State Implementation Plan 

Revision Package 

Revisions to the 

Maricopa County Air Pollution Control Regulations 

Rule 300 – Visible Emissions

Prepared by 

Maricopa County Air Quality Department 

Planning & Analysis Division 

1001 North Central Avenue, Suite 595 

Phoenix, Arizona 85004 

(602) 372-1465 

Completeness Checklist 
Completeness Checklist

1. Agency: Maricopa County Air Quality Department 

2. Submitted Rule: 

Number Title Adoption Date

300 Visible Emissions March 12, 2008 

3. EPA Analogous Approved Rule (Applicable SIP): 

Rule 300 is analogous to the EPA applicable SIP approved Rule 30 of April 12, 1982. 

4. State/District Authority for Adoption/Implementation: 

Authorizing Statutes: Arizona Revised Statutes (A.R.S.) §49-112 (A), § 49-479, §49-

501, §11-251.63 and §11-871. 

Implementing Statute: Arizona Revised Statutes (A.R.S.) §49-479 and §49-501. 

5. Pollutants Regulated by Rule: 

PM_9__, SOX___, VOC____, NOx___, CO____, Pb____

6. Identification of Sources by Name or Number/Location (City, County, or District) 

Area's Attainment and Plan Status (Group by Size/Subcategory, if Necessary): 

Sources may consist of any permitted sources, pollution control vendors, contractors, 

consultants, lawyers, the County, private persons and consumers. The County estimates 

that as few as 20-30 sources might be actually affected by the rulemaking. Although many 

industry categories, including woodworking operations, metallurgical operations, scrap 

metal operations and cotton gins are potentially subject to Rule 300 most of these sources 

will be unaffected by this rule as they already comply with either form of data reduction for 

determining compliance with the standards, are already subject to 20% or lower opacity 

standards, or are regulated by New Source Performance Standards (NSPS). 

PM10 Classification: Serious (As of June 10, 1996) 

Carbon Monoxide Classification: Attainment (As of April 8, 2005) 

1-Hour Ozone Classification1

: Attainment (June 14, 2005) 

8-Hour Ozone Classification: Nonattainment (As of April 15, 2004) 

1

Note: on June 15, 2005 EPA revoked the 1-Hour Ozone standard for all areas in Arizona. 

7. Summary of Rule/Rule Changes: 

The Maricopa County Air Quality Department (MCAQD) is proposing revisions to Rule 

300. The proposed revisions are in relation to commitments made in the Five Percent 

Plan for PM10. Since the region did not attain the PM10 standard by December 31, 2006, 

the region needs to submit to the Environmental Protection Agency (EPA) a Five Percent 

Plan for PM10 by December 31, 2007. The Five Percent Plan for PM10 must demonstrate 

5% reductions per year in emissions from the date of submission to the EPA. The 

proposed revisions include changing the procedures for determining compliance with the 

20% opacity limitation from “averaging” to “aggregating” and adding a requirement that 

1 
no air contaminant remain visible in the atmosphere at the property line. Also, as part of 

this rulemaking, the MCAQD may add, delete, or modify additional rules as necessary. 

Section 200: To add “See Rule 100-General Provisions and Definitions of these rules for 

definitions of terms that are used but not specifically defined in this rule.” 

Section 201: To delete “Intermittent Source – A source which causes or discharges 

visible emissions for a duration of less than 6 consecutive minutes.” 

Section 301: To delete from heading “Opacity/General”. To delete “No person shall 

discharge into the ambient air from any single source of emissions any air contaminant, 

other than uncombined water, in excess of 20% opacity.” 

Section 301.1: To add “No person shall discharge into the ambient air, from any single 

source of emissions, any air contaminant, other than uncombined water, in excess of 20% 

opacity for a period aggregating more than three minutes in any 60-minute period.” 

Section 301.2: To add “No person shall cause, suffer, allow, or permit diffusion of visible 

emissions, including fugitive dust, beyond the property line within which the emissions are 

generated. 

Section 501: To delete “except as provided in Section 502 of this rule” and to add “as 

modified by EPA Reference Method 203B.” 

Section 502: To delete “Compliance Determination-Opacity of Visible Emissions From 

Intermittent Sources: Opacity of visible emissions from intermittent sources shall be 

determined by observations of visible emissions conducted in accordance with EPA 

Reference Method 9, except that at least 12 rather than 24 consecutive readings shall be 

required at 15-second intervals for the averaging time.” 

8. Rule's Effect on Emissions: 

There is no direct effect on emissions from the changes made to this rule. The intended 

effect is to provide States with an expanded array of data reduction procedures for 

determining compliance with SIP opacity regulations. These areas that successfully met 

the December 31, 2006 attainment date administer rules that utilize a time-exception 

form of the standard expressed as “... shall not exceed 20% opacity for more than three 

minutes out of any 60-minute period.” This form of data reduction for the 20% opacity 

standard limits the number of excursions over the 20% visible emission standard and 

results in a more consistent compliance with the standard. 

9. Demonstration That NAAQS (PSD) Increments/RFP Demonstration are Protected 

(as appropriate): 

The MCAQD is proposing these revisions to Rule 300 to implement a control measure 

and increase compliance with existing rules for the Five Percent Plan for PM10. On June 

6, 2007, the Environmental Protection Agency (EPA) finalized its finding that the 

Phoenix nonattainment area did not attain the 24-hour PM10 standard by the deadline 

mandated in the Clean Air Act (CAA), December 31, 2006. (72 FR 31183, June 6, 2007). 

Under Section 189(d) of the CAA, serious PM10 nonattainment areas that fail to attain are 

required to submit within 12 months of the applicable attainment date, “plan revisions 

2 
which provide for attainment of the PM10 air quality standard and, from the date of such 

submission until attainment, for an annual reduction in PM10 or PM10 precursor 

emissions within the area of not less than 5% of the amount of such emissions as reported 

in the most recent inventory prepared for such area.” In accordance with the CAA 

Section 179(d)(3), the attainment deadline applicable to an area that misses the serious 

area attainment date is as soon as practicable. The region needs to submit to a Five 

Percent Plan for PM10 by December 31, 2007. 

10. Modeling Information Used to Support Rule Revision:

The changes to the rule doe not relax the SIP; therefore modeling was not needed. 

Information on regional modeling activities can be found in the Technical Support 

Document for the Maricopa County Five Percent Plan (available at: 

http://www.mag.maricopa.gov/pdf/cms.resource/PM10_2007_Appendices_vol-3.pdf) 

which was submitted to EPA in December 2007. 

11. Evidence That Emission Limitations are Based on Emission Reduction Technology, 

Add-On Controls, Reformulated Materials, and/or Industrial/Process Equipment 

Designs: 

The amendments to Rule 300 will result in a lowering of particulate matter emissions 

based upon two practices listed Section 301 of the amended rule. These practices are the 

prohibition of visible emissions of particulate matter beyond the property line within 

which the emissions are generated and to modify EPA Reference Method 9 by 

incorporation of EPA Reference Method 203B. These new procedures are not considered 

a technology or an add-on control or an industrial /process equipment design.

12. Identification of Section/Paragraph in Rule That Contains Emissions Limitations, 

Work Practice Standards, Averaging Times, Test Procedures and/or 

Recordkeeping/Reporting Requirements: 

Emission limitations are listed in Section 301.1. Test procedures are listed in Section 501. 

13. Compliance/Enforcement Strategies to be Used to Determine Compliance (Including 

Frequency of Inspection): 

Not Applicable. 

14. Special Economic/Technological Justifications for Deviations From EPA Policies (As 

Appropriate): 

Not Applicable. 

15. Other Comments: 

Attached Support Documentation Includes the Following: 

Appendix 1 Notice of Proposed Rulemaking 

Appendix 2 Agenda Form and Notice of Final Rulemaking 

Appendix 3 Notice of Public Hearing 

Appendix 4 Affidavit of Publication 

3 
Appendix 5 Certified Excerpts From the Minutes of the Board of Supervisors' Public 

Hearing 

Appendix 6 Final Adopted Version of Rule 

4 
For EPA Use Only

SIP RULE REVISION IS: ______COMPLETE _____INCOMPLETE 

Name Telephone Number

District Contact: Jo Crumbaker (602) 506-6705 

State Contact: Ira Domsky (602) 771-2365 

 Diane Arnst (602) 771-2375 

State Submittal Date: _____________________________________________________ 

5 
EPA SIP Enforceability Statement

1. APPLICABILITY 

a. What sources are being regulated? 

Sources may consist of any permitted sources, pollution control vendors, 

contractors, consultants, lawyers, the County, private persons and consumers. The 

County estimates that as few as 20-30 sources might be actually affected by the 

rulemaking. Although many industry categories, including woodworking 

operations, metallurgical operations, scrap metal operations and cotton gins are 

potentially subject to Rule 300 most of these sources will be unaffected by this rule 

as they already comply with either form of data reduction for determining 

compliance with the standards, are already subject to 20% or lower opacity 

standards, or are regulated by New Source Performance Standards (NSPS). 

b. What exemptions are provided?

302.1 Charging Electric Arc Furnaces: When charging or back-charging any 

electric arc furnace for which construction commenced prior to February 2, 1963, 

a person may discharge air contaminants, other than uncombined water, in excess 

of the applicable opacity limit in Section 301 of this rule for no more than an 

aggregate of 3 minutes in any 45 minute period; however, visible emissions 

resulting from such discharge of air contaminants shall not exceed 40% opacity. 

302.2 Emergency Diesel Generators (EDGs) and Equipment: When emergency 

diesel generators (EDGs) and equipment must run for safety reasons and/or for 

safety and operational tests to meet the requirements legally imposed by the 

Nuclear Regulatory Commission, a person may discharge air contaminants, other 

than uncombined water, in excess of the applicable opacity limit in Section 301 of 

this rule. Any discharge of air contaminants, other than uncombined water, in 

excess of the opacity limit in Section 301 of this rule should not contribute to a 

violation of the national ambient air quality standard. 

302.3 Firing of Ordnance At Test Facilities: Visible emissions exceeding the 

opacity standards for short periods of time resulting from firing test rounds in 

enclosed bunkers at ordnance test facilities which do not exceed 6 minutes in 

length shall not constitute a violation of Section 301 of this rule. 

302.4 Opacity Training: Equipment or processes used to train individuals in 

opacity observations shall be exempt from opacity standards during the 

preparation for and/or during the actual training session(s). 

c. What are the units of compliance? 

The units of compliance are in percentages. 

d. Is bubbling or averaging of any type allowed? 

No. 

6 
7 

e. If there is a redesignation, will this change the emissions limitations? 

No. 

2. COMPLIANCE DATES 

a. What is the compliance date? 

The compliance date is the date of rule adoption – March 12, 2008. 

b. What is the attainment date? 

Particulates attainment date: December 31, 2006 or as expeditiously as 

possible thereafter. 

8-hour Ozone attainment date: June 15, 2009 

3. SPECIFICITY OF CONDUCT 

a. What test methods are required? 

EPA Reference Method 203B. 

b. What is the averaging time in the compliance test method? 

Not Applicable. 

4. RECORDKEEPING

a. What records are required to determine compliance? 

Rule 300 basically addresses a change to the way visible emissions are conducted. 

and does not contain records requirements. Many sources subject to Rule 300 

would have to comply with other rules specific to their industry or process that 

would contain records requirements utilizing the testing technique listed in Rule 

300.

b. In what forms or units must records be kept? 

Opacity shall be determined by observations of visible emissions conducted in 

accordance with EPA Reference Method 203B. Opacity is reported in percentages. 

c. On what time basis must records be kept? 

Recordkeeping is not addressed in Rule 300. 
Appendix 1 
NOTICE OF PROPOSED RULEMAKING 

MARICOPA COUNTY AIR POLLUTION CONTROL REGULATIONS 

RULE 300 - VISIBLE EMISSIONS 

PREAMBLE

1. Sections affected Rulemaking action

Rule 300 Amend 

2. Statutory authority for the rulemaking:

Authorizing statutes: A.R.S. §§ 49-474, 49-479, and 49-480 

Implementing statute: A.R.S. § 49-112 

3. List of all previous notices appearing in the register addressing the proposed rule:

Notice of Rulemaking Docket Opening: 13 A.A.R. 3373, October 5, 2007 

4. The name and address of agency personnel with whom persons may communicate regarding the

rulemaking:

Name: Johanna M. Kuspert or Jo Crumbaker 

 Maricopa County Air Quality Department 

Address: 1001 N. Central Ave, Suite 595 

 Phoenix, AZ 85004 

Telephone: 602-506-6710 or 602-506-6705 

Fax Number: 602-506-6179 

Email Address: jkuspert@mail.maricopa.gov or jcrumbak@mail.maricopa.gov 

5. An explanation of the rule, including the agency’s reasons for initiating the rulemaking:

The Maricopa County Air Quality Department (MCAQD) is proposing revisions to Rule 300. The 

MCAQD is proposing these revisions to Rule 300 to implement a control measure and increase compliance with existing rules for the Five Percent Plan for PM10. On June 6, 2007, the Environmental 

Protection Agency (EPA) finalized its finding that the Phoenix Nonattainment Area did not attain the 

24-hour PM10 standard by the deadline mandated in the Clean Air Act (CAA), December 31, 2006. (72 

FR 31183, June 6, 2007). Under Section 189(d) of the CAA, serious PM10 nonattainment areas that fail 

to attain are required to submit within 12 months of the applicable attainment date, “plan revisions 

which provide for attainment of the PM10 air quality standard and, from the date of such submission 

until attainment, for an annual reduction in PM10 or PM10 precursor emissions within the area of not 

less than 5 percent of the amount of such emissions as reported in the most recent inventory prepared 

1 
for such area.” In accordance with the CAA section 179(d)(3), the attainment deadline applicable to an 

area that misses the serious area attainment date is as soon as practicable. The region needs to submit 

to a Five Percent Plan for PM10 by December 31, 2007. 

PM10 Nonattainment Status History: 

In accordance with 1990 Clean Air Act Amendments, the Maricopa County nonattainment area was 

initially classified as "moderate" for PM10 pollution. As a moderate nonattainment area, Maricopa 

County was required to submit to the EPA a moderate PM10 nonattainment area plan and to show 

attainment of the PM10 national ambient air quality standards (NAAQS) by December 31, 1994. 

Moderate PM10 nonattainment area plans were submitted to the EPA in 1991 and 1993. 

The Maricopa County moderate PM10 nonattainment area, upon the EPA’s findings, failed to attain the 

NAAQS by December 31, 1994. Consequently, on May 10, 1996, the EPA reclassified Maricopa 

County as a serious PM10 nonattainment area. Maricopa County was then required to submit a serious 

PM10 nonattainment area plan, which had to include best available control measures (BACM), 

measures designed to achieve the maximum degree of emissions reduction for PM10 sources. Maricopa 

County had to show attainment of the PM10 NAAQS by December 21, 2001. 

Emission inventories and air quality modeling analysis of existing control measures showed that 

attainment could not be reached by December 21, 2001. A shortfall of a 16.4% reduction in PM10

concentration was identified. The CAA allows states to request an extension of this attainment date for 

up to five years, providing the state demonstrates that the plan includes the most stringent measures 

(MSM) that are included in any state’s plan or achieved in practice by any State, and can be feasibly 

implemented in the area. Consequently, a rigorous planning effort was conducted to develop 77 

additional control measures. The serious PM10 nonattainment area plan was submitted to the EPA on 

July 9, 1999. The EPA approved the revised serious PM10 nonattainment area plan in April 2002, 

contingent on the completion of three commitments by Maricopa County. The revisions to Rule 310 

(adopted April 7, 2004) addressed the commitments. 

As a result of litigation on the moderate PM10 nonattainment area plan, the Arizona Department Of 

Environmental Quality (ADEQ's) prepared and submitted a Plan For Attainment Of The 24-Hour PM10

Standard–Maricopa County PM10 Nonattainment Area in May 1997. EPA partially disapproved the 

Arizona 24-hour Standard PM10 SIP revision triggering a federal implementation plan (FIP) obligation, 

which remains in place, related to the area’s PM10 moderate area plan. The obligation resulted from 

EPA disapproved those sections of the SIP addressing unpaved roads, unpaved shoulders, unpaved 

parking lots, vacant lots and agriculture. EPA found that the SIP did not contain measures to reduce the 

emissions from or the number of existing sources in these categories and therefore failed to implement 

2 
reasonably available control measures. Under the court ordered consent decree, EPA finalized a FIP in 

July 1998 for the Maricopa County PM10 nonattainment area that addresses those four categories of 

sources. 

On July 2, 2002, the Environmental Protection Agency (EPA) found the controls proposed in the, 

inadequate to ensure the attainment of the PM10 national ambient air quality standards (NAAQS) at the 

Salt River air quality monitoring sites. The finding of inadequacy included the State Implementation 

Plan’s (SIP’s) attainment and reasonable further progress (RFP) demonstrations for the 24-hour PM10

standard at the Salt River monitoring sites and three other microscale sites in the Maricopa County 

PM10 nonattainment area (Maryvale, Gilbert, and West Chandler). 

Although the EPA approved Arizona's 1997 SIP revision and additional required controls proposed by 

Maricopa County on August 4, 1997, EPA's Aerometric Information Retrieval System (AIRS) 

continued to show exceedances at the Maricopa County PM10 nonattainment area Salt River site - 

recording expected exceedances in 1999, 2000, and through three quarters of 2001. Consequently, the 

EPA required Arizona to submit a SIP revision to identify and implement corrective PM10 control 

provisions in the Salt River Study Area and for similar significant sources in the Maricopa County 

PM10 nonattainment area. 

Arizona's SIP revision was required to provide for attainment in the Salt River site no later than 

December 31, 2006, in accordance with CAA §189(b)(1)(A) and 188(e), and was required to include 

control strategies that meet the best available control measures (BACM) test and the most stringent 

measures (MSM) test for significant sources and source categories. 

The Final Revised PM10 State Implementation Plan For The Salt River Area dated August 2004

contained Arizona’s revisions to the State Implementation Plan for the Maricopa County PM10 serious 

nonattainment area and included the following State Implementation Plan requirements, as described 

by the EPA in its Federal Register notice of disapproval (67 FR 44369, July 2, 2002): 

● A modeling demonstration showing that the level of emissions reductions from application of 

BACM-MSM for all significant sources of PM10 will result in attainment of the 24-hour NAAQS 

by December 31, 2006, at the Salt River PM10 monitoring site, in accordance with CAA 

§189(b)(1)(A) and §188(e). 

● Commitments to implement best available control measures (BACM)-most stringent measures 

(MSM) for sources significantly contributing to exceedances of the 24-hour PM10 standard in the 

Salt River area as expeditiously as possible (CAA §189(b)(1)(B)) and a commitment that all 

BACM and MSM control measures adopted and applied to sources in the Salt River Study Area 

3 
will be applied to all similar sources throughout the Maricopa County PM10 serious 

nonattainment area. 

● A demonstration that the plan constitutes Reasonable Further Progress (RFP) up to the attainment 

deadline - December 31, 2006. 

● A demonstration that all the requirements of the federal Clean Air Act Amendments that pertain to 

serious PM10 nonattainment areas are met - including CAA §110(l), §110(a)(2)(E)(i), and 40 CFR 

§51.280 and §51.111). 

Explanation For Current Rulemaking Proposals: 

For the Five Percent Plan for PM10, an analysis was again conducted to identify additional measures 

to reduce emissions and/or improve compliance with existing requirements. Finally, the MCAQD is 

also proposing to include a control measure adopted as BACM/MSM in Maricopa County Air 

Pollution Control Rule 316 in June 2005 for the Salt River SIP in Rule 300. Specifically, the MCAQD 

is proposing to add a no visible emissions of particulate matter at the property line standard to Rule 

300. This proposed revision will make Rule 300 consistent with Rule 310, Rule 310.01, and Rule 316 

that also limit particulate matter. 

The MCAQD further sought to review rules from other agencies to increase the consistency of 

compliance with the existing visible emission standard of 20%. The MCAQD reviewed rules from 

Clark County, Nevada; South Coast Air Quality Management District, California (SCAQMD); and San 

Joaquin Unified Air Pollution Control District, California (SJUAPCD) to identify difference between 

County rules and rules from areas that successfully met the December 31, 2006 attainment date. The 

MCAQD also reviewed EPA’s notice finalizing Method 203 (A), (B), and (C) (71 FR 55119, September 21, 2006). In the summary of that notice EPA states, “The intended effect is to provide States 

with an expanded array of data reduction procedures for determining compliance with SIP opacity 

regulations.” These areas that successfully met the December 31, 2006 attainment date administer rules 

that utilize a time-exception form of the standard expressed as “... shall not exceed 20% opacity for 

more than 3 minutes out of any 60 minute period.” This form of data reduction for the 20% opacity 

standard limits the number of excursions over the 20% level of the standard resulting in more 

consistent compliance with the existing standard. 

Section By Section Explanation Of Changes: 

Section 200: To add “See Rule 100-General Provisions And Definitions of these rules for 

definitions of terms that are used but not specifically defined in this rule.” 

Section 201: To delete “Intermittent Source - A source which causes or discharges visible 

emissions for a duration of less than 6 consecutive minutes.” 

4 
Section 301: To delete from heading “Opacity/General”. To delete “No person shall discharge 

into the ambient air from any single source of emissions any air contaminant, other 

than uncombined water, in excess of 20% opacity.” 

Section 301.1: To add “No person shall discharge into the ambient air, from any single source of 

emissions, any air contaminant, other than uncombined water, in excess of 20% 

opacity for a period aggregating more than three minutes in any 60-minute period.” 

Section 301.2: To add “No person shall cause, suffer, or allow visible emissions of particulate 

matter, including fugitive dust, beyond the property line within which the emissions 

are generated.” 

Section 501: To delete “except as provided in Section 502 of this rule” and to add “as modified by 

EPA Reference Method 203B.” 

Section 502: To delete “Compliance Determination-Opacity Of Visible Emissions From 

Intermittent Sources: Opacity of visible emissions from intermittent sources shall be 

determined by observations of visible emissions conducted in accordance with EPA 

Reference Method 9, except that at least 12 rather than 24 consecutive readings shall 

be required at 15–second intervals for the averaging time.” 

6. Demonstration of compliance with A.R.S. §49-112:

Under ARS §49-479(C), a county may not adopt a rule or ordinance that is more stringent than the 

rules adopted by the Director of the Arizona Department of Environmental Quality (ADEQ) for similar 

sources unless it demonstrates compliance with the requirements of ARS §49-112: 

ARS §49-112 (A) 

When authorized by law, a county may adopt a rule, ordinance, or other regulation that is more 

stringent than or in addition to a provision of this title or rule adopted by the director or any board or 

commission authorized to adopt rules pursuant to this title if all the following conditions are met: 

1. The rule, ordinance or other regulation is necessary to address a peculiar local condition; 

2. There is credible evidence that the rule, ordinance or other regulation is either: 

 (a) Necessary to prevent a significant threat to public health or the environment that results from 

a peculiar local condition and is technically and economically feasible. 

 (b) Required under a federal statute or regulation, or authorized pursuant to an intergovernmental 

agreement with the federal government to enforce federal statutes or regulations if the county rule, 

ordinance or other regulation is equivalent to federal statutes or regulations. 

The MCAQD is proposing to revise Rule 300 in order to address a peculiar local condition: EPA’s 

finding that the Phoenix Nonattainment Area did not attain the 24-hour PM10 standard by the deadline 

mandated in the Clean Air Act (CAA), December 31, 2006. (72 FR 31183, June 6, 2007). The Phoenix 

5 
Nonattainment Area is the only nonattainment area designated serious for PM10 in Arizona. 

Consequently, stronger regulations must be adopted in this area to address a serious health threat. 

Under Section 189(d) of the CAA, serious PM10 nonattainment areas that fail to attain are required to 

submit within 12 months of the applicable attainment date, “plan revisions which provide for 

attainment of the PM10 air quality standard and, from the date of such submission until attainment, for 

an annual reduction in PM10 or PM10 precursor emissions within the area of not less than 5 percent of 

the amount of such emissions as reported in the most recent inventory prepared for such area.” In 

accordance with the CAA section 179(d)(3), the attainment deadline applicable to an area that misses 

the serious area attainment date is as soon as practicable. The region needs to submit to a Five Percent 

Plan for PM10 by December 31, 2007. The Phoenix Nonattainment Area is one of three areas in the 

entire country for which EPA has issued a finding that Section 189(d) has been triggered. Because of 

this, the revision complies with A.R.S. § 49-112 (A)(1) and A.R.S. § 49-112 (A) (2). 

7. A reference to any study relevant to the rule that the agency reviewed and either proposes to rely

on in its evaluation of or justification for the rule, where the public may obtain or review each 

study, all data underlying each study, and any analysis of each study and other supporting 

material:

Not applicable. 

8. A showing of good cause why the rule is necessary to promote a statewide interest if the rule will 

diminish a previous grant of authority of a political subdivision:

Not applicable. 

9. The preliminary summary of the economic, small business, and consumer impact:

Rule Identification: 

This rulemaking amends Rule 300, “Visible Emissions,” in Maricopa County Air Pollution Control 

Regulations. The proposed rule adds a no visible emissions of particulate matter at the property line 

standard to Rule 300. This proposed revision will make Rule 300 consistent with Rules 310, 310.01 

and Rule 316 that also limit particulate matter. A second proposed revision changes the data reduction 

methodology for the existing 20% and reads “... shall not exceed 20% opacity for more than 3 minutes 

out of any 60 minute period.” This form of data reduction for the 20% opacity standard limits the 

number of excursions over the 20% level of the standard resulting in more consistent compliance with 

the existing standard. 

Entities Directly Impacted: 

Entities directly impacted by this rulemaking include certain permitted sources, pollution control 

vendors, contractors, consultants, lawyers, the County, private persons and consumers. The County 

6 
estimates that as few as 20-30 sources might be affected by this rulemaking. Although many industry 

categories, including woodworking operations, metallurgical operations, scrap metal operations, and 

cotton gins are potentially subject to Rule 300, most of these sources will be unaffected by this rule as 

they already comply with either form of data reduction for determining compliance with the standard, 

are already subject to 20%, or lower, opacity standards, or are regulated by New Source Performance 

Standards (NSPS), Title 40, Part 60 of the Code of Federal Regulations. 

Probable Costs and Benefits: 

A. Costs to the state of Arizona: 

If Arizona is unable to submit a plan that demonstrates a Five Percent per year reduction and demonstrates attainment at the monitors based on implemented control measures such as this rule, EPA will 

be required to make a nondiscretionary finding that Arizona has failed to submit an approvable plan. If 

the County and Arizona fail to correct the identified deficiencies within the timeframe specified in the 

notice, the sanctions under § 179 of the Clean Air Act (CAA) will be imposed. Sanctions include loss 

of highway funds and stricter emission offset requirements for major sources. In addition, under § 

110(c) of the CAA, EPA would then need to promulgate a Federal Implementation Plan no later than 

24 months after the date of publication of the notice. 

B. Potential Costs and Benefits to the Public: 

The most obvious benefit arising from promulgation of this rule is reduction in the harmful effects of 

air pollution, most notably particulates. Air pollution harms lung function, damages lung tissue, and 

increases respiratory symptoms, such as coughing, shortness of breath, wheezing and asthma attacks, 

and can impair the body’s immune system response to inhaled particles. Results may include restricted 

activities, and work time and revenues lost due to increased hospital admissions, illness and death. PM 

associated health risks occur even more frequently in susceptible subpopulations, such as the elderly, 

children with asthma, and persons with cardiopulmonary disease, and may contribute to up to 65,000 

excess deaths in the U.S. annually (STAPPA and ALAPCO, Controlling Particulate Matter Under the 

Clean Air Act: A Menu of Options, July 1996). Even very low concentrations of particulate matter 

may increase risk of early death, particularly in elderly populations with preexisting cardiopulmonary 

diseases (STAPPA and ALAPCO, supra). Chronic obstructive pulmonary disease (COPD), a major 

cause of morbidity and mortality in the U.S., cost the country more than 32 billion dollars in 2002, a 

figure which does not include costs attributable to asthma (American Lung Assoc., “Trends in Chronic 

Bronchitis and Emphysema: Morbidity and Mortality,” Epidemiology and Statistics Unit, Research 

and Scientific Affairs, March 2003). Notably, asthma death rates in Arizona equaled or exceeded U.S. 

rates from 1991-1998. In addition, in 1998, an estimated 316,200 Arizonans suffered breathing 

discomfort and asthma related stress (Arizona Department of Health Services, “Asthma Control 

Program,” Office of Nutrition and Chronic Disease Prevention Services, October, 2002). Therefore, 

7 
the County expects the countywide property line standard and change in data reduction methodology to 

translate into cost-saving benefits to the general public by reducing emissions-related adverse health 

effects and the concurrent lost revenue and health care costs. In addition to direct health-related effects, 

a statewide opacity limit of 20% will affect the general quality of life, particularly for those persons 

living near sources. A lower opacity limit will concurrently increase visibility and enhance the public’s 

enjoyment of Arizona’s natural resources. 

C. Potential Costs and Benefits to the Regulated Community: 

Both the proposed property line standard for particulate matter and the new data reduction methods for 

the existing opacity standard will require that owners/operators more closely monitor their activities, 

processes, and controls to ensure proper operation at all times. As described in the explanation in #5 

above, a number of western serious PM-10 nonattainment areas administer rules that include both of 

the proposed revisions. Those areas contain many similar sources that comply with the proposed 

standards and are in the same business as sources in Maricopa County. Furthermore, an EPA study 

(Office of Air Quality Planning and Standards, “Opacity Regulations: A Summary of State Regulations 

and Rulemaking Status”, Special Report February 1983) contains information indicating that the state 

or a local agency in 28 states has adopted a time-exception form of data reduction for their opacity 

standard. 

Although each regulated facility is unique, the costs of compliance associated with the new rule are 

similar and may include: new capital equipment or modification of existing equipment, adjusting or 

enhancing operations and maintenance; replacement or modification of processes and designs; and 

indirect and administrative costs. Compliance might also result, however, in a variety of offsetting 

financial benefits for the source. They range from lower operation and maintenance costs, as a result of 

updated and more efficient equipment, to fewer man-hours lost and lower health care costs due to a 

decrease in pollution-exacerbated illnesses. During the informal workshop process for this rulemaking, 

the County requested that information on source-specific costs to achieve compliance with these 

standards, but has not yet received any information. The County is specifically requesting in this 

preliminary EIS source-specific information on costs to achieve compliance with the new data 

reduction methodology for determining compliance with the existing 20% opacity standard and no 

visible emissions at the property line standard. 

Small Business Analysis: 

Several small business categories were represented during the stakeholder process for this proposed 

rule. The County has not identified all small businesses that could be affected by this rulemaking, 

however, those who did participate did not express any reservations about compliance. The County has 

considered a variety of methods to reduce the impact of this rule on small businesses, including five 

8 
methods prescribed by A.R.S. § 41-1035: establish less stringent compliance or reporting requirements; establish less stringent schedules or deadlines for compliance or reporting requirements; 

consolidate or simplify the rulemaking’s reporting requirements; establish performance requirements 

to replace design or operational standards; or exempt them from some or all of the rule requirements. 

For the reasons stated in item #5 of the preamble, and due to the inherent difficulty in identifying all 

sources which are small businesses, including the possibility that such status may change from year to 

year, the County has determined that it is not feasible to apply a separate opacity standard to small 

businesses. The County does employ an ombudsman in the Business Resource Division, to whom 

small businesses may address their issues with regard to compliance with the rule. 

Both the proposed property line standard for particulate matter and the new data reduction methods for 

the existing opacity standard will require that owners/operators more closely monitor their activities, 

processes, and controls to ensure proper operation at all times. 

As described in the explanation in #5 above, a number of western serious PM10 nonattainment areas 

administer a property line standard. Those areas contain many similar sources that comply with 

property line standards and are in the same business as sources in Maricopa County. Furthermore, 

existing Maricopa County sources are already required to employ good housekeeping practices and 

monitor control equipment. To date no source has provided examples of the activities, processes or 

controls that may need to be modified to comply with this new requirement. The MCAQD is asking for 

information or examples that would allow for more than a qualitative analysis of the economic impact 

of the proposed standard. 

As described in the explanation in #5 above, a number of western serious PM10 nonattainment areas 

administer a time-exception data reduction methodology for their visible opacity limits. Furthermore, 

an EPA study (Office of Air Quality Planning and Standards, “Opacity Regulations: A Summary of 

State Regulations and Rulemaking Status”, Special Report February 1983) contains information 

indicating that the state or a local agency in 28 states has adopted a time-exception form of data 

reduction for their opacity standard. Those areas contain many similar sources that comply with timeexception data reduction methods for visible emission standards and are in the same business as 

sources in Maricopa County. To date no source has provided examples of the activities, processes or 

controls that may need to be modified to comply with this new requirement. The MCAQD is asking for 

information or examples that would allow for more than a qualitative analysis of the economic impact 

of the proposed standard. 

10. Name and address of department personnel with whom persons may communicate regarding the 

accuracy of the economic, small business, and consumer impact statement:

9 
Name: Johanna M. Kuspert or Jo Crumbaker 

 Maricopa County Air Quality Department 

Address: 1001 N. Central Ave, Suite 595 

 Phoenix, AZ 85004 

Telephone: 602-506-6710 or 602-506-6705 

Fax Number: 602-506-6179 

Email Address: jkuspert@mail.maricopa.gov or jcrumbak@mail.maricopa.gov 

11. The time, place and nature of the proceedings for the amendment of the rule:

Written comments will be accepted if received between the date of this publication and December 11, 

2007, 5:00 p.m. Written comments may be mailed or hand delivered to the Maricopa County Air 

Quality Department (see #4 above). Written comments received during the comment period will be 

considered formal comments to the proposed rules and will be responded to in the Notice Of Final 

Rulemaking. 

An oral proceeding will be held on December 10, 2007 at 9:00 am at the Maricopa County Flood 

Control District, 2801 West Durango, Operations Building. All comments made at this oral proceeding 

will be considered formal comments and will be recorded and transcribed. All formal comments will 

be addressed in the Notice Of Final Rulemaking. 

12. Any other matters prescribed by the statute that are applicable to the specific agency or to any 

specific rule or class of rules:

Not applicable 

13. Incorporations by reference and their location in the rules:

Incorporation By Reference Location

EPA Reference Method 9 Rule 300, Section 501 

EPA Reference Method 203B Rule 300, Section 501 

14. The full text of the rule follows:

REGULATION III – CONTROL OF AIR CONTAMINANTS 

RULE 300 

VISIBLE EMISSIONS 

INDEX 

10 
SECTION 100 – GENERAL

101 PURPOSE 

102 APPLICABILITY 

SECTION 200 – DEFINITIONS

201 INTERMITTENT SOURCE

 202201 OPACITY 

 203202 PERCENT OPACITY 

 204203 SHUTDOWN 

 205204 STARTUP 

 206205 UNCOMBINED WATER 

SECTION 300 – STANDARDS

301 LIMITATIONS – OPACITY/GENERAL

302 EXCEPTIONS 

SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE)

SECTION 500 – MONITORING AND RECORDS

501 COMPLIANCE DETERMINATION - OPACITY 

502 COMPLIANCE DETERMINATION - OPACITY OF VISIBLE EMISSIONS FROM 

INTERMITTENT SOURCES

11 
Revised 07/13/88 

Revised 08/05/94 

Revised 02/07/01 

MARICOPA COUNTY 

AIR POLLUTION CONTROL REGULATIONS 

REGULATION III – CONTROL OF AIR CONTAMINANTS 

RULE 300 

VISIBLE EMISSIONS 

SECTION 100 - GENERAL 

101 PURPOSE: To limit the emission of air contaminants into the ambient air by establishing 

standards for visible emissions and opacity. 

102 APPLICABILITY: This rule applies to visible emissions from sources for which no sourcespecific opacity requirements apply. Exceptions to this rule are described in Section 302 of this 

rule. 

SECTION 200 – DEFINITIONS: For the purpose of this rule, the following definitions shall apply. See 

Rule 100-General Provisions And Definitions of these rules for definitions of terms that are used 

but not specifically defined in this rule.

201 INTERMITTENT SOURCE – A source which causes or discharges visible emissions for a 

duration of less than 6 consecutive minutes.

202201 OPACITY - A condition of the ambient air, or any part thereof, in which an air contaminant 

partially or wholly obscures the view of an observer. 

203202 PERCENT OPACITY - The degree to which an effluent plume or any other emission of air 

contaminants obscures the transmission of light expressed as a percentage. 

204203 SHUTDOWN - The cessation of operation of any air pollution control equipment and/or process 

equipment for any purpose, except routine phasing out of process equipment. 

205204 STARTUP - The setting into operation of any air pollution control equipment and/or process 

equipment for any purpose, except routine phasing in of process equipment. 

206205 UNCOMBINED WATER - Condensed water containing no more than analytical trace amounts 

of other chemical elements or compounds. 

12 
SECTION 300 – STANDARDS 

301 LIMITATIONS – OPACITY/GENERAL: No person shall discharge into the ambient air from 

any single source of emissions any air contaminant, other than uncombined water, in excess of 

20% opacity.

301.1 No person shall discharge into the ambient air, from any single source of emissions, any 

air contaminant, other than uncombined water, in excess of 20% opacity for a period 

aggregating more than three minutes in any 60-minute period.

301.2 No person shall cause, suffer, or allow visible emissions of particulate matter, including 

fugitive dust, beyond the property line within which the emissions are generated.

302 EXCEPTIONS:

 302.1 Charging Electric Arc Furnaces: When charging or back-charging any electric arc 

furnace for which construction commenced prior to February 2, 1963, a person may 

discharge air contaminants, other than uncombined water, in excess of the applicable 

opacity limit in Section 301 of this rule for no more than an aggregate of 3 minutes in any 

45 minute period; however, visible emissions resulting from such discharge of air 

contaminants shall not exceed 40% opacity. 

302.2 Emergency Diesel Generators (EDGs) And Equipment: When emergency diesel 

generators (EDGs) and equipment must run for safety reasons and/or for safety and 

operational tests to meet the requirements legally imposed by the Nuclear Regulatory 

Commission, a person may discharge air contaminants, other than uncombined water, in 

excess of the applicable opacity limit in Section 301 of this rule. Any discharge of air 

contaminants, other than uncombined water, in excess of the opacity limit in Section 301 

of this rule should not contribute to a violation of the national ambient air quality 

standard. 

302.3 Firing Of Ordnance At Test Facilities: Visible emissions exceeding the opacity 

standards for short periods of time resulting from firing test rounds in enclosed bunkers at 

ordnance test facilities which do not exceed 6 minutes in length shall not constitute a 

violation of Section 301 of this rule. 

13 
14 

302.4 Opacity Training: Equipment or processes used to train individuals in opacity 

observations shall be exempt from opacity standards during the preparation for and/or 

during the actual training session(s). 

SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE) 

SECTION 500 – MONITORING AND RECORDS 

501 COMPLIANCE DETERMINATION - OPACITY: Opacity shall be determined by 

observations of visible emissions conducted in accordance with EPA Reference Method 9 as 

modified by EPA Reference Method 203B. , except as provided in Section 502 of this rule.

502 COMPLIANCE DETERMINATION - OPACITY OF VISIBLE EMISSIONS FROM 

INTERMITTENT SOURCES: Opacity of visible emissions from intermittent sources shall be 

determined by observations of visible emissions conducted in accordance with EPA Reference 

Method 9, except that at least 12 rather than 24 consecutive readings shall be required at 15–

second intervals for the averaging time.
Appendix 2 

NOTICE OF FINAL RULEMAKING 

MARICOPA COUNTY AIR POLLUTION CONTROL REGULATIONS 

RULE 300 – VISIBLE EMISSIONS 

PREAMBLE

1. Sections affected Rulemaking action

Rule 300 Amend 

2. Statutory authority for the rulemaking:

Authorizing statutes: A.R.S. §§ 49-474, 49-479, and 49-480 

Implementing statute: A.R.S. § 49-112 

3. The effective date of the rule:

Date of Adoption: March 12, 2008 

4. List of all previous notices appearing in the Register addressing the rulemaking:

Notice of Rulemaking Docket Opening: 13 A.A.R. 3373, October 5, 2007 

Notice of Proposed Rulemaking: 13 A.A.R. 3864, November 9, 2007 

5. The name and address of agency personnel with whom persons may communicate regarding the

rulemaking:

Name: Johanna M. Kuspert or Jo Crumbaker 

Maricopa County Air Quality Department 

Address: 1001 N. Central Ave, Suite 595 

 Phoenix, AZ 85004 

Telephone: 602-506-6710 or 602-506-6705 

Fax Number: 602-506-6179 

Email Address: jkuspert@mail.maricopa.gov or jcrumbak@mail.maricopa.gov 

6. An explanation of the rule, including the agency’s reasons for initiating the rulemaking:

The Maricopa County Air Quality Department (MCAQD) revised Rule 300 to implement a control 

measure and increase compliance with existing rules for the Five Percent Plan for PM10. On June 6, 

2007, the U.S. Environmental Protection Agency (EPA) finalized its finding that the Phoenix 

nonattainment area did not attain the 24-hour PM10 standard by the deadline mandated in the Clean Air 

Act (CAA), December 31, 2006. (72 FR 31183, June 6, 2007). Under Section 189(d) of the CAA, 

serious PM10 nonattainment areas that fail to attain are required to submit within 12 months of the 

1
applicable attainment date, “plan revisions which provide for attainment of the PM10 air quality 

standard and, from the date of such submission until attainment, for an annual reduction in PM10 or 

PM10 precursor emissions within the area of not less than 5% of the amount of such emissions as 

reported in the most recent inventory prepared for such area.” In accordance with the CAA section 

179(d)(3), the attainment deadline applicable to an area that misses the serious area attainment date is 

as soon as practicable. The region submitted a Five Percent Plan for PM10 by December 31, 2007. 

PM10 Nonattainment Status History: 

The 1990 Clean Air Act Amendments initially classified Maricopa County as a "moderate" nonattainment area for PM10 pollution. This classification required the Phoenix nonattainment area to 

show attainment of the PM10 national ambient air quality standards (NAAQS) by December 31, 1994. 

The Maricopa County moderate PM10 nonattainment area failed to attain the NAAQS by this deadline. 

Consequently, on May 10, 1996, the EPA reclassified Maricopa County as a serious PM10 nonattainment area. The EPA partially disapproved the PM10 SIP revision triggering a federal implementation plan (FIP) obligation. The EPA disapproved those sections of the SIP addressing unpaved 

roads, unpaved shoulders, unpaved parking lots, vacant lots, and agriculture. Under the court ordered 

consent decree, the EPA finalized a FIP in July 1998 for the Maricopa County PM10 nonattainment 

area that addressed four of those categories. In response to the EPA’s disapproval, a SIP was prepared 

by the Arizona Department of Environmental Quality (ADEQ) to include implementation of Best 

Available Control Measures (BACM) demonstrating attainment of the PM10 NAAQS by December 21, 

2001. 

Emission inventories and air quality modeling analysis of these control measures found a 16.4% PM10

reductions shortfall, so attainment was not achieved by the December 2001 target date. A Serious Area 

Plan for PM10 was submitted to EPA on July 9, 1999 containing 77 additional control measures. This 

revised serious area plan was approved by the EPA in April 2002 contingent on the completion of 

three commitments by Maricopa County. Revisions to Rule 310 adopted on April 7, 2004 addressed 

these commitments. 

On July 2, 2002, the EPA found the SIP control inadequate to ensure the attainment of the PM10

NAAQS at the Salt River air quality monitoring sites and three other microscale sites in the Maricopa 

County nonattainment area (Maryvale, Gilbert, and West Chandler). The EPA’s Aerometric 

Information Retrieval System (AIRS) continued to show exceedances at the Maricopa County PM10

nonattainment area Salt River site, recording exceedances in 1999, 2000, and through three quarters of 

2001. Consequently, the EPA required Arizona to submit a SIP revision to identify and implement 

corrective PM10 control provisions in the Salt River Study Area and for similar significant sources in 

the Maricopa County PM10 nonattainment area. 

2
Arizona’s Salt River SIP revision provided attainment by December 31, 2006, in accordance with 

CAA § 189(b)(1)(A) and 188(e), and was required to include control strategies that meet the Best 

Available Control Measures (BACM) test and the Most Stringent Measures (MSM) test for significant 

sources and source categories. 

The Final Salt River PM10 State Implementation Plan dated August 2004 included the following 

requirements, as described by the EPA in its Federal Register notice of disapproval (67 FR 44369, July 

2, 2002): 

● A modeling demonstration showing that the level of emissions reductions from application of 

BACM-MSM for all significant sources of PM10 will result in attainment of the 24-hour NAAQS 

by December 31, 2006, at the Salt River PM10 monitoring site, in accordance with CAA 

§189(b)(1)(A) and §188(e). 

● Commitments to implement BACM-MSM for sources significantly contributing to exceedances of 

the 24-hour PM10 standard in the Salt River area as expeditiously as possible (CAA §189(b)(1)(B)) 

and a commitment that all BACM and MSM control measures adopted and applied to sources in 

the Salt River Study Area will be applied to all similar sources throughout the Maricopa County 

PM10 serious nonattainment area. 

● A demonstration that the plan constitutes Reasonable Further Progress (RFP) up to the attainment 

deadline (December 31, 2006). 

● A demonstration that all the requirements of the federal Clean Air Act Amendments that pertain to 

serious PM10 nonattainment areas are met, including CAA §110(l), §110(a)(2)(E)(i), and 40 CFR 

§51.280 and §51.111). 

Explanation for Current Rulemaking Proposals: 

The Phoenix nonattainment area did not attain the 24-hour PM10 standard by the deadline of December 

31, 2006 mandated in the Clean Air Act (CAA) (72 FR 31183, June 6, 2007). Now, the required 5% 

Plan for PM10 must demonstrate 5% reductions per year in emissions from the date of submission to 

the EPA. 

The MCAQD conducted an analysis to identify additional measures to reduce emissions and/or 

improve compliance with existing requirements. In this analysis, the MCAQD reviewed current rules 

to determine the Most Stringent Measures (MSM) application of the 20% visible emission standard. 

This review included rules from Clark County, Nevada; South Coast Air Quality Management District, 

California (SCAQMD); and San Joaquin Unified Air Pollution Control District, California 

(SJUAPCD) in an effort to identify the differences between Maricopa County rules and rules from 

areas that successfully met the December 31, 2006 attainment date. The MCAQD also reviewed the 

3
EPA’s notice finalizing Method 203 (A), (B), and (C) (71 FR 55119, September 21, 2006). In the 

summary of that notice the EPA states: “The intended effect is to provide States with an expanded 

array of data reduction procedures for determining compliance with SIP opacity regulations.” These 

areas that successfully met the December 31, 2006 attainment date administer rules that utilize a timeexception form of the standard expressed as “... shall not exceed 20% opacity for more than three 

minutes out of any 60-minute period.” This form of data reduction for the 20% opacity standard limits 

the number of excursions over the 20% visible emission standard and results in a more consistent 

compliance with the standard. 

Section by Section Explanation of Changes: 

Section 200: Added “See Rule 100 – General Provisions and Definitions of these rules for 

definitions of terms that are used but not specifically defined in this rule” and renumbered definitions to be consistent with definition changes. 

Section 201: Deleted “Intermittent Source – A source which causes or discharges visible 

emissions for a duration of less than 6 consecutive minutes.” Re-numbered 

definitions to be consistent with definition changes. 

Section 301: Deleted from heading “Opacity/General”. Added “for a period aggregating more 

than three minutes in any 60-minute period” and added “of this rule” for reference 

purposes. 

Section 501: Deleted “except as provided in Section 502 of this rule” and added “as modified by 

EPA Reference Method 203B.” 

Section 502: Deleted “Compliance Determination – Opacity of Visible Emissions From 

Intermittent Sources: Opacity of visible emissions from intermittent sources shall be 

determined by observations of visible emissions conducted in accordance with EPA 

Reference Method 9, except that at least 12 rather than 24 consecutive readings shall 

be required at 15–second intervals for the averaging time.” 

7. Demonstration of compliance with A.R.S. §49-112:

Under ARS §49-479(C), a county may not adopt a rule or ordinance that is more stringent than the 

rules adopted by the Director of the Arizona Department of Environmental Quality (ADEQ) for similar 

sources unless it demonstrates compliance with the requirements of ARS §49-112, which in Section 

(A) states: 

When authorized by law, a county may adopt a rule, ordinance, or other regulation 

that is more stringent than or in addition to a provision of this title or rule adopted by 

the director or any board or commission authorized to adopt rules pursuant to this 

title if all the following conditions are met: 

1. The rule, ordinance or other regulation is necessary to address a peculiar local 

condition; 

2. There is credible evidence that the rule, ordinance or other regulation is either: 

4
(a) Necessary to prevent a significant threat to public health or the environment 

that results from a peculiar local condition and is technically and 

economically feasible. 

(b) Required under a federal statute or regulation, or authorized pursuant to an 

intergovernmental agreement with the federal government to enforce federal 

statutes or regulations if the County rule, ordinance, or other regulation is 

equivalent to federal statutes or regulations. 

The MCAQD revised Rule 300 in order to address a peculiar local condition: EPA’s finding that the 

Phoenix nonattainment area did not attain the 24-hour PM10 standard by the December 31, 2006 

deadline mandated in the Clean Air Act (CAA; 72 FR 31183, June 6, 2007). The Phoenix 

nonattainment area is the only nonattainment area designated serious for PM10 in Arizona. 

Consequently, stronger regulations must be adopted in this area to address a serious health threat. 

Under Section 189(d) of the CAA, serious PM10 nonattainment areas that fail to attain are required to 

submit within 12 months of the applicable attainment date “plan revisions which provide for 

attainment of the PM10 air quality standard and, from the date of such submission until attainment, for 

an annual reduction in PM10 or PM10 precursor emissions within the area of not less than 5% of the 

amount of such emissions as reported in the most recent inventory prepared for such area.” In 

accordance with the CAA Section 179(d)(3), the attainment deadline applicable to an area that misses 

the serious area attainment date is as soon as practicable. The region submitted a Five Percent Plan for 

PM10 by December 31, 2007. The Phoenix nonattainment area is one of three areas in the entire 

country for which the EPA has issued a finding that Section 189(d) has been triggered. Because of this, 

the revisions to Maricopa County Rule 300 comply with A.R.S. § 49-112 (A)(1) and A.R.S. § 49-112 

(A)(2). 

8. A reference to any study relevant to the rule that the agency reviewed and either proposes to rely 

on in its evaluation of or justification for the rule, where the public may obtain or review each 

study, all data underlying each study, and any analysis of each study and other supporting 

material:

Not applicable. 

9. A showing of good cause why the rule is necessary to promote a statewide interest if the rule will 

diminish a previous grant of authority of a political subdivision:

Not applicable. 

10. A preliminary summary of the economic, small business, and consumer impact:

Rule Identification: 

This rulemaking amends Rule 300 – Visible Emissions in the Maricopa County Air Pollution Control 

Regulations. The revision changes the data reduction methodology for the existing 20% opacity limit 

and reads “... shall not exceed 20% opacity for more than three minutes out of any 60-minute period.” 

5
This form of data reduction for the 20% opacity standard limits the number of excursions over the 20% 

visible emission standard and results in a more consistent compliance with the standard. 

Entities Directly Impacted: 

Entities directly impacted by this rulemaking include certain permitted sources, pollution control 

vendors, contractors, consultants, lawyers, the County, private persons and consumers. The Maricopa 

County Air Quality Department (MCAQD) estimates that as few as 20 to 30 sources might be affected 

by this rulemaking. Although many industry categories, including woodworking operations, 

metallurgical operations, scrap metal operations, and cotton gins are potentially subject to Rule 300, 

most of these sources will be unaffected by this rule. Such sources either already comply with a form 

of data reduction for determining compliance with the standard, are already subject to the 20% opacity 

standard or lower opacity standards, or are regulated by New Source Performance Standards (NSPS) 

under Title 40, Part 60 of the Code of Federal Regulations. 

Probable Costs and Benefits: 

A. Costs to the state of Arizona:

If Arizona is unable to submit a plan that demonstrates a 5% per year reduction in PM10 and is unable 

to demonstrate attainment at the monitors based on implemented control measures such as this rule, the 

EPA will be required to make a nondiscretionary finding that Arizona has failed to submit an 

approvable plan. If the County and Arizona fail to correct the identified deficiencies – described in the 

EPA’s nondiscretionary finding – within the timeframe specified in the EPA’s nondiscretionary 

finding, the sanctions under § 179 of the Clean Air Act (CAA) will be imposed. Sanctions include loss 

of highway funds and stricter emission offset requirements for major sources. In addition, under § 

110(c) of the CAA, the EPA would then need to promulgate a Federal Implementation Plan (FIP) no 

later than 24 months after the date of publication of the notice of EPA’s nondiscretionary finding. 

B. Potential Costs and Benefits to the Public:

The most obvious benefit arising from promulgation of this rule is reduction in the harmful effects of 

air pollution, most notably particulates. Air pollution harms lung function, damages lung tissue, and 

increases respiratory symptoms, such as coughing, shortness of breath, wheezing and asthma attacks, 

and can impair the body’s immune system response to inhaled particles. Results may include restricted 

activities, work time lost, revenues lost due to increased hospital admissions, illness, and death. PM 

associated health risks occur even more frequently in susceptible subpopulations, such as the elderly, 

children with asthma, and persons with cardiopulmonary disease, and may contribute to up to 65,000 

excess deaths in the U.S. annually (STAPPA and ALAPCO, Controlling Particulate Matter Under the 

Clean Air Act: A Menu of Options, July 1996). Even very low concentrations of particulate matter 

may increase risk of early death, particularly in elderly populations with preexisting cardiopulmonary 

6
diseases (STAPPA and ALAPCO, supra). Chronic obstructive pulmonary disease (COPD), a major 

cause of morbidity and mortality in the U.S., cost the country more than 32 billion dollars in 2002, a 

figure which does not include costs attributable to asthma (American Lung Assoc., “Trends in Chronic 

Bronchitis and Emphysema: Morbidity and Mortality,” Epidemiology and Statistics Unit, Research 

and Scientific Affairs, March 2003). Notably, asthma death rates in Arizona equaled or exceeded U.S. 

rates from 1991–98. In addition, in 1998, an estimated 316,200 Arizonans suffered breathing 

discomfort and asthma related stress (Arizona Department of Health Services, “Asthma Control 

Program,” Office of Nutrition and Chronic Disease Prevention Services, October, 2002). Therefore, 

Maricopa County expects the change in data reduction methodology; i.e., utilizing a time-exception 

form of the standard expressed as “... shall not exceed 20% opacity for more than three minutes out of 

any 60-minute period”, to translate into cost-saving benefits to the general public by reducing 

emissions-related adverse health effects and the concurrent lost revenue and health care costs. In 

addition to direct health-related effects, a statewide opacity limit of 20% will affect the general quality 

of life, particularly for those persons living near sources. 

C. Potential Costs and Benefits to the Regulated Community:

The change in the data reduction methodology for the existing opacity standard in Rule 300 will 

require that owners/operators more closely monitor their activities, processes, and controls to ensure 

proper operation at all times. Areas that successfully met the December 31, 2006 PM10 attainment date 

– including Clark County, Nevada; South Coast Air Quality Management District, California; San 

Joaquin Unified Air Pollution Control District, California; and six out of 14 western states that are 

members of the Western Regional Air Partnership (WRAP) – all administer rules that include the data 

reduction methodology adopted in Rule 300. These areas contain sources similar to sources in 

Maricopa County and such similar sources comply with the adopted standard. 

Although each regulated facility is unique, the costs of compliance associated with the revision to Rule 

300 are similar and may include: new capital equipment or modification of existing equipment, 

adjusting or enhancing operations and maintenance; replacing or modifying processes and designs; and 

indirect and administrative costs. Compliance might also result, however, in a variety of offsetting 

financial benefits for the source. Such benefits range from lower operation and maintenance costs, as a 

result of updated and more efficient equipment, to fewer man-hours lost and lower health care costs 

due to a decrease in pollution-exacerbated illnesses. During the informal workshop process for this 

rulemaking, the Maricopa County Air Quality Department (MCAQD) requested, from sources 

participating in the rulemaking process, information on source-specific costs to achieve compliance 

with these standards. The MCAQD did not receive any information. 

Small Business Analysis: 

7
The MCAQD has not identified all small businesses that could be affected by this rulemaking; 

however, several small business categories were represented during the rulemaking process for Rule 

300 and such businesses did not express any reservations about compliance. The MCAQD has 

considered a variety of methods to reduce the impact of this rule on small businesses, including five 

methods prescribed by A.R.S. § 41-1035: (1) establish less stringent compliance or reporting 

requirements; (2) establish less stringent schedules or deadlines for compliance or reporting 

requirements; (3) consolidate or simplify the rulemaking’s reporting requirements; (4) establish 

performance requirements to replace design or operational standards; or (5) exempt them from some or 

all of the rule requirements. For the reasons stated in Item #6 of this Notice of Final Rulemaking and 

due to the inherent difficulty in identifying all sources which are small businesses, including the 

possibility that such status may change from year to year, the MCAQD has determined that it is not 

feasible to apply a separate opacity standard to small businesses. The MCAQD does employ an 

ombudsman in the Business Resource Division, to whom small businesses may address their issues 

regarding compliance with the rule. 

The change in the data reduction methodology for the existing opacity standard in Rule 300 will 

require that owners/operators more closely monitor their activities, processes, and controls to ensure 

proper operation at all times. Areas that successfully met the December 31, 2006 PM10 attainment date 

– Clark County, Nevada; South Coast Air Quality Management District, California; San Joaquin 

Unified Air Pollution Control District, California; and six of 14 western states that are members of the 

Western Regional Air Partnership (WRAP) – all administer rules that include the data reduction 

methodology adopted in Rule 300. These areas contain sources similar to sources in Maricopa County 

and such similar sources comply with the adopted standard. 

Although each regulated facility is unique, the costs of compliance associated with the revision to Rule 

300 are similar and may include: new capital equipment or modification of existing equipment, 

adjusting or enhancing operations and maintenance; replacing or modifying processes and designs; and 

indirect and administrative costs. Compliance might also result, however, in a variety of offsetting 

financial benefits for the source. Such benefits range from lower operation and maintenance costs, as a 

result of updated and more efficient equipment, to fewer man-hours lost and lower health care costs 

due to a decrease in pollution-exacerbated illnesses. During the informal workshop process for this 

rulemaking, the Maricopa County Air Quality Department (MCAQD) requested, from sources 

participating in the rulemaking process, information on source-specific costs to achieve compliance 

with these standards. The MCAQD did not receive any information. 

11. Name and address of department personnel with whom persons may communicate regarding the 

accuracy of the economic, small business, and consumer impact statement:

8
9

Name: Johanna M. Kuspert or Jo Crumbaker 

Maricopa County Air Quality Department 

Address: 1001 N. Central Ave, Suite 595 

 Phoenix, AZ 85004 

Telephone: 602-506-6710 or 602-506-6705 

Fax Number: 602-506-6179 

Email Address: jkuspert@mail.maricopa.gov or jcrumbak@mail.maricopa.gov 

12. Description of the changes between the proposed rule, including supplemental notices and final 

rule:

Since the final draft of Rule 300 was published in the Notice of Proposed Rulemaking on November 9, 

2007 and in response to formal comments received during the formal comment period (November–

December 2007), the following changes to Rule 300 were made. These changes appear in the text of 

the final rule published in this Notice of Final Rulemaking: 

Rule 300, Section 301.1: Moved new Section 301.1 to existing Section 301. In Section 301, deleted 

from heading “Opacity/General” and added “for a period aggregating more than three minutes in any 

60-minute period.” Section 301 reads: “Limitations: No person shall discharge into the ambient air 

from any single source of emissions any air contaminant, other than uncombined water, in excess of 

20% opacity for a period aggregating more than three minutes in any 60-minute period.” 

Rule 300, Section 301.2: Deleted new Section 301.2: “No person shall cause, suffer, or allow visible 

emissions of particulate matter, including fugitive dust, beyond the property line within which the 

emissions are generated.” 

13 A summary of the comments made regarding the rule and the department response to them:

The Maricopa County Air Quality Department (MCAQD) conducted two Public Workshops 

throughout the rulemaking process for Rule 300 (in April and August 2007), and received formal 

comments during the formal comment period (November–December 2007) from Arizona Public 

Service (APS) and Salt River Project (SRP), Arizona Associated General Contractors, Arizona 

Department of Agriculture, and Joint Environmental Task Force. The formal comments and the 

MCAQD’s responses to such formal comments are summarized below: 
Comment #1:

APS and SRP are concerned with the proposed changes to this section as it relates to stack emissions. 

Based on information provided in the 2005 Maricopa County Emissions Inventory, modeling analyses 

performed by the Maricopa Association of Governments (MAG) and the Arizona Department of 

Environmental Quality (ADEQ), recommended Control Measures identified by the Air Quality 

Technical Advisory Committee of the MAG, and conditions set forth in Senate Bill 1552, it appears 

the intent of the five percent plan is to reduce particulate matter emissions from fugitive dust sources. 

However, the requirements set forth in this rule apply to emissions that have no applicable sourcespecific opacity requirement. It is clear that fugitive dust sources have a source specific opacity 

requirement under Rule 310 and 310.01; therefore, the changes in this rule do not address fugitive dust 

sources, but would instead impact point sources. As such, the changes set forth in this rule are beyond 

the scope of the five percent plan and do not reduce fugitive dust emissions. 

Response #1:

The technical analysis associated with the Salt River Area PM10 SIP revision submitted in 2005 

determined that stationary sources contribute significantly to exceedances of the 24-hour PM10

standard that occur under stagnant conditions. That analysis characterized the specific types, number, 

and size of sources present in the modeling domain; land use; the topography of the area; and the 

design day specific meteorological conditions present at the monitor recording the exceedance. 

Attainment demonstrations for nonattainment areas required under the Clean Air Act must to the 

greatest extent practical depict the actual conditions present that cause exceedances in the nonattainment area. Therefore, the nonattainment area plans for the Phoenix nonattainment area for PM10

are required under the Clean Air Act, in effect, to address actual local conditions that are unique to a 

geographical area. Further, the EPA’s latest particulate matter implementation rule, Clean Air Fine 

Particle Implementation Rule (72 FR 20586, April 25, 2007), identifies “revised opacity standard” in a 

list of possible stationary source measures. The rule also lists improved monitoring as a control 

measure. The EPA notes that improved monitoring control measures would require facilities to pay 

more attention to the operations of add-on air pollution control devices, work practices, and other 

control measure activities. The additional attention will reduce periods during which control devices 

and other control measures do not operate as intended or required. The result would be increased 

emissions reductions from implementing existing and new rules. 

Comment #2:

The language "no person shall discharge" should be replaced with the phrase "an owner/operator shall 

take reasonable measures to prevent discharge into ambient air" in Section 301.1 and Section 301.2. 

There should be consistency when the phrase "reasonable measure" substitutes "no person shall 

discharge" in Rules 300, 310, and 310.01. 

10
Response #2:

Using the term “reasonable” represents a relaxation of the State Implementation Plan (SIP). The term 

"reasonable" would not add to or clarify the meaning. Since "reasonable" is a qualitative term, it would 

simply lead to more ambiguity. 

Comment #3:

With respect to Section 301.1, APS and SRP agree with the concerns regarding the legality of this 

change to the existing rule as stated in a letter from Mr. Roger Ferland, on behalf of the Business 

Coalition, to Mr. Robert Kard dated August 10, 2007: 

“Under Method 9, the opacity is determined as the average of 24 consecutive observations recorded at 

15-second intervals. As such, the opacity determination is based on a six-minute average of 24 

observations. In Method 203B, the number of observations above the applicable standard are counted 

and multiplied by 0.25 to determine the number of minutes a source is above the opacity standard. In 

essence, the Method 203B calculation methodology eliminates the averaging effect of readings below 

the standard...Obviously a data reduction method that results in noncompliance is more stringent than 

one that does not. This increased stringency of the opacity limit rule is multiplied by the fact that your 

department has proposed to expand the applicability of Appendix C to include determining compliance 

with opacity limits applicable to point source emissions...” 

“Under the provisions of A.R.S. §49-112(A), the County may only adopt rules that are more stringent 

than those adopted by the Arizona Department of Environmental Quality (ADEQ) if all conditions of 

[A.R.S. §49-112(A)] are met...The ADEQ regulations pertaining to the measurement of visible 

emissions from nonpoint sources (A.A.C. R18-2-614) and point sources (A.A.C. R18-2-702(B)) rely 

solely upon EPA Test Method 9 and not Method 203B to determine compliance with opacity limits. 

Thus, the MCAQD’s proposal to substitute Method 203B for Method 9 is subject to the requirements 

of A.R.S. §49-112(A)...”. 

“To date we have seen nothing to suggest the MCAQD intends to provide the evidence or can provide 

the evidence necessary to meet the statutory requirements.” 

It has been suggested that since the change in opacity test methods was bundled with a proposal for 

more stringent PM10 regulations that the “peculiar local condition” referred to in the statute was 

somehow connected to PM10. However, this cannot be the case. Visible emissions limits are intended 

to indicate the proper operation of particulate control technologies such as baghouses or dust 

suppression technologies. They are not intended to measure and cannot measure PM10 emissions or the 

11
emissions of any other pollutant. For this reason, source category specific rules typically specify both 

an opacity limit and an emission limit...” 

“Since there is no coincidence between PM10 emissions and opacity, there is no reason to believe that a 

more stringent opacity limit, particularly one of the kind at issue here, would result in lower PM10 (or 

any other) emissions...” 

“Either the MCAQD must make the showings and provide the evidence required by statute (which we 

judge to be unlikely) or the proposal should be immediately withdrawn...” 

Response #3:

The revision to the data reduction methodology to EPA Method 203B, which is associated with 

Maricopa County's 20% opacity standard, is intended to further efforts to increase compliance. This 

form of data reduction for the 20% opacity standard limits the number of excursions over the 20% 

opacity standard, which results in more consistent compliance with the existing standard. A rule 

effectiveness study conducted 2006 through 2007 by the MCAQD found that compliance with the 

existing rules is lower than anticipated. 

The commenter also states that the proposed revisions to the data reduction methodology make the 

20% opacity standard substantially more stringent that the current rule. The MCAQD disagrees and 

believes that the comment overstates the stringency of EPA Method 203B. Throughout the informal 

and formal rulemaking process, the MCAQD has repeatedly asked for examples of changes or 

modifications that would be necessary to comply with the proposed revision to Rule 300, using EPA 

Method 203B data reduction methodology. The MCAQD did not receive any additional information. 

Further, areas that successfully met the December 31, 2006 PM10 attainment date – including Clark 

County, Nevada; South Coast Air Quality Management District, California; San Joaquin Unified Air 

Pollution Control District, California; and six out of 14 western states that are members of the Western 

Regional Air Partnership (WRAP) – all administer rules that include the data reduction methodology 

proposed in Rule 300. These areas contain sources similar to sources in Maricopa County and such 

similar sources comply with the adopted standard. 

In addition, if EPA Method 203B were substantially more stringent than EPA Method 9, then the 

MCAQD would have been required to include the measure in the most stringent measure 

demonstration contained in the MAG Serious Area PM10 Nonattainment Area Plan and Attainment 

Date Extension Request. 

12
13

The technical analysis associated with the Salt River Area PM10 SIP revision submitted in 2005 

determined that stationary sources contribute significantly to exceedances of the 24-hour PM10

standard that occur under stagnant conditions. That analysis characterized the specific types, number, 

and size of sources present in the modeling domain; land use; the topography of the area; and the 

design day specific meteorological conditions present at the monitor recording the exceedance. 

Attainment demonstrations for nonattainment areas required under the Clean Air Act must to the 

greatest extent practical depict the actual conditions present that cause exceedances in the 

nonattainment area. Therefore, the nonattainment area plans for the Phoenix nonattainment area for 

PM10 are required under the Clean Air Act, in effect, to address actual local conditions that are unique 

to a geographical area. Further, the EPA’s latest particulate matter implementation rule, Clean Air Fine 

Particle Implementation Rule (72 FR 20586, April 25, 2007), identifies “revised opacity standard” in a 

list of possible stationary sources measures. The rule also lists improved monitoring as a control 

measure. The EPA notes that improved monitoring control measures would require facilities to pay 

more attention to the operations of add-on air pollution control devices, work practices, and other 

control measure activities. The additional attention will reduce periods during which control devices 

and other control measures do no operate as intended or required. The result would be increased 

emissions reductions from implementing existing and new rules. 

The MCAQD disagrees that there is no coincidence between PM10 emissions and opacity. Within an 

individual source, a change in opacity indicates a change in PM emissions. It is not necessary to 

demonstrate a correlation between mass emissions and opacity across all source categories, when a 

goal of the standard is to demonstrate compliance with BACT, BACM, and MSM levels of control. 

Opacity has also long been used as an indicator of visible particulate pollution. In the discussion on 

improved monitoring control measures in the proposal for the fine particle implementation rule 

referenced above, the EPA states, “...visible emissions and the opacity of visible emissions are 

indicators of a change in PM emissions levels...” In the EPA’s fact sheet on the rule finalizing 

Methods 203A, B, and C, the EPA states, “Evaluating the opacity of emissions serves as a surrogate 

for particulate emissions. Numerous state and federal regulations require that opacity of emissions be 

measured or monitored.” In the EPA’s Response to Comments on the Portland Cement Manufacturing 

NESHAP (page 227), the EPA states, “An opacity limit was established to ensure effective PM 

control, but opacity is a separately enforced pollutant ...” In other NESHAPs, where the EPA uses PM 

as a surrogate for hazardous air pollutants (HAPs), the EPA consistently states that opacity limits are 

separately enforceable emissions limits which represent and demonstrate continuous compliance with 

the MACT floor of particulate HAP control. 
Comment #4:

We are opposed to a zero property line standard. To date we have received no guidance from the 

County on how this will be regulated with consistency. This requirement also needs to be enforced 

across all air permits – not just Rule 310 and Rule 316, including Non-Title V and Title V permit 

holders (their permits state they must follow Rule 310 as well), as well as Rule 310.01 sources, if the 

County is going to successfully achieve the PM10 reductions than all sources of trackout throughout 

the County need to be held to the same standard. Stopping drag-out from a site is going to be a 

constant challenge, either a permitted source is going to create mud at the exit and have trackout (new 

25 foot standard) or it will be a little dry and will have property emissions because of drag-out. 

Response #4:

The Maricopa County Air Quality Department (MCAQD) clarified the proposed property line standard 

to provide more consistent enforcement in Rules 310 and 310.01. The MCAQD withdrew the property 

line standard from Rule 300 as the routine dust generating operations at stationary sources are subject 

to Rule 310. The MCAQD will develop a policy/guideline and train compliance staff to ensure 

consistent enforcement of the property line standard. 

As noted in the comment, Rule 310 applies to Non-Title V and Title V permit holders as well as Dust 

Control Permit holders. The MCAQD inspectors currently address and will continue to address 

stationary source dust generating operations during site inspections. The MCAQD has included the 

property line standard in Rule 310.01 that addresses sources that are not required to obtain permits. 

The MCAQD believes the property line provisions in Rules 310, 310.01 and 316 effectively cover all 

sources over which Maricopa County has jurisdiction. Un-permitted sources outnumber permitted 

sources. Many of the new measures in the Five Percent Plan include additional municipal codes and 

ordinances to address un-permitted sources. The MCAQD is also in the process of adding additional 

field staff to address un-permitted sources. The MCAQD intends to begin implementation of the new 

rule provisions upon adoption by the Board of Supervisors. 

Comment #5:

With respect to Section 301.2, APS and SRP agree with the property line standard conclusion in the 

letter from the Arizona Chamber of Commerce and Industry Air Quality Subcommittee to Ms. Johanna 

Kuspert dated September 10, 2007. This letter states that promulgating a standard to not allow visible 

emissions across the property boundary line is unconstitutional and cited Ross Neely Exp. v. ADE, and 

CF&U v. CAPCC. Although the context of this letter was with Maricopa County Rule 310 and 310.01, 

the same legal analysis and conclusion are directly applicable to Rule 300. Section 301.2, as written, is 

unconstitutionally vague and unenforceable and should, therefore, be removed from this rule. 

14
Furthermore, there is no indication that this requirement will result in any reduction in particulate 

matter emissions, since there is no credible link between opacity and particulate matter emissions. 

“The MCAQD’s draft Rule 310.01 would relax the regulation of fugitive dust emissions from Countyowned unpaved roads, compared to the current air quality requirements for County-owned unpaved 

roads (Rule 310.10, Section 304) that have been in effect for several years and already are part of the 

State Implementation Plan (SIP). This unusual proposal to reduce the existing level of fugitive dust 

regulation for County-owned property stands in contrast to the MCAQD’s efforts to increase the 

regulation of almost every other type of activity that emits fugitive dust within Maricopa County...The 

changes proposed in the draft rule would be an impermissible relaxation of the SIP. Moreover, the 

concept of decreasing regulation of County-owned sources of fugitive dust while increasing the 

regulation of so many other categories of emitters is inequitable.” 

“In the draft rules, County-owned unpaved roads have fewer and less strict dust control requirements 

than do business-owned unpaved roads...If the MCAQD intends to impose increased obligations on 

the business sector, including requirements for business-owned unpaved roads that are more stringent 

than the requirements for County-owned unpaved roads, then the MCAQD should clearly justify the 

disparity...” 

“At least two other jurisdictions have concluded that absolute prohibitions against visible emissions 

crossing the property line are unconstitutional. In Ross Neely Exp. v. ADE, the Alabama Supreme 

Court held that a state rule prohibiting visible emissions from crossing the property line: is clearly 

overbroad, encompassing every situation in which visible fugitive dust emissions move across a lot 

line, without regard to damage, injury, or inconvenience caused, reasonable attempts to control, etc. 

This invades the area of protected freedom, severely restricting the use of property, and creates a 

situation where discriminatory enforcement is almost inevitable. See also, CF&U v. CAPCC, 640 P.2d 

238 (Colo. App. 1981) (holding that property boundary standard “contravenes fundamental due 

process rights”).” 

Response #5:

The MCAQD withdrew the property line standard from Rule 300 and further clarified the property line 

standard in Rules 310 and 310.01 as it applies to fugitive dust. Since stationary sources regulated by 

Rule 300 are also subject to the fugitive dust limitations in Rule 310, the property line standard in Rule 

300 was duplicative of the standard in Rule 310. 

The Maricopa County Air Quality Department (MCAQD) does not agree that the property line 

standard is unconstitutionally vague and unenforceable and does not agree that the requirement will not 

15
result in any emission reductions. In 1987, since both court decisions were issued, the EPA refined the 

national ambient air quality standard for particulate matter to inhalable particulate matter 10 microns or 

less in aerometric diameter. Unlike the two jurisdictions cited in the comment, the Phoenix PM10

nonattainment area failed to meet the 24-hour PM10 standard by December 31, 2006. As a result, 

residents still have the potential to be exposed to unhealthy levels of PM10. Exceedances are recorded 

under both stagnant and elevated wind conditions. Since secondary aerosols are not significant 

contributors to the exceedances recorded in Maricopa County, geologic material (e.g. dust) remains the 

dominant constituent of PM10. Locally generated PM10 significantly contributes to recorded 

exceedances of the PM10 standard and can be released from dust generating activities or any 

unstabilized surface exposing residents to unhealthy levels of particulates. 

The property line standard can serve as a simple visual technique to monitor the dust released by the 

operation. To address the feasibility concerns expressed, the MCAQD clarified the property line 

standard in Rules 310 and 310.01. 

The MCAQD disagrees that there is no credible link between opacity and particulate matter emissions. 

In fact, the next sentence in the EPA notice cited by the comment states, “Nonetheless, because there is 

at least an indirect relationship between opacity and PM emissions, including the use of opacity to 

track the effectiveness of PM control equipment operation ...” The MCAQD’s goal with the change in 

Rule 300 is to improve the monitoring of dust control measures by providing a simple visual tool that 

can be applied by employees as well as the MCAQD to evaluate the effectiveness of the dust control 

measure. 

Comment #6:

Include to the Exceptions section, "The provisions of this rule shall not apply to normal farm cultural 

practices according to Arizona Revised Statutes (ARS) § 49-457 and ARS § 4957" [sic]. This 

exemption is currently found in Rule 310 and Rule 310.01, Section 103. 

Response #6:

The intent of Rule 300 is to cover sources of visible emissions that are not covered by source-specific 

rules like Rule 310 and Rule 310.01. Therefore, source-specific exemptions like agricultural activities 

or construction activities are not included in the Rule 300. 

Comment #7:

Rule 300, Section 302.2 Emergency Diesel Generators and Equipment: All emissions from such 

sources should be taken into account as sources of PM10? Emergency generators and “non-road” 

engines are exempted. Large engines put out significant amounts of pollution and should be counted. 

16
Response #7:

This exemption is very limited in scope as it only applies to emergency diesel generators and 

equipment at nuclear power facilities. All other emergency diesel generators and equipment are subject 

to the standards of Section 300. 

Comment #8:

With respect to Rule 300, Section 501, APS and SRP agree with the concerns regarding the legality of 

this change to the existing rule as stated in a letter from Mr. Roger Ferland, on behalf of the Business 

Coalition, to Mr. Robert Kard dated August 10, 2007. A copy of this letter has been attached for your 

convenience. 

Response #8

See Response #3 regarding revision from time averaging to time exception data reduction. 

Comment #9:

There are not classes offered to agricultural producers or livestock owners to become qualified in EPA 

Reference Method 9, which includes determining 20% opacity. Therefore producers should not be 

required to comply with a standard for which no training is available. For example a Maricopa County 

4-H member (age 9-18) who is raising goats or a community member who keeps horses would be 

totally unfamiliar with this standard. 

Response #9:

At least two training providers in Maricopa County offer EPA Method 9 Visible Emissions 

Observation Certification Training to anyone required to complete periodic visible emissions 

observations: The ASU Environmental Technology Management (ETM) program offers EPA Method 

9 Certification training. Information on the ETM training can be found at 

http://www.azdeq.gov/environ/air/compliance/smoke.html or by calling 480-727-1322. In addition, 

Arizona Smoke School offers Method 9 training. Information on Arizona Smoke School can be found 

at http://www.arizonasmokeschool.com/ or by calling 480-226-0945. 

Comment #10:

Reduction in the number of readings for Determination of Visual Opacity (EPA Method 9) from 12 to 

24 readings. We believe this along with disallowing the zero readings to become part of the count sets 

the permitted source up for failure of the opacity test. Once recorded this becomes a possible violation 

for the permitted source. 

Response #10:

17
The revision to the data reduction methodology to EPA Method 203B, which is associated with 

Maricopa County's 20% opacity standard, is intended to further efforts to increase compliance. This 

form of data reduction for the 20% opacity standard limits the number of excursions over the 20% 

opacity standard, which results in more consistent compliance with the existing standard. 

In 2006 through 2007, the MCAQD conducted a rule effectiveness study and found that compliance 

with the existing rules is lower than anticipated. The MCAQD conducted an analysis to identify 

additional measures to reduce emissions and/or improve compliance with existing requirements. In this 

analysis, the MCAQD reviewed current rules to determine the Most Stringent Measures (MSM) 

application of the 20% visible emission standard. This included a review of rules from Clark County, 

Nevada; South Coast Air Quality Management District, California (SCAQMD); and San Joaquin 

Unified Air Pollution Control District, California (SJUAPCD) in an effort to identify the differences 

between Maricopa County rules and rules from areas that successfully met the December 31, 2006 

attainment date. The MCAQD also reviewed the EPA’s notice finalizing Method 203 (A), (B), and (C) 

(71 FR 55119, September 21, 2006). In the summary of that notice the EPA states, “The intended 

effect is to provide States with an expanded array of data reduction procedures for determining 

compliance with SIP opacity regulations.” These areas that successfully met the December 31, 2006 

attainment date administer rules that utilize a time-exception form of the standard expressed as 

“...shall not exceed 20% opacity for more than three minutes out of any 60-minute period.” This form 

of data reduction for the 20% opacity standard limits the number of excursions over the 20% visible 

emission standard and results in a more consistent compliance with the standard. 

Areas that successfully met the December 31, 2006 PM10 attainment date – including Clark County, 

Nevada; South Coast Air Quality Management District, California; San Joaquin Unified Air Pollution 

Control District, California; and six out of 14 western states that are members of the Western Regional 

Air Partnership (WRAP) – all administer rules that include the data reduction methodology adopted in 

Rule 300. These areas contain sources similar to sources in Maricopa County and such similar sources 

comply with the proposed standard. 

Comment #11:

Define the term "immediately". This term needs a reasonable timeframe and consistency in draft Rules 

300, 310, and 310.01. 

Response #11:

The term “immediately” is not used in Rule 300. 

Comment #12:

18
Opacity should be measured whenever a plant is operating. Checking opacity at night should be 

implemented. Using the word “visible” should not limit opacity measurements to sunny days. Find a 

technique that works at night and use it. 

Response #12:

The MCAQD has set up a class for inspectors to be certified to read opacity at night. After successfully 

completing the class, inspectors will be certified to measure opacity at night. 

Comment #13:

Item #7 of the Preamble involves “demonstration of compliance with ARS 49-112”. This should not be 

a consideration since A.R.S. § 49-112 conflicts with the Clean Air Act. 

Response #13:

The MCAQD is required to demonstrate compliance with A.R.S. § 49-112 as part of changes to or 

updates to rules and regulations that are part of a State Implementation Plan (SIP). It is unclear to the 

MCAQD why the commenter believes A.R.S. § 49-112 conflicts with the federal Clean Air Act. 

14 Any other matters prescribed by the statute that are applicable to the specific department or to 

any specific rule or class of rules:

No 

15 Incorporation by reference and their location in the rule:

EPA Reference Method 9 Rule 300, Section 501 

EPA Reference Method 203B Rule 300, Section 501 

16 Was this rule previously an emergency rule?

No 

17 The full text of the rule follows:

REGULATION III – CONTROL OF AIR CONTAMINANTS 

RULE 300 

VISIBLE EMISSIONS 

INDEX 

SECTION 100 – GENERAL

101 PURPOSE 

19
102 APPLICABILITY 

SECTION 200 – DEFINITIONS

201 INTERMITTENT SOURCE

202201 OPACITY 

203202 PERCENT OPACITY 

204203 SHUTDOWN 

205204 STARTUP 

206205 UNCOMBINED WATER 

SECTION 300 – STANDARDS

301 LIMITATIONS – OPACITY/GENERAL

302 EXCEPTIONS 

SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE)

SECTION 500 – MONITORING AND RECORDS

501 COMPLIANCE DETERMINATION – OPACITY 

502 COMPLIANCE DETERMINATION - OPACITY OF VISIBLE EMISSIONS FROM 

INTERMITTENT SOURCES

20
Revised 07/13/88 

Revised 08/05/94 

Revised 02/07/01 

Revised 03/12/08 

MARICOPA COUNTY 

AIR POLLUTION CONTROL REGULATIONS 

REGULATION III – CONTROL OF AIR CONTAMINANTS 

RULE 300 

VISIBLE EMISSIONS 

SECTION 100 – GENERAL 

101 PURPOSE: To limit the emission of air contaminants into the ambient air by establishing 

standards for visible emissions and opacity. 

102 APPLICABILITY: This rule applies to visible emissions from sources for which no sourcespecific opacity requirements apply. Exceptions to this rule are described in Section 302 of this 

rule. 

SECTION 200 – DEFINITIONS: For the purpose of this rule, the following definitions shall apply. See 

Rule 100 – General Provisions and Definitions of these rules for definitions of terms that are used 

but not specifically defined in this rule.

201 INTERMITTENT SOURCE – A source which causes or discharges visible emissions for a 

duration of less than 6 consecutive minutes.

202201 OPACITY – A condition of the ambient air, or any part thereof, in which an air contaminant 

partially or wholly obscures the view of an observer. 

203202 PERCENT OPACITY – The degree to which an effluent plume or any other emission of air 

contaminants obscures the transmission of light expressed as a percentage. 

204203 SHUTDOWN – The cessation of operation of any air pollution control equipment and/or process 

equipment for any purpose, except routine phasing out of process equipment. 

205204 STARTUP – The setting into operation of any air pollution control equipment and/or process 

equipment for any purpose, except routine phasing in of process equipment. 

206205 UNCOMBINED WATER – Condensed water containing no more than analytical trace amounts 

of other chemical elements or compounds. 

21
SECTION 300 – STANDARDS 

301 LIMITATIONS – OPACITY/GENERAL: No person shall discharge into the ambient air from 

any single source of emissions any air contaminant, other than uncombined water, in excess of 

20% opacity for a period aggregating more than three minutes in any 60-minute period.

302 EXCEPTIONS: 

302.1 Charging Electric Arc Furnaces: When charging or back-charging any electric arc 

furnace for which construction commenced prior to February 2, 1963, a person may 

discharge air contaminants, other than uncombined water, in excess of the applicable 

opacity limit in Section 301 of this rule for no more than an aggregate of three minutes in 

any 45-minute period; however, visible emissions resulting from such discharge of air 

contaminants shall not exceed 40% opacity. 

302.2 Emergency Diesel Generators (EDGs) and Equipment: When emergency diesel 

generators (EDGs) and equipment must run for safety reasons and/or for safety and 

operational tests to meet the requirements legally imposed by the Nuclear Regulatory 

Commission, a person may discharge air contaminants, other than uncombined water, in 

excess of the applicable opacity limit in Section 301 of this rule. Any discharge of air 

contaminants, other than uncombined water, in excess of the opacity limit in Section 301 

of this rule should not contribute to a violation of the national ambient air quality 

standard. 

302.3 Firing of Ordnance at Test Facilities: Visible emissions exceeding the opacity 

standards for short periods of time resulting from firing test rounds in enclosed bunkers at 

ordnance test facilities which do not exceed six minutes in length shall not constitute a 

violation of Section 301 of this rule. 

302.4 Opacity Training: Equipment or processes used to train individuals in opacity 

observations shall be exempt from opacity standards during the preparation for and/or 

during the actual training session(s). 

SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE) 

SECTION 500 – MONITORING AND RECORDS 

22
23

501 COMPLIANCE DETERMINATION – OPACITY: Opacity shall be determined by 

observations of visible emissions conducted in accordance with EPA Reference Method 9, except 

as provided in Section 502 of this rule as modified by EPA Reference Method 203B. 

502 COMPLIANCE DETERMINATION - OPACITY OF VISIBLE EMISSIONS FROM 

INTERMITTENT SOURCES: Opacity of visible emissions from intermittent sources shall be 

determined by observations of visible emissions conducted in accordance with EPA Reference 

Method 9, except that at least 12 rather than 24 consecutive readings shall be required at 15–

second intervals for the averaging time.
Appendix 3 
NOTICE OF PUBLIC HEARING 

FOR MARICOPA COUNTY AIR POLLUTION CONTROL REGULATIONS 

AND STATE IMPLEMENTATION PLAN (SIP) REVISIONS 

Notice is hereby given that the Maricopa County Board of Supervisors will conduct a public hearing on March 

12, 2008 at 9:00 AM on proposed revisions to the Maricopa County Air Pollution Control Regulations, Rules 

280 (Fees), 300 (Visible Emissions), 314 (Open Outdoor Fires & Indoor Fireplaces at Commercial & 

Institutional Establishments), and 316 (Nonmetallic Mineral Processing). The Public Hearing will be held 

at the Maricopa County Board of Supervisors’ Auditorium, 205 West Jefferson Street Phoenix, Arizona. Copies 

of the final draft rule will be available at least 30 days prior to the hearing for public inspection at the offices of 

the Maricopa County Air Quality Department (MCAQD), 1001 N. Central Ave. #595, Phoenix, Arizona, 

85004. For current information call (602) 372-1465 or visit MCAQD’s website at http://www.maricopa.gov/aq

and click on the date of the Public Hearing on the calendar on the right-hand side. Accommodations for 

individuals with disabilities, alternative format materials, sign language interpretation, and assistive listening 

devices are available upon 72 hours advance notice. If you need accommodation in order to participate in any 

forthcoming meeting or hearing, please contact Michelle Mada at michellemada@mail.maricopa.gov or (602) 

372-1465 or contact the Maricopa County ADA Office at 602-506-1778. 

PUBLISH 

Arizona Republic Saturday, February 9, 2008 and Saturday, February 16, 2008 

Record Reporter Wednesday, February 13, 2008 and Wednesday, February 20, 2008 

Business Gazette Thursday, February 14, 2008 and Thursday, February 21, 2008 
Appendix 4 


Appendix 5 

Appendix 6 
REGULATION III – CONTROL OF AIR CONTAMINANTS 

RULE 300 

VISIBLE EMISSIONS 

INDEX 

SECTION 100 – GENERAL 

101 PURPOSE 

102 APPLICABILITY 

SECTION 200 – DEFINITIONS 

201 OPACITY 

202 PERCENT OPACITY 

203 SHUTDOWN 

204 STARTUP 

205 UNCOMBINED WATER 

SECTION 300 – STANDARDS 

301 LIMITATIONS 

302 EXCEPTIONS 

SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE) 

SECTION 500 – MONITORING AND RECORDS 

501 COMPLIANCE DETERMINATION-OPACITY 

300.1
BLANK PAGE 

300.2
Revised 07/13/88 

Revised 08/05/94 

Revised 02/07/01 

Revised 03/12/08 

MARICOPA COUNTY 

AIR POLLUTION CONTROL REGULATIONS 

REGULATION III – CONTROL OF AIR CONTAMINANTS 

RULE 300 

VISIBLE EMISSIONS 

SECTION 100 – GENERAL 

101 PURPOSE: To limit the emission of air contaminants into the ambient air by 

establishing standards for visible emissions and opacity. 

102 APPLICABILITY: This rule applies to visible emissions from sources for which no 

source-specific opacity requirements apply. Exceptions to this rule are described in 

Section 302 of this rule. 

SECTION 200 – DEFINITIONS: For the purpose of this rule, the following definitions shall 

apply. See Rule 100-General Provisions and Definitions of these rules for definitions of terms 

that are used but not specifically defined in this rule. 

201 OPACITY – A condition of the ambient air, or any part thereof, in which an air 

contaminant partially or wholly obscures the view of an observer. 

202 PERCENT OPACITY – The degree to which an effluent plume or any other emission 

of air contaminants obscures the transmission of light expressed as a percentage. 

203 SHUTDOWN – The cessation of operation of any air pollution control equipment and/or 

process equipment for any purpose, except routine phasing out of process equipment. 

204 STARTUP – The setting into operation of any air pollution control equipment and/or 

process equipment for any purpose, except routine phasing in of process equipment. 

205 UNCOMBINED WATER – Condensed water containing no more than analytical trace 

amounts of other chemical elements or compounds. 

SECTION 300 – STANDARDS 

301 LIMITATIONS: No person shall discharge into the ambient air from any single source 

of emissions any air contaminant, other than uncombined water, in excess of 20% opacity 

for a period aggregating more than three minutes in any 60-minute period. 

300.3
300.4

302 EXCEPTIONS:

302.1 Charging Electric Arc Furnaces: When charging or back-charging any 

electric arc furnace for which construction commenced prior to February 

2, 1963, a person may discharge air contaminants, other than uncombined 

water, in excess of the applicable opacity limit in Section 301 of this rule 

for no more than an aggregate of three minutes in any 45-minute period; 

however, visible emissions resulting from such discharge of air 

contaminants shall not exceed 40% opacity. 

302.2 Emergency Diesel Generators (EDGs) and Equipment: When 

emergency diesel generators (EDGs) and equipment must run for safety 

reasons and/or for safety and operational tests to meet the requirements 

legally imposed by the Nuclear Regulatory Commission, a person may 

discharge air contaminants, other than uncombined water, in excess of the 

applicable opacity limit in Section 301 of this rule. Any discharge of air 

contaminants, other than uncombined water, in excess of the opacity limit 

in Section 301 of this rule should not contribute to a violation of the 

National Ambient Air Quality Standard. 

302.3 Firing of Ordnance at Test Facilities: Visible emissions exceeding the 

opacity standards for short periods of time resulting from firing test rounds 

in enclosed bunkers at ordnance test facilities which do not exceed six 

minutes in length shall not constitute a violation of Section 301 of this 

rule. 

302.4 Opacity Training: Equipment or processes used to train individuals in 

opacity observations shall be exempt from opacity standards during the 

preparation for and/or during the actual training session(s). 

SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE) 

SECTION 500 – MONITORING AND RECORDS 

501 COMPLIANCE DETERMINATION – OPACITY: Opacity shall be determined by 

observations of visible emissions conducted in accordance with EPA Reference Method 9 

as modified by EPA Reference Method 203B.