MATES VI Multiple Air Toxics Exposure Study

The Multiple Air Toxics Exposure Study VI (MATES VI) is a monitoring and air quality modeling study conducted in the South Coast Air Quality Management District. The study is a follow up to previous air toxics studies in the region.

MATES VI will include a fixed site monitoring program, an updated emissions inventory of toxic air contaminants, and a modeling effort to characterize risk across the South Coast Air Quality Management District. The study focuses on the cancer risk and chronic non-cancer risk from exposure to air toxics but does not estimate mortality or other health effects from air pollutant exposures. 

MATES VI is currently in the planning stage and will be conducted over the next several years. Until results are available, the MATES V study published in the summer of 2021 provides the most up to date assessment of air toxics risk throughout the region.

MATES VI Technical Advisory Group Roster

MATES VI Roster (PDF, 111 KB)

Request for Proposals
Brake and Tire Wear Exposure Concentrations in the South Coast Air Basin and Coachella Valley (PDF, 1.76 MB)
Responses to Questions on the Request for Proposals
Exposure Surface Boundary for RFP P2024-09 (ZIP, 85 KB)

Meeting Documents:

October 6th 2023 Governing Board Presentation (presentation starts at 1:03:40)

TAG Meeting #1
October 26, 2023: 
Agenda (PDF, 157 KB)
Presentations (PDF, 5.5 MB)

TAG Meeting #2
January 16, 2024: 
Agenda (PDF, 160 KB)
Presentations (PDF, 2.5 MB)

Bidders’ Conference for Brake and Tire Wear Exposure Concentrations RFP
March 8, 2024 & March 13, 2024
Agenda (PDF, 295 KB)
Presentations (3 MB)
Recording of Bidders' Conference #1
Recording of Bidders' Conference #2

For More Information:

Sign up to receive information on upcoming MATES VI Technical Advisory Group Meetings and document releases at (the MATES signup list is located in the Clean Air Plans/CEQA section).

Previous MATES Studies

MATES V was conducted in 2018-2019 with a final report published in 2021 and contained several improvements over past MATES studies including an expanded air quality modeling domain to include the Coachella Valley; the evaluation of health impacts form multiple exposure pathways; an exploratory analysis of chronic non-cancer health impacts in addition to the traditional cancer risk analysis; inclusion of advanced statistical methods to analyze measurements from MATES III to MATES V to enhance data comparability and visualize trends over time; and new online tools to enhance public access to the MATES data and increase public knowledge of air toxics health impacts. 

MATES IV was conducted in 2012-2013 and was the first of the MATES studies to include comprehensive continuous ultrafine particle (UFP) and black carbon (BC) measurements.  

As part of the 2003-04 Environmental Justice Workplan (PDF, 52kb), the AQMD conducted a Multiple Air Toxics Exposure Study beginning in 2004. A Technical Advisory Group was formed and met periodically to provide technical review and input to staff during this study. These meetings were open to the public. Results are available in the MATES III Final Report.

At its October 10, 1997 meeting, the SCAQMD Governing Board directed staff to conduct a major air toxic evaluation program, referred to as MATES II (Multiple Air Toxics Exposure Study) to quantify the current magnitude of population exposure risk from existing sources of selected air toxic contaminants. This program was more comprehensive than a similar study conducted over a decade ago in MATES I, in that more sites were sampled, more toxic compounds were analyzed, and other elements such as microscale modeling were also incorporated into the study. The AQMD conducted this study in three parts addressing; (1) Air Toxic Monitoring; (2) Air Toxic Emissions Inventory Enhancements; and (3) Air Toxic Modeling and Risk Assessment. Further information is found in the MATES II Final Report.

The first Multiple Air Toxics Exposure Study was conducted in 1986-87 and the findings published in June 1987. This document is not available online, but a reference copy may be consulted in the AQMD's Library.


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