From: Kotchenruther, Robert To: Chi, John Subject: RE: Review Assistance Date: Tuesday, May 24, 2016 1:17:10 PM

Hi John,

Sorry it took me a while, it was a while since I had looked at the Medford CO emissions inventory, and I didn’t remember seeing the final version, so wanted to quickly look through it and make sure everything looked okay. It does look okay, and I don’t see anything in what you wrote below that is any problem.

Cheers Bob

======================================== Robert Kotchenruther, Ph.D. Environmental Scientist U.S. EPA Region-10 Office of Environmental Review and Assessment 1200 Sixth Avenue, Mailstop OERA-140 Seattle, WA 98101-3140 (206) 553-6218 Kotchenruther.Robert@epa.gov

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From: Chi, John Sent: Thursday, May 19, 2016 10:26 AM To: Kotchenruther, Robert <Kotchenruther.Robert@epa.gov> Subject: Review Assistance

Hi Bob, I’m working on the Medford CO Second 10-Year Maintenance Plan. Claudia reviewed my draft for me and recommended that I ask you to review the following section on the emissions inventory or potentially review the emissions inventory for the plan and write a memo to be used for this section. I think the first option would be more ideal, but if you see anything glaring please let me know. Thank you again for your help!



### A. Base Year Emissions Inventory The LMP must contain an attainment year emissions inventory to identify a level of CO
emissions in the area that is sufficient to attain the CO NAAQS. The submittal, contains a summary of the CO emissions inventory for the Medford area for the base year 2008. The emission inventory lists CO emissions by general source category – stationary point sources, stationary area sources,

on-road mobile sources and non-road mobile sources. On-road mobile sources emissions for the2008 base year inventory were estimated with the EPA’s Motor Vehicle Emissions Simulator

(MOVES) 2010b. [1] The methods used to determine the Medford area CO emission inventory are consistent with the EPA’s most recent guidance on developing emission inventories. Historically, exceedances of the CO standard in the Medford area have occurred during the winter months, when cooler temperatures contribute to incomplete combustion, and when CO emissions are trapped near the ground by atmospheric inversions. Sources of carbon monoxide include industry, motor vehicles, non-road mobile sources, (e.g., construction equipment, recreational vehicles, lawn and garden equipment, and area sources (e.g., outdoor burning, woodstoves, fireplaces, and wildfires). The CO season is defined as three consecutive months - December 1 through the end of February. As such, season day emissions in addition to annual emissions are included in the inventory. The unit of measure for annual emissions is in tons per year (tpy), while the unit of measure for season day emissions is in pounds per day (lb/day). In addition, the county-wide emissions inventory data is spatially allocated to the Medford urban growth boundary (UGB), and to buffers around the UGB, depending on emissions category. 

### 2008 Emissions Inventory, Main Source Category Subtotals

Main Source Category Annual Emissions Tons per Year CO Emissions Pounds per Winter Day Stationary Point Sources 2.367.1 13,159 On-road Mobile Sources 5,730.0 28,731 Non-road Mobile Sources 4,488.2 10,061 Stationary Area Sources 3,333.1 30,399 Total 15,927.4 82,350

John Chi EPA Region 10 Office of Air and Waste (206) 553-1185

[1] MOVES2010b was the most current model available at the time that the ODEQ was performing its analysis. The EPA released MOVES2014 on October 7, 2014 (79 FR 60343).