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. 

This 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 use 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

-------------------------------------------------------------------------------------------------------------------------------------

Rahul Pendse│Managing Consultant│rpendse@trinityconsultants.com

Trinity Consultants│301 Main Street, Suite 900 │Baton Rouge, LA 70825

Office: 225-346-4003 │Fax: 225-346-4032│Cell: (714) 454-0518
From: "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 yesterday’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 

review 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 application 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 assumptions 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 with 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 drilling 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 the basis for exemption from preconstruction 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 itself, 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 exceedance.

- The court also vacated the PM2.5 SMC. Project impacts less than the SMC can no longer be 
used to exempt the project from pre-construction ambient air quality monitoring. If existing air 

quality observations are proposed in lieu of pre-construction 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 increment 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 to Table 3-1. 

- Ambient concentrations both equal to and greater than the SMC and SIL are significant. - NO2

NAAQS compliance modeling is not typically used to demonstrate minimum ozone impacts 

from project NO2 emissions. 

- In terms of pre-construction NO2 monitoring waiver, information on existing ambient 

measurements and proposed project impacts need to be evaluated before the requirement for 

project specific pre-construction NO2 measurements can be waived. 

- The Federal Land Managers for the three 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 

CALPUFF 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 characteristics, 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 

would 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 increment 
compliance assessment, it is suggested 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 assessments. 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 vessels 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 assessment 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 AQRV 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

404/562-9123 (Phone) 404/562-9091 (Fax)

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