Chapter 5	Air Quality and Health Risk			Table 5-76										

Sacramento Valley Air Basin Toic Air Contaminants-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	1.29			1.37	1.04	0.39	1.03	1.05	0.92	1.23	0.83	0.74	1.14
	Health Risk	6			7	5	2	5	5	4	6	4	4	6
Benzene	Annual Avg	2.02	1.88	1.35	1.00	1.02	0.80	0.56	0.55	0.50	0.56	0.45	0.42	0.44
	Health Risk	187	174	125	92	95	74	51	51	47	52	42	39	41
"1,3-Butadiene"	Annual Avg	0.38	0.33	0.28	0.29	0.22	0.19	0.18	0.16	0.15	0.13	0.12	0.13	0.12
	Health Risk	142	125	106	108	83	70	66	60	58	48	45	47	44
Carbon Tetrachloride	Annual Avg	0.12	0.12		0.11		0.10	0.08				0.09	0.09	0.09
	Health Risk	33	32		29		26	21				25	23	24
"Chromium, Hexavalent"	Annual Avg			0.17	0.14	0.13	0.18	0.11	0.10	0.10	0.10	0.10	0.10	
	Health Risk			26	21	19	26	16	15	15	15	15	15	
para-Dichlorobenzene	Annual Avg			0.11	0.10	0.20	0.14	0.11	0.14			0.10	0.13	0.15
	Health Risk			7	7	14	9	7	10			7	9	10
Formaldehyde	Annual Avg	1.57			1.77	1.75	1.91	2.76	2.92	2.52	3.61	2.51	2.41	3.79
	Health Risk	12			13	13	14	20	22	19	27	18	18	28
Methylene Chloride	Annual Avg	0.65	0.56	0.55	0.98	0.66	0.53	0.54	0.52		0.60	0.57	0.29	0.08
	Health Risk	2	2	2	3	2	2	2	2		2	2	1	0
Perchloroethylene	Annual Avg	0.07	0.07	0.06	0.05	0.17	0.05	0.06	0.05			0.06	0.03	0.03
	Health Risk	3	3	3	2	7	2	2	2			2	1	1
Diesel Particulate Matter**	Annual Avg	(2.5)					(1.6)					(1.2)		
	Health Risk	(750)					(480)					(360)		
Average Basin Risk***	Without Diesel PM	385	336	269	282	238	225	190	167	143	150	160	157	154
	With Diesel PM	(1135)					(705)					(520)		

*    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 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."