California Air Resources Board 2008 Almanac (web)			
Chapter 5	San Diego		Table 5-58
"San Diego - 1,3-Butadiene"			
Emissions Source	tons/year	Percent Air Basin	Percent State
Stationary Sources	1	<1%	<1%
Area-wide Sources	< 1	<1%	<1%
On-Road Mobile	101	42%	3%
   Gasoline Vehicles	99	41%	3%
   Diesel Vehicles	3	1%	<1%
Other Mobile	87	36%	2%
   Gasoline Fuel	56	23%	2%
   Diesel Fuel	6	2%	<1%
   Other Fuel	24	10%	1%
Natural Sources	52	22%	1%
Total	241	100%	7%
Total Statewide	3589