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)