From: Spencer, Janet@ARB
To: Ungvarsky, John Cc: Amir Fanai ; Armen Kamian ; LEVIN, NANCY ; Ruiz, Gabe@ARB ; OConnor, Karina Subject: RE: paved road dust emissions in Chico and Bay Area PM2.5 inventories
Date: Thursday, December 12, 2013 11:24:07 AM

Hi John – An addendum to the paved road dust methodology described in my prior message (forwarded below): 2008 base year emissions for both Butte and the Bay Area were projected to 2011 and 2010, respectively, using centerline miles.
-Janet

_____________________________________ Janet Spencer, Air Pollution Specialist California Air Resources Board Air Quality Planning and Science Division jspencer@arb.ca.gov Phone: 916.324.2717

From: Ungvarsky, John [mailto:Ungvarsky.John@epa.gov] Sent: Wednesday, December 11, 2013 4:04 PM To: Spencer, Janet@ARB Cc: Amir Fanai; Armen Kamian; LEVIN, NANCY; Ruiz, Gabe@ARB; OConnor, Karina Subject: RE: paved road dust emissions in Chico and Bay Area PM2.5 inventories



### Thank you! John Ungvarsky
Environmental Scientist Air Planning Office, Air Division USEPA Region 9 415-972-3963 (primary office) 510-667-9743 (alternate work site)

From: Spencer, Janet@ARB < jspencer@arb.ca.gov > Sent: Wednesday, December 11, 2013 3:23 PM
To: Ungvarsky, John
Cc: Amir Fanai; Armen Kamian; LEVIN, NANCY; Ruiz, Gabe@ARB Subject: RE: paved road dust emissions in Chico and Bay Area PM2.5 inventories

Hi John – Yes, CARB provided the paved road dust PM2.5 estimates to the districts. We estimated annual PM10 emissions using the Jan. 2011 AP-42 paved road dust emission factor equation with California-specific silt loadings. Historical days of rain were used for the rainfall adjustment factor. We used CARB’s California speciation profile #471 to calculate PM2.5 from PM10 (PM2.5 = 0.15 * PM10). http://www.arb.ca.gov/ei/speciate/dnldoptvv10001.php#specprof This differs from the 25% particle size fraction for PM2.5/PM10 given in the AP-42. Emissions estimates used 2008 annualized VMT per average weekday from EMFAC-2011SG,apportioned to road category using 2008 Caltrans HPMS travel fractions. I am attaching the draft methodology that was used to develop the inventory. While it has not been officially finalized, the methodology itself has not changed since the 2008 estimates were developed. Please let me know if you need further information.
-Janet

_____________________________________ Janet Spencer, Air Pollution Specialist California Air Resources Board Air Quality Planning and Science Division jspencer@arb.ca.gov Phone: 916.324.2717

From: Ungvarsky, John [ mailto:Ungvarsky.John@epa.gov ] Sent: Monday, December 09, 2013 9:42 AM To: Spencer, Janet@ARB Cc: Amir Fanai; Armen Kamian; LEVIN, NANCY Subject: paved road dust emissions in Chico and Bay Area PM2.5 inventories

Hi Janet –

EPA has drafted a Federal Register notice to act on SIP submittals for the Butte County (Chico) and San Francisco Bay Area PM2.5 nonattainment areas. The submittals concern emission inventories for PM2.5. The Chico inventory is for 2011, and SF Bay Area’s is for 2010. I am contacting you to help me tie up a couple of loose ends regarding these inventories. In terms of the estimates for PM2.5 paved road dust emissions, my understanding is that CARB provided the estimates to the districts. Can you confirm that the Jan 2011 AP-42 equation was used in calculating the estimates? Also can you clarify whether vehicle miles traveled or centerline miles was used in the calculation of the estimates?

Please call if you’d like to discuss.

Thank you.



### John Ungvarsky

Environmental Scientist USEPA, Region 9 Air Division, Planning Office 415-972-3963 (office) 510-667-9743 (alternate work location on Tuesdays and Thursdays)