From: Ungvarsky, John 

Sent: Tuesday, December 17, 2013 3:45 PM

To: Ruiz, Gabe@ARB

Cc: akamian@bcaqmd.org; LEVIN, NANCY

Subject: RE: OFFROAD Model Updates

Thanks Gabe. 

John Ungvarsky

Environmental Scientist

Air Planning Office, Air Division

USEPA Region 9

415-972-3963 (primary office)

510-667-9743 (alternate work site)

From: Ruiz, Gabe@ARB <gruiz@arb.ca.gov>

Sent: Tuesday, December 17, 2013 2:10 PM

To: Ungvarsky, John

Cc: akamian@bcaqmd.org; LEVIN, NANCY

Subject: OFFROAD Model Updates

John,

I think the best way to characterize the off-road updates for the PM2.5 SIP would be to say that ARB did 

not produce an integrated version of the OFFROAD model for 2011 (i.e., the is no OFFROAD2011).

Instead, off-road emissions were estimated using a suite of models that provide inventory estimates 

specific to different categories of vehicles. Many of these category-specific models were developed to 

support recent regulations including in-use off-road equipment, ocean-going vessels, and others. In 

those instances when a category-specific model was not created, OFFROAD2007 was used.

I presume you got the list of categories that were updated from Armen; otherwise, let me know if you 

would like me to send it. Also, I’m copying Nicole Dolney of our Mobile Source Analysis Branch in case 

you have any more specific questions about the updates.

--Gabe

From: Ungvarsky, John [mailto:Ungvarsky.John@epa.gov] 

Sent: Tuesday, December 17, 2013 1:46 PM

To: Ruiz, Gabe@ARB

Cc: akamian@bcaqmd.org; LEVIN, NANCY

Subject: re EMFAC2011

Hi Gabe -

I am assisting Nancy Levin with a pending action to approve the Chico and San Francisco Bay 

Area PM2.5 inventories. At this point, we are just tying up a few remaining loose ends. I think 

we understand how the off-road emissions estimates were calculated, but we are trying to 

determine how to best characterize the collective methods used. Is it safe to say that there is 

not an "OFFROAD2011 model" that includes all of the off-road 
categories? Does "OFFROAD2011 model" represent the individual modules used for some, but 

not all, of the off-road categories? Or, does it include all of the modules, inluding any updates 

through 2011?

Thanks

John Ungvarsky

Environmental Scientist

Air Planning Office, Air Division

USEPA Region 9

415-972-3963 (primary office)

510-667-9743 (alternate work site)

From: Armen Kamian [mailto:akamian@bcaqmd.org] 

Sent: Friday, December 13, 2013 4:21 PM

To: LEVIN, NANCY

Subject: FW: PM 2.5 Emissions Inventory

Hi Nancy,

This came back quickly. I’m just about out of here, but I hope this information helps -

Armen

From: Ruiz, Gabe@ARB [mailto:gruiz@arb.ca.gov] 

Sent: Friday, December 13, 2013 4:20 PM

To: Armen Kamian

Subject: RE: PM 2.5 Emissions Inventory

Yes, we provided the mobile source emission estimates. We used EMFAC2011 for on-road sources; 

however, we did not have an OFFROAD2011 model per se. Instead, the various off-road categories were 

updated using individual modules. Let me know if you have any further questions.

--Gabe

From: Armen Kamian [mailto:akamian@bcaqmd.org] 

Sent: Friday, December 13, 2013 4:11 PM

To: Ruiz, Gabe@ARB

Subject: FW: PM 2.5 Emissions Inventory

Gabe, thanks for your help earlier – I have one more question from Nancy Levin at EPA- David said he 

thought you (ARB) had estimated our mobile source emissions1. Please confirm that mobile source emissions were estimated by CARB using the EMFAC 

2011 and OFFROAD2011 models

Armen