Reply to Attn Of: AWT

- 107

MEMORANDUM

DATE: April 2, 2014

SUBJECT: Technical Support Document for the Central Puget Sound Maintenance Area,

Section 110(a)(1) Ozone Maintenance Plan

FROM: K eith Rose , Environmental Scientist

TO: Docket EPA

- R10

- OAR

- 2008

- 0122

TABLE OF CONTENTS

I. Purpose

II. Background

III. Review of the Maintenance Plan

IV. Evaluation of the Maintenance Plan

V. Conclusion

VI. Recommended Agency Action

I. Purpose

This technical support document (TSD) provides information supporting EPA’s action to approve the State of Washington’s January 10 , 2008 State Implementation Plan (SIP) revision of

a Section 110(a)(1) Ozone Maintenance Plan for the Central Puget Sound Are a. Th is TSD

documents how th e maintenance plan in this SIP revision meets the Clean Air Act (CAA) 110(a)(1) requirements

, and demonstrates that the Central Puget Sound area wil l be able to

remain in attainment with both the 1997 and 2008 Ozone NAAQS through 2015.

II. Background

Ozone is a summertime air pollution problem . It is formed when photochemical precursors react with sunlight in the atmosphere

. Precursors include volatile organic compounds (VOC) and nitrogen oxi des (NO
x ), with some influence by carbon monoxide (CO). These precursors come from anthropogenic sources such as mobile sources

, industrial and commercial solvent use, as well as natural biogenic sources. Levels of ozone are usually highest in the aftern oon because of intense sunlight , increased temperatures, and the precursors have had a longer period of time to
react and form ozone. Ozone levels are also highly affected by weather conditions

. Atmospheric chemical dispersion modeling has repeatedly sho wn that the Puget Sound urban

area is “VOC

- limited,” which means that reducing VOC emissions most effectively reduces ambient concentrations of ozone at the locations of greatest concentration.2

Elevated ozone concentrations can cause reduced lung function and respiratory irritation, and can aggravate asthma

. People with respiratory conditions should limit outdoor exertion if ozone levels are high. Ozone has also been linked to impaired immune system function and g round

level ozone can also damage agricultural crops and forests, interfering with their ability to produce food and grow. In the Puget Sound region, the hot sunny days that are favorable for ozone formation also tend to have light north

- to

- northwest winds. Ozone has typically been

transp orted 10 to 30 miles downwind from the original source by the time the highest concentrations have formed in the afternoon and early evening. Highest ozone concentrations

are measured in towns such as North Bend and Enumclaw, which are the communities

dow nwind of the Seattle

- Tacoma urban area.

On November 15, 1990, the C AA Amendments of 1990 were enacted. Under section 107(d) (1) of the CAA, EPA designated the Central Puget Sound area, which includ es all of Pierce County, almost all of King County except the northeast corner , part of Snohomish County, and lands within the Puyallup, Tulalip, Muckleshoot, Stillaguamish, and Nisqually Reservations

, as nonattainment because the area violated the 1

- hour ozone standard, 0.12 parts per million (ppm), during the p eriod of 1989

- 1991. Because of this violation, t h e Central Puget Sound area was classified as "marginal" under section 181(a)(1) of the CAA. On January 28, 1993

, the State of Washington Department of Ecology (Ecology) submitted a State Implementation Pla n (SIP) for compliance with the 1

- hour ozone NAAQS. Ecology submitted an Ozone Maintenance Plan and

re designation r equest for the Central Puget Sound area on March 4, 1996. On September 26, 1996, the Central Puget Sound area was re

- designated to attainment for ozone

, and the ozone maintenance plan for this area was approved.

In 1997 EPA changed the ozone NAAQS to 0.08 ppm for the three

- year average of the annual fourth highest 8

- hour average ozone concentration, and in 2008 EPA revised the ozone standard to 0.075 ppm for the three

- year average of the annual fourth highest 8

- hour average ozone

concentration. Since 1997 there have been no violations of either 8

- hour ozone standard at any ozone monitoring site in the Puget Sound area.

On January 10 , 2008 Ecology submitted for approval under section 110 of the CAA a revised 8

- hour ozone m aintenan ce p lan for the Central Puget Sound area

. This p lan was developed by the Puget Sound Clean Air Agency (PSCAA) with collaboration from 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 PSCAA

.

Th is maintenance p lan demonstrates how Ecology intend s to remain in attainment with the 1997

and 2008 8

- hour ozone NAAQS through 2015 for the Central Puget Sound area . Th e

m aintenance p lan contains a base

- year inventory for 2002

, and demonstrates that emissions will not be greater than the base year in 2015. The proposed m aintenance p lan commits to tracking progress and identifies measures that would be available to promptly correct any ozone NAAQS violation. Ecology’s SIP submittal addresses all the CAA requirements for SIP submittals under

CAA S ection 110(a)(1). Additionally, Ecology’s s ubmittal also addresses the requirements of CAA section 110(l) and CAA section 193.

III. Review of the Maintenance Plan

A. What are the components of a section 110(a)(1) 8

- hour ozone Maintenance Plan ?3

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 within the state. On May 20, 2005

, EPA issued guidance that applies to areas that are designated maintenance for the 1

- hour ozone NAAQS but unclassifiable/attainment for the 8

- hour ozone standard. The purpose of t hat guidance was to identify required elements of a

maintenance plan that would meet the requirements in section 110(a)(1) of the CAA

. The guidance identifies five required components of an 8

- hour ozone m aintenance p lan , which are :

1. Attainment Inventory

– The plan should include an attainment inventory based on actual “typical summer day” emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx) for a 10

- ye ar maintenance period. For purposes of an attainment emissions inventory, the state must choose any one of the three years in which the 8

- hour ozone attainment designation was based. As many states are already required to develop an inventory for 2002 un der EPA’s Consolidated Emissions Reporting Rule (67 FR 39602), EPA recommends that states use that year as the attainment emission inventory base year for the section 110(a)(1) Maintenance Plan

. Ecology used 2002 as the base year for the Puget Sound atta inment inventory.

2. Maintenance Demonstration

– The plan should demonstrate how the area will remain in compliance with the 8

- hour ozone NAAQS for a period of 10 years following the effective date of designation as unclassifiable/attainment. For areas with an effective date of designation for the

8

- hour NAAQS of June 15, 2004, the maintenance plan must project attainment through 2014 or beyond. Maintenance may also be demonstrated by modeling future ozone concentrations on a typical summer da y based on a future projected emission inventory. In th e Central Puget Sound

ozone maintenance plan, Ecology demonstrated attainment by projecting emission inventories for 2015, and modeling ozone concentrations for 2015 based on these projected inventorie s.

3. Ambient Air Quality Monitoring

- The plan should include a commitment by the state to continue to operate air quality monitors , and collect quality assured data, in accordance with 40 CFR Part 58 to verify continued attainment of the 8

- hour ozone standard.

4. Contingency Plan

– The plan should include contingency measures to reduce emissions that can be implemented as expeditiously as practicable in the event of a violation of the 8

- hour ozone NAAQS

.

5. Verification of Continued Attainment

– The plan should indicate how the state intends on tracking and verifying progress toward attainment in the m aintenance p lan

. This is necessary because the emissions projections made for the maintenance demonstration depend on assumptions of point, area and mobile source growth , and need to be verified

.

B. Components of the Central Puget Sound 8

- hour ozone Maintenance Plan

1. Attainment Inventory

– In its SIP submi ttal

, Ecology provided a comprehensive emissions inventory for VOCs and NOx using 2002 as the base year for attainment

. The effective year of

the 8

- hour ozone initial designation was 2004 , and therefore Ecology project ed emissions for

ozone precursors to the year 2015, which is 10 years or beyond the effective date of the initial designation. In the m aintenance p lan, Ecology included information on anthropogenic source categories of VOCs and NOx , including p oint sources

, o n

- road sources

, n onroad sources, and4

area sources. Projected emissions from these source categories were dete rmined based on the

follow ing assumptions :

a. All point source emissions were held constant from 1999 values through 2015.

b. Area source emissions were based on population and economic growth factors applied to base year. Stationary area source projection facto rs ranged from 0.24 for residential coal combustion to 1.51 for liquefied petroleum gas.

c. Non

- road vehicle source emissions were estimated using the NONROAD model with Reid Vapor Pressures (RVP) of 7.8 and 8.7 to address both a low RVP scenario and a high RVP scenario.

d. Marine vessel emissions (a subset of the non

- road category) were projected from 1999 to 2015 using a projection factor of 2 based on the projected dramatic increase in the units of cargo shipped to Washington ports over this period.

e. On

- road mobile source emissions were based on model runs of EPA’s MOBILE 6.2 using projected future vehicle miles traveled.

Table 1 shows the VOC and NOx emission inventor ies for 2002 , and table 2, based on the above growth assumptions , shows the VOC and NOx em ission inventories for 2015

.

Table 1: Central Puget Sound 2002 Attainment Inventories ( tons /day)

Source Category NOx VOC

Onroad Mobile 301 220

Nonroad Mobile 113 92 Stationary Area 14 157

Point Sources 18 5

Total 446 474

Table 2

Central Puget Sound 2015 Maintenance Demonstration, Typical Summer Day (tons /day )

Source Category NOx VOC

Onroad Mobile 100 81

Nonroad Mobile 271 70 Stationary Area 13 172

Point Sources 27 17

Total 411 346

These tables show a projected 8% reduction in NOx between 2002 and 2015, and a projected

27% reduction in VOCs between 2002 and 2015. The 2002 Consolidated Emissions Reporting Rule (CERR) emissions data submitted by Ecology and PSCAA to EPA’s National Emis sion Inventory (NEI) were used as the basis for the 2002 attainment year inventory. Figure 1 shows the trends of NOx and VOC emissions from 1998 through 2015.5

Figure 1: Central Puget Sound 1998 through 2015 Emission projections used for

Maintenance Demo nstration ( tons/day )

The t echnical a

ppendices submitted with Ecology’s Maintenance Plan contain more detailed

information on the emissions inventories for each source category . Emissions for all source categories were calculated following EPA guidance and are properly documented in the appendix titled “2002 Emission Inventory

– Seasonal” of the Maintenance Plan

2. Maintenance Demonstration

– T he proposed Maintenance Plan must demonstrate

maintenance of the 8 hour ozone NAAQS to 2014 or beyond

. Th e Central Puget Sound A rea Maintenance Plan meets this criterion by first demonstrating that the inventories of ozone precursors in 2015 will be below the 2002 attainment year

. Specific ally, VOC emissions are projected to decrease from 474 tons/year in 2002, to 420 tons/year in 2005, and to 346 tons/year in 2015. NOx emissions are projected to decrease from 446 tons/year in 2002, to 390 tons/year in 2005, and to 411 tons/year in 2015. Ev en though there is a slight increase in NOx emissions

between 2005 and 2015, there is an overall decrease in NOx emissions of 35 tons/year between

2002 and 2015. The second demonstrat ion is that the highest 3

- year average of the 4 th highest ozone value (th e ozone design value) in the Central Puget Sound Area in 2015 is projected to be below the 2008 ozone NAAQS

.

Ecology initially conducted a maintenance demonstration by using dispersion modeling to show that the Puget Sound area will remain in compliance with the 8

- hour ozone standard through

2015. This demonstration was included as an appendix to the maintenance plan and is titled,

“ Ozone Modeling for Maintenance Plan Revision for Pu get Sound in Western Washington” ( October 2001 ). This analysis shows th at even with an increase in total NOx emissions between 2005 and projected 2015, the downward trend in VOC emissions leads to lower ozone concentrations and continued compliance with the ozone NAAQS.6

In order to demonstrate continued maintenance with the ozone NAAQS through 2015, Ecology and PSCAA conducted a second dispersion modeling to more accurately estimate the comprehensive impacts of emission growth, weather patterns , estimate of future emissions of VOCs and NOx from offshore marine vessels, and th e transport of ozone precursors from areas outside of the State of Washington on ozone concentrations in the Central Puget Sound area

. This ozone modeling was included in an appendix to the maintenance plan tit l ed, “Modeling Analysis of Future Emission Sc enarios for Ozone Impacts in the Puget Sound Area” (August 2006) . Based on this modeling, the highest ozone design value for 2015 in the Puget Sound area was projected to be 0.068 parts per million (ppm). This modeling confirms the previous modeling resul ts which indicated that the Puget Sound area will maintain attainment with the current ozone NAAQS through 2015. These most recent modeling results are shown in Table 3.

Table 3: Maintenance Demonstration Projected 2015 8

- hour ozone design values for the Puget Sound area

Monitoring Site 1996

- 2000 Design Value (ppm) Relative Reduction

Factor 2015 Design Value (ppm)

Enumclaw 0.0756 0.901 0.068

Lake Sam m amish 0.0603 0.970 0.058

Pack Forest 0.073 0.936 0.068

3. Ambient Air Quality Monitoring

– Ecology and PSCAA 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 the Central Puget Sound area

. A ny modification to the ambient air monitoring network, such as removal of duplicative or unnecessary monitors, will be identified in the Washington annual monitoring network plan for EPA approval. I n the case of proposed network

reductions , p roposed network modifications would be accompanied by technical and statistical analysis sufficient to document that a given monitor may be removed because it is unnecessary or duplicative

. In accordance with 40 CFR 58, the annual monitoring network plans

, and the 5

- year monitoring network assessments

, 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 m aintenance p lan

, that

would assure continued attainment in the event of a violation of the 8

- hour ozone NAAQS. The maintenance p lan should identify the events that would “trigger” the adoption and implementation of a ny contingency measures, the specific contingency measures that would be adopted and implemented, and the schedule for adopt ing and implement ing the se measure s

.

There are two contingenc y measures identified in this maintenance plan. They are PSCAA Regulation I, Section 8.06, Outdoor Burning Ozone Contingency Measure, and PSCAA Regulation II, Section 2.10, Gasoline Station Ozone Contingency Measure . Both the outdoor burning and the gasol ine station contingency regulations are triggered by a written finding from7

EPA of a quality assured violation of the ozone NAAQS, and that future violations can reasonable be addressed through implementation of the se regulations

. These regulations were

in cluded as contingency measures in the ozone second 10

- year maintenance plan for the Central Puget Sound area and were approved by the EPA on August 5, 2004 (69 FR 47364 and 69 FR 47365).

5. Verification of Continued Attainment

– Ecology and PSCAA will continue to monitor ambient air quality ozone levels in the Central Puget Sound area during the ozone season (May through September) using the ozone monitoring network as described in Ecology’s annual ambient air monitoring network plan approved by E PA. Ecology and PSCAA will update countywide emission inventories in the National Emissions Inventory every three years as required by the Consolidated Emission and Reporting Rule (CERR). If ambient ozone levels begin to significantly increase above baseli ne levels , Ecology and PSCAA will compare CERR updates with the 2002 and 2015 emissions inventories and re evaluate the assumptions used in the 2015 emissions projections to determine if they are still valid.

IV

. Evaluation of the Central Puget Sound 8

- hour O zone Maintenance Plan

The EPA has determined that the Central Puget Sound Ozone Maintenance Plan adequately addressed the five required elements for a 110(a)(1) maintenance plan including: an attainment year emission inventory, a maintenance demo nstration for 2014 or beyond, a commit ment to operate an ozone air quality monitoring network in accordance with 40 CFR 58 to verify

maintenance of the 8

- hour ozone NAAQS in the Central Puget Sound area

, contingency measures to be triggered if the ozone NAAQS were to be violated, and verification of attainment through ambient air monitoring and updat ing of countywide emission inventories in the National Emissions Inventory every three years

. In addition, h istorical monitoring shows th at the Central Puget Sound area has been in compliance with all other criteria air pollutant NAAQS since the

1980s

. Additionally, EPA’s evaluation of the impacts of the changes proposed in this maintenance p lan has determined t hat 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, a n approval of this plan revision will not interfere with any applicable requirement

concern ing attainment or maintenance of any applicable NAAQS. Therefore, approval of the State of Washington’s section 110(a)(1) 8

- hour Ozone Maintenance Plan for the Central Puget

Sound area is recommended.

V. Conclusion and Recommended Action

This SIP revision satisfies all applicable CAA requirements for an acceptable 110(a)(1) 8

- hour ozone maintenance plan , and therefore should be approved

.