Appendix C	Butte County: Chico - Manzanita Avenue Air Quality and Health Risk													Table C-45			

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
Acetaldehyde	Annual Avg	 	 	 	1.55	1.11	0.54	1.15	1.17	0.96	1.41	0.89	1.1	1.33	1.14	1.32	1.4
	Health Risk	 	 	 	8	5	3	6	6	5	7	4	5	6	6	6	7
Benzene	Annual Avg	 	 	 	1.1	1.14	0.85	0.67	 	0.55	0.64	0.52	0.499	0.544	0.449	0.533	0.427
	Health Risk	 	 	 	102	106	78	62	 	51	59	48	46	50	42	49	40
"1,3-Butadiene"	Annual Avg	 	 	 	0.295	0.249	0.205	0.216	 	0.17	0.149	0.142	0.157	0.154	0.111	0.132	0.108
	Health Risk	 	 	 	111	94	77	81	 	64	56	54	59	58	42	50	41
Carbon Tetrachloride	Annual Avg	 	 	 	0.108	 	0.1	0.079	 	 	 	 	0.088	0.087	0.093	 	
	Health Risk	 	 	 	29	 	26	21	 	 	 	 	23	23	24	 	
"Chromium, Hexavalent"	Annual Avg	 	 	 	0.15	0.13	0.16	0.1	0.1	0.1	0.1	0.1	0.1	0.058	0.048	0.075	0.058
	Health Risk	 	 	 	23	19	24	16	15	15	15	15	15	9	7	11	9
para-Dichlorobenzene	Annual Avg	 	 	 	0.1	0.13	0.1	0.12	 	 	 	 	0.13	0.15	0.15	0.15	0.15
	Health Risk	 	 	 	7	8	7	8	 	 	 	 	9	10	10	10	10
Formaldehyde	Annual Avg	 	 	 	2.08	1.78	2.04	2.99	3.42	2.63	4.15	2.76	3.25	4.47	3.82	3.4	3.28
	Health Risk	 	 	 	15	13	15	22	25	19	31	20	24	33	28	25	24
Methylene Chloride	Annual Avg	 	 	 	0.81	0.5	0.53	0.58	 	 	 	 	0.36	0.09	0.07	0.08	0.09
	Health Risk	 	 	 	3	2	2	2	 	 	 	 	1	 <1	 <1	 <1	 <1
Perchloroethylene	Annual Avg	 	 	 	0.057	0.265	0.047	0.049	 	 	 	 	0.024	0.024	0.015	0.014	0.028
	Health Risk	 	 	 	2	11	2	2	 	 	 	 	 <1	1	 <1	 <1	1
Diesel PM	Annual Avg	No Monitoring Data Available															
	Health Risk																
Total Health Risk		 	 	 	300	258	234	220	46	154	168	141	182	190	159	151	132
																	
"1  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 ppb."																	
2  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.