Multiple Air Toxics Exposure Study

The Multiple Air Toxics Exposure Study IV (MATES IV) is a monitoring and evaluation study conducted in the South Coast Air Basin (Basin).  The study is a follow up to previous air toxics studies in the Basin.

The MATES IV Study includes a monitoring program, 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.  An additional focus of MATES IV is the inclusion of measurements of ultrafine particle concentrations.  

Final MATES IV Report, released on May 1, 2015 (PDF, 3MB)

Mates IV Final Appendices
Appendix I List of Substances and Their Associated Risk Factor  (PDF, 25kb)
Appendix II MATES IV Technical Advisory Group Members  (PDF, 10kb)
Appendix III Ambient Sampling Methods and Laboratory Analysis Methods (PDF, 301kb)
Appendix IV Summaries for the MATES IV Fixed Monitoring Sites (PDF, 86kb)
Appendix V Comparison Between the West Long Beach Site in MATES III and MATES IV (PDF, 1,730kb)
Appendix VI Black Carbon Measurements at Fixed Sites (PDF, 2,663kb)
Appendix VII Particle Count at Fixed Sites (PDF, 194kb)
Appendix VIII 2012 Emissions by Major Source Category (PDF, 945kb)
Appendix IX Regional Modeling Analyses (PDF, 3,263kb)
Appendix X The Spatial and Temporal Trends of PM2.5, PM10, and TSP Components in the South Coast Air Basin (PDF, 119kb)
Appendix XI Estimating Diesel Particulate (PDF, 97kb)
Appendix XII Comments Received (PDF, 5,580kb)
Appendix XIII Responses to Comments on MATES IV Draft Report (PDF, 62kb)

MATES IV Carcinogenic Risk Interactive Map

Click on the link for the Interactive Map of the South Coast Air Basin to identify the estimated modeled carcinogenic risk from air toxics by geographic location as shown in Figure ES-5 in the Executive Summary of the MATES IV Report.  See Chapter 4 of the Report and Appendix IX for details of the modeling analysis. 

Estimated Risk Levels Explained

Links to previous Mates IV documents: 

MATES IV FInal Draft Report, released on April 1, 2015 (PDF, 16MB)
Appendices - April 1, 2015 (15MB)

Draft MATES IV Study, released on October 3, 2014
 (PDF, 4MB)
Appendicies - April 1, 2015 (9MB)

MATES IV Technical Advisory Group Members  (PDF, 48kb)

Meetings and Agendas
Mates IV Presentation-Governing Board Retreat March 14, 2013 (PDF, 1.2MB)
Mates IV Presentation-Governing Board Retreat April 13, 2012 (PDF, 137kb)
Previous MATES Studies

Board Presentations:
May 2015 (PDF, 1,452kb)
October 2014 (PDF, 1,907kb)

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