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About the Air Pollutant Watch List

The Air Pollutant Watch List alerts technical personnel to cities and counties within the state that have areas with elevated concentrations of air pollutants.

What is the Air Pollutant Watch List?

The Air Pollutant Watch List (APWL) is a list of areas in Texas where specific pollutants were monitored at levels of concern. The APWL is maintained by the TCEQ's APWL Coordinator in cooperation with the TCEQ's Toxicology Division (TD), and is composed of the following information.

  • Area of concern listed by:
    • County
    • City
    • TCEQ Region
    • APWL Site Number
    • Year Added
    • Pollutant of Interest
    • Area Boundaries

Use the Air Monitoring Site Information Table or Air Monitoring Site Information Map to see the location of monitors in a particular area.

Air Pollutant Watch List Protocol

The APWL protocol is a document that outlines the framework that the TCEQ will follow for APWL issues, such as listing and delisting of APWL areas. The TCEQ Chief Engineer's Office provided an opportunity for public comment on the development of the APWL protocol and is providing responses to all comments submitted on the draft protocol.

What Air Pollutants are Monitored?

Texas monitors and evaluates ambient air concentrations of air toxics, which are pollutants known or suspected to cause cancer or other serious health effects. The TCEQ obtains data on approximately 150 air toxics from stationary monitors and also from the deployment of mobile monitoring projects. The TCEQ monitors for volatile organic compounds (such as benzene), carbonyls (such as formaldehyde), polycyclic aromatic hydrocarbons (such as naphthalene), and metals (such as nickel).

How is Ambient Monitoring Data Evaluated?

The TCEQ established ambient state regulatory standards for two air toxics--sulfur dioxide and hydrogen sulfide. For all other monitored air toxics, the TD establishes pollutant-specific air quality guideline levels known as Air Monitoring Comparison Values (AMCVs) to protect human health and welfare. The TCEQ establishes APWL areas where ambient monitoring indicates persistent concentrations above state standards or AMCVs.

The U.S. Environmental Protection Agency also established ambient air quality standards for criteria pollutants. These standards are known as the National Ambient Air Quality Standards, or NAAQS, and each state must develop a State Implementation Plan, or SIP to demonstrate how it will comply with and attain the NAAQS. The Texas SIP is the mechanism that the TCEQ uses for regulating criteria pollutants; the APWL is the mechanism that the TCEQ uses to reduce air toxic emissions and ensure that ambient concentrations of air toxics are below levels of concern.

What is the Purpose of the APWL?

The purpose of the APWL is to—

  • Heighten awareness in areas of concern for interested parties, such as:
    • TCEQ personnel (Air Permits Division, Office of Compliance and Enforcement, etc.)
    • Industry representatives
    • Private citizens
  • Encourage efforts to reduce emissions
  • Help the TCEQ focus resources to:
    • Conduct facility inspections and field investigations
    • Pursue enforcement activities
    • Increase pollution prevention efforts
    • Prioritize mobile monitoring efforts
  • Help in review of air permit applications as outlined in the Modeling and Effects Review Applicability Technical Guidance Package

What is an Area of Concern?

An area of concern is defined as an area in which one or more air toxics have been measured at a level that can potentially cause adverse short-term or long-term health effects (or both) or odor. The area of concern is determined by:

  • Reviewing all available data, which includes:
    • Comparing monitored data to:
      —Short- and long-term, health-based and odor-based AMCVs
      —state (TCEQ) regulatory standards
    • Source-determination analysis based on meteorological data and network monitoring data in order to assess significant sources and locate sensitive receptors (such as humans, livestock, and plants)
    • Evaluation of how often regulatory values are exceeded and by how much
    • Trend analyses for the pollutant in the area of concern to identify possible seasonal or time-related emissions
    • Other factors that include, but are not limited to, proximity of area of concern to high-traffic roadways, land-use designation, emissions data, and compliance history for industries in the area
  • Defining its boundary using streets, highways, and other geographical boundaries

How Does an Area or Pollutant get on or off the List?

  • An area or pollutant (or both) are added to the APWL when:
    • Persistent elevations of measured concentrations of the pollutant of interest are determined to be of concern for potential to cause adverse short- or long-term health effects (or both) or odor. (For a detailed list of all data considered for review, see Data Considerations for the APWL.)
  • An area or pollutant (or both) are removed from the APWL when:
    • Monitored concentrations of the pollutant of interest in an area of concern indicate a downward trend over time. (For a detailed list of all data considered for review, see Data Considerations for the APWL.)
    • The TCEQ determines that no potential to cause adverse health effects remains.
  • Prior to revising the APWL:
    • Legislative officials whose districts fall within the APWL areas are notified of the addition to or removal from the APWL prior to the public.
    • A 30-day public comment period has ended.

Recommend an Area be Added to or Removed from the APWL

Interested parties may suggest that specific pollutants and locations be considered for addition to or removal from the APWL by sending an email to the APWL Coordinator at APWL@tceq.texas.gov.  Requests should include a description of the location, the pollutant of concern, any supporting information, and contact information.

For assistance regarding environmental complaints, visit the TCEQ Complaints Reporting Web site. 

APWL Areas Considered But Not Adopted

The TCEQ often receives recommendations for additions to and/or removals from the APWL. Every recommendation is carefully investigated to provide a status report on:

  • efforts in place by a facility to reduce emissions
  • related agreements with the TCEQ
  • current ambient air data available for the chemical of interest

View recommendations for addition to (or removal from) the APWL that were not adopted.

Areas Currently under Consideration

Proposal to Delist Bastrop from the APWL

The TCEQ accepted comments on its proposal to remove Bastrop from the APWL through January 20, 2012. More details regarding the proposed Bastrop APWL delisting are provided in the Proposed Air Pollutant Watch List Revision Document and Bastrop APWL Area Q & A Document.

Boundary Reevaluation for Lynchburg Ferry

The TCEQ accepted comments on its proposal to revise the Lynchburg Ferry APWL boundary through December 23, 2011. The TCEQ is currently evaluating the comments.

Proposed Lynchburg Ferry Map

Lynchburg Ferry Boundary Reevaluation Document

Contact the TCEQ About the APWL

For further information, contact TCEQ's APWL Coordinator, Tara Capobianco, at (512) 239-1117 or via email at APWL@tceq.texas.gov.

Sign Up to Receive APWL Announcements

To receive free updates by email regarding the APWL, visit the TCEQ GovDelivery Exit the TCEQ  Web site and check the box for Air Pollutant Watch List under the Air Quality heading.

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Last Modified Wed, 08 Feb 2012
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