California Air Resources Board 2009 Almanac (web)			
Chapter 5	Table 5-8		Statewide
"1,3-Butadiene"			
County	Air Basin	tons/year	Percent
Los Angeles	South Coast	369	10%
San Diego	San Diego	233	6%
Tulare	San Joaquin Valley	158	4%
Orange	South Coast	119	3%
Fresno	San Joaquin Valley	113	3%
San Bernardino	Mojave Desert	111	3%
Siskiyou	Northeast Plateau	110	3%
San Bernardino	South Coast	108	3%
Tuolumne	Mountain Counties	106	3%
Plumas	Mountain Counties	91	2%