Appendix C	Air Quality and Health Risk		Table C-37										

BASIN SUMMARY - 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	0.409	0.36	0.236	0.339	0.323	0.264	0.222	0.195	0.233	0.177	0.158	0.15
	Health Risk	154	135	89	127	121	99	83	73	88	67	59	56
Carbon Tetrachloride	Annual Avg	0.128	0.129		0.109		0.098	0.077		0.114		0.096	0.086
	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	0.9
Perchloroethylene	Annual Avg	0.126	0.133	0.104	0.473	0.067	0.068	0.068	0.056	0.039		0.076	0.052
	Health Risk	5	5	4	19	3	3	3	2	2		3	2
Diesel PM	Annual Avg	(2.6)					(1.7)					(1.3)	
	Health Risk	(780)					(510)					(390)	
Average Basin Health Risk		450	401	280	360	304	305	231	194	235	181	196	169.9

*    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.													
**   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.													
"**   The Diesel PM concentrations are estimates based on receptor modeling.  Because data are not available for all years, Diesel PM is not included in the Average Basin Health Risk number."