UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION IX 

AIR DIVISION 

Technical Support Document 

for 

EPA's Proposed Rulemaking 

for the 

California State Implementation Plan 

Great Basin Unified Air Pollution Control District 

Rule 502 Conservation Management Practices, and 

List of Conservation Management Practices for Agricultural Operations 

Prepared by: 

Nancy Levin 

May 14, 2014 
2 

Agency: 

Great Basin Unified Air Pollution Control District 

Subject of this TSD: 

Rule 502 Conservation Management Practices; Adopted July 7, 2005; Submitted October 20, 

2005. 

List of Conservation Management Practices for Agricultural Operations; Adopted July 7, 2005; 

Submitted October 20, 2005, revised December 2011, re-submitted May 9, 2014. 

RULE SUMMARY 

Rule 502 contains requirements to limit fugitive dust emissions from agricultural operation sites. 

This rule establishes a Conservation Management Practice (CMP) Program that requires 

owners/operators of agricultural operation sites to select and implement CMPs from a list 

prepared by the Great Basin Unified Air Pollution Control District (GBUAPCD). Each 

owner/operator, unless exempted, is required to submit a CMP Application to the Air Pollution 

Control Officer (APCO) for approval as the CMP Plan. The application must include specified 

information about the agricultural operation site, the CMPs selected for implementation on each 

parcel within the site, and a description of the practice(s) chosen. Agricultural operations 

providing grazing on open rangeland or pasture are exempt. 

The program requirements are phased in over three years: Owens Valley (October 1, 2005); 

Mammoth Lakes, Mono Basin and Coso Junction (October 1, 2006); and all other areas in the 

Great Basin (October 1, 2007). 

BACKGROUND 

Rule 502 was adopted as one of several rule revisions and new rules developed in response to 

California Senate Bill 700. Other GBUAPCD revisions and rules adopted at the same time as 

Rule 502 removed the exemption for agricultural operations (Rule 216, Rule 405) and 

established a fee structure for implementing Rule 502 (Rule 307). 

Rule 502 is based on the San Joaquin Valley Air Pollution Control District (SJVAPCD) Rule 

4550, which was adopted on May 20, 2004 and approved by EPA into the State Implementation 

Plan (SIP) on February 14, 2006 (71 FR 7683). 

The GBUAPCD CMP List (CMP List), entitled “List of Conservation Management Practices for 

Agricultural Operations Including Best Available Control Measures (BACM) and Best Available 

Retrofit Control Technology (BARCT) for Agricultural Practices” (Staff Report Attachment C; 

July 7, 2005) was adapted from the California Air Pollution Control Officers Association 

(CAPCOA) Agricultural Sources Clearinghouse of Air Pollution Reduction Methods 

http://www.capcoa.org/ag-clearinghouse/. The CMP list is not the same as, but similar to, that 

which was adopted in SJVUACPD Rule 4550. It was updated in December 2011. 

EPA EVALUATION 

The Great Basin Valleys planning area contains one serious nonattainment area (Owens Valley), 

two moderate nonattainment areas (Mammoth Lakes and Mono Basin), and one attainment area 
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(Coso Junction) for the National Ambient Air Quality Standard (NAAQS) for coarse particulate 

matter (PM-10). 

 

Owens Valley: The Owens Valley area is a serious nonattainment area for PM-10. 40 CFR 

81.305. Pursuant to §§189(b)(l)(B) and (b)(2) of the Clean Air Act (CAA), serious PM-10 

nonattainment areas must implement best available control measures (BACM). EPA fully 

approved California’s serious area plan for the PM-10 NAAQS in Owens Valley, including the 

related BACM demonstration, on September 3, 1999 (64 FR 48305). 

While the State’s submittal to EPA does not contain an explicit discussion of significant sources, 

the emissions inventory and other statements in the SIP generally indicate that agriculture is a de 

minimis (insignificant) source of PM-10 emissions. The emissions inventory shows that 

agriculture has an emission potential of less than 1 ton per year out of 85.6 thousand tons per 

year of total estimated PM-10 emissions. The estimated emission potential for unpaved roads 

(including non-agricultural roads) is 84 tons per year. (Chapter 4: Emissions Inventory, Figure 

4.1; 2008 Owens Valley PM10 Planning Area Demonstration of Attainment State 

Implementation Plan, January 28, 2008). Given it appears that agricultural operations do not 

contribute significantly to ambient PM-10 levels in the area, EPA is not at this time evaluating 

Rule 502 for compliance with BACM for PM-10. 

Mammoth Lakes and Mono Basin: Mammoth Lakes and Mono Basin areas are moderate 

nonattainment areas for PM-10 (40 CFR 81.305) and are therefore subject to the requirement to 

implement Reasonably Available Control Measures (RACM) for existing sources. CAA §189(a). 

EPA is not at this time evaluating Rule 502 for compliance with RACM for PM-10 and will do 

so in separate rulemaking actions, as appropriate. 

Mammoth Lakes: The Mammoth Lakes emissions inventory does not list agriculture as a PM-10 

source category. (Section 3 – Emissions Inventory 3-7, Air Quality Management Plan for the 

Town of Mammoth Lakes (November 30, 1990)). The predominant emissions in Mammoth 

Lakes are re-suspended road dirt/cinders from paved roads, wood stoves, fireplaces, motor 

vehicles, and industrial sources. 

Mono Basin: The primary source of PM-10 emissions is from lake shore windblown dust 

resulting from erosion of salt deposits and exposed soils and sediments. (Section 4 – Emissions 

Inventory, Mono Basin PM-10 SIP, May 1995). 

Coso Junction: EPA re-designated Coso Junction as attainment for the PM-10 NAAQS in 2010. 

75 FR 54031. Accordingly, the GBUAPCD is not currently subject to the requirements to 

implement BACM or RACM for PM-10 in this area. 

Criteria 

We have evaluated Rule 502 in accordance with the following criteria: 

 Enforceability: Rule 502 contains a requirement for control measures, a requirement for 

submission of a CMP Application to the APCO, a schedule for implementation of the 

CMP Plan, and recordkeeping requirements. The rule states that an owner/operator shall 
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select and implement one (1) CMP from the CMP list for each of the applicable CMP 

categories for each agricultural parcel of an agricultural operation site (Section 6.2). The 

applicable CMP categories and CMPs are clearly described, with one exception noted 

below in recommendation #7. We believe that GBUAPCD’s regulation can be enforced 

consistent with the requirements of CAA § 110(a). 

 SIP Revisions - We have evaluated this SIP revision to determine whether it would 

interfere with any applicable requirement concerning attainment and reasonable further 

progress (RFP) or any other applicable requirement of the Act (CAA 110(l)) or modify, 

in a nonattainment area, any SIP-approved control requirement in effect before 

November 15, 1990 (CAA 193). There is no prior version of GBUAPCD regulations in 

the SIP for agriculture, and we find that our action does not interfere with applicable 

requirements of CAA §110(l). 

Conclusion 

Rule 502 fulfils the relevant CAA requirements regarding SIP revisions and enforceability and 

therefore EPA recommends full SIP approval. 

Additional Recommendations for the Next Rule Revision 

The following recommended revisions are not currently the basis for rule disapproval, but are 

recommended for the next time the rule is amended: 

1. Section 3.8 states that “(t)he District’s list of CMPs shall constitute best available control 

measures (BACM) and best available retrofit control technology (BARCT) for 

agricultural practices at agricultural sources of air pollution in the District. The December 

2011 List of Conservation Management Practices for Agricultural Operations (CMP 

List)1

 also states that it represents BACM (see cover page and page 2). We recommend 

removing the statements about BACM. EPA has not evaluated this list for BACM (CAA 

§ 189(b)(1)) in the Great Basin Valleys. 

2. We are aware that the Great Basin Valleys Air Basin has windblown dust problems. 

Other California air districts with windblown dust problems have mandatory control 

measures for agriculture (e.g., South Coast Rule 403, Imperial County Rule 806). We 

recommend that the GBUAPCD develop mandatory windblown dust control 

requirements for agriculture. 

3. Section 6.2.3.1: This paragraph states that an owner/operator must obtain the interim 

approval of the APCO prior to using a new CMP that is not on the CMP list. There is no 

explanation of what “interim approval” means. Please include an explanation of this term. 

4. Section 6.2.3.2 requires the APCO to perform an independent analysis of the proposed 

CMPs. There is no schedule for the APCO to complete the independent analysis or make 

an approval/disapproval decision. We recommend including this information. 

 

1

 http://www.gbuapcd.org/farm/ListOfConservationManagementPracticesForAgriculturalOperations.pdf 
5 

5. Section 6.4.3: This paragraph states that a CMP application for a modification to a CMP 

Plan can be "conditionally approved" within 30 days. There is no explanation of what 

"conditional approval" means. Please include an explanation of this term. 

6. We recommend that the GBUAPCD review the CMP List periodically to ensure that 

listed CMPs are still appropriate. 

7. The December 2011 CMP List contains the list of CMP categories A-G on page 2. 

Categories F and G pertain to unpaved vehicle/equipment areas with 50 or more vehicle 

trips per year, and less than 50 vehicle trips per year, respectively. However, pages 8, 9, 

16, and 17 include an additional threshold for average daily trips by 3 (or more) axled 

vehicles. The Supplemental Applications Forms CMP-1 and CMP-2 for categories F and 

G also contain 50 vehicle trips per day and the 3 (or more) axled vehicle thresholds, and 

contain an additional threshold for maximum daily trips on any day. We recommend that 

the thresholds be made consistent throughout the CMP List and Supplemental 

Application Forms. We also recommend that the District add thresholds for 3 (or more) 

axled vehicles and maximum daily trips to Categories D and E (Unpaved Roads). 

EPA ACTION 

EPA staff recommends a full approval of Rule 502 and the CMP List pursuant to CAA 

§110(k). 

ATTACHMENTS 

1. Rule 502 Conservation Management Practices; Adopted July 7, 2005; Submitted October 

20, 2005. 

2. List of Conservation Management Practices for Agricultural Operations; Adopted July 7, 

2005; Submitted October 20, 2005; Revised December 2011; Re-submitted May 9, 2014. 

REFERENCES 

1. The Bluebook (Issues Relating to VOC Regulation Cutpoints, Deficiencies, and 

Deviations, EPA, May 25, 1988) and the Little Bluebook (Guidance Document for 

Correcting Common VOC & Other Rule Deficiencies, EPA Region 9, August 21,2001) 

were used to help evaluate compliance with the CAA 31 10(a)(2)(A) requirement for 

enforceability.

2. "Fugitive Dust Background Document and Technical Information Document for Best 

Available Control Measures," EPA-45012-92-004, September 1992.

3. "Control Techniques for Particulate Emissions from Stationary Sources," Volume I 

(EPA-45013-8 11005a) and Volume I1 (EPA-45013-8 1/005b), September 1982.

4. "Control of Open Fugitive Dust Sources," EPA-45013-88-008, September 1988.
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5. "State Implementation Plans; General Preamble for the Implementation of Title I of the 

Clean Air Act Amendments of 1990," (General Preamble) 57 FR 13498 (April 16, 1992); 

57 FR 18070 (April 28, 1992). 

6. "State Implementation Plans for Serious PM- 10 Nonattainment Areas, and Attainment 

Date Waivers for PM-10 Nonattainment Areas Generally; Addendum to the General 

Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990," 

(Addendum) 59 FR 41998 (August 16, 1994). 

7. 71 FR 7683, Revisions to the California State Implementation Plan, San Joaquin Valley 

Unified Air Pollution Control District Rule 4550, February 14, 2006. 

8. 73 FR 12639, Revisions to the California State Implementation Plan, South Coast Air 

Quality Management District Rule 403, March 10, 2008. 

9. 78 FR 23677, Revisions to the California State Implementation Plan, Imperial County Air 

Pollution Control District Rule 806, April 22, 2013.