Appendix C	San Francisco County: San Francisco-Arkansas Street Air Quality and Health Risk										Table C-28			

Annual Average Concentrations and Health Risks														
TAC	Conc.*/Risk**	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002
Acetaldehyde	Annual Avg	1.32				0.98	0.40		0.75	0.54			0.57	0.54
	Health Risk	6				5	2		4	3			3	3
Benzene	Annual Avg		1.49	1.25		1.07	0.95	0.53	0.51	0.63	0.65	0.48	0.38	
	Health Risk		138	116		99	88	49	48	59	61	45	35	
"1,3-Butadiene"	Annual Avg		0.25	0.23		0.26	0.23	0.18	0.17	0.22	0.17	0.13	0.11	
	Health Risk		95	88		97	85	68	62	81	65	48	42	
Carbon Tetrachloride	Annual Avg		0.12				0.10	0.08				0.10	0.09	
	Health Risk		33				26	21				25	23	
"Chromium, Hexavalent"	Annual Avg				0.19	0.18	0.25	0.12	0.13	0.10		0.12		0.09
	Health Risk				29	26	37	18	19	15		18		13
para-Dichlorobenzene	Annual Avg		0.15	0.13		0.10	0.15	0.12	0.12			0.11	0.14	
	Health Risk		10	9		7	10	8	8			7	9	
Formaldehyde	Annual Avg	1.71				1.33	1.58		1.62	1.45			1.51	2.03
	Health Risk	13				10	12		12	11			11	15
Methylene Chloride	Annual Avg		3.22	0.88		0.60	0.63	0.66	0.50			0.60	0.26	
	Health Risk		11	3		2	2	2	2			2	1	
Perchloroethylene	Annual Avg		0.23	0.13		0.11	0.09	0.08	0.07			0.07	0.07	
	Health Risk		9	5		4	4	3	3			3	3	
Diesel PM	Annual Avg	No Monitoring Data Available												
	Health Risk													
Total Health Risk		19	296	221	29	250	266	169	158	169	126	148	127	31

"*    Concentrations for Hexavalent Chromium are expressed as ng/m3, and concentrations for Diesel PM are expressed as ug/m3.  Concentrations for all other TACs are expressed as ppb."														
**  Health Risk represents the number of excess cancer cases per million people based on a lifetime (70-year) exposure to the annual average concentration.  Total Health Risk represents only those compounds listed in														
this table and only those with data for that year.  There may be other significant compounds for which monitoring and/or health risk information are not available.