United States Environmental Protection Agency , Region IX, A ir Division Technical Support Document

for EPA's Notice of Proposed Rulemaking

on revisions to the Arizona State Implementation Plan as submitted by

the State of Arizona for the Maricopa County

Air Quality

Department EPA's Analy sis of Maricopa County

Air Quality

Department Rule 300
- Visible Emissions

March 2010 Prepared by

Joanne Wells Approved by

Andrew Steckel- 2 -

Maricopa County Air Quality Department (MCAQD) Rule 300 - Visible Emissions 1. Rule Adoption and Submittal Chronology On April 12, 1982 (47 FR 15579), EPA incorporated MCAQD Rule 30, Visible Emissions into the Arizona SIP. This rule was amended and renumbered as Rule 300 o n July 13, 1988 and submitted to EPA on January 4, 1990. However, EPA did not take action on th is submittal. Rule 300 was further amended on August 5, 1994 and February 7, 2001, but these versions were not submitted for approval to EPA. Rule 300 was amended again on Mar ch 12, 2008 and submitted to EPA on July 10, 2008 . This submittal was determined complete by EPA on March 13, 2009. Though we can act only on the most recent version of the submitted rule, we have reviewed previously submitted v ersions. 2. Nonattainment History of Maricopa County Upon enactment of the Clean Air Act (CAA) Amendments of 1990, Maricopa County was initially designated as a “moderate” nonattainment area for the National Ambient Air Quality Standard (NAAQS) for PM 10 . Maricopa County failed t o attain the NAAQS by December 31, 1994 and was reclassified as a serious PM 10 nonattainment area on June 10, 1996 . The region still did not attain the standard by December 31, 2006 and continues to be classified as a serious nonattainment area for PM 10 . Part of Maricopa County

and the Apache Junction Pinal County Area were designated nonattainment for the 1997 8
- hour ozone standard effective June 15, 2004. The 8
- hour area was not classified and EPA was going to treat the area as a "subpart 1 Basic" nonattainment area, until a court decision in December 2006 vacated our implementing regulations in this regard. Although EPA proposed to classify the 8
- hour ozone nonattainment area as "marginal" based on 2001 - 2003 ozone monitoring data, we have not (as of Fe bruary 2010) finalized that action. The pre - existing 1
- hour ozone nonattainment area portion of Maricopa County was redesignated to attainment and a maintenance plan was approved effective June 14, 2005 . 3 . Rule Summary & Background MCAQD Rule 300 is intended to limit the emissions of air contaminants into the ambient air by establishing standards for visible emissions and opacity . The revisions adopted March 12, 2008 relate to commitments made in Maricopa’s Five Percent Plan for PM 10 . Since the ar ea did not attain the PM 10 NAAQS by December 31, 2006, Arizona had to submit to EPA a Five Percent Plan by December 31, 2007. Th is Plan must demonstrate 5% reductions per year in emission s , and MCAQD revised Rule 300 to implement a control measure and in crease compliance with existing rules for the Five Percent Plan.- 3 -

The March 12, 2008 submitted version of Rule 300 would revise the 1982 SIP

– approved version Rule 30 by :
 Renumbering the rule to Rule 300, updating the format and adding sections: 101 , Pur pose ; 102 , Applicability ; 200 , Definitions ; 300 , Standards ; and 500 , Monitoring and Records.  Changing the limit for opacity (Section 301) from 40% to 20% opacity for a period aggregating more than three minutes in any 60 minute period.  Adding the four exceptions in Section 302: 302.1 , Charging Electric Arc Furnaces ; 302.2 , Emergency

Diesel Generators (EDGs) and Equipment ; 302.3 , Firing of Ordnance at Test Facilities ; and 302.4 , Opacity Training.  Adding Section 501 , Compliance Determination using EPA Method 9 as modified by EPA Reference Method 203B.  Making various minor editorial changes s uch as renumbering , definitions , and several word additions and title changes to improve clarity . 4. Rule Evaluation EPA is primarily

using the following three criteria to evaluate Rule 300. a. Rule Stringency

– Maricopa County is a serious P M 10 nonattainment area , therefore the area is subject to CAA § 189 PM requirements regarding Reasonably and Best Available Contro l Measures (RACM and BACM). b. Enforceability

– CAA § 110(a)(2)(A) requires that regulations submitted to EPA for SIP approval must be clear and legally enforceable. c. Anti
- Backsliding
- CAA §110(l) and §193 restrict certain SIP revisions that would r elax existing SIP - approved requirements. EPA must compare the March 12, 2008 version of Rule 300 with the SIP - approved Rule 30. The revisions made to Rule 30 and later to Rule 300 strengthen the SIP rule by lowering the opacity limit from 40% to 20%. This was further strengthened by changing the procedures for determining compliance with the 20% opacity limitation from “averaging to aggregating”. This form of data reduction for 20% opacity standard limits the number of excursions over the 20% visible e mission standard and results in more consistent compliance with the standard. The four exceptions included in Section 302 of R ule 300 address a small number of very specific sources of emissions and each exception includes reasonable limits on excess emi ssions of visible emissions. The addition of Section 500 , Monitoring and Records, includes appropriate test and data reduction methods improving enforceability of the rule.- 4 -

Since the MCAQD is classified as a serious nonattainment are a for PM 10 , the rul e must meet requirements for RACM and BACM. Generally , the 20% opacity limit meets the requirements for both RACM and BACM. T he cumulative changes made to Rule 30 / Rule 300 greatly improve the clarity , enforceability , and stringency

of the rule , and EPA finds that Rule 300 reasonably fulfills the three evaluation criteria. 5. Rule Deficiency

– No deficiencies were identified in Rule 300 . 6. Additional Recommendations for the Next Rule Revision - The following revision s are not currently the basis for rule disapproval, but are recommended for the next time the rule is amended. 1. Section 200
- Definitions: for clarity add a definition of visible emissions. See , for example, San Joaquin Valley Unified Air Pollution Control District Rule 4101 , Visible Emiss ions , section 3.4. 2. Section 302.1

– Charging Electric Arc Furnaces : please evaluate the need for this exception since it is possible that there are no electric arc furnaces for which construction commenced prior to February 2, 1963 currently

operating in Maricopa County . 3. Section 302.2

– Emergency Diesel Generators (EDGs) and Equipment: please evaluat e non - emergency

operational testing requirements for these emergency diesel generators and equipment and see if there are reasonable time limits, such as minutes per hour and hours per month to ensure that excess emissions are limited for this activity . See , for example, San Diego Air Pollution Control District Rule 69.4, Stationary Reciprocating Internal Combustion Engines, (b) Exemptions (2) (iii) : “Any emergency standby engine at a nuclear power generating station subject to the requirements of the Nuclear Regulatory Commission provided that the operation of the engine for non
- emergency purposes does not exceed 200 hours per calendar year.” 4. Section 302 .3 Firing of Ordnance at Test Facilities
- please defin e “short periods of time” and describe a reasonable number of hours per month or year to ensure that excess emission s from this activity are appropriately limited by a reasonable time limit. 7. EPA Action
– EPA staff recommends full approval of the July 10, 2008 submittal of MCAQD Rule 300

– Visible Emissions, amended on March 12, 2008. 8. References a. MCAQD Rule 300
- Visible Emissions, adopted March 12, 2008.- 5 -

b. MCAQD Rule 30

– Visible Emissi ons, approved into SIP April 12, 1982 c . “Notice of Final Rulemaking, Maricopa County Air Pollution Control Regulations, Rule 300
- Visible Emissions, Date of Adoption: March 12, 2008. ”