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AQMD Begins Year-Long Air Sampling of Toxic Air Pollution in Southland

July 11, 2012

The South Coast AQMD recently began a year-long air sampling initiative in its fourth study of levels of cancer-causing toxic air pollutants and the risk they pose to Southland residents.

“While we saw an overall decrease in the risk from toxic air contaminants in our 2008 study, the risks are still unacceptable,” said William A. Burke, Ed.D., AQMD’s Governing Board Chairman.  “Data collected will help guide efforts to continue to reduce overall exposures to air toxics.” 

AQMD has started collecting air samples for substances to be measured in the Multiple Air Toxics Exposure Study IV (MATES IV), a follow up to three previous air toxics studies done in the Southland.  To assess trends over time, the same 10 monitoring sites used for the last study, MATES III (see list below), will be used for this year’s study.  Monitoring at each site will be for a 24-hour period and occur every one-in-six days for one year. A final report is expected by March 2014. 

MATES IV will monitor for more than 20 toxic air contaminants and several other substances.  This year’s study will also include additional monitoring of ultra fine particles and black carbon.  Mobile monitoring stations will be used to conduct short-term monitoring in about eight locations to assess localized impacts from combustion sources, such as airports, freeways, rail yards, busy intersections and warehouse operations. The modeling area will also be expanded this year to include the Coachella Valley.

A technical advisory group was formed to provide advice and assistance in selecting the specific neighborhood monitoring sites.  The group includes representatives of other environmental agencies, universities, industry and environmental groups, and will help guide the study from start to finish.

The results of MATES III, completed in 2008, found:

  • An 8 percent decrease overall in estimated cancer risk from air pollution, from 931 in 1 million in 1998-99 to 853 in 1 million in 2005;
  • A 17 percent increase in estimated cancer risk from air pollution around ports, likely due to an increase in container shipments;
  • Slight increases in estimated cancer risk in areas of Riverside County, possibly due to increased truck traffic and warehouse growth; and
  • About 84 percent of all estimated cancer risk from air pollution is due to diesel exhaust from trucks, trains, ships, locomotives and other diesel equipment;

AQMD continues to adopt policies and implement programs to reduce exposures to air toxics across the region, including ongoing incentive funding to replace older diesel school buses and heavy-duty trucks with cleaner models, school air filtration projects and the adoption of the 2010 Clean Communities Plan to address air toxics and air-related nuisances, with an emphasis on addressing cumulative impacts.

AQMD is the air pollution control agency for Orange County and major portions of Los Angeles, San Bernardino and Riverside counties.


MATES IV Fixed Monitoring Site Locations

  • Anaheim
  • Burbank
  • Compton
  • Fontana
  • Huntington Park
  • North Long Beach
  • Central Los Angeles
  • Pico Rivera
  • Rubidoux
  • West Long Beach

Toxic Air Contaminants to be Monitored in MATES IV

  • 1,3-Butadiene
  • Acetaldehyde
  • Arsenic
  • Benzene
  • Beryllium
  • Cadmium
  • Carbon Tetrachloride
  • Chloroform
  • Diesel PM
  • Formaldehyde
  • Hexavalent Chromium
  • Lead
  • Manganese
  • Methylene Chloride
  • Naphthalene
  • Nickel
  • Perchloroethylene
  • Polycyclic Aromatic Hydrocarbons (PAHs)
  • Trichloroethylene
  • Vinyl Chloride

Other Substances to be Monitored: 

  • PM10
  • PM2.5
  • Ultra Fine Particles
  • Elemental Carbon
  • Organic Carbon
  • Total Carbon
  • Black Carbon

This page updated: July 11, 2012