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Texas, Houston/Galveston Area, Ozone, Post-1999 Rate-of-Progress Plan Summary

Texas Houston/Galveston Area Ozone Post-1999 Rate of Progress Plan

Purpose of Plan: To reduce emissions of Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NOx) by 9% during each of the time periods during years 2000-2002 and 2003-2005 and by 6% during the period 2006-2007.

Area Covered: Houston/Galveston area, Texas (Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller counties)
Type of Pollutant: Ozone (caused by reactions between VOCs and NOx)

Under the Clean Air Act, the Houston/Galveston area (Houston) was designated “severe” for the nonattainment of ozone National Ambient Air Quality Standards (NAAQS).  As a result, Houston was given a deadline of November 15, 2007 to bring its ozone levels into attainment.

To ensure that Houston meets the deadline, the Clean Air Act requires that Texas submit, for EPA approval, plans that demonstrate a continued Rate Of Progress (ROP) in decreasing VOC and NOx emissions.

The first ROP requirement is to decrease emissions by 15% between 1990 and 1996.  This plan is called the 15% ROP plan.  Texas submitted its 15% ROP plan for Houston on November 14, 1993, May 9, 1994, and August 9, 1996, and the EPA gave it conditional interim approval on November 10, 1998 and complete approval November 14, 2001 (see Houston Ozone 15% ROP Plan Summary).  Houston had been granted a temporary waiver for NOx emissions reductions, so the 15% ROP only dealt with reducing VOC emission levels.

After 1996, ozone nonattainment areas are required to reduce emissions by 3% each year (averaged over 3 years) until the area reaches attainment.  The plan for 1996-1999 is referred to as the Post-1996 Rate of Progress plan, or Post-1996 ROP plan, and subsequent plans are referred to as Post-1999 ROP plans.  Texas submitted the Post-1996 plan for Houston on November 9, 1994 and August 9, 1996, and the EPA approved it April 25, 2001  (See Houston Ozone Post-1996 ROP Plan Summary).  Texas submitted Houston’s Post-1999 ROP plans on December 20, 2000 with revisions June 15, 2001, and they were approved November 14, 2001.

Pollution Data:
Texas was required to submit an emissions inventory for base year 1990 from which to calculate the required 15% ROP and subsequent 3% yearly emission reductions.  Although the EPA approved the original base year emissions inventory on November 8, 1994, the inventory has undergone several revisions.  Texas submitted the most recent revision in December 2000 along with the Post-1999 ROP and Attainment Demonstration.  This revision was based on data gathered from the 1993 and 1996 periodic emission inventories.

The Post-1999 ROP plans aim for 3% NOx and 6% VOC in emissions reduction between 1999-2002, 9% NOx reduction between 2003-2005, and 6% NOx reduction from 2005-2007.  Calculating from the revised base year inventory, the target levels for VOC emissions are 696.25 tons per day in 2002, 694.81 in 2005, and 693.84 in 2007.  The target levels for NOx emissions are 1127.08 tons per day in 2002, 1011.33 in 2005, and 935.67 in 2007.

Pollution Control Measures:
The Houston Post-1999 Ozone SIP did not rely on new state regulations to achieve the required reductions.  Rather, the plan predicted enough emission reductions would result from implementing existing federal regulations.  These regulations are listed in the tables below.

Federal Regulations:

Regulation Description Date FR citation
Pulp and Paper MACT Requires pulp and paper manufacturing facilities to meet Maximum Available Control Technology (MACT) standards 4/15/1998 63 FR 18504
New Non-Road Small Engines Controls emissions from lawn and garden equipment 6/3/1995 60 FR 34581
Tier I Motor Vehicle Control Program Tightens tailpipe emission standards on 1994 and later model light duty vehicles and trucks 7/5/1991 56 FR 25724
Tier II Motor Vehicle Control Program Phases in more stringent emission standards for cars, light trucks, medium-duty passenger vehicles, and gasoline beginning in 2004 2/10/2000 65 FR 6697
Reformulated Gasoline Tightens emission requirements on gasoline sold and distributed in certain areas 2/16/1994 59 FR 7716
National Low Emissions Vehicle Program Car manufacturers voluntarily agreed to further tighten tailpipe emission standards on new cars beginning in 2001 3/9/1998 63 FR 11374
Heavy Duty Diesel Vehicles Tightens emission standards on heavy duty diesel engines beginning in 2002 and 2004 10/21/1997
62 FR 54694
63 FR 59330
64 FR 58471
New Non-Road Small Engines (1999-2000) Controls emissions from lawn and garden equipment.  Contingency reduction credit is taken from availability of cleaner burning lawn equipment in 2000 6/3/1995 60 FR 34581
Spark-Engine Gasoline Marine Engines (2000) Controls emissions from outboard marine engines and personal watercraft.  Contingency reduction credit is taken from additional turnover of boats in the year 2000 10/4/1996 61 FR 52087

The Post-1999 ROP plans also rely on emissions reductions from state-mandated controls such as the inspection and maintenance plan for motor vehicles (30 TAC 114.50-114.53) and NOx point source controls.

Contingency Measures:
ROP plans are required to include contingency measures to be implemented if the nonattainment area is unable to reach its rate of progress goal.  Contingency measures must, if implemented, be able to reduce emissions by 3% of the base year inventory.  Texas did not submit any new control measures as part of its Post-1999 ROP contingency strategy, instead relying on predicted excess emission reductions from the control measures listed above.

Subsequent Action and Events:

Attainment Demonstration:
Texas submitted an attainment demonstration for the Houston ozone SIP, including modeling analysis projecting ozone levels in 2007 (Houston’s deadline for achieving NAAQS) and several enforceable commitments.  The EPA approved this attainment demonstration through parallel processing on November 11, 2001.

Texas had planned to fund TERP with taxes on out-of-state vehicle registrations, this tax was found to be unconstitutional in February of 2002, leaving Texas without the funds it needed to achieve the projected emission reductions.  In August of 2002, the EPA proposed to find that Texas was not complying with the terms of the attainment demonstration.  However, funding for TERP was restored by Texas House Bill 1365, signed by the state Governor June 22, 2003.

Federal Register Actions:

EPA Action Date Federal Register citation
Proposed approval of Houston Ozone Post-1999 ROP plans 7/12/2001 66 FR 36656
Final approval of Houston Ozone Post-1999 ROP plans 11/14/2001 66 FR 57160

EPA Region 6 Contacts:
     Bill Deese or Joanne Sum-Ping at 214-665-7253 or


This SIP Citation Was Last Modified on: 08/14/2003