Annual Average Concentration*										Health Risk**									
COUNTY	SITE NAME	TAC	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999
Butte	Chico-Manzanita	Acetaldehyde				1.55	1.11	0.54	1.15	1.17	0.96	1.41				8	5	3	6	6	5	7
		Benzene				1.1	1.14	0.85	0.67		0.55	0.64				102	106	78	62		51	59
		"1,3-Butadiene"				0.3	0.25	0.21	0.22		0.17	0.15				111	94	77	81		64	56
		Carbon Tetrachloride				0.11		0.1	0.08							29		27	21			
		Chromium (Hexavalent)				0.15	0.13	0.16	0.1	0.1	0.1					23	19	24	16	15	15	
		para-Dichlorobenzene				0.1	0.13	0.1	0.12							7	8	7	8			
		Formaldehyde				2.08	1.78	2.04	2.99	3.42	2.63	4.15				15	13	15	22	25	19	31
		Methylene Chloride				0.81	0.5	0.53	0.58							3	2	2	2			
		Perchloroethylene				0.06	0.27	0.05	0.05							2	11	2	2			
		Diesel PM	No Monitoring Data Available																			
	Total Health Risk															299	258	233	219	46	154	152

	Chico-Salem Street	Acetaldehyde	1.27										6									
		Benzene	1.96	1.91									182	177								
		"1,3-Butadiene"	0.4	0.36									151	136								
		Carbon Tetrachloride	0.12	0.12									33	33								
		Chromium (Hexavalent)																				
		para-Dichlorobenzene																				
		Formaldehyde	1.49										11									
		Methylene Chloride	0.53	0.57									2	2								
		Perchloroethylene	0.05	0.05									2	2								
		Diesel PM	No Monitoring Data Available																			
	Total Health Risk												387	350								

Placer	Roseville-North Sunrise Blvd.	Acetaldehyde					0.96	0.25	0.9	0.93	0.88						5	1	4	5	4	
		Benzene					0.91	0.75	0.44	0.46	0.45	0.48					84	70	40	42	42	44
		"1,3-Butadiene"					0.19	0.17	0.14	0.12	0.14	0.11					73	63	51	46	52	40
		Carbon Tetrachloride						0.1	0.08									26	20			
		Chromium (Hexavalent)					0.13	0.19	0.11	0.1	0.1						19	29	16	15	15	
		para-Dichlorobenzene					0.28	0.17	0.1	0.15							19	11	7	10		
		Formaldehyde					1.71	1.78	2.52	2.42	2.42						13	13	19	18	18	
		Methylene Chloride					0.82	0.54	0.5	0.5							3	2	2	2		
		Perchloroethylene					0.07	0.05	0.06	0.06							3	2	2	3		
		Diesel PM	No Monitoring Data Available																			
	Total Health Risk																217	217	161	139	131	85

			Annual Average Concentration*										Health Risk**									
COUNTY	SITE NAME	COMPOUND	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999
Sacramento	Citrus Heights-Sunrise Blvd.	Acetaldehyde	1.32										6									
		Benzene	2.08	1.85	1.41								192	171	130							
		"1,3-Butadiene"	0.35	0.3	0.31								133	114	115							
		Carbon Tetrachloride	0.12	0.12									33	32								
		Chromium (Hexavalent)																				
		para-Dichlorobenzene			0.11										7							
		Formaldehyde	1.66										12									
		Methylene Chloride	0.76	0.54	0.5								3	2	2							
		Perchloroethylene	0.1	0.09	0.08								4	4	3							
		Diesel PM	No Monitoring Data Available																			
	Total Health Risk												383	323	257							

All Counties	BASIN SUMMARY	Acetaldehyde	1.29			1.37	1.04	0.39	1.03	1.05	0.92	1.23	6			7	5	2	5	5	5	6
		Benzene	2.02	1.88	1.35	1	1.02	8	0.56	0.55	0.5	0.56	187	174	125	93	95	74	51	51	47	52
		"1,3-Butadiene"	0.38	0.33	0.28	0.29	0.22	0.19	0.18	0.16	0.15	0.13	142	125	106	108	83	70	66	60	58	48
		Carbon Tetrachloride	0.12	0.12		0.11		0.1	0.08				33	33		29		26	21			
		Chromium (Hexavalent)			0.17	0.14	0.13	0.18	0.11	0.1	0.1				26	21	19	26	16	15	15	
		para-Dichlorobenzene			0.11	0.1	0.2	0.14	0.11	0.14					7	7	14	9	7	10		
		Formaldehyde	1.57			1.77	1.75	1.91	2.76	2.92	2.52	3.61	12			13	13	14	20	22	19	27
		Methylene Chloride	0.65	0.56	0.55	0.98	0.66	0.53	0.54	0.52		0.6	2	2	2	3	2	2	2	2		2
		Perchloroethylene	0.07	0.07	0.06	0.05	0.17	0.05	0.06	0.05			3	3	3	2	7	2	2	2		
		Diesel PM***	-2.5					-1.6				-1.2	-750					-480				-360
	Average Basin Health Risk												385	336	269	282	238	225	190	166	143	134

"*      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 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 the 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.  The 1999 concentrations reflect an estimate for the year 2000.  Because data are not available for all years, Diesel PM is not included in the "
         Average Basin Health Risk number.