Background
The MATES V Study includes a fixed site monitoring program with ten stations, an updated emissions inventory of toxic air contaminants, and a modeling effort to characterize risk across the Basin. The study focuses on the carcinogenic risk from exposure to air toxics but does not estimate mortality or other health effects from particulate exposures. 

The purpose of the MATES V fixed site monitoring is to characterize long-term regional air toxics levels in residential and commercial areas. To complement and enhance the fixed site monitoring, MATES V efforts will include advanced state-of-the-art monitoring technologies, low-cost sensor networks, and near real-time data and community engagement to conduct enhanced air toxics monitoring at local scales with a focus on EJ communities, especially those near refineries.

The motivation behind the enhanced monitoring efforts is to better characterize air toxics levels in highly impacted areas, to provide higher resolution air quality data, and to better understand emissions from petroleum refineries and warehouses.

MATES V Data Visualization Tool

MATES V Air Monitoring Dashboard

MATES V Final Report (PDF, 11 MB)

MATES V Final Appendices (PDF, 47 MB)

Appendix I - Cancer Potency Factors and Chronic RELs (PDF, 242 KB)
Appendix II - MATES V Technical Advisory Group Roster (PDF, 85 KB)
Appendix III - Monitoring and Laboratory Analysis Protocol (PDF, 406 KB)
Appendix IV - Summaries for the MATES II-V Fixed Monitoring Sites (PDF, 24MB)
Appendix V - Quality Assurance and Quality Control for Monitoring and Analysis (PDF, 120 KB)
Appendix VI - Black Carbon Measurements at Fixed Sites (PDF, 853 KB)
Appendix VII - Ultrafine Particle Measurements at Fixed Sites (PDF, 1MB)
Appendix VIII - 2018 Emissions by Major Source Category (PDF, 2 MB)
Appendix IX - Regional Modeling Analyses (PDF, 7 MB)
Appendix X - Spatial and Temporal Trends of PM2.5 and TSP Components in the South Coast Air Basin (PDF, 790 KB)
Appendix XI - Monitoring Data Treatment Methodologies (PDF, 78 KB)
Appendix XII - Biomass Burning Contribution to PM2.5 (Levoglucosan Data Analysis) (PDF, 1 MB)
Appendix XIII - Black Carbon and Elemental Carbon Comparison (PDF, 497 KB)
Appendix XIV - Comments Received on MATES V Report (PDF, 7 MB)
Appendix XV - Response to Comments on MATES V Report (PDF, 121 KB)

MATES V Advanced Monitoring  of Refineries
MATES V Advanced Monitoring of Refineries - Final Report (PDF, 11 MB)

MATES V Technical Advisory Group Roster
MATES V Roster (PDF, 104 KB)

Meeting Documents:
June 17, 2021: 
Agenda (PDF, 82 KB)
Presentation (PDF, 603 KB)

April 14, 2021:
Agenda (PDF, 116k)
Presentation (item 2) Overview of Results and Major Changes (PDF, 2.1 MB)
Presentation (item 3) Emissions Inventory, Modeling Methods, Results (PDF, 1.9 MB)
Presentation (item 4) Monitoring Methods and Results  (PDF, 2 MB)
Presentation (item 5) Interactive Air Monitoring Data Dashboard (PDF, 742 KB)
Presentation (item 6) Data Visualization Health Risk Data (PDF, 4.1MB)

July 6, 2017:
Agenda (PDF, 231 KB)
Presentation (item 2) - Overview of goals, previous studies (PDF, 508 KB)
Presentation (item 3) - Overview of Fixed Site Measurements  (PDF, 1 MB).
Presentation (item 4) - Regional Modeling Analysis (PDF, 981 KB)
Presentation (item 5) - Diesel Particulate Estimation (PDF, 363 KB)
Presentation (item 6) - Advanced Monitoring (PDF, 1 MB)

August 24th, 2017:
Agenda (PDF, 396 KB)
Presentation (item 4) - Refinery EJ Maps (PDF, 967 KB)
Presentation (item 5) - Potential Projects (PDF, 1 MB)
Presentation (item 5) - Projects Summary (PDF, 73 KB)
Presentation (item 6) - Discussion (PDF, 67 KB)

Board letters
Fixed-Site Monitoring (July 2017 Board Meeting):
Transfer Funds, Appropriate Funding, Execute Purchase Orders, Execute Contract and Authorize Release of RFQs for the Fifth Multiple Air Toxics Exposure Study

Associated presentation: Multiple Air Toxics Exposure Study (PDF, 1 MB)

Enhanced Monitoring (November 2017 Board Meeting):
Transfer and Appropriate Funds, Authorize Contracts, RFQs and Purchase Orders, and Execute Contracts for Advanced Monitoring During MATES V

Associated presentation: Proposed Advanced Monitoring during MATES V (PDF, 1 MB)
Related Board presentation: Update on Current and Upcoming Community Air Toxics Monitoring Efforts (PDF, 1 MB)

Previous MATES studies

MATES IV
Multiple Air Toxics Exposure Study (MATES IV) was conducted in 2012-2013. The final MATES IV report is available.

MATES III
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.

MATES II
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.

MATES I
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.