2002 Almanac (page 453) Table C-17 San Francisco Bay Area Air Basin: Annual Average Concentrations and Health Risks by Site Annual Average Concentration* Health Risk** COUNTY / SITE TAC 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 ALAMEDA Fremont-Chapel Way Acetaldehyde 1.28 1.6 1.02 1.28 1.23 0.35 0.88 0.65 0.72 6 8 5 6 6 2 4 3 4 Benzene 1.92 1.67 1.21 1.35 1.25 1.24 0.58 0.76 0.61 0.53 178 155 112 125 116 115 54 71 57 49 "1,3-Butadiene" 0.28 0.26 0.19 0.32 0.25 0.27 0.2 0.24 0.18 0.14 106 97 72 120 95 101 75 90 66 51 Carbon Tetrachloride 0.13 0.13 0.11 0.1 0.08 0.1 35 34 28 27 20 25 Chromium (Hexavalent) 0.2 0.19 0.21 0.2 0.11 0.1 0.1 0.1 30 28 32 30 16 15 15 16 para-Dichlorobenzene 0.11 0.11 0.1 0.12 0.1 0.1 7 7 7 8 7 7 Formaldehyde 1.84 1.98 1.3 1.37 1.78 2.02 2.16 1.79 1.96 14 15 10 10 13 15 16 13 15 Methylene Chloride 0.76 0.58 0.52 0.83 0.5 0.62 0.5 0.5 3 2 2 3 2 2 2 2 Perchloroethylene 0.19 0.21 0.13 0.11 0.09 0.12 0.07 0.08 8 8 5 5 3 5 3 3 Diesel PM Total Health Risk 350 319 243 332 274 305 197 16 195 138 153 CONTRA COSTA Concord-2975 Treat Blvd Acetaldehyde 1.41 1.39 1.46 0.62 0.86 0.76 0.87 7 7 7 3 4 4 4 Benzene 1.84 1.58 1.41 1.13 1.08 1.09 0.48 0.56 0.57 0.57 171 147 130 105 100 101 44 52 53 53 "1,3-Butadiene" 0.32 0.27 0.25 0.31 0.23 0.24 0.15 0.18 0.19 0.16 118 100 95 114 87 91 56 66 72 58 Carbon Tetrachloride 0.13 0.13 0.11 0.1 0.08 34 33 29 27 22 Chromium (Hexavalent) 0.19 0.18 0.21 0.11 0.11 0.1 28 27 32 16 17 15 para-Dichlorobenzene 0.15 0.13 0.14 0.13 0.13 0.14 10 8 9 9 8 9 Formaldehyde 1.99 1.99 1.69 2.21 2.3 2.05 2.64 15 15 12 16 17 15 19 Methylene Chloride 0.67 0.51 0.66 0.54 0.54 0.55 0.55 0.5 2 2 2 2 2 2 2 2 Perchloroethylene 0.34 0.42 0.39 0.2 0.1 0.15 0.08 0.1 13 17 16 8 4 6 3 4 Diesel PM No Monitoring Data Available Total Health Risk 360 299 253 316 248 287 172 169 125 149 CONTRA COSTA Richmond-13th Street Acetaldehyde 0.78 0.92 0.36 0.59 4 4 2 3 Benzene 1.92 1.54 1.76 1.7 1.44 1 177 143 163 157 133 92 "1,3-Butadiene" 0.27 0.26 0.39 0.31 0.3 0.25 102 98 148 116 113 94 Carbon Tetrachloride 0.12 0.11 0.1 0.08 33 29 25 21 Chromium (Hexavalent) 0.19 0.15 0.26 0.13 28 23 39 19 para-Dichlorobenzene 0.14 0.12 0.12 0.1 0.12 0.19 9 8 8 7 8 13 Formaldehyde 1.08 1.32 2.22 4.27 8 10 16 31 Methylene Chloride 0.62 0.54 0.67 0.5 0.54 0.65 2 2 2 2 2 2 Perchloroethylene 0.15 0.09 0.09 0.06 0.04 0.03 6 4 4 2 2 1 Diesel PM No Monitoring Data Available Total Health Risk 329 295 354 321 340 276 CONTRA COSTA San Pablo-El Portal Acetaldehyde 0.55 3 Benzene 0.56 0.42 52 39 "1,3-Butadiene" 0.15 0.12 56 45 Carbon Tetrachloride Chromium (Hexavalent) 0.1 15 para-Dichlorobenzene Formaldehyde 1.24 9 Methylene Chloride Perchloroethylene Diesel PM No Monitoring Data Available Total Health Risk 108 111 SAN FRANCISCO San Francisco-Arkansas Street Acetaldehyde 1.32 0.98 0.4 0.75 0.54 6 5 2 4 3 Benzene 1.49 1.25 1.07 0.95 0.53 0.51 0.63 0.65 0.48 138 116 99 88 49 48 59 61 45 "1,3-Butadiene" 0.25 0.23 0.26 0.23 0.18 0.17 0.22 0.17 0.13 95 88 97 85 68 62 81 65 48 Carbon Tetrachloride 0.12 0.1 0.08 0.1 33 26 21 25 Chromium (Hexavalent) 0.19 0.18 0.25 0.12 0.13 0.1 0.12 29 26 37 18 19 15 18 para-Dichlorobenzene 0.15 0.13 0.1 0.15 0.12 0.12 0.11 10 9 7 10 8 8 7 Formaldehyde 1.71 1.33 1.58 1.62 1.45 13 10 12 12 11 Methylene Chloride 3.22 0.88 0.6 0.63 0.66 0.5 0.6 11 3 2 2 2 2 2 Perchloroethylene 0.23 0.13 0.11 0.09 0.08 0.07 0.07 9 5 4 4 3 3 3 Diesel PM No Monitoring Data Available Total Health Risk 19 296 221 29 250 266 169 158 169 126 148 SANTA CLARA San Jose-4th Street Acetaldehyde 1.53 1.55 1.41 1.58 1.27 0.35 1.04 0.97 0.77 0.93 0.79 7 8 7 8 6 2 5 5 4 4 Benzene 3.02 2.44 2.03 1.89 1.88 1.55 0.97 0.93 1.04 0.73 0.7 280 226 188 175 174 144 89 86 97 68 65 "1,3-Butadiene" 0.55 0.39 0.44 0.49 0.39 0.35 0.31 0.29 0.29 0.23 0.19 207 145 164 182 145 131 117 108 110 85 72 Carbon Tetrachloride 0.13 0.13 0.11 0.1 0.08 0.1 33 34 28 27 20 25 Chromium (Hexavalent) 0.29 0.25 0.25 0.33 0.17 0.13 0.11 0.1 0.13 43 37 38 49 25 20 17 15 19 para-Dichlorobenzene 0.12 0.12 0.1 0.12 0.14 0.12 0.12 8 8 7 8 10 8 8 Formaldehyde 2.27 2 2.09 1.83 2.16 2.28 2.7 2.56 2.24 2.69 2.24 17 15 15 13 16 17 20 19 16 20 16 Methylene Chloride 0.83 6.65 0.66 0.58 0.8 0.69 0.55 0.75 0.5 3 23 2 2 3 2 2 3 2 Perchloroethylene 0.16 0.15 0.1 0.09 0.06 0.07 0.07 0.1 0.09 6 6 4 4 3 3 3 4 4 Diesel PM No Monitoring Data Available Total Health Risk 553 457 431 457 392 383 291 253 244 192 215 BASIN SUMMARY Acetaldehyde 1.3 1.4 1.03 1.31 1.17 0.42 0.83 0.73 0.65 0.76 0.68 6 7 5 6 6 2 4 4 3 4 3 Benzene 2.18 1.82 1.49 1.49 1.4 1.26 0.71 0.61 0.71 0.6 0.56 202 169 138 138 129 116 66 56 66 55 52 "1,3-Butadiene" 0.36 0.29 0.28 0.37 0.29 0.28 0.22 0.19 0.22 0.17 0.15 135 108 103 138 108 104 82 70 82 64 56 Carbon Tetrachloride 0.13 0.13 0.11 0.1 0.08 0.09 34 33 29 26 21 25 Chromium (Hexavalent) 0.23 0.2 0.19 0.25 0.13 0.12 0.1 0.1 0.12 34 29 29 37 19 17 15 15 18 para-Dichlorobenzene 0.12 0.12 0.12 0.11 0.13 0.14 0.12 0.11 8 8 8 7 8 9 8 7 Formaldehyde 1.87 1.73 1.43 1.56 1.66 2.06 2.62 1.85 1.76 2.09 1.77 14 13 11 11 12 15 19 14 13 15 13 Methylene Chloride 1.04 2.32 0.65 0.72 0.59 0.6 0.58 0.55 0.53 4 8 2 2 2 2 2 2 2 Perchloroethylene 0.2 0.23 0.17 0.13 0.08 0.09 0.07 0.07 0.08 8 9 7 5 3 4 3 3 3 Diesel PM*** 2.5 1.9 1.6 750 570 480 Average Basin Health Risk 403 355 308 366 296 314 225 174 179 153 179 * 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. "