Chapter 5	Air Quality and Health Risk		Table 5-54										

San Joaquin Valley Air Basin Toxic Air Contaminants - Annual Average Concentrations and Health Risks													
TAC*	Conc./ Risk	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001
Acetaldehyde	Annual Avg	1.94	1.84	1.38	1.73	1.29	0.54	1.28	1.19	1.3	1.56	1.09	1.15
	Health Risk	9	9	7	8	6	3	6	6	6	8	5	6
Benzene	Annual Avg	2.45	2.11	1.36	1.32	1.33	1.16	0.73	0.71	0.76	0.69	0.63	0.54
	Health Risk	227	196	126	122	123	107	68	66	71	64	58	50
"1,3-Butadiene"	Annual Avg	0.41	0.36	0.24	0.34	0.32	0.26	0.22	0.2	0.23	0.18	0.16	0.15
	Health Risk	154	135	89	127	121	99	83	73	88	67	59	56
Carbon Tetrachloride	Annual Avg	0.13	0.13		0.11		0.1	0.08		0.11		0.1	0.09
	Health Risk	34	34		29		26	20		30		25	23
Chromium (Hexavalent)	Annual Avg			0.23	0.21	0.19	0.28	0.13	0.11	0.1	0.1	0.12	
	Health Risk			34	31	29	42	20	16	15	15	18	
para-Dichlorobenzene	Annual Avg		0.11	0.11	0.13	0.11	0.11	0.1	0.13			0.11	0.13
	Health Risk		7	7	9	7	8	7	9			7	9
Formaldehyde	Annual Avg	2.45	1.81	1.46	1.67	1.8	2.1	2.96	2.77	2.86	3.44	2.61	3.08
	Health Risk	18	13	11	12	13	15	22	20	21	25	19	23
Methylene Chloride	Annual Avg	0.76	0.59	0.55	0.76	0.59	0.61	0.54	0.53	0.52	0.5	0.53	0.27
	Health Risk	3	2	2	3	2	2	2	2	2	2	2	1
Perchloroethylene	Annual Avg	0.13	0.13	0.1	0.47	0.07	0.07	0.07	0.06	0.04		0.08	0.05
	Health Risk	5	5	4	19	3	3	3	2	2		3	2
Diesel Particulate Matter**	Annual Avg	(2.6)					(1.7)					(1.3)	
	Health Risk	(780)					(510)					(390)	
Average Basin Risk***	Without Diesel PM	450	401	280	360	304	305	231	194	235	181	196	170
	With Diesel PM	(1230)					(815)					(586)	

*    Concentrations for Chromium (Hexavalent) are expressed as ng/m3 and concentrations for Diesel PM are expressed as ug/m3.  Concentrations for all other TACs are expressed as parts per billion.													
"**   Diesel PM concentration estimates are based on receptor modeling techniques, and estimates are available only for selected years."													
***  Health Risk represents the number of excess cancer cases per million people based on a lifetime (70-year) exposure to the annual average concentration.  It reflects only those compounds listed in this table													
and only those with data for that year.  There may be other significant compounds for which we do not monitor or have health risk information.  Additional information about interpreting the toxic air contaminant air													
"quality trends can be found in Chapter 1, Interpreting the Emission and Air Quality Statistics."