 965 965

AREA 665 786 786

2002 Actual 2015 Growth Projection 2015 Maintenance 

Demonstration

 

3

 Letter from Clark L. Gaulding, Chief Air Programs Branch, US EPA Region 10 to Peter Hildebrandt, Assistant 

Director, Office of Air Programs, State of Washington, dated June 12, 1978. 
7

Table 2 

Vancouver Area 2015 Maintenance Demonstration, Typical Summer Day, lb/day Clark 

County 

Vancouver Area 2015 Maintenance Demonstration

 Typical Summer Day, lb/day

 Clark County

2015 2015 2015

 Source Type VOC NOx CO

AREA 21,860 786 5,337

BIOGENIC 79,417 965 0

NONROAD 9,339 15,183 271,651

ON-ROAD 16,026 19,482 159,167

POINT 9,682 22,965 3,780

Total 136,323 59,381 439,935

Figure 3 

Vancouver Area 

2015 VOC Maintenance Demonstration

BIOGENIC

58%

ON-ROAD

12%

POINT

7% AREA

16%

NONROAD

7%

AREA BIOGENIC NONROAD ON-ROAD POINT

Vancouver Area 

2015 NOx Maintenance Demonstration

NONROAD

26%

ON-ROAD

33%

AREA

1% BIOGENIC

2% POINT

38%

AREA BIOGENIC NONROAD ON-ROAD POINT

Vancouver Area 

2015 CO Maintenance Demonstration

NONROAD

62%

BIOGENIC

0%

AREA

1% POINT

1%

ON-ROAD

36%

AREA BIOGENIC NONROAD ON-ROAD POINT

Table 3 

Vancouver Area VOC and NOx Emissions (lb/day), % Change 2002-2015

(Clark County)

--- VOC, lbs per day --- --- NOX, lbs per day ---

2015 2015

Source 2002 Maintenance % Source 2002 Maintenance %

Type Actual Demonstration Change Type Actual Demonstration Change

AREA 18,014 21,860 21.3% AREA 665 786 18.2%

BIOGENIC 79,417 79,417 BIOGENIC 965 965

NONROAD 15,374 9,339 -39.3% NONROAD 23,222 15,183 -34.6%

ON-ROAD 38,315 16,026 -58.2% ON-ROAD 50,495 19,482 -61.4%

POINT 3,572 9,682 171.0% POINT 6,089 22,965 277.2%

---------- ---------- ---------- ----------

154,692 136,323 81,436 59,381

The submissions support the conclusion that Vancouver’s area on-road emissions are expected to 

decrease significantly: 58% less VOC emissions and 61% less NOx emissions, primarily due to 

implementation of federal motor vehicle emission and fuel standards and continuing 

implementation of the vehicle inspection program. Non-road emissions also show an 

approximate 35% decrease in NOx and 39% reduction in VOC emissions due to the phase-in of 

federal emission and fuel standards. The eventual shift from Stage II vapor recovery at gas 

stations to on-board canisters in cars is reflected in the 2015 modeling projections and 
8

maintenance demonstration of this plan. Point source “actual” emissions are not expected to 

change significantly. The bar chart above shows the “actual” emissions in the 2002 attainment 

inventory, the 2015 growth projection and the “allowable” emissions with the growth allowance 

used in the 2015 Maintenance Demonstration. This demonstrates that the net VOC emissions are 

lower by about 13% and NOx emissions lower by about 37% in 2015 compared to 2002 levels. 

Point Sources, with the growth allowance emissions included show the greatest increase with onroad mobile sources showing the greatest decrease. 

Ecology’s submissions summarize the results of dispersion modeling study performed for the 

Pdx/Van Maintenance Area in 2004 by the Washington State University (WSU) (see table and 

chart below). For further details of the study see Appendix 4 - Modeling and Attainment 

Demonstration, of the Ecology SIP submittal. These results are shown in the table below. 

Table 4 

2015 Maintenance Demonstration for the Pdx/Van Maintenance Area (ozone values) 

8-hour ozone standard = 0.08 ppm 

Exceedance ≥ 0.085 ppm maximum 

Violation >0.085 ppm Predicted Design Value 

Monitoring Site 1998 Current 

Design Value, 

ppm 

Relative 

Reduction 

Factor 

2015 Predicted Design Value*, 

ppm 

Portland/Carus 0.075 0.955 0.072 

Portland/Milwaukie 0.059 1.046 0.062 

Portland/Sauvie Island 0.059 0.923 0.054 

Vancouver/Mountain View 0.063 0.975 0.061 

*Predicted Design Value is calculated using the EPA statistical procedure called the Relative Reduction 

Factor described in Appendix 6 of the Ecology’s submittal and in EPA’s 8-hour ozone modeling guidance. 

Predicted design value is compared to the 8-hour ozone standard to determine compliance. 

Figure 4

Portland-Vancouver 8-hour Ozone Trend 

(1997-2005) and 2015 projection

3 year averages of the 4th highest daily ozone value

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

1997 1998 1999 2000 2001 2002 2003 2004 2005 2015

Year

8 hr Ozone (ppm) 3 year rolling average of 4th highest

Portland/Carus

Portland/Milwaukie

Portland/Sauvie Island

Vancouver/Mtn.View

Ozone AQ Standard 0.085 ppm

Ozone Monitoring Sites
9

These results in Table 4 and Figure 4 clearly illustrate that the Pdx/Van AQMA will maintain 

compliance with the 8-hour ozone standard through 2015. The Carus monitoring site, downwind 

of Portland, has historically been the site with the highest ozone readings in the region. The 

model predicted that the Milwaukie site would produce a slightly higher maximum value under 

worst case meteorological conditions, and the maximum values at both Milwaukie and Carus 

would exceed but not violate the standard. However, the Carus site is expected to remain the 

highest and most important site for determining compliance with the ozone standard. The 4th

high design values at Carus and all other sites demonstrate continued compliance with the ozone 

NAAQS. 

Supplemental Review for CAA Compliance

Does Ecology’s proposed 8-hour ozone Maintenance Plan meet other CAA pre-requisites for 

approval? 

A review of whether this Plan revision meets all CAA requirements was done per Section 110(l) 

of the CAA which states “....The Administrator shall not approve a revision of a plan if the 

revision would interfere with any applicable requirement concerning attainment and reasonable 

further progress (as defined in section 171), or any other applicable requirement of this Act.” 

The Ozone NAAQS was revised in 2008. The 2008 8-hour Ozone NAAQS were promulgated in 

March 2008 with primary and secondary standards at 0.075 ppm or 75 ppb. All monitoring data 

in the area shows that the area is not in violation of the 2008 ozone NAAQS. These are the 

currently applicable NAAQS and the attainment demonstration has to clearly show that the 2008 

NAAQS is also not being violated into the future due to the changes proposed by the State of 

Washington. As seen from the Table 4 and Figure 4 above, the 2015 predicted design values are 

below the 2008 NAAQS. Therefore, this plan demonstrates compliance with all applicable 

Ozone NAAQS. 

We applied the same standard of review for all criteria pollutant NAAQS. Historical monitoring 

shows this area is in compliance with other criteria air pollutants NAAQS4

. Additionally, EPA’s 

evaluation of the impacts of the changes proposed in this Plan has determined that these changes 

will not cause an increase in direct or precursor emissions that will interfere with the attainment 

or maintenance of any other NAAQS. 

Therefore, an approval of this plan revision will not interfere with any applicable requirement 

concerning attainment or maintenance of any applicable NAAQS. 

Control Strategies for the Vancouver, WA area, applicable rules and changes

The control strategies in the Portland-Vancouver Ozone Maintenance Plans are supported by 

current effective rules that are described below. Both the strategies in the current effective rules 

and the proposed revised rules were relied upon in the maintenance demonstration. The 

following strategies are supported by the rules that are in the currently approved SIP and will 

continue to remain in the Vancouver Ozone Maintenance Plan as they currently apply to sources 

in the Clark County, Washington area. 

 

4

 EPA’s AirData database at http://www.epa.gov/oar/data/reports.html 
10

Control Strategies (Included in current Federally Approved SIP) 

 General Regulations for Air Pollution Sources (SWCAA 400) 

o Air Discharge Permit Applications (Notice of Construction) (400-109) – submittal 

and processing of Air Discharge Permit (ADP) applications. 

o New Source Review (400-110) – General requirements for ADP issuance, Best 

Available Control Technology (BACT) is required of all sources 

o Requirements for New Sources in Nonattainment Areas (400-112) New source 

review for nonattainment areas 

o Requirements for Replacement of Substantial Alteration of Emission Control 

Technology at an Existing Stationary Source (400-114) Reasonably Available 

Control Technology (RACT) for control equipment required 

o Maintenance of Equipment (400-116) – minimum maintenance requirements 

o Requirements for Nonattainment Areas (400-190) - procedural requirements for 

developing nonattainment provisions 

 Emission Standards and Controls for Sources Emitting VOCs (SWCAA 490) – category 

specific requirements for gasoline loading and dispensing facilities, drycleaners, surface 

coater, graphic arts systems, flatwood panel manufacturers and surface finishing facilities 

 Emission Standards and Controls for Sources Emitting Gasoline Vapors (SWCAA 491) – 

requirements for gasoline stations (includes Stage I and Stage II gasoline vapor recovery) 

and specific requirements for fixed roof gasoline storage tanks, gasoline loading 

terminals, bulk gasoline tanks and gasoline transport tanks. 

 VOC Area Source Rules for reducing emissions from Consumer Products, Spray Paints, 

Motor Vehicle Refinishing and Area Source Common Provisions (SWCAA 493-100 

through 500) 

Control Strategies with Proposed Rule Revisions:

The following rules were submitted by Ecology for incorporation into the federally enforceable 

SIP in order to implement the proposed Maintenance Plan. 

Revised Emission Check Rules for the Washington SIP

Ecology submitted changes to the Emission Check Program (ECP) WAC 173-422 for EPA 

approval and adoption into Washington’s federally approved State Implementation Plan (SIP). 

EPA had previously approved Washington’s ECP and modifications. The most important 

changes in this submission allow late model vehicles to be tested with their on-board diagnostic 

systems instead of with a tail-pipe test and make related changes to the section of the rules 

related to vehicle repair. Ecology is also requesting that fee-provisions that are in the current 

Washington SIP be removed. 

Rules submitted for approval and inclusion in the federally approved SIP: 

WAC 173-422-020 Definitions. 

WAC 173-422-030 Vehicle emission inspection requirement. 

WAC 173-422-031 Vehicle emission inspection schedules. 

WAC 173-422-060 Gasoline vehicle emission standards. 
11

WAC 173-422-065 Diesel vehicle exhaust emission standards. 

WAC 173-422-070 Gasoline vehicle exhaust emission testing procedures. 

WAC 173-422-075 Diesel vehicle inspection procedure. 

WAC 173-422-190 Emission specialist authorization. 

WAC 173-422-195 Listing of authorized emission specialists. 

These rules submitted by Ecology are in the docket for this proposed action. EPA reviewed these 

rule changes and is satisfied that the substantive changes allow late-model vehicles to be tested 

with on-board diagnostic (OBD) systems as opposed to the tailpipe test, and related changes to 

the sections of the rule on vehicle repair. Other changes include updates to the rules to reflect 

changing technology in automobiles, and to enhance clarity of the rules. Significant changes to 

the Diesel Vehicle Inspection Procedures include the adoption of the snap-acceleration procedure 

for testing and related changes. 

Additionally, Ecology has requested removal of WAC 173-422-130 Inspection fees provision, 

and the words “twelve or less dollars” from WAC 173-422-160 Fleet and diesel owner vehicle 

testing requirements. 

Ecology’s January 8, 2007 Maintenance Plan submittal noted that revisions were also made to 

Southwest Clean Air Agency rules that support the maintenance determination. Specifically, 

Ecology noted that revisions were made to SWCAA 400-111, Requirements for New Sources in 

Maintenance Plan Areas; and SWCAA 400-113, Requirements for New Sources in Attainment 

or Unclassifiable Areas. The revised rules were included in the January 8, 2007 submittal. 

However, as Ecology has indicated to EPA that these rule revisions were included with the 

submission for informational purposes only and not for incorporation into the federally 

enforceable SIP, EPA is not taking any action on these rule revisions. Instead EPA is relying on 

and maintaining the federally enforceable SWCAA 400-030, 400-101, 400-111 and 400-113 SIP 

approved rules (62 FR 27204) for supporting the Maintenance Plan demonstration. However, as 

Ecology has demonstrated that the NAAQS is not violated using the new established growth 

allowances, EPA is approving those new growth allowances along with this submittal to be used 

instead of the 1996 growth allowances. 

Ecology and SWCAA submitted information that supports that the various control strategies 

summarized above work together with other elements in the Maintenance Plan, including the 

tracking of emissions growth, ambient ozone monitoring and the early warning and action 

elements in the contingency plan, to meet air quality management goals and protect compliance 

with standards. 

In summary, EPA proposes to approve changes to the Inspection & Maintenance Emissions 

Check Program and incorporate them into the federally enforceable SIP for the State of 

Washington. EPA is also proposing to approve the new industrial growth allowances used for the 

maintenance demonstration to be used with the existing federally approved versions of SWCAA 

400-111 and 400-113 (62 FR 27204) as the applicable rules. These changes were included in the 

technical attainment demonstration which establishes compliance with all applicable ozone 

NAAQS for this area. 
12

Voluntary Measures not relied upon for SIP approval

Washington implements other programs such Commute Trip Reduction and the Public Education 

programs that can also contribute to ozone precursor emission reductions. However these 

reductions have not been quantified or relied upon for the maintenance demonstration of this SIP 

approval action. 

3. Ambient Air Quality Monitoring – Ecology and the South West Clean Air Agency 

(SWCAA) commit to operate an ozone air quality monitoring network in accordance with 40 

CFR 58 to verify maintenance of the 8-hour ozone standard in Vancouver, WA (see Appendix 1 

of Ecology’s submittal). The agencies further commit that any modification to the ambient air 

monitoring network, such as removal of duplicative or unnecessary monitors, will be 

accomplished through close consultation with the EPA Regional office. Proposed network 

modifications would be accompanied by technical and statistical analysis sufficient to document 

a given monitor may be removed because it is unnecessary or duplicative in the case of network 

reductions, or to justify the value of investing in monitoring network enhancements. In 

accordance with 40 CFR 58, the final network design will be subject to the approval of the EPA 

Regional Administrator. 

4. Contingency Plan – Section 110(a)(1) of the CAA requires that the state develop a 

contingency plan which will ensure that any violation of a NAAQS is promptly corrected. The 

purpose of the contingency plan is to adopt measures, outlined in the Maintenance Plan, in order 

to assure continued attainment in the event of a violation of the 8-hour ozone NAAQS. The 

Maintenance Plan should identify the events that would “trigger” the adoption and 

implementation of a contingency measure(s), the contingency measure(s) that would be adopted 

and implemented, and the schedule indicating the time frame by which the state would adopt and 

implement the measure(s). 

The provisions specified under Part A of the Contingency Plan for the Portland-Vancouver 

AQMA are linked to ambient concentrations of ozone and would be triggered if measured ozone 

levels at any of the ozone monitoring sites (Mountain View, Sauvie Island, Milwaukie, or Carus) 

exceed the early-warning thresholds below, or if a violation of the 8-hour ozone standard occurs. 

EPA is satisfied that the measures specified in Part A of the Contingency Plan in the proposed 

Maintenance Plan for the Vancouver portion of the Pdx/Van AQMA will promptly correct any 

violation of the NAAQS. 

5. Verification of Continued Attainment – Ecology and SWCAA will continue to monitor 

ambient air quality ozone levels in the Vancouver portion of the Portland-Vancouver AQMA 

during the ozone season (May through September) using the ozone monitoring network as 

described in Appendix 1 of Ecology’s submittal. Ecology and SWCAA will update countywide 

emission inventories every three years as required by the Consolidated Emission and Reporting 

Rule (CERR) to update the National Emissions Inventory. If ambient ozone levels increase, 

Ecology and SWCAA will compare CERR updates with the 2002 and 2015 emissions 

inventories and evaluate the assumptions used in the 2015 emissions projections to determine 

whether emissions are increasing at a rate not anticipated in the Maintenance Plan. 
13

III. Evaluation

The State of Washington has met the requirements to submit a Section 110(a)(1) Maintenance 

Plan that presents satisfactory information regarding the five elements of the Maintenance Plan 

and has satisfied Sections 110(l) and 193 of the CAA. Therefore, approval of the State of 

Washington’s 8-hour Ozone Maintenance Plan is recommended. 

IV. Conclusion

This SIP revision request satisfies all requirements for an acceptable SIP revision. 

V. Recommended Agency Action 

The SIP revision request should be approved. 

Rules Approved with the Action

WAC 173-422-020 Definitions. 

WAC 173-422-030 Vehicle emission inspection requirement. 

WAC 173-422-031 Vehicle emission inspection schedules. 

WAC 173-422-060 Gasoline vehicle emission standards. 

WAC 173-422-065 Diesel vehicle exhaust emission standards. 

WAC 173-422-070 Gasoline vehicle exhaust emission testing procedures. 

WAC 173-422-075 Diesel vehicle inspection procedure. 

WAC 173-422-190 Emission specialist authorization. 

WAC 173-422-195 Listing of authorized emission specialists. 

Removal of WAC 173-422-130 Inspection fees, and deletion of the words “of twelve or 

less dollars” from WAC 173-422-160 Fleet and diesel owner vehicle testing 

requirements.