Appendix C	Air Quality and Health Risk		Table C-30										

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	1.3	1.4	1.03	1.31	1.17	0.42	0.83	0.73	0.65	0.76	0.68	0.73
	Health Risk	6	7	5	6	6	2	4	4	3	4	3	4
Benzene	Annual Avg	2.18	1.82	1.49	1.49	1.4	1.26	0.71	0.61	0.71	0.6	0.56	0.43
	Health Risk	202	169	138	138	129	116	66	56	66	55	52	39
"1,3-Butadiene"	Annual Avg	0.359	0.287	0.275	0.367	0.287	0.277	0.218	0.187	0.217	0.17	0.149	0.133
	Health Risk	135	108	103	138	108	104	82	70	82	64	56	50
Carbon Tetrachloride	Annual Avg	0.128	0.125		0.108		0.1	0.078				0.094	0.087
	Health Risk	34	33		29		26	21				25	23
Chromium (Hexavalent)	Annual Avg			0.23	0.2	0.19	0.25	0.13	0.12	0.1	0.1	0.12	
	Health Risk			34	29	29	37	19	17	15	15	18	
para-Dichlorobenzene	Annual Avg		0.12	0.12	0.12	0.11	0.13	0.14	0.12			0.11	0.14
	Health Risk		8	8	8	7	8	9	8			7	9
Formaldehyde	Annual Avg	1.87	1.73	1.43	1.56	1.66	2.06	2.62	1.85	1.76	2.09	1.77	2.32
	Health Risk	14	13	11	11	12	15	19	14	13	15	13	17
Methylene Chloride	Annual Avg	1.04	2.32	0.65	0.72	0.59	0.6	0.58	0.55			0.53	0.27
	Health Risk	4	8	2	2	2	2	2	2			2	0.9
Perchloroethylene	Annual Avg	0.204	0.232	0.169	0.128	0.082	0.094	0.067	0.071			0.078	0.059
	Health Risk	8	9	7	5	3	4	3	3			3	2
Diesel PM	Annual Avg	(2.5)					(1.9)					(1.6)	
	Health Risk	(750)					(570)					(480)	
Average Basin Health Risk		403	355	308	366	296	314	225	174	179	153	179	144.9

*    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."