CALIFORNIA AIR RESOURCES BOARD 

APCD/AQMD RULE EVALUATION FORM – Page 1 

(Electronic Format) 

I. GENERAL INFORMATION

District: SJVUAPCD

Rule No(s): 4306, 4307, and 4320 Date adopted/Amended/Rescinded: Amended Rule 4306 and Rule 4307, and 

Adopted Rule 4320 October 16, 2008.

Rule Title(s): Rule 4306 (Boilers, Steam Generators, And Process Heaters - Phase 3), Rule 4307 (Boilers, Steam 

Generators, And Process Heaters - 2.0 MMBtu/hr to 5.0 MMBtu/hr), and Rule 4320 (Advanced Emission 

Reduction Options For Boilers, Steam Generators, And Process Heaters Greater Than 5.0 MMBtu/hr)

Date Submitted to ARB: November 27, 2008

If an Amended Rule, Date Last Amended (or Adopted): Rule 4306 Amended March 17, 2005, Rule 4307 Amended April 

20, 2006.

Is the Rule Intended to be Sent to the U.S. EPA as a SIP Revision? Yes No (If No, do not complete remainder of form)

District Contact: Manuel Salinas Phone Number: (559) 230-5800 E-mail Address: manuel.salinas@valleyair.org

Narrative Summary of New Rule or Rule Changes: New Rule Amended Rule 

Amendments to Rule 4306 and Rule 4307, and new Rule 4320 satisfy control measure commitments included in 

both the Disrict's 2007 Ozone Plan and the 2008 PM2.5 Plan. Amendments to Rule 4306 corrected the rule 

deficiencies identified by EPA in order to make Rule 4306 fully approvable for inclusion in the State 

Implementation Plan (SIP). Amendments to Rule 4307 removed the existing exemption for units used at schools, 

as well as the limted exemption for atmospheric units used in oilfields or refineries and glycol reboilers. 

Additionally, Rule 4307 existing low-use unit threshold has been lowered from 5.0 billion Btu/year heat input to 1.8 

billion Btu/year heat input. New Rule 4320, which will eventually supercede existing Rule 4306, establishes more 

stringent NOx limits for boilers, steam generators, and process heaters with a rated heat input greater than 5 

MMBtu/hr. In addition, Rule 4320 includes provisions to control emissions of PM10, SOx, and CO. Details of the 

proposed changes to Rules 4306 and 4307, and the provisions of new Rule 4320 are discussed in Section II of the 

final draft staff report.

Pollutant(s) Regulated by the Rule (Check): ROG (NOx) SO2 

 (CO) PM TAC (name): 

II. EFFECT ON EMISSIONS

Complete this section ONLY for rules that, when implemented, will result in quantifiable changes in emissions. Attach reference(s) for emission 

factor(s) and other information. Attach calculation sheet showing how the emission information provided below was determined. 

Net Effect on Emissions: Increase Decrease N/A 

Emission Reduction Commitment in SIP for this Source Category: NOx: 0.69 tons per day from Rule 4320 and

0.51 tons per day from Rule 4307. SOx: 0.5 tons per day from Rule 4320.

Inventory Year Used to Calculate Changes in Emissions: 2011 Area Affected: SJV Air Basin

Future Year Control Profile Estimate (Provide information on as many years as possible): 

Percent reduction from 2011- 2011: 5.8% 2012: 31.1% 2013: 31.1% 2014: 54.4% 2015: 54.4%
 

CALIFORNIA AIR RESOURCES BOARD 

APCD/AQMD RULE EVALUATION FORM - Page 2 

(Electronic Format) 

Baseline Inventory in the SIP for the Control Measure: 4.6 tons per day of NOx and 2.57 tons per day of SOx.

Emissions Reduction Commitment in the SIP for the Control Measure: NOx: 0.69 tons per day from Rules 4306 and 4320 

and 0.51 tons per day from Rule 4307. SOx: 0.5 tons per day from Rule 4320.

Revised Baseline Inventory (if any): None

Revised Emission Reduction Estimate (if developed): For Rule 4320: NOx: 3.3 tons per day (47% reduction from 

calculated baseline emissions of 7.1 tons per day of NOx); SOx: 3.6 tons per day (73% reduction from calculated baseline 

emissions of 4.9 tons per day of SOx) 

For Rule 4307: NOx: 1.2 tons per day (64% reduction from calculated baseline emissions of 1.8 tons per day of NOx) 

SOx: No reduction since a large majority of units are already firing on PUC- quality natural gas which will be in compliance 

with the SOx control requirements. 

Note that the district’s input to the Rule Evaluation Form will not be used as input to the ARB’s emission forecasting and 

planning. 

III. SOURCES/ATTAINMENT STATUS

District is: Attainment Nonattainment Split 

Approximate Total Number of Small (<100 TPY) Sources Affected by this Amendment: N/A

Percent in Nonattainment Area: N/A% 

Number of Large (> 100 TPY) Sources Controlled: N/A Percent in Nonattainment Area: N/A% 

Name(s) and Location(s) (city and county) of Large (> 100 TPY) Sources Controlled by Rule (Attach additional sheets as 

necessary): N/A

IV. EMISSION REDUCTION TECHNOLOGY

Does the Rule Include Emission Limits that are Continuous? Yes No 

If Yes, Those Limits are in Section(s) 5.0 of the Rule. 

Other Methods in the Rule for Achieving Emission Reductions are: N/A

V. OTHER REQUIREMENTS

The Rule Contains: 

Emission Limits in Section(s): 5.0 Work Practice Standards in Section(s): 5.0

Recordkeeping Requirements in Section(s): 6.0 Reporting Requirements in Section(s): 6.0
 

5/1/2002 

CALIFORNIA AIR RESOURCES BOARD 

APCD/AQMD RULE EVALUATION FORM - Page 3 

(Electronic Format) 

VI. IMPACT ON AIR QUALITY PLAN

 No Impact Impacts RFP Impacts attainment 

Discussion: 

1. Rule 4320 would impose new advanced NOx, SOX and PM control options that go well beyond Reasonably Available 

Control Technology (RACT), on larger units (greater than 5 MMBtu/hr) based on their size, fuel type, and fuel usage. The 

rule also includes special Staged Enhanced Schedules that first require interim Initial Emission Limits be achieved with a 

lower Final Emission Standards to be met at a later date. These schedules would produce required reductions at the 

earliest possible date with even greater reductions in the future. Because the affected units have typically had several 

levels of NOx controls, obtaining additional reductions can require expensive systems. Although the technology is

available, for certain units, those technologies are not economically feasible. Therefore, the rule provides an option 

allowing payment of an emissions fee rather than installation of additional NOx controls. To comply with federal 

requirements, the fee would be based on the total actual emissions. The fees would be used by the District to fund

projects which could achieve cost effective reductions. The affected sources will have the option, on an annual basis, to 

stop the fee option and install controls specified in the rule.

2. Particulate emissions from these sources is primarily generated from the fuel sulfur content so the rule amendments 

and new rule propose PM2.5 controls based on fuel sulfur limits or SOX limits on exhaust gases. Most of these units are 

fired on PUC-quality natural gas which is considered to be a reasonable level of SOX control. Units firing on field gas, 

refinery gas, or digester gas would either meet similar fuel sulfur levels or install an exhaust gas control. Extended 

compliance schedules have been provided for some larger units that are currently in compliance with NOx limits but need 

appropriate time to design and install the additional SOX controls.

3. Units subject to Rule 4306 would also be subject to Rule 4320. Rule 4306 amendments are administrative changes to 

address EPA concerns and make Rule 4306 approvable for inclusion in the State Implementation Plan (SIP). Specifically,

Section 5.3.4 of Rule 4306 would be modified to clarify that the exemption from BACT and offset requirements when 

adding start-up or shutdown conditions in the Permit to Operate (PTO) is not automatic but depends on Rule 2201 

language.

4. Amendments to Rule 4307 apply to smaller units (2 MMBtu/hr to 5 MMBtu/hr) and generate NOx emissions reductions 

by removing or altering existing exemptions from the rule. The total exemption for units used at schools would be 

removed, as well as the limited exemption for atmospheric units used in oilfields or refineries, and glycol reboilers. The 

low use unit threshold would drop from a limit of 5.0 billion Btu per year heat input to no more than 1.8 billion Btu per 

calendar year. After July 1, 2015 these units must meet all applicable requirements of the rule. New and replacement 

units would have to meet lower 9 or 12 ppmv NOx limits. This provision allows operators to lengthen useful life of units 

that recently upgraded to meet the current limits. SOX and PM2.5 requirements would be similar to Rule 4320 but these 

units are typically fired on Public Utility Corrlmission quality natural gas so the provisions serve as backstop language with 

little cost and nominal emission reductions.