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About Air Monitoring Comparison Values (AMCVs)

Information about AMCVs used in the review of ambient air monitoring data, AMCV lists, and the difference between them and ESLs.

AMCV is a collective term used to describe chemical-specific air concentrations used to evaluate air monitoring data that are set to protect human health and welfare. Short-term AMCVs are based on data concerning acute health effects, odor potential, and acute vegetation effects, while long-term AMCVs are based on data concerning chronic health or vegetation effects. AMCVs may contain health-based Reference Values (ReVs) and health- and welfare-based ESL values.

AMCVs and ESLs are screening levels for ambient air set to protect human health and welfare.

AMCVs are screening levels used in TCEQ’s evaluation of ambient air monitoring data to assess the potential for measured concentrations of specific chemicals to cause health or welfare effects. Health-based AMCVs are safe levels at which exposure is unlikely to result in adverse health effects. Long-term AMCVs are similar to the USEPA’s inhalation reference concentrations.

ESLs are screening levels used in the TCEQ’s air permitting process to establish maximum emission rates that are written into enforceable air permits. Health-based ESLs are set 70 percent lower than the safe level, or AMCV. This additional buffer allows TCEQ to take into account exposure to chemicals from multiple sources in air permit reviews. A more detailed discussion of the differences can be found in Attachment C of the Uses of ESLs and AMCVs Document, or the Fact Sheet (which discusses the health-based values used to review air permits and air monitoring data).

About the TCEQ Toxicity Factor Database

The Toxicity Factor Database is now a part of Texas Air Monitoring Information System (TAMIS) database. This database is a one-stop-shop for information about all toxicity factors developed by the TCEQ. If you previously used Excel spreadsheets to access the toxicity factors, you will now access them via the TAMIS database. The TAMIS database includes not only Effects Screening Levels (ESLs), but also Air Monitoring Comparison Values (AMCVs) and their supporting documentation. The TCEQ created the database in order to reduce errors, improve database structure, provide more information and detail to our customers, and allow more dynamic and efficient data entry.

Learn more about the Toxicity Factor Database and query the Toxicity Factor Database to search for AMCVs.