VENTURA COUNTY APCD

STAFF REPORT

Proposed Amended Rules 54, Sulfur Compounds and 42, Permit Fees

FINAL – November 2013

EXECUTIVE SUMMARY

The Ventura County Air Pollution Control District 

(District) is proposing revisions to District Rule 54, 

Sulfur Compounds, and Rule 42, Permit Fees. Staff 

is proposing to add the 2010 primary 1-hour sulfur 

dioxide (SO2) National Ambient Air Quality Standard 

(NAAQS) of 75 parts per billion as a ground or sea 

level concentration limit to Rule 54’s current 

concentration limits. This value must be compared to 

a “design value” generated through ambient air 

monitoring or computer modeling of SO2

concentrations at or beyond an affected facility’s 

property line. Staff is also proposing to add a 

description of the design value that must be 

calculated to compare to the 2010 SO2 NAAQS 

concentration limit to determine compliance with the 

rule. 

Rule 54’s current property line limits are based on the 

California ambient air quality standards (CAAQS) for 

SO2. Because of its form, the 2010 SO2 NAAQS is 

not directly comparable to the existing CAAQS-based 

limits. Therefore, the 2010 SO2 NAAQS limit was 

added as a new subsection B.2.a. This amendment is 

required to bring Rule 54 up to date with current 

Federal requirements.

The proposed revisions might affect approximately 

21 existing significant sources of SO2 (see Table 1). 

For the purpose of this report, a source was 

considered significant if its permitted SO2 emissions 

are greater than 40 tons per year and/or five 

(5) pounds per hour. The total permitted or potential 

SO2 emissions from these operations are

approximately 197 tons SO2 per year. 

Since the limit being added to Rule 54 is an ambient 

air limit, compliance will most often be determined 

during the initial Authority to Construct process. If 

any ambient monitor or ambient SO2 concentration 

modeling shows concentrations above the limit, 

sources suspected of contributing to the exceedance

will be required to demonstrate compliance, typically

through dispersion modeling.

Since all new sources that emit SO2 must be equipped 

with Best Available Control Technology (BACT), it 

is unlikely that any new source will exceed the 

ambient concentration limits at the property line. In 

addition, the current sources of SO2 are either already 

well controlled, are low quantity emitters, or have 

flares on offshore oil platforms that are exempt from 

the limits in sections B.1, and B.2 of Rule 54 during 

emergencies for safety concerns. Therefore, no 

significant emissions reductions are expected as a 

result of this rule amendment.

The costs associated with compliance with the 

proposed ground or sea level concentration limits 

would be associated with air dispersion modeling 

used to demonstrate compliance and possibly with 

equipment or work practices to reduce SO2 emissions. 

However, the addition of the 2010 NAAQS SO2

standard would not increase the need for modeling 

compliance since the significant emission rate (the 

annual emission increase for a new or modified 

source that requires modeling to demonstrate 

compliance with the NAAQS) has not changed.

The estimated cost for additional SO2 emissions 

reductions or other strategies to achieve compliance 

with the new limitations are difficult to determine. 

Since BACT must be applied to all new or modified 

sources of SO2, any additional control technologies 

above and beyond BACT would likely be 

experimental and/or not previously implemented on a 

commercial scale. Thus the costs of implementing

the proposed rule revision are impossible to predict. 

The last time Rule 54 was updated in June of 1994, 

USEPA noted a minor deficiency during the State 

Implementation Plan revision process. Staff proposes 

to correct the deficiency during this revision by 

including a statement that the limit to combustion

exhaust in subsection B.1.a is on a dry basis corrected 

to a percent oxygen based on the combustion source. 

In addition, this revision includes clarification of the 

method of calculating the planned flaring excess 

emission fees in Rule 54 and Rule 42.

This report contains five sections: (1) Background, 

(2) Proposed Rule Revisions, (3) Comparison of 

Proposed Rule Requirements with Other Air 

Pollution Control Requirements, (4) Impact of the 

Proposed Rule, and (5) Environmental Impacts of 

Methods of Compliance. The first section provides 

background information including regulatory history, 

latest air pollution control technology, and source 

description. The second section explains the key 

features of the proposed revisions. The third section 

compares the proposed requirements with existing 

federal requirements and BACT. The fourth section 

is an analysis of the proposed amendment's effect on 

SO2 emissions, cost-effectiveness, and socioeconomic 

impacts. The last section examines the possible 

environmental impacts of compliance methods and 

mitigation of those impacts.
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 2

BACKGROUND

Introduction

Rule 54, Sulfur Compounds, was last amended in 

June of 1994. At that time, the rule was updated to 

include the most recent CAAQS for SO2. An 

exemption for flares on outer continental shelf oil 

production platforms was also added to allow flaring 

of high sulfur gas during emergencies. 

Ventura County is currently designated attainment for

the SO2 CAAQS1and the 1971 SO2 NAAQS. 

However, upon promulgation of the 2010 primary 

1-hour SO2 NAAQS, USEPA revoked both the 1971 

24-hour and the annual average primary SO2 NAAQS

and, moreover, the 1971 NAAQS will no longer 

apply one year after an area’s effective date of 

designation.

2

 In June 2011, the California Air 

Resources Board sent a letter to USEPA 

recommending that all areas of California be 

designated attainment for the 2010 SO2 NAAQS3. 

On February 6, 2013, the USEPA Region IX 

Administrator responded with a letter stating that 

USEPA had insufficient information to determine the 

attainment status for any area of California for the 

2010 SO2 NAAQS4. USEPA was required to 

complete the designations by June 3, 2013 but as of 

the date of this report has not issued final 

designations for California. Hence, at this time 

Ventura County has not received an attainment 

designation for the 2010 SO2 NAAQS but expects to 

be designated in attainment of the standard when 

USEPA completes its designation process. 

2010 SO2 NAAQS

On June 22, 2010 the USEPA strengthened the 

federal health-based or “primary” standard for SO2 by 

establishing a new standard for 1-hour average SO2

concentrations at 75 parts per billion (ppb) to protect 

public health from the adverse health effects of SO2. 

With that action USEPA revoked the existing federal

24-hour and annual SO2 standards set in 1971. In 

addition, USEPA changed the form of the standard to 

a “design value” for determining compliance with the 

standard.5 

Design values are mathematically determined air 

pollutant concentrations that must be reduced to, or 

maintained at or below a NAAQS, to assume 

compliance and/or attainment. The design value for 

the 2010 1-hour NAAQS is derived from the 3-year 

average of annual 99th percentile daily maximum 1-

hour values for a monitoring site. This value is also 

known as “the 1-hour primary standard design value.”

Emission Source Inventory

The 21 operations currently permitted by the District

that have SO2 emissions that would be considered 

significant and possibly affected by the proposed rule 

revisions are shown in Table 1. These include crude 

oil production, port and military base operations, 

electricity generation, mineral processing, sewage 

treatment and other operations that involve the 

combustion of sulfur-containing fuels.

The table provides the permitted or potential 

emissions of SO2 from stationary sources located at 

each listed facility. The estimated total permitted 

emissions from these sources are approximately 200

tons of SO2 per year. A facility’s actual SO2

emissions depend on its production levels and its

corresponding combustion of sulfur-containing fuel.

The emissions thresholds used to determine 

significant SO2 sources for this rule revision were 40 

tons SO2 per year and 5 pounds SO2 per hour. The 

40-ton threshold is the standard SO2 significance 

threshold for Prevention of Significant Deterioration

(PSD) permitting set by USEPA6. USEPA did not 

change this threshold when it promulgated the 2010 

SO2 NAAQS. Since the 2010 SO2 NAAQS is a short 

term (hourly) standard, staff determined that an 

hourly screening threshold was appropriate. Direct 

conversion of 40 tons per year to average pounds per 

hour yields 9.1 pounds per hour. Since the 2010 SO2

NAAQS is more stringent than the 1971 standards, 

staff selected 5 pounds per hour as a reasonable 

threshold for this rule analysis.

In its draft document “Guidance for 1-Hour SO2

NAAQS SIP Submissions,” EPA stated that it 

expected states to “focus performance of attainment 

demonstration modeling on areas with larger sources 

(e.g., those sources emitting over 100 tons per year 

(tpy) of SO2), and any other sources that we 

anticipate to cause or contribute to a violation to 

determine compliance with the new SO2 NAAQS.”7 

Since none of the Ventura County sources listed in 

Table 1 emit greater than 100 tons of SO2 per year, 

modeling of these existing sources will likely not be 

required to demonstrate attainment of the 2010 

NAAQS.
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 3

However, additional guidance from USEPA indicates 

that some refined modeling might be required to 

demonstrate attainment of the 2010 SO2 NAAQS. 

The sources that should be modeled using screening

modeling and those that must be included in refined 

modeling will be clarified with the additional USEPA

guidance. If modeling used to determine attainment 

status of the 2010 SO2 NAAQS shows violation(s) of 

the standard, then the sources contributing to the 

violation(s) will be required to reduce emissions. 

This is not expected to be the case for Ventura 

County, however.

1994 Rule Deficiency

On April 19, 2000 the USEPA finalized a limited 

approval of revisions to the Ventura County Air 

Pollution Control District portion of the California 

State Implementation Plan (SIP). The approval was 

limited due to minor deficiencies USEPA identified 

in their February 22, 2000 proposed limited approval 

of the SIP revisions. 

In the proposal, USEPA identified the following 

deficiency in Rule 54: “The rule specifies a 300 ppm 

SO2 limit at the point of discharge for any combustion 

operation. The rule should also indicate that the 

standard is on a dry basis and should specify the 

percent excess air.” EPA also recommended 

changing the period of record retention specified in 

Rule 54 to be consistent with the federal record

retention requirement of 5 years, stating this would be 

an improvement to the rule.

8

Additional Clarifications and Corrections

The 1994 revisions to Rule 54 included an excess 

emission fee for planned flaring events on outer 

continental shelf oil platforms that exceed the 

emission rate limits in Section B.1 of the rule. The 

rule requirements did not exactly correspond to the 

intent as described in the May 12, 1994 rule 

development staff report. In addition, the District 

Compliance Division manager at that time issued 

policies to clarify the implementation of the excess 

emission fee requirements to correspond with the 

staff report. 

Since staff determined that the staff report and 

Compliance division policy reflected the actual 

implementation of the rule in practice, this revision 

includes changes to Rule 54 to codify the current 

practice. Similar changes to Rule 42 Section N are 

proposed to maintain consistency between the two

rules. 

Table 1

Permitted Operations Possibly Affected by Proposed Rule Revisions

Facility 

ID Facility Name

Permitted SO2 Emissions

Type of Operation

SIC 

(tons/year) (lb/hour) Code

00003 Rincon Island Ltd. Partnership 0.98 8.18 Crude Oil Production 1311

00012 Tenby Production Facility 28.26 55.3 Crude Oil Production 1311

00036 Trinity ESC 63.55 15.89 Mineral Treating/Grinding 3295

00041 Aera Energy LLC 7.00 106.29 Crude Oil Production 1311

00065 Ormond Beach Gen. Station 37.04 8.8 Electricity Generation 4911

00143 Ventura Co. Medical Center 0.41 14.55 Medical/Surgical Hospital 8062

00144 Los Robles Hospital & Medical Ctr. 0.33 10.51 Medical/Surgical Hospital 8062

00157 New-Indy Oxnard, LLC 0.86 30.26 Paperboard Mill 2631

00165 Simi Vly Water Qlty Control Plant 6.38 5.27 Sewerage Systems 4952

00310 Vintage Production California LLC 0.76 10.03 Natural Gas Plants 1321

00970 Rincon Onshore Facility 2.00 66.97 Crude Oil Production 1311

00997 Naval Base Ventura County 1.91 8.17 National Security 9711

01139 Ventura Port District 0.87 7.22 Dredges/Pile Drivers 1629

01207 Naval Base Ventura County 6.01 9.24 National Security 9711

01266 Manson Construction Company 1.21 5.87 Dredges/Pile Drivers 1629

01267 Trustees of CSU & CSUCI Site Auth. 25.01 55.04 Electricity Generation 4911

01491 Platform Gina 4.75 76.91 Crude Oil Production 1311

01492 Platform Gilda 2.91 11.94 Crude Oil Production 1311

01493 Platform Grace 2.77 390.8 Crude Oil Production 1311

01494 Platform Gail 3.50 632.89 Crude Oil Production 1311

07294 Schlumberger Tech (Vent. Well Srvs) 0.08 6.97 Oilfield Services 1389

TOTAL PERMITTED EMISSIONS 197
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 4

PROPOSED RULE REVISIONS

The Ventura County Air Pollution Control District 

(District) is proposing revisions to District Rule 54, 

Sulfur Compounds and Rule 42, Permit Fees. The 

proposed revisions include adding the 2010 SO2

NAAQS as an ambient concentration limit,

addressing deficiencies identified by the USEPA, and 

clarifications to the planned flaring excess emission 

fee provisions.

2010 SO2 NAAQS

Staff is proposing to add the 2010 sulfur dioxide 

(SO2) National Ambient Air Quality Standard 

(NAAQS) of 75 parts per billion as a ground or sea 

level concentration limit to Rule 54’s current 

concentration limits. Staff is also proposing to add a 

description of the design value that must be 

calculated to compare to the 2010 SO2 NAAQS 

concentration limit to determine compliance with the 

rule.

The current ground or sea level limits in Rule 54, 

based on the California ambient air quality standards 

(CAAQS) for SO2, will be retained. The limits based 

on the CAAQS either have a different averaging time 

(24 hours) or are direct limits on 1-hour 

concentration that may not be exceeded, providing a 

maximum hourly concentration not covered by the 

proposed limit.

The addition of the 2010 SO2 NAAQS would not 

directly reduce SO2 emissions from stationary sources 

in Ventura County. However, adding the 2010 SO2

NAAQS to Rule 54 would clarify the requirements 

for affected facilities and District permit engineers. If 

modeling required for Authority to Construct review, 

PSD review or attainment demonstrations indicates

violations of the standard, emissions reductions 

would be required at that time. 

 

1994 Rule Deficiency

Staff is proposing to clarify the combustion source 

emission limit in Rule 54 Subsection B.1.a by adding 

the requirement that the limit is on a dry basis 

corrected to a percent oxygen based on the 

combustion source type. Since different combustion 

sources are designed to function with different excess 

air input, staff determined that it would be 

unreasonable to set a single excess air requirement for 

all sources subject to Rule 54. Therefore, staff 

reviewed existing District rules that apply to 

combustion sources. The Subsection B.1.a revisions 

reference other District rules in order to be consistent 

in setting the percent oxygen correction values.

To cover all sources, staff included a final 

requirement that all other sources correct the SO2

concentration to 15% oxygen. Staff reviewed 

combustion operations not covered by another 

District rule and determined that they operate at 

higher excess air (10% - 19% oxygen) than boilers. 

Therefore the “other” category will be required to 

correct SO2 emissions concentration to 15% oxygen. 

Processes combusting fuels subject to District Rule 

64 – Sulfur Content of Fuels, will be always in 

compliance with the emission limit of 300 ppm SO2 at

15% oxygen if they are in compliance with the fuel 

sulfur limits (see Table 2). 

Table 2

Theoretical Exhaust Concentrations at 

Rule 64 Fuel Sulfur Content Limits

Gaseous Fuel Liquid Fuel

Rule 64 Limit 50 grains S per 

100 cubic feet

0.005 pound S 

per pound fuel

Exhaust SO2

Concentration 

@ 15% O2

24.91 ppmv 95.65 ppmv

Exhaust SO2

Concentration 

@ 3% O2

75.57 ppmv 290.2 ppmv

Staff declined to change the record retention 

requirement in Rule 54. Staff determined that a

two-year retention period is consistent with the 

requirements of District Rule 24 and is sufficient for 

minor sources since Compliance Division staff 

inspects minor sources in the District annually. In 

addition, District Rule 33 requires Title V sources to 

retain records for five years as required by Federal 

rules. Therefore, the five-year retention requirement 

is already in place where required.

Additional Clarifications and Corrections

Rule 54 was also reviewed by staff to determine if 

any clarifications of the existing rule are needed. 

Staff found two typographical errors in Rule 54. This 

revision corrects the typographical by making the 

word “Subsection” plural in Subsection C.1.e and 

correcting the South Coast AQMD test method 

reference in Subsection D.1 (the correct test method 

number is 307-91).

In addition, staff determined that some provisions 

relating to the planned flaring excess emission fee in 

Rule 54 Subsection C.2.f and Rule 42 Section N did 

not accurately reflect the intention as described in the 
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 5

staff report prepared in conjunction with the 1994 

revision. The 1994 staff report states that the flare 

gas volume allowance should be calculated based on 

the baseline period from 1988 through 1993 for 

existing sources. 

The existing Rule 54 Section C.2.f and Rule 64 

Section N state the “flare gas volume allowance is 91 

percent of the average of the two highest, 

consecutive, annual flare gas volumes in the 

preceding 5 years.” Staff believes this wording might 

have been added to the rule to address potential new 

sources. However, it was not intended to create a 

rolling baseline for existing sources. The District 

Compliance Division has been operating under Policy 

F-1, which states that the flare gas volume allowance 

should be calculated based on the baseline period 

from 1988 through 1993. 

The proposed rule revisions set the baseline period 

for sources operating prior to January 1, 1988 as the 

period from January 1, 1988 through December 31, 

1993. This aligns the rules with the current policy in 

effect with the District Compliance Division and the 

1994 staff report. Table 3 lists the calculated flare 

gas volume allowance for the existing offshore oil 

platforms.

Table 3

Flare Gas Volume Allowances for Existing Sources

Platform Name

Flare Gas Volume 

Allowance (cubic feet)

Gail 37,990,000

Gilda 27,012,000

Gina 2,492,000

Grace N/A (see below)

The operators of platform Grace did not submit data

to the District and they have no flaring reduction plan 

on file. They do not expect to exceed the exhaust or 

sea level concentration limits since the gas produced 

at platform Grace historically has low sulfur content.

To accommodate potential new sources, the proposed 

rules set the baseline period for sources constructed 

after January 1, 1988 as the first six whole calendar 

years of operation. The rule revisions also clarify that 

the baseline flare volume is based on planned flaring 

only and does not include unplanned flare volume.

Public Workshop

Staff held a public workshop to present the proposed 

rule revisions to the public on August 7, 2013. Staff 

notified all 185 sources in the District with permitted 

emissions of sulfur compounds greater than zero by 

sending a postcard with the subject matter, date and 

time of the workshop to each source on July 24, 2013. 

In addition, notice of the workshop was posted on the 

District web page on July 18, 2013. Staff held the 

workshop at the appointed date and time but no 

industry representatives or members of the public 

attended the workshop. Staff received no written 

comments from the public before or after the 

workshop.

Thirty days prior to the public workshop, staff 

submitted the draft revised rules to the California Air 

Resources Board (ARB) and USEPA for review. 

ARB responded stating they had no comments on the 

draft revised rules. USEPA responded by telephone 

with comments requesting correction of a 

typographical error in the staff report and minor 

clarifications to three subsections of Rule 54. The 

changes to the Rule 54 text requested by EPA are as 

follows:

1. Include language in Subsection B.2.a that 

screen modeling software should be EPA 

approved;

2. Insert the date of the Bay Area Manual of 

Procedure referenced in Subsection D.2. 

(7/20/1994); and

3. Revise the reference to the EPA Quality 

Assurance Handbook in Subsection D.2.b to 

reference the current document.

Staff made all of the requested changes and EPA 

noted in its written comments that the comments had 

been addressed in the version posted on the District 

website prior to the public workshop.

During the public workshop, staff reviewed the rule 

with District management. Minor editorial changes 

were suggested. In addition, staff determined the SO2

emission limit for combustion sources at municipal 

solid waste landfills should have percent oxygen 

correction values based on the combustion source at 

the landfill. Subsection B.1.a.7 was edited 

accordingly.

Advisory Committee

Staff presented the proposed rule revisions to the 

District Advisory Committee on September 24, 2013. 

Efforts to notify affected sources and the public

similar to those for the public workshop were 

employed. Again, no industry representatives or 

members of the public attended the Advisory 

Committee meeting. The Advisory Committee 

unanimously passed a resolution recommending the 

proposed revisions be adopted by the Air Pollution 

Control Board.

The Advisory Committee received one written 

comment at the September 24 meeting from Phil 

White, President of AE Mechanical Engineering, Inc. 
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 6

and former Director of the District. The comment 

supported the changes to Rule 54 in a general 

statement and went on to address separate issues not 

related to these rule amendments. No changes were 

made to the proposed rule amendments as a result of 

the comment. No changes to the proposed rule 

amendments have been made after the Advisory 

Committee meeting on September 24, 2013.

COMPARISON OF PROPOSED RULE REQUIREMENTS

WITH OTHER AIR POLLUTION CONTROL REQUIREMENTS

Health and Safety Code Section 40727.2 requires 

Districts to compare the requirements of a proposed 

revised rule with other air pollution control 

requirements. These other air pollution control 

requirements include federal New Source 

Performance Standards (NSPS), federal National 

Emissions Standards for Hazardous Air Pollutants 

(NESHAPS), Best Available Control Technology 

(BACT), and any other District rule that applies to 

the same equipment.

Comparison with Federal NSPS and NESHAPS

Multiple NSPS regulations include SO2 emission 

limits. Only one NESHAP, Part 63 Subpart UUU –

Sulfur Recovery Units, limits SO2 emissions. One 

other NESHAP, Part 63 Subpart UUUUU – Coaland Oil-Fired Electric Utility Steam Generating 

Units, includes an optional SO2 emission limit as a 

method of demonstrating compliance. Neither of 

these NESHAPS regulates ambient air concentrations 

of SO2 at or outside the property line of the source 

facility.

The elements of the NSPS and NESHAPS were 

compared to proposed amendments to Rule 54. None 

of the proposed amendments to the rule affect the:

 Units used for emission standards

 Monitoring Frequency

 Test Methods

 Recordkeeping Requirements

None of the Federal rules regulate ground or sea level

concentrations of SO2 at or outside the property line 

of the source facility. In summary, there are no 

conflicting requirements with the federal NSPS or

NESHAPS. 

Comparison with BACT Requirements

Health and Safety Code Section 40727.2 (a) requires 

that the proposed rule amendments be compared with 

Best Available Control Technology (BACT). The 

CAPCOA Engineering Manager Rule Development 

Subcommittee developed guidance on this matter. 

Under this guidance, it is recommended that BACT 

be interpreted as a District’s BACT determination.

BACT for SO2 emissions is specific to the type of 

emission unit. However, the top-down BACT 

analysis used by the District does not consider 

ambient air concentrations. BACT is a technologybased standard that requires installation of controls 

and use of work practices to minimize emissions from 

new and modified sources. The ground or sea level

concentration standards in Section B.2 of Rule 54 are 

separate and are applied differently. 

If a source of SO2 is constructed or modified, BACT 

must be applied. If the new source review process 

requires modeling of ambient air concentrations of 

SO2, and the modeling results indicate ground or sea 

level concentrations greater than the limits in Rule 54, 

emissions must be reduced to meet the limits or a 

permit will not be issued. Thus, the ambient air 

standards in Rule 54 do not conflict with BACT but 

are complementary and constitute an additional layer 

of protection for the public.

IMPACT OF THE PROPOSED RULE

SO2 Emissions Impacts

As shown earlier in Table 1, the total permitted SO2

emissions of facilities with significant SO2 emissions 

are approximately 197 tons per year. Since the

proposed property line limit does not directly affect 

emissions, it is difficult to determine if any emission 

reductions will be necessary as a result of this rule

revision.

As stated above, the significance level for PSD 

review and modeling of emissions for compliance 

with the ambient air standards has not changed. 

However, District Engineering staff screen all new 

and modified sources of SO2 for compliance with the 
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 7

ground or sea level concentration limits in Rule 54. 

To date, all sources have demonstrated compliance 

with the existing concentration limits. Engineering 

staff expects that any source that implements BACT 

will readily demonstrate compliance with the 

proposed ground or sea level concentration limit.

Cost-Effectiveness

The costs associated with compliance with the

proposed ground or sea level SO2 concentration limits 

are associated with air dispersion modeling to 

demonstrate compliance and possibly equipment or 

work practices to reduce SO2 emissions. However, 

the addition of the 2010 NAAQS SO2 standard would 

not increase the need for dispersion modeling since 

the significant emission rate (the annual emission 

increase for a new or modified source that requires 

modeling to demonstrate compliance with the 

NAAQS) has not changed. 

AERMOD modeling software can be obtained for 

free from several sources on the Internet. Software 

packages with additional functionality are available 

for an initial cost of between $1,500 and $2,000 and 

up to $600 annually for updates and technical 

support. AERMOD is a steady-state dispersion 

model designed for short-range (up to 50 kilometers) 

dispersion modeling of air pollutant emissions from 

stationary industrial sources.

During the Authority to Construct process, the 

District normally performs a screening analysis at 

little or no cost to the applicant. Rarely, a facility 

would be required to hire a consultant to conduct any 

required air dispersion modeling. The cost for a 

screening level model run to demonstrate compliance 

for a single source in a simple facility would likely be 

no more than $1,000. The cost of a more complex 

model for a few emission points in a more complex 

building environment would likely be between $2,000 

and $10,000. Very complex modeling using the more 

sophisticated CALPUFF model can run well over 

$20,000. CALPUFF is an advanced non-steady-state 

meteorological and air quality modeling system that 

simulates the effects of time- and space-varying 

meteorological conditions on pollution transport, 

transformation, and removal. CALPUFF can be 

applied for long-range transport and for complex 

terrain.

The costs of additional SO2 emissions reductions or 

other strategies to achieve compliance with the new 

limitations are difficult to estimate. Since BACT 

must be applied to all new or modified sources of 

SO2, any additional control technologies beyond 

BACT will likely be experimental and/or not 

previously implemented on a commercial scale. Thus 

the cost of implementing this proposed rule revision 

is impossible to predict. 

In the Regulatory Impact Report for the 2010 SO2

NAAQS, USEPA estimated that unidentified controls 

would cost $15,000/ton of SO2 removed on an 

annualized basis.9 The BACT cost effectiveness 

screening level adopted by the District’s governing 

board in December 1988 is $5 per pound of SO2

emissions reduced (equivalent to $10,000 per ton).

10

 

This indicates that the cost of some controls that 

might be required under the proposal might exceed 

the District BACT screening levels for cost. 

However, it should be noted that $10,000 in 1988 

dollars is equivalent to $19,109 in 2012 dollars.

It is important to note that all costs discussed here are 

based on compliance with the 2010 SO2 NAAQS. 

Compliance with the 2010 NAAQS limit is required 

regardless of the amendments to Rule 54 so the 

proposed revisions will not increase costs. Since the 

combustion emission limit is less restrictive than the 

Rule 64 limits even with the correction for oxygen 

content and dry basis, it is unlikely that any source 

will exceed the limit and incur additional cost. The 

proposed changes to the planned flaring excess 

emission fee calculation merely align the rule text 

with actual practice so no increase in fees is expected. 

Incremental Cost-Effectiveness Analysis

Health and Safety Code Section 40920.6(a) requires 

air agencies to identify one or more potential control 

options, assess the cost-effectiveness of those options, 

and calculate the incremental cost-effectiveness. 

Health and Safety Code Section 40920.6 also requires 

an assessment of the incremental cost-effectiveness 

for proposed regulations for ozone, carbon monoxide

(CO), sulfur oxides (SOx), nitrogen oxides (NOx), 

and their precursors.

Incremental cost-effectiveness is defined as the 

difference in control costs divided by the difference 

in emission reductions between two potential control 

options achieving the same emission reduction goal 

of a regulation. The proposed amendments to Rule 

54 do not specify control options and may not require

emission reductions. Therefore, the incremental costeffectiveness analysis does not apply to this proposed 

rulemaking.

Socioeconomic Analysis

Assembly Bill 2061 (Polanco), which became 

effective January 1, 1992, requires that the District’s 

governing board consider the socioeconomic impacts 
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 8

of any new rule or rule revision. The Board must 

therefore evaluate the following socioeconomic 

information on proposed amendments to Rule 54. 

(1) The type of businesses, including small 

businesses, affected by the rule or regulation.

The adoption of amendments to this rule may

directly affect the 21 permitted operations in the 

county considered significant in this report (see 

Table 1). These include crude oil production, 

port and military base operations, electricity 

generation, mineral processing, sewage 

treatment and other operations that involve the 

combustion of sulfur-containing fuels. 

(2) The impact of the rule amendments on 

employment and the economy of the region.

Revisions to this rule are not expected to have a 

negative impact on either employment or the 

economy of Ventura County. New or modified 

sources are already required to implement 

BACT, and the proposed property line limits 

would not likely cause additional cost to 

industry. In addition, the proposed limits are 

currently in effect as NAAQS, so this rule does 

not impose more stringent requirements.

(3) The range of probable costs, including costs to 

industry or business, including small business, 

of the rule or regulation.

The proposed rule amendments would not cause 

any specific costs to most, if not all, existing 

facilities. If USEPA designates Ventura County 

attainment for SO2, then no modeling of existing 

facilities would be required since none exceed 

100 tons per year actual emissions. If USEPA 

requests modeling for some sources, modeling 

would likely cost between $1,000 and $20,000 

per facility. 

All new and modified sources of SO2 are 

evaluated for compliance with Rule 54 limits in 

the Authority to Construct process. This is 

normally done without additional cost to the 

applicant through fuel content analysis or 

engineering calculations. The addition of the 

2010 SO2 NAAQS limit to Rule 54 will not 

change this process, though sources not 

considered trivial might require increased 

scrutiny due to the stringency of the proposed 

limit.

New and modified sources with SO2 emissions 

increase of 40 tons per year or more would be 

required to conduct dispersion modeling to 

determine compliance with the proposed limit. 

This could add $20,000 or more to the cost of 

implementing the project. If additional controls 

are required, it could add hundreds of thousands 

of dollars to the project cost. Note however that 

the proposed limit is a Federal NAAQS and 

these costs would be incurred regardless of this 

rule amendment.

Small businesses with SO2 emissions less than 

40 tons per year or 5 pounds per hour would not 

be likely to incur any additional costs.

(4) The availability and cost-effectiveness of 

alternatives to the rule or regulation being 

proposed or amended.

Since the proposed rule amendments are merely 

adding new Federal requirements to the District 

rules, no other alternatives were evaluated.

(5) The emission reduction potential of the rule or 

regulation.

Since the proposed ground or sea level 

concentration limit does not directly affect 

emissions, it is difficult to determine if any 

emissions reductions would be necessary as a 

result of the rule amendments.

(6) The necessity of adopting, amending, or 

repealing the rule or regulation to attain state 

and federal ambient air standards pursuant to 

Chapter 10 (commencing with Section 40910).

This rule amendment is necessary to bring the 

District Rule 54 up to date with the current

Federal SO2 NAAQS. 

ENVIRONMENTAL IMPACTS OF METHODS OF COMPLIANCE

California Public Resources Code Section 21159 requires the District perform an environmental analysis of the 

reasonably foreseeable methods of compliance for the subject amended rule. Pursuant to paragraphs 21159(a)(1) to 

(3), the environmental analysis must include the following information on the proposed revisions to Rule 54:

(1) An analysis of the reasonably foreseeable environmental impacts of the methods of compliance.
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 9

(2) An analysis of the reasonably foreseeable feasible mitigation measures.

(3) An analysis of the reasonably foreseeable alternative means of compliance with the rule or regulation.

Table 4 lists all reasonably foreseeable compliance methods, the environmental impacts of those methods, and 

feasible measures that could be used to mitigate the identified environmental impacts of compliance methods, if any.

Table 4

Environmental Impacts of and Feasible Mitigation Measures for Methods of Compliance

Compliance Methods (including all 

reasonably foreseeable alternative 

means of compliance)

Reasonably Foreseeable 

Environmental Impacts 

Reasonably Foreseeable 

Feasible Mitigation Measures

Exhaust stack reconfiguration (not to 

exceed Good Engineering Practice 

height)

Environmental Impacts: None – this 

option neither reduces emissions nor 

creates additional emissions of other 

pollutants.

N/A 

Switch fuel to lower sulfur content 

fuels

Environmental Impacts: None – this 

option reduces emissions without 

creating additional emissions of other 

pollutants or additional waste streams.

N/A

Install add-on control devices such as 

scrubbers or baghouses with lime 

injection

Air Quality Impacts: Scrubber or 

baghouse technology could increase 

particulate emissions.

District rules limit particulate 

emissions and require high 

efficiency control devices that

mitigate these impacts.

Water Impacts: Improper disposal of 

scrubber liquor could impact water 

resources.

Compliance with wastewater 

discharge standards and waste 

disposal requirements would 

mitigate these impacts.

Solid Waste Disposal Impacts: 

Sorbents from scrubber system may be 

disposed of in landfills.

Certain sorbent systems create 

gypsum, which can be sold on 

commercial markets to avoid 

impacts to landfills.

Noise Impacts: Fans and equipment

associated with add-on controls may 

increase noise levels.

Sound walls or enclosures may be

constructed around the control 

equipment to mitigate these 

impacts as required by noise 

ordinances and industrial hygiene 

standards.

Refined computer modeling of SO2

concentrations at the property line

Environmental Impacts: None – this 

option would merely develop more 

accurate estimates of SO2

concentrations and would not reduce 

actual emissions or pollutant 

concentrations.

N/A

Ambient air monitoring of SO2

concentrations

Environmental Impacts: None – this 

option demonstrates compliance with 

ambient air standards and would not 

affect actual emissions or pollutant 

concentrations.

N/A

This analysis demonstrates that the adoption of the proposed revisions to Rule 54 would not have a significant 

adverse effect on the environment.
Staff Report Rule 54 & Rule 42 Revisions 11/13 FINAL Page 10

REFERENCES

 

1

2012 Area Designations for State Ambient Air Quality Standards SULFUR DIOXIDE. California Air Resources 

Board Web site. http://www.arb.ca.gov/desig/adm/2012/state_so2.pdf. February, 2012. Accessed May 13, 2013.

2 Title 40, Code of Federal Regulations, Part 50 §50.4 National primary ambient air quality standards for sulfur 

oxides (sulfur dioxide). http://www.ecfr.gov/cgi-bin/textidx?c=ecfr&SID=94a55a14061941755da6f1f646d09c88&rgn=div8&view=text&node=40:2.0.1.1.1.0.1.4&idno=40. 

Accessed June 11, 2013.

3 Goldstene J. N. Recommended Area Designations For The 2010 Federal Sulfur Dioxide (SO2) Standard Staff 

Report. United States Environmental Protection Agency Web site. 

http://www.epa.gov/so2designations/recletters/R9_CA_rec_wtechanalysis.pdf. June 20, 2011. Accessed May 13, 

2013

4 Blumenfeld J. United States Environmental Protection Agency Web site. 

http://www.epa.gov/so2designations/eparesp/09_CA_resp.PDF. February 6, 2013. Accessed May 13, 2013

5

Primary National Ambient Air Quality Standard for Sulfur Dioxide; Final Rule. United States Environmental 

Protection Agency Web site. http://www.epa.gov/ttn/naaqs/standards/so2/fr/20100622.pdf. June 22, 2010. 

Accessed May 13, 2013

6 General Guidance for Implementing the 1-hour SO2 National Ambient Air Quality Standard in Prevention of 

Significant Deterioration Permits, Including an Interim 1-hour SO2 Significant Impact Level. United States 

Environmental Protection Agency Web site. (2010, June). 

http://www.epa.gov/region07/air/nsr/nsrmemos/appwso2.pdf. August 23, 2010. Accessed May 13, 2013

7 Guidance for 1-Hour SO2 NAAQS SIP Submissions. United States Environmental Protection Agency Web site. 

http://www.epa.gov/air/sulfurdioxide/pdfs/DraftSO2Guidance_9-22-11.pdf. September 22, 2011. Accessed May 

13, 2013

8

“Approval and Promulgation of Implementation Plans; California State Implementation Plan Revision, Ventura 

County Air Pollution Control District,” 65 Federal Register 135 (22 February 2000) pp. 8676-8679.

9

Final Regulatory Impact Analysis (RIA) for the SO2 National Ambient Air Quality Standards (NAAQS). United 

States Environmental Protection Agency Web site. http://www.epa.gov/ttn/ecas/regdata/RIAs/fso2ria100602full.pdf. 

June 2010. Accessed May 13, 2013

10 Villegas M. BACT Implementation Permitting Policy. Ventura County Air Pollution Control District Web site. 

http://www.vcapcd.org/pubs/Engineering/permits2000/BACTPolicy111009.pdf. November 10, 2009. Accessed 

May 13, 2013