California Air
Resources Board
Highest 24-Hour PM10 Concentration
in California Air Basins, 1994-1996
The graph below presents the highest 24-hour PM10 concentration measured in each air basin from 1994 through 1996.  Data affected by extreme concentration events are excluded.

Highest 24-hour PM10 Concentrations
The highest measured PM10 concentration, excluding data affected by extreme concentration events and other highly irregular or infrequent events, is the basis for determining an area's designation status with respect to the State PM10 standards.  The designation criteria provide for excluding unrepresentative pollutant concentrations because it is not reasonable to mitigate these concentrations through the regulatory process.  The unrepresentative concentrations may be caused by the following types of highly irregular or infrequent events:
Exceptional events
Extreme concentration events, and
Unusual concentration events.
Explanation of PM10 terminology and related PM10 programs
Back to the Statewide PM10 Web Page
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This page last revised on October 9, 1997
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