California Air Resources Board 2004 Almanac (web)				
Chapter 5	"Statewide 1,3 Butadiene Emissions"			Table 5-6
"1,3-Butadiene"				
Emissions Source	tons/year	Percent State		
Stationary Sources	22	1%		
Area-wide Sources	390	12%		
On-Road Mobile	1452	45%		
   Gasoline Vehicles	1426	44%		
   Diesel Vehicles	25	1%		
Other Mobile	1227	38%		
Natural Sources	136	4%		
Total Statewide	3228	100%