California Air Resources Board

Sources Excluded from Current Risk Analysis

Page Reviewed July 28, 2010
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Aircraft Emissions:  Top of Page

Aircraft emissions (commercial/military/civil) currently need work related to geographical distribution. Staff determined that the crop dusting emission distribution was adequate, so this was the lone aircraft emissions category included.

Biogenic Emissions: 

Biogenic emissions are not currently included in the analysis.

Boats: Recreational and commercial:  Top of Page

Accurate geographical distributions of these sources are not currently available, so a major portion of these emissions were excluded from this analysis.

Geological Dust: 

The geological dust sources, such as windblown dust, road dust, and similar categories have been excluded from these maps.  This is because the speciation profiles are not based on robust scientific data. The profiles tend to cause these categories to overwhelm (especially in rural areas) all other particulate matter toxic compound risk. If these speciation profiles are improved these categories will be included in the maps.


Wildfires continue to be excluded from the risk analysis (as they were for the previously posted modeled risk maps). ARB staff are currently working to improve the estimates for emissions, geographic distribution, and speciated compounds released during burning. As these data are improved, they may be included at a later time.

International emissions sources:  Top of Page

For Imperial and San Diego counties, emissions originating in Mexico can have a major impact. These maps do not include emissions originating in Mexico.

Outer continental shelf: 

Most outer continental shelf emissions data are not included in these maps.

Industrial sources with inadequate location data: 

Many industrial sources have been excluded from these maps because of unreliable source location data. We will continue working with local air quality districts to improve source location information.

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A department of the California Environmental Protection Agency