2002 Almanac (page 209)  Table 5-1  Toxic Air Contaminant Unit Risk Factors	

Toxic Air Contaminant Unit Risk Factors	
Toxic Air Contaminant	Unit Risk/Million People*
Acetaldehyde	2.7
Benzene	29
"1,3-Butadiene"	170
Carbon Tetrachloride	42
Chromium (Hexavalent)	"150,000"
para-Dichlorobenzene	11
Formaldehyde	6
Methylene Chloride	1
Perchloroethylene	5.9
Diesel Particulate Matter	300**

*  The Unit Risk represents the number of excess cancers per million people per	
microgram per cubic meter TAC concentration over a 70-year lifetime exposure.
** A diesel particulate matter unit risk value of 300 is used as a reasonable estimate
"in the ""Risk Reduction Plan to Reduce Particulate Matter Emissions from Diesel-Fueled"
" Engines and Vehicles"" (ARB, October 2000)."