629 Entler Avenue, Suite 15 

Chico, C4 95928 

(530) 332-9400 

(530) 332-9417 Fax 

Gerardo Rios 

Chief, Air Permits Office (Air-3) 

EPA Region 9 

75 Hawthorne Street 

San Francisco, CA 94105 

April 8, 201~\EC\E.~V\E.D 1 

~~~ ~ ~ i~~rs 

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____ ..... 

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W. James Wagoner 

Air Pollution Control Officer 

Robert McLaughlin 

Asst. Air Pollution Control Officer 

RE: Additional Clarifications for Rule 1107 -- Prevention of Significant Deterioration 

(PSD) Permits 

Dear Mr. Rios: 

On February 6, 2013, the California Air Resources Board (CARB) submitted for Environmental 

Protection Agency's (EPA) approval Butte County Air Quality Management District (District) 

Rule 1107 - Prevention of Significant Deterioration (PSD) Permits. The District provided 

clarification on the District's intent to implement the PSD program in correspondence to you 

dated November 13, 2014. This follow-up letter is intended to clarify the District's position 

concerning the application of the PM2.5 Significant Monitoring Concentration (SMC) in its PSD 

program in light of the January 22, 2013 decision by the U.S. Court of Appeals for the District of 

Columbia (Court) in Sierra Club v. EPA, 705 F.3d 458. 

In Sierra Club v. EPA, the Court granted a request from EPA to vacate and remand to EPA the 

portions of two PSD rules (40 CFR 51.166(k)(2) and 40 CFR 52.21(k)(2)) addressing the SILs 

for PM2.

5 so that EPA could voluntarily correct an error in these provisions. The Court also 

vacated the parts of these two PSD rules (40 CFR 51.166(i)(5)(i)(c) and 40 CFR 

52.21(i)(5)(i)(c)) establishing a PM2.5 SMC, finding that EPA was precluded from using the 

PM2.5 SMC to exempt permit applicants from the statutory requirement to compile and submit 

preconstruction monitoring data as part of a complete PSD application. On December 9, 2013, 

revisions to 40 CFR 51.166 and 52.21 were published in the Federal Register to remove the 

affected provisions from the PSD regulations, effective as of that date. 78 Fed. Reg. 73698. 

To implement the PSD permitting program under the Clean Air Act, the District adopted Rule 

1107, which incorporated 40 CFR 52.21 by reference into the rule (with certain exceptions and 

revisions), as in effect on June 28, 2012. As advised by EPA Region 9, Rule 1107 excludes the 

vacated provisions for the PM2.

5 SILs that were formerly at 40 CFR 52.21 (k)(2). However, Rule 

1107 includes the vacated provisions described above relating to the PM2.5 SMC as part of the 

SIP revision submitted to EPA for approval. Following the Court's decision in Sierra Club v. 

EPA, EPA requested clarification from the District concerning its interpretation of Rule 1107 to 

the extent that it incorporates by reference 40 CFR 52.21(i)(5)(i)(c). 

I am writing to clarify that the District interprets and intends to implement the PSD program in a 

manner that is consistent with the Court's decision in Sierra Club v. EPA and EPA's subsequent 

revisions to its PSD regulations consistent with that decision. 
Mr. Gerardo Rios 

April 8, 2015 

PM2.s SMC 

District Rule 1107 incorporates by reference the federal regulation at section 52.21 (i)(5)(i), 

which provides that the APCO may exempt a proposed major stationary source or major 

modification from the requirements of paragraph (m) of this section, with respect to monitoring 

for a particular pollutant, if the emissions increase or net emissions increase is below the 

applicable SMC. Thus, this provision, specifically at section 52.21(i)(5)(i)(c), as incorporated by 

reference in Rule 1107, provides the District with the discretion to determine whether it is 

appropriate to apply the SMC for PM2.5 to exempt a permit applicant from the requirement to 

compile and submit preconstruction ambient monitoring data for PM2.5 as part of a complete 

PSD application. Consistent with the Court's decision in Sierra Club v. EPA vacating the PM2.s 

SMC, the District affirms that it will not exercise its discretionary authority to use the PM2.s 

SMC in order to exempt PSD permit applicants from the requirement in Clean Air Act section 

165( e)(2) that ambient monitoring data for PM2.s be included in applications subject to the PSD 

program for PM2.5• Accordingly, the District will require all applicants requesting a PSD permit 

from the District, including those that have already applied for but which have not yet received 

the permit, to submit ambient PM2.5 monitoring data in accordance with Clean Air Act 

requirements when proposed increases of direct PM2.5 emissions or any emissions of a PM2.s 

precursor equal or exceed a significant amount. In summary, the District intends to implement 

the PSD program consistent with the Court's decision. 

If you have any questions or need additional clarification regarding this correspondence, please 

contact me at (530) 332-9400, extension 112. 

Sincerely, 

Air 

w~~ Pollution Control Officer 

T:\Source Programs\PSD Pennitting\GHG SIP Revisions\Clarification letter for PM2.5 SMC 04-03-2015.docx