                                       
                                       
                                       
                                       
           United States Environmental Protection Agency, Region IX
                                       
                                 Air Division
                                       
                          Technical Support Document
                                       
                                      for
                                       
                      EPA's Notice of Proposed Rulemaking
                                       
                                   for the 
                                       
                     California State Implementation Plan
                                       
             Northern Sonoma County Air Pollution Control District
                           Rule 130  -  Definitions
                                       
                                       
                                      AND
                                       
               Mendocino County Air Quality Management District
                           Rule 130  -  Definitions
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                Laura Yannayon
                                       
                                 March 9, 2011

                               Table of Contents

Section	Page

Introduction	1

PSD Program SIP Revision Submittals	1

Background	1

Rule Summaries	2

Rule Evaluation	2

Section 110(l) of the Act	3

Section 193 of the Act	3

Recommendations	4

Attachments	4





Introduction

      Part C of title I of the Clean Air Act (CAA or Act) contains the provisions for the Prevention of Significant Deterioration (PSD) of air quality in areas designated as "attainment" or "unclassifiable" for the national ambient air quality standards (NAAQS).  Part D of title I of the Act contains the requirements for areas designated "nonattainment" for any of the NAAQS.  Both parts C and D of the Act require pre-construction permit programs for certain new or modified stationary sources of pollutants.  The requirements under part C, referred to as "PSD New Source Review" (PSD) apply to certain new or modified sources that would be located within attainment  or unclassifiable areas, and apply to all regulated pollutants, except those pollutants for which an area has been designated as "nonattainment."  The requirements under part D, referred to as "Nonattainment NSR," (NSR) apply to certain new or modified sources of nonattainment pollutants in nonattainment areas.  Collectively, the pre-construction permit requirements related to PSD and Nonattainment NSR are commonly referred to simply as "NSR."  Both of these programs apply to "major" stationary sources and "major modifications" as those terms are defined in 40 CFR Part 51, Subpart I.  In addition to the regulation of major stationary sources, states are also required to adopt a program to provide for the regulation of the construction and modification of minor stationary sources and minor modifications at major sources, to assure that the NAAQS are achieved.  These pre-construction requirements are commonly referred to as "minor NSR."


PSD Program SIP Revision Submittals
      
      Rule 130  - Definitions was adopted by the Northern Sonoma County Air Pollution Control District (NSCAPCD or District) on December 14, 2010.  Rule 130  - Definitions was adopted by the Mendocino County Air Quality Management District (MCAQMD or District) on February 15, 2011.  The California Air Resources Board (ARB) submitted both rules to EPA by a letter dated February 28, 2010.  ARB is the governor's designee for submitting official revisions of the California State Implementation Plan (SIP) to EPA.  Previous versions of Rule 130 are currently approved into the SIP for both Districts.  For NSCAPCD and MCAQMD, Rule 130 was last approved into the SIP on February 9, 1999 and July 31, 1998, respectively (See 64 FR 6223 and 63 FR 40830).  There are no other pending submittals of these rules.


Background

      Both the NSCAPCD and MCAQMD are currently designated as attainment or unclassifiable for all NAAQS, and are therefore required to adopt and maintain a SIP-approved PSD permit program, CAA Section 161.  In both Districts, a combination of SIP approved rules make up the PSD permit program, including Rules 130  -  Definitions, 200  -  Permit Requirements, 220  -  New Source Review Standards, and 260  -  Exclusions.  
      
      The submitted revisions to Rule 130  -  Definitions are being evaluated together in this TSD because both the existing SIP rules and proposed revisions are very similar.  In each case, the District has revised Rule 130 to provide new and revised definitions in order to ensure consistency with CAA requirements for PSD programs.  The specific changes are discussed below in the Rule Evaluation section of this document. 


Rule Summaries

Mendocino Rule 130  -  Definitions 
      Rule 130 defines various terms used throughout the District's Regulations.  In particular it provides definitions of several key terms related to the PSD program.  In this revision, the District has added new definitions for the terms Greenhouse Gases, PM10, and PM2.5, and revised the definitions for the terms Precursor, Prevention of Significant Deterioration (PSD) Increment, and Significant.  The District also made other minor technical corrections.  The purpose of these changes was to make the terms consistent with the current definitions contained in EPA PSD regulations codified in 40 CFR 51.166.  
      
Northern Sonoma Rule 130  -  Definitions 
      Rule 130 defines various terms used throughout the District's Regulations.  In particular it provides definitions of several key terms related to the PSD program.  In this revision, the District has added new definitions for the terms Greenhouse Gases, PM10, and PM2.5, and revised the definitions for the terms Precursor, Prevention of Significant Deterioration (PSD) Increment, and Significant.  The District also made other minor technical corrections.  The purpose of these changes was to make the terms consistent with the current definitions contained in EPA PSD regulations codified in 40 CFR 51.166.  


Rule Evaluation

      For this TSD, we have reviewed each Rule 130 SIP submittal to ensure the new and revised definitions meet the requirements of section 110 and part C of title I of the Act and implementing regulations at 40 CFR 51.166.  This TSD describes the rule revisions and the reasons for our proposed action on the Rule 130 submittals.  Since both Districts have made identical revisions to their rules, the changes are only discussed once below.  The Act requires all States with attainment or unclassifiable areas to submit a PSD program that contains specific PSD program provisions.  Since the submitted rules only consist of definitions, our evaluation focuses on whether the definitions contain language which is either identical or equivalent to that found in 40 CFR 51.100 and 51.166.  
      
New Definitions
         *          A new definition has been added for Greenhouse Gases (GHG).  This term is defined within the definition of the term "subject to regulation" in 40 CFR 51.166 (b)(48).  The District's definition is equivalent in that it includes the same six gases as EPA's definition of GHGs.
      
         *          A new definition has been added for PM10, and PM2.5.  These definitions are consistent with the definitions of these NAAQS pollutants found in 40 CFR 51.100(qq), 50.6, 50.7, and 50.13.  
      
Revised Definitions
         *          The current definition for the term Precursor has been revised to specify that VOC and NOx are ozone precursors, and that NOx and SOX are PM2.5 precursors.  These changes make this definition consistent with the precursors identified by the Administrator, within the definition of "regulated NSR pollutant" in 40 CFR 51.166 (b)(49).  
      
         *          The current definition for the term Prevention of Significant Deterioration (PSD) Increment has been revised to update the allowable increments for PM10, and add the allowable increments for PM2.5, consistent with the values listed in 40 CFR 51.166(c)  -  Ambient air increments and other measures.  
      
         *          The current definition for the term Significant has been revised to add significant emission rate thresholds for PM2.5 and municipal waste combustors.  These changes make this definition consistent with the definition of "significant," in 40 CFR 51.166 (b)(23).  
      
Summary
      As discussed above, each of the new or revised terms is consistent with the applicable definitions for these terms in 40 CFR 51.100 and 51.166 and part 50.  


Section 110(l) of the Act

      Section 110(l) of the Act prohibits EPA from approving any revision of a SIP if the revision would interfere with any applicable requirement concerning attainment and reasonable further progress, or any other applicable requirement of the Act.  The approval of these rules would strengthen the applicable SIP by adding and updating terms that establish applicability and evaluation criteria for pollutants subject to the PSD program.  The rules do not represent any type of relaxation and therefore would not interfere with attainment and reasonable further progress, and thus are approvable under Section 110(l) of the Act. 


Section 193 of the Act

      Section 193 of the Act, which was added by the Clean Air Act Amendments of 1990, only applies to control requirements in nonattainment areas.  Neither the NSCAPCD and MCAQMD are classified nonattainment for any NAAQS; therefore Section 193 does not apply to this rulemaking action.


Recommendations
      Pursuant to section 110(k)(3) of the Act, we recommend full approval of the submitted rules.  We recommend approval of the submitted rules based on our determination that the rules comply with applicable statutory and regulatory provisions, including section 110(a)(2)(C) and part C of title I of the Act.  In support of this recommendation, we have concluded that our approval of Rule 130 (for each District) complies with section 110(l) of the Act because the rules do not represent a relaxation of any current SIP provision.  If we finalize this action as proposed, our approval would be codified through revisions to 40 CFR 52.220 (identification of plan).


Attachments

 
 1) Submitted NSCAPCD Rule 130 and MCAQMD Rule 130.
 
 2) SIP Approved NSCAPCD Rule 130 and MCAQMD Rule 130.
