Appendix C	San Diego County: Chula Vista Air Quality and Health Risk													Table C-39	

Annual Average Concentrations and Health Risks															
TAC	Conc.*/Risk**	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003
Acetaldehyde	Annual Avg	1.10	1.21	0.99	1.16	1.32	0.64	0.83	0.91	0.70	0.91	0.75	0.78	0.75	0.72
	Health Risk	5	6	5	6	6	3	4	4	3	4	4	4	4	3
Benzene	Annual Avg	2.00	1.21	1.03	0.80	1.08	0.81		0.63	0.61		0.55	0.42	0.42	
	Health Risk	186	112	95	74	100	75		58	56		51	39	39	
"1,3-Butadiene"	Annual Avg	0.28	0.18	0.18	0.23	0.26	0.21		0.16	0.15		0.14	0.11	0.11	
	Health Risk	105	69	69	85	98	77		61	57		51	41	40	
Carbon Tetrachloride	Annual Avg	0.13	0.13		0.10		0.10					0.09	0.09	0.09	
	Health Risk	35	34		27		26					25	23	24	
"Chromium, Hexavalent"	Annual Avg			0.24	0.20	0.17	0.20	0.11	0.10	0.10	0.11	0.10		0.05	0.06
	Health Risk			37	30	25	29	16	15	15	16	16		8	9
para-Dichlorobenzene	Annual Avg		0.10	0.11	0.13	0.12	0.11		0.13				0.15	0.15	
	Health Risk		7	7	8	8	7		8				10	10	
Formaldehyde	Annual Avg	1.26	1.30	1.10	1.46	2.08	1.81	2.10	2.37	2.00	2.49	2.14	2.54	2.56	2.30
	Health Risk	9	10	8	11	15	13	15	17	15	18	16	19	19	17
Methylene Chloride	Annual Avg	0.58	0.59	0.81	1.01	0.57	0.57		0.62			0.65	0.16	0.13	
	Health Risk	2	2	3	3	2	2		2			2	1	0	
Perchloroethylene	Annual Avg	0.24	0.23	0.21	0.14	0.13	0.15		0.10			0.08	0.06	0.05	
	Health Risk	9	9	8	6	5	6		4			3	2	2	
Diesel PM	Annual Avg	No Monitoring Data Available													
	Health Risk														
Total Health Risk		351	249	232	250	259	238	35	169	146	38	168	139	146	29

"*    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."															
**  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.