Annual Average Concentrations and Health Risks																			
TAC	Conc.1/Risk2	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
Acetaldehyde	Annual Avg	1.47	1.75	1.07	1.31	1.1		0.9	0.9	1	1.07	0.64	0.59	0.8	0.81	0.87	0.99	0.93	0.88
	Health Risk	7	9	5	6	5		4	4	5	5	3	3	4	4	4	5	5	4
Benzene	Annual Avg	2.01	1.95	1.37		1.23	1.05	0.64	0.52	0.69	0.65	0.58	0.454	0.521	0.437	0.37	0.358	0.317	0.271
	Health Risk	186	181	127		113	97	60	48	64	60	54	42	48	40	34	33	29	25
"1,3-Butadiene"	Annual Avg	0.336	0.321	0.217		0.281	0.25	0.206	0.181	0.206	0.18	0.155	0.13	0.146	0.096	0.079	0.085	0.063	0.057
	Health Risk	126	121	82		106	94	77	68	77	68	58	49	55	36	30	32	24	22
Carbon Tetrachloride	Annual Avg	0.131	0.136				0.099	0.077		0.115		0.098	0.087	0.091	0.098				
	Health Risk	35	36				26	20		30		26	23	24	26				
"Chromium, Hexavalent"	Annual Avg			0.22	0.25	0.25		0.14			0.1	0.12		0.123	0.13	0.123	0.12	0.063	0.06
	Health Risk			33	37	37		21			15	18		18	20	18	18	9	9
para-Dichlorobenzene	Annual Avg		0.1	0.1		0.1	0.11	0.1	0.11			0.11	0.13	0.15	0.15	0.15	0.15	0.15	
	Health Risk		7	7		7	7	7	7			7	9	10	10	10	10	10	
Formaldehyde	Annual Avg	1.81	1.88	1.24	1.38	1.56		2.35	2.24	2.33	2.68	1.61	1.48	2.07	1.91	1.79	1.94	2.16	2.02
	Health Risk	13	14	9	10	12		17	16	17	20	12	11	15	14	13	14	16	15
Methylene Chloride	Annual Avg	0.63	0.5	0.6		0.5	0.75	0.53	0.5	0.5	0.5	0.53	0.27	0.14	0.16	0.12	0.12	0.11	0.1
	Health Risk	2	2	2		2	3	2	2	2	2	2	<1	<1	<1	<1	<1	<1	<1
Perchloroethylene	Annual Avg	0.129	0.113	0.12		0.066	0.061	0.068	0.09	0.033		0.108	0.053	0.035	0.03	0.022	0.024	0.018	0.02
	Health Risk	5	5	5		3	2	3	4	1		4	2	1	1	<1	1	<1	<1
Diesel PM	Annual Avg																		
	Health Risk																		
Total Health Risk		374	375	270	53	285	229	211	149	196	170	184	139	175	151	109	113	93	75






San Joaquin																			
Stockton-Hazelton Street