From: Rahul Pendse <rpendse@trinityconsultants.com>

Sent: Thursday, August 15, 2013 4:02 PM

To: Krivo, Stan

Cc: Land, Eva; Sara.Carlson@anadarko.com; Kathryn.Maness@anadarko.com; Jill_Webster@fws.gov;
mpitrolo@fs.fed.us
Subject: Re: Review Comments

- Anadarko Air Quality Modeling Protocol

Attachments: Anadarko5

- year PSD Title V Permit Modeling Protocol

- v5 after EPA
Comments.pdf

Hello Stan,

Per our phone discussion today, please find a revised air dispersion modeling protocol attached herewith.

Thi s revised version incorporates your comments in the email below and also reflects several phone communications we had regarding this document. Per our discussion, I am listing the key changes in this protocol:

1. Anadarko proposes to address secondary PM2.5 impacts qualitatively (refer to Section 3.1.2)

2. The support vessels will be modeled as a point source. The point source will be located 25 nautical miles from the drillship in the direction of the nearest receptor. (See Section 5.3)

3. Anadarko proposes to u se this protocol for two PSD/Title V applications

- Blackhawk and

Blackhornet

4.

Per your recommendation, I am copying Jill Webster of FWS and Melanie Pitrolo of FS on this email.

Thanks!

Jill and Melanie,

Section 4.2 of this protocol addresses Class I AQRV requirements. Please let me know if you have any questions or I could be of help.

Thanks!

Best Regards,

Rahul Pendse

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- 0518From: "Krivo, Stan" < Krivo.Stanley@epa.gov >

To: "Rahul Pendse ( rpendse@trinityconsultants.com )" < rpendse@trinityconsultants.com >, Cc: "Land, Eva" < Land.Eva@epa.gov > Date: 07/10/2013 10:15 AM Subject: Review Comments

- Anadarko Air Quality Modeling Protocol

Rahul,

This is a follow up to yes terday’s conference call discussing Anadarko’s air quality modeling protocol for the development of PSD/Title 5 Permit Applications for exploratory drilling and other activities in the Outer Continental Shelf (OCS) of the GOM. The following provides the

r eview comments and observations discussed in this call.

Proposed Operations and Associated Support Vessels

– The following comments are associated with the various support vessels for the proposed drilling and other OCS activities.

- The PSD applicati on should describe the function and operations expected for each of the identified type of support vessels.

- The protocol noted “suitable assumption” would be used to conservatively account for the

worst

- case emissions from the support vessels. These as sumptions should consider the fleet of available ships and all applicable pollutants/averaging periods. The modeled ship configuration (e.g., number of simultaneous operating ships, number of operating engines and loads, etc.)

should be that associated wi th the ship(s) producing the maximum ambient impacts. Permit limitations will commensurate with the ambient impact modeling conditions.

- The application should include the helicopter expected operational frequency and characteristics to support its exclusion from the impact assessment.

- To support the planned use of the drilling emissions for all permitted phases of well operations, the application should include estimated emissions and operational characteristics of all proposed phase of the drill ing activities.

Recent Court Decision

- PM2.5 SMC and SIL

- The modeling procedures should consider the impact of the recent court decision concerning use of the PM2.5 significant monitoring concentration (SMC) and significant impact levels (SIL) as t he basis for exemption from pre

construction air quality monitoring and cumulative NAAQS and PSD increment compliance modeling affects this application.

- The court has vacated and remained the PM2.5 SIL. Project impacts less than the SIL cannot, by itse lf, be used as justification to eliminate cumulative NAAQS and PSD increment compliance modeling. Additional information should be provided to support a conclusion that the project’s impacts would not cause or contribute to a NAAQS or PSD increment exceed ance.

- The court also vacated the PM2.5 SMC. Project impacts less than the SMC can no longer beused to exempt the project from pre

- construction ambient air quality monitoring. If existing air

quality observations are proposed in lieu of pre

- constructi on monitoring, supporting information should be provided to demonstrate that existing ambient air quality data would provide representative or conservative ambient concentrations for the impact area.

Modeled Procedures

- The following comments are associated with the proposed ambient impact modeling procedures.

- The protocol includes, in various sections, modeling procedures acceptable for land based projects well as those for OCS projects in the eastern GOM. For example, the land based modeling procedure of determining the project’s significant impact area is not appropriate for

OCS sources in the eastern GOM. The nearest modeled PSD Class II receptor for OCS sources will be 25 nautical miles offshore from each state’s seaward boundary.

- If the initial significant impact modeling for project emissions reveals concentrations greater or equal to the SIL, additional refined modeling will be needed to identify all significant receptors

at resolutions of 100 m. More refined receptor grid may also be needed if the initial project SIL modeling reveals concentrations challenging (i.e., nearly equal to) the SILs.

- If the initial significant impact modeling for project emissions reveals concentrations greater or equal to the SIL, cumulative PSD incre ment and NAAQS compliance modeling will be

needed. A supplemental air quality modeling protocol is suggested to address the development of appropriate emission inventories and modeling procedures.

- The PM10 annual PSD increment and SIL should be added t o Table 3

- 1.

- Ambient concentrations both equal to and greater than the SMC and SIL are significant.

- NO 2 NAAQS compliance modeling is not typically used to demonstrate minimum ozone impacts from project NO 2 emissions.

- In terms of pre

- constructi on NO 2 monitoring waiver, information on existing ambient measurements and proposed project impacts need to be evaluated before the requirement for project specific pre

- construction NO 2 measurements can be waived.

- The Federal Land Managers for the thr ee PSD Class I areas should be provided an opportunity to review and comment on the AQRV modeling procedures and assumptions proposed in this modeling protocol.

- Recognizing that CALPUFF is not an EPA regulatory model for secondary pollutants, the

CALP UFF estimates of secondary PM2.5 concentrations appear appropriate for use to addressing the contribution of secondary PM2.5 impacts.

- Note that the EPA regulatory status of CALPUFF does not include the deposition and chemistry components. Therefore, these options should not be selected in the regulatory application of CALPUFF for ambient concentration estimates.

- In addressing the impacts to soils/vegetation and growth, it is suggested that the expected drilling operational characteristic s, the drilling location in the OCS, and the nearest shore Class II area receptor concentrations may be sufficient to demonstration minimal project impacts.

- The applicability of the statement (page 18) that the PM2.5 Class I area increment analysis

woul d be no different than the analysis conducted using PM10 as the AQRV analysis is not clear; additional explanation may be needed.

- If the PSD Class I area impact assessment indicates the need for cumulative PSD incrementcompliance assessment, it is sug gested that a supplemental protocol be prepared to address the

development of appropriate emission inventories and modeling procedures.

- The selection of the CALPUFF model (Section 5.1

– page 47) is appropriate for both PSD Class I and Class II impact as sessments. The default settings should not include deposition and chemistry when run to estimate ambient concentrations for EPA regulatory applications.

- The proposed use of 25 nautical mile long volume line source modeling procedure for the

support v essels is acceptable given appropriate initial input parameters and modeling technique. Therefore, it is suggested that the detailed information on the planned modeling procedure be provided for review.
[Note: An additional acceptable procedure used by other OCS permit applicants conservatively modeled the support vessels as point sources located 25 nautical miles from the drilling vessel in direction closest to shoreline receptors.]

- The description of the ambient ozone concentration for this assessm ent indicates the use of 80 ppb background ozone level. The reason ozone measurements from the Sumatra, FL monitor were also proposed should be explained.

- The IWAQM default recommendations for CALPUFF are only appropriate for the FLM assessments of AQR V and deposition.

Please let me know if I have over looked any item or want further discussion on any item. Thanks...sjk

Stanley J. Krivo
U.S. Environmental Protection Agency
Atlanta Federal Center, 61 Forsyth Street, SW
Atlanta, GA 30303 404/56 2

- 9123 (Phone) 404/562

- 9091 (Fax)

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