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Texas, El Paso Area, Carbon Monoxide, Attainment Plan Summary

Texas, El Paso Area, Carbon Monoxide Attainment Plan Summary

Federal Register Dates:
     Proposed Rule:        July 2, 2003 (68 FR 39506-39507).
     Direct Final Rule:    July 2, 2003 (68 FR 39457-39460).
     Effective Date:       September 2, 2003

Area Covered: El Paso Carbon Monoxide Nonattainment Area which consist of a portion of the City Limits of El Paso.  See the "Texas--Carbon Monoxide" table in 40 CFR 81.344 (Texas Attainment Status Designations) for the boundaries.

Type of Pollutant: Carbon Monoxide (CO)

Below is relevant information copied from the direct final approval Federal Register action.
See 68 FR 39457 (September 2, 2003) for the complete Federal Register.

TITLE: Approval and Promulgation of Implementation Plans for Texas; Approval
of Section 179B Demonstration of Attainment, Carbon Monoxide Motor Vehicle
Emissions Budget for Conformity, and Contingency Measure for El Paso Carbon
Monoxide Nonattainment Area

ACTION: Direct final rule.

SUMMARY: The EPA is approving, through direct final action, a revision
to the Texas State Implementation Plan (SIP), submitted to show
attainment of the Carbon Monoxide (CO) National Ambient Air Quality
Standard (NAAQS) in the El Paso CO nonattainment area, but for
emissions emanating from outside of the United States. The EPA is also
approving the El Paso area's CO emissions budget, and a CO contingency
measure requirement. The State submitted the revisions to satisfy
sections 179B and other Part D requirements of the Federal Clean Air
Act (CAA).

    Throughout this document ``we,'' ``us,'' and ``our'' means EPA.

Table of Contents

I. What is the background for this action?
II. What did the State submit and how did we evaluate it?
    A. Modeling.
    B. CO motor vehicle emissions budget.
    C. Contingency measures.
    D. Has the EPA approved other parts of the SIP before now?
    E. How close is El Paso to attainment of the CO standard?
III. What is our final action?
IV. Why is this a ``final action?''
V. Regulatory Assessment Requirements.

I. What Is the Background for This Action?

    El Paso, Texas, was designated nonattainment for CO and classified
as moderate under sections 107(d)(4)(A) and 186(a) of the CAA. The El
Paso CO nonattainment area is restricted to a narrow strip along the
Rio Grande, adjacent to Ciudad Juarez, Mexico.
    The CAA requires that CO nonattainment areas designated moderate
and above demonstrate attainment through air quality modeling or any
other analytical method determined by the Administrator to be at least
as effective. Section 179B of the CAA contains special provisions for
nonattainment areas that are affected by emissions emanating from
outside the United States. Under section 179B, the EPA will approve a
SIP if the area meets all other CAA requirements, and establishes that
implementation of the plan would achieve attainment of the CO standard
by the CAA statutory deadline ``but for emissions emanating from
outside the United States.'' This is the type of demonstration that the
State of Texas has made.

II. What Did the State Submit and How Did We Evaluate It?

A. Modeling

    The Governor of the State of Texas submitted a revision to the
Texas SIP for the El Paso CO moderate nonattainment area via a letter
dated September 27, 1995, which was supplemented in February 1998. This
included air quality modeling, under section 179B of the CAA, that
demonstrates that El Paso would attain the CO NAAQS, but for emissions
emanating from outside of the United States.
    El Paso and Juarez, Mexico, share an air-shed. However, emission
inventory data was not available for Juarez, so modeling of the entire
air-shed was not possible. In such an instance, section 179B allows an
area such as El Paso to perform modeling using only U.S. pollutant
emission data in performing the attainment demonstration.
    In its demonstration, Texas used two models, RAM, and CAL3QHC. RAM
modeling was used to estimate background CO concentrations, and CAL3QHC
was used to estimate hot-spot concentrations, or those areas that are
the most likely to produce the highest concentrations of CO. Using RAM
modeling, Texas identified the worst-case meteorological episode
conducive for CO concentration. This was subsequently used in the
CAL3QHC modeling to determine CO concentrations at six selected
intersections. These concentrations were then combined with hourly
variables in the 8-hour period with the highest RAM-determined
background CO concentration. The modeling results for El Paso indicate
that the area would attain the CO standard but for emissions emanating
from outside the United States. Texas performed its CO modeling
analyses for El Paso, according to EPA guidance, using conservative
inputs to EPA guideline models.

B. CO Motor Vehicles Emissions Budget

    The Governor of Texas submitted the 1996 CO motor vehicle emissions
budget of 96.90 tons/day on September 27, 1995. The finding that the
budget of the El Paso CO attainment plan was adequate was made in a
letter on September 1, 1999.\1\ It is EPA's conclusion that the SIP
demonstrates attainment with the budget and contains the measures
necessary to support the budget. Today, we are approving this budget,
under section 176(c) of the CAA.

    \1\ EPA later determined that this motor vehicle emission budget
was adequate for transportation conformity purposes (see 64 FR
55911, October 15, 1999).

C. Contingency Measures

    Nonattainment areas must adopt contingency measures that are
implemented in the event the area does not attain the standard by the
attainment date. Under section 187(a)(4) of the CAA's CO requirements,
El Paso must have at least a basic Inspection and Maintenance (I/M)
program. However, El Paso was also bound to the CAA's ozone
requirements for serious areas, which under section 182(c)(3), requires
an enhanced program. These two programs yield different levels of CO
reductions. The difference in emissions reductions could be called
incremental credit. That is, incremental reductions in CO are
reductions produced by a control program more stringent than required
by CO provisions in the CAA.
    The El Paso area is not subject to the section 187(a)(2)(A) Vehicle
Miles Traveled (VMT) forecasts and the section 187(a)(3) contingency
measures requirements, because its design value was below 12.7 ppm. It
is, however, subject to the section 172(c)(9) contingency measures
requirement. The CAA does not specify how many contingency measures are
needed or the magnitude of the emission reductions (or VMT reductions)
they must provide. In the EPA's General Preamble,\2\ EPA provides its
belief that for moderate areas that fail to attain by the attainment
date, States may select contingency measures for the reduction of CO
emissions. EPA believes that one appropriate choice of contingency
measures would be to provide for the implementation of sufficient VMT
reductions or emissions reductions to counteract the effect of 1 year's
growth in VMT. The State used this approach to calculate the magnitude
of emission reductions it must provide, which is approximately 10.4
tons per day of CO reductions in El Paso. A basic I/M program would
produce 43 tons per day of CO reductions. The low-enhanced I/M program
approved for El Paso was credited in the SIP for 89 tons per day of CO
reductions, which is 46 tons per day of CO reductions beyond the
reductions obtained from a basic program. This is well above the 10.4
tons per day the State calculated was required to meet the contingency
requirements. The more stringent requirements of the low-enhanced
program generate these incremental reductions in CO, thus fulfilling
the requirement. The EPA is approving all of the incremental credit of
46 tons per day into the SIP as meeting the CO contingency measures

    \2\ EPA has issued a ``General Preamble'' describing EPA's
preliminary views on how EPA intends to review SIPs and SIP
revisions submitted under title I of the Act (57 FR 13498, April 16,
1992, and 57 FR 18070, April 28, 1992).

D. Has the EPA Approved Other Parts of the SIP Before Now?

    All CO nonattainment areas must adopt SIPs that contain the
following core elements:\3\

    \3\ As outlined in section 187 of the CAA, additional
requirements pertain to moderate nonattainment areas with design
values above 12.7 ppm, and to severe nonattainment areas.


    1. An inventory of all actual emissions of CO sources in the area
(sections 187(a)(1) and 172(c)(3) of the CAA);
    2. A revised inventory every three years (sections 187(a)(5) and
    3. A permit program for the construction and operation of new and
modified major stationary sources of CO (sections 172(c)(5)and 173);
    4. Contingency measures that are to be implemented if the area
fails to attain the standard by the deadline (section 172(c)(9));
    5. An I/M program that meets applicable requirements (section
187(a)(4)); and
    6. An oxygenated fuels program, if the design value was 9.5 ppm or
above based on 1988 and 1989 data (section 211(m)); The EPA:
    1. Approved an emissions inventory on September 12, 1994 (59 FR
    2. Approved an oxygenated fuels program on September 12, 1994 (59
FR 46766);
    3. Approved a permit program for new and modified major sources of
CO on September 27, 1995 (60 FR 49781);
    4. Received a periodic update of the CO inventory;
    5. Approved the Texas Motorist Choice Vehicle Inspection and
Maintenance Program (includes El Paso) on November 14, 2001 (66 FR
57261); and
    6. Is approving a CO contingency measure in this action.

E. How Close Is El Paso to Attainment of the CO Standard?

    Data from the El Paso monitoring network from 1999 to the end of
2002 appear to indicate that the area is in attainment of the CO
standard. The State has informed EPA that it may request redesignation
in the near future.

III. What Is Our Final Action?

    The EPA is approving a revision to the Texas SIP, which was
submitted to show attainment of the CO standard in the El Paso CO
nonattainment area by the applicable attainment date, but for emissions
from Mexico. The revision satisfies section 179B of the CAA.
    The EPA believes that all section 179B approvals should be on a
contingency basis. This modeling-based approval is valid only as long
as the area's modeling continues to show that the El Paso CO area would
be in attainment, but for emissions from outside the United States. If
the EPA later determines by rulemaking that additional CO reductions
are needed from sources in the United States, the EPA will require
Texas to submit a new CO attainment SIP for El Paso.
    The EPA is also approving El Paso's CO motor vehicle emissions
budget, under section 176(c) of the CAA. Lastly, the EPA is approving
the use of 46 tons per day in incremental CO reduction credits from the
Texas low-enhanced vehicle inspection and maintenance program, as
fulfillment of the State's CO attainment contingency measure
requirement for the El Paso nonattainment area under section 172(c)(9).

*     *     *     *     *


 Chapter I, title 40 of the Code of Federal Regulations is amended as


 1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7402 et seq.

Subchapter SS--Texas

 2. The table in Sec.  52.2270(e) entitled ``EPA approved nonregulatory
provisions and quasi-regulatory measures in the Texas SIP'' is amended
by adding to the end of the table three entries for the El Paso carbon
monoxide nonattainment area to read as follows:

Sec.  52.2270  Identification of plan.

* * * * *
    (e) * * *

       EPA Approved Nonregulatory Provisions and Quasi-Regulatory Measures in the Texas SIP
Name of SIP provision           Applicable geographic or    submittal/       EPA approval date      Comments
                                   nonattainment area     effective date

                                                 * * * * * * *

Section 179B Demonstration of       El Paso CO non-      09/27/95             07/02/03     Supplemented 02/11/98.
  Attainment for Carbon Monoxide    attainment area.                                  
  for El Paso.

Carbon Monoxide On-Road Emissions   El Paso CO non-      09/27/95             07/02/03    
  Budget for Conformity.            attainment area.

Contingency Measure for El Paso     El Paso CO non-      09/27/95             07/02/03    
  Carbon Monoxide Area.             attainment area.

EPA Region 6 Contact:
     Bill Deese or Joe Kordzi at (214-665-7253),


This SIP Citation Was Last Modified on: 07/16/2004