United States Environmental Protection Agency,

 Region IX, Air 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 Analysis of

 Maricopa County Air Quality Department 

Rule 300 - Visible Emissions

	

	

March 2010

Prepared by Joanne Wells

Approved by Andrew Steckel

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 on July 13, 1988 and submitted to EPA on January 4, 1990.
However, EPA did not take action on this 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 March 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 versions.

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 PM10. 
Maricopa County failed to attain the NAAQS by December 31, 1994 and was
reclassified as a serious PM10 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 PM10.

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 February 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 PM10.  Since the area did not
attain the  PM10 NAAQS by December 31, 2006, Arizona had to submit to
EPA a Five Percent Plan by December 31, 2007.  This Plan must
demonstrate 5% reductions per year in emissions, and MCAQD revised Rule
300 to implement a control measure and increase compliance with existing
rules for the Five Percent Plan.

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, Purpose; 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 such 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 PM10 nonattainment
area, therefore the area is subject to CAA §189 PM requirements
regarding Reasonably and Best Available Control 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 relax 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 emission standard and results in more
consistent compliance with the standard. 

The four exceptions included in Section 302 of Rule 300 address a small
number of very specific sources of emissions and each exception includes
reasonable limits on excess emissions of visible emissions.  

The addition of Section 500, Monitoring and Records, includes
appropriate test and data reduction methods improving enforceability of
the rule.

Since the MCAQD is classified as a serious nonattainment area for PM10,
the rule must meet requirements for RACM and BACM. Generally, the 20%
opacity limit meets the requirements for both RACM and BACM.

The 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 revisions are not currently the basis for rule disapproval,
but are recommended for the next time the rule is amended.

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 Emissions, section 3.4.    

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 . 

Section 302.2 – Emergency Diesel Generators (EDGs) and Equipment:
please evaluate 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.” 

Section 302.3 Firing of Ordnance at Test Facilities - please define
“short periods of time” and describe a reasonable number of hours
per month or year to ensure that excess emissions 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.

b. MCAQD Rule 30 – Visible Emissions, 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.”

 

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