California Air Resources Board 2004 Almanac (web)				
Chapter 5	"Top Ten Counties - 1,3 Butadiene Emissions"		Table 5-7	
"1,3-Butadiene"				3227.943877
County	Air Basin	tons/year	Percent	
Los Angeles	South Coast	518	16%	
San Diego	San Diego	229	7%	
Orange	South Coast	172	5%	
Santa Clara	San Francisco Bay Area	109	3%	
Ventura	South Central Coast	108	3%	
Tulare	San Joaquin Valley	103	3%	
San Bernardino	South Coast	99	3%	
Alameda	San Francisco Bay Area	94	3%	
Riverside	South Coast	91	3%	
Fresno	San Joaquin Valley	81	3%