Release 99-39
October 29, 1999
CONTACT: Jerry Martin
(916) 322-2990 
Richard Varenchik
(626) 575-6730


ARB Updates Motor Vehicle Emissions Inventory

        SACRAMENTO   The California Air Resources Board (ARB) today released an updated on-road emissions inventory an inventory which gives the most accurate picture to date of air emissions from motor vehicles.

        "We are always working to improve our air quality tools.  The new inventory gives us an improved tool to use with daily monitoring for cleaning the air," said Executive Officer Michael Kenny.   "Long-term trends show that we have been making correct air quality decisions.  The proof is continuing improvement in air quality, particularly in Southern California," he added.

        This year, the Los Angeles area has had its best air quality since pollution data has been recorded.  For instance, the Los Angeles area had 116 stage-one smog alerts in 1978; 77 stage-one alerts in 1988;  and 12 stage-one alerts in 1998.   There have been no stage-one alerts in the Los Angeles area in 1999.
        The ARB has published emission inventories and updates for more than 25 years, however, the refinements in the new inventory, known as Emission Factors 2000 (EMFAC 2000), are the most significant in recent years.  Improvements to EMFAC 2000 include new data factors that more accurately match real-world data gathered during monitoring.  Major changes to the model include:

        The new EMFAC 2000 model reflects updated statewide inventory amounts of several pollutants.  These include 700 tons-per-day (TPD) of hydrocarbons (HC), a 78 percent increase; 1,000 TPD of NOx, a 68 percent increase; and 7,700 TPD of carbon monoxide (CO), a 93 percent increase.

        "The new inventory will become part of the existing review and updating process for all ARB programs that use on-road motor vehicle information," Kenny said.  "This improved data will allow us to better fight air pollution in the most logical, cost-effective way," he added.

        The Air Resources Board, one of six agencies of the California Environmental Protection Agency, is California's air pollution control agency.  The ARB's mission is to promote and protect public health, welfare, and ecological resources through effective reduction of air pollutants while recognizing and considering effects on the economy.  The ARB oversees all air pollution control efforts in California to attain and maintain health based air quality standards.

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