1 

### Palma, Elizabeth

From: Palma, Elizabeth

Sent: Tuesday, December 15, 2015 12:19 PM

To: 'Nancy Kruger'

Subject: Invitation: NACAA call on exceptional events - Question regarding calculating Q/D in Draft

Wildfire/Ozone Guidance

Nancy

–

Thank you for the opportunity to participate in the NACAA conference call on Friday, December 11, 2015, and respond

to members’ clarifying questions regarding the EPA’s draft wildfire ozone guidance and proposed revisions to the

Exceptional Events Rule.

One of the clarifying questions asked, “In the Draft Wildfire/Ozone Guidance, EPA proposes to use the Q/D metric to

determine the Tier that will be required for a demonstration. The procedure for calculating distance (D) between a

monitor and a fire is unclear, particularly in the event of large (thousands of acres) wildfire or multi

‐ fire complex. Can

you provide clarification on U.S. EPA's expectations as to how that calculation would be done?”

Although we verbally provided the response below, we thought it would also be helpful to send our response via email

so that you can see the “math.”

We will include this email in Docket EPA

‐ HQ

‐ OAR

‐ 2015

‐ 0229 so that other interested parties can also see our response.

Thank you for your continued interest in the Exceptional Events process.

Regards,

Beth

Beth W. Palma

USEPA Office of Air Quality Planning and Standards

109 TW Alexander Drive (C539

‐ 04)

Research Triangle Park, NC 27711

palma.elizabeth@epa.gov

919.541.5432

*************************************

For situations where only one fire parcel is thought to affect a monitored ozone concentration:

The distance between the latitude and longitude of the monitor and the latitude and longitude of the fire

(accounting for the curvature of the Earth should be used). The reported latitude and longitude of the fire from

inventories is generally the centroid of the fire parcel.

For situations where multiple fires are thought to contribute to a monitored ozone concentration:

The distance (D) between the “fire” and monitor should be determined using an emissions weighted average

distance between the fire and the monitor. Two hypothetical scenarios are presented below

– one for 2 fire parcels

that contribute to an ozone concentration and one for 3 contributing fire parcels.

For example, if 2 fire parcels A and B are found to contribute to an ozone concentration on a given day, find the

locations and emissions (sum of NOx and VOC) for each fire parcel. If parcel A is the closest fire, at 100 km from the

monitor and has relatively low emissions such as 1,000 tons while parcel B is further from the monitor at 200 km

and has larger emissions such as 10,000 tons, then you would calculate the emissions weighted distance as

emissions A times distance A plus emissions B times distance B. Then this weighted sum is divided by the sum of the2 emissions A and B. Or, filling in the numbers, 100*1,000 + 200*10,000 divided by 11,000. The emissions weighted

distance would then be 190.9 km, and the Q/D would be 11,000/190.9 or 57.6 tons/km. This makes sense that the

weighted distance would be closer in magnitude to the fire with the larger emissions, but sli ghtly smaller than the

actual distance to parcel B because there may be some contribution from the closer, smaller fire A.

For example, if an agency determines that 3 fire parcels contribute to the ozone concentration, the distance

between center of fire parcel and monitor would be:

ൌ ܽ݊ܿ݁ݐݏ݀݅	ܽ݃݁ݎ݁ݒܽ	݁݀ݐ݄݁݅݃ݓ	ݏ݊݋݅ݏݏ݁݉݅ ሺ ܦ ஺∗ ܳ ஺ ሻ ൅ ሺ ܦ ஻ ܳ ஻ ሻ ܦሺ ൅ ஼ ܦ ஼ ሻ

ܳ ஺ ൅ ܳ ஻ ൅ ܳ ஼

Distance between

center of fire

parcel and

monitor (km) Sum of NOx and

VOC emissions on

day being

investigated Weighted

distance between

the aggregate fire

and the monitor Q/D

Fire A 100 km 10,000 tons

Fire B 150 km 5,000 tons

Fire C 50 km 1,000 tons

16,000 tons 112.5 142.2 tons/km

From: Nancy Kruger [mailto:nkruger@4cleanair.org]

Sent: Wednesday, December 02, 2015 9:38 PM

To: Palma, Elizabeth <Palma.Elizabeth@epa.gov>

Cc: Jones, Rhea <Jones.Rhea@epa.gov>; Mathias, Scott <Mathias.Scott@epa.gov>

Subject: Invitation: NACAA call on exceptional events



### Dear Beth,

NACAA invites you and your EPA co lleagues to join us on a conference call on Friday, December 11,

2015, to respond to our members' cl arifying questions on EPA's proposed exception al events rule and

draft wildfire guidance. T he call will be g in at 1:30 PM Eastern and we ex pect this Q&A portion to run

about 30 minutes after which we'll continue with a NACAA-only discussion. The call-in number and

access code are

We will ask our members to provide questions in advance and will forw ard those to you on

Wednesday, December 9. We'll start with those questions and then open it up for additional

questions as time allows. I don't think we'll need an EPA overview of the proposal and draft

guidance; hopefully folks have already begun digging into these documents.

We'll take roll at the begi nning of the call and I'll provide you with a list of participating NACAA state

and local air agencies following the call.

Please confirm your particip ation and also let me know if you have any questions.

Thanks,

-Nancy3 _________________________________ Nancy Kruger

Deputy Director

National Association of Clean Air Agencies

444 North Capitol Street, NW

Suite 307

Washington, DC 200011 

### Palma, Elizabeth

From: Palma, Elizabeth

Sent: Wednesday, December 16, 2015 10:31 AM

To: Palma, Elizabeth

Subject: FW: Invitation: NACAA call on exceptional events - List of Attendees (For Docket)

EPA Participants on the December 11, 2015 Call

Beth Palma, USEPA/OAQPS

Mark Evangelista, USEPA/OAQPS

Justin Spenillo, USEPA/Region 10

Michael Flagg, USEPA/Region 9

From: Nancy Kruger [mailto:nkruger@4cleanair.org]

Sent: Wednesday, December 16, 2015 8:27 AM

To: Palma, Elizabeth <Palma.Elizabeth@epa.gov>

Subject: Re: Invitation: NACAA call on exceptional events

‐ List of Attendees



### Hi Beth,

Here's the list from roll call:

Rhode Island

Connecticut

Massachusetts

Maryland

Pennsylvania

West Virginia

Alabama

Tennessee

Georgia

South Carolina

Mississippi

Kentucky

Wisconsin

Minnesota

Illinois

Michigan

Oklahoma

Arkansas

New Mexico

Iowa

Missouri

Kansas

Utah

Wyoming

Colorado

Nevada

California2 

### Washington

Idaho

Alaska

Knox Co., TN

Vandenburg Co., IN

Harris Co., TX

Ventura, CA

Sacramento, CA

San Diego, CA

Los Angeles, CA

Washoe Co., NV

Seattle, WA

Yakima, WA

Spokane, WA

NACAA

SESARM

CenSARA

WESTAR

Thanks again,

-Nancy

____________________________ Nancy Kruger

Deputy Director

National Association of Clean Air Agencies

444 North Capitol Street, NW

Suite 307

Washington, DC 20001