UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 10 1200 Sixth Avenue, Suite 900 Seaitle, WA 98101-3140

Stu Clark Washington State Department ofEcology P. 0. Box 47600 Olympia, Washington 98504-7600 Craig Kenworthy 1904 Third Avenue, Suite 105 Seattle, Washington 9810 DearMr. Clark and Mr. Kenworthy: OFFICE OF AIR, WASTE AND TOXICS

Thank you for the opportunity to work so closely with your staffon the technical development of the Tacoma-Pierce County Nonattainment Area Emission Inventory. Based on ourpre-submittal review, webelieve the version provided to us on September 10, 2012 would satisfythe emission inventory requirements of40 CFR 51.1008 assuming there are no substantive changes to the final version or issues that arise during the state public comment period. TheEPA will make a final decision based on its review ofthe complete State Implementation Plan that is submitted following your public process and after consideration ofany comments we receive as part of EPA'spublic process. Ifyou have any questions please feel free to contact me at 206-553-1847 or have your staff contact either, Debra Suzuki, State and Tribal AirPrograms Unit Manager, at 206-553-0985 or JeffHunt, PM2.5 stafflead, at 206-553-0256. Sincerely,

R chard Albright, Director Ollice ofAir, Waste, and Taxies



## Q**P~lnted o~**  RecycledPaper_UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 10 1200 Sixth Avenue, Suite 900 Seattle, WA 98101-3140
OFFICE OF ENVIRONMENTAL ASSESSMENT



### MEMORANDUM SUBJECT:
FROM: TO: Review ofDraft Tacoma-Pierce County PM25Nonattainment Area Emission Inventory Robert Kotchenruther,

# E.;!ii.,~~Z~~~**U~["Pfcol(.** JeffHunt, Tacoma-Pierce County Nonattainment Area PM25 Lead State and Tribal Air Programs Unit I reviewed the draftAppendixA: Tacoma-Pierce County NonattainmentArea Emission Inventory Documentation thatEcology provided to EPA on September 10, 2012. I believe this draft would satisfy the emission inventory requirements of40 CFR 51.1008 assuming there are no substantive changes to the final version orissues that arise during the state public comment period. Highlights ofthe draft include:

• Non-point Sources: according to the emissions inventory, residential wood smoke combustion accounts for 74% ofthe total fine particle winter clay emissions. This information supports Washington Department ofEcology and Puget Sound Clean Air Agency's general control measure strategy ofimproving enforcement ofburn bans and removing uncertified solid fuel devices.

• Point Somces: for nonattainment areas, the federal regulations define point sources as any stationary source having the potential to emit 100 tons per year ofa criteria pollutant. These sources require Air Operating (Title V) Permits. There are 9 Title V sources in Pierce County. These sources account for 2% ofwinter clay fine particulate emissions.

• Mobile Sources: onroad and nonroad sources account for 9% and 5% ofwinter clay fine particulate emissions, respectively. Onroad mobile source emissions come from exhaust, evaporation, and brake and tire wear and were calculated using EPA's MOVES model. Nonroad mobile sources include all off-road vehicles and equipment and include locomotives and marine vessels. Due to fleet turnover, on-going clean diesel projects, and reduced sulfur content ofshipping fuel, EPA expects mobile source emissions to remain generally low or diminish over time as a percentage ofoverall wintertime emissions.