Table 6.
Example indoor air and subslab, soil vapor screening levels for petroleum-related chemicals.
| Chemical | Indoor Air 1 | Subslab Soil Vapor 2 | ||
|---|---|---|---|---|
| Residential (µg/m3) | Commercial/Industrial (µg/m3) | Residential (µg/m3) | Commercial/Industrial (µg/m3) | |
| Benzene | 0.31 | 1.6 | 310 | 3,200 |
| Ethylbenzene | 0.97 | 4.9 | 970 | 9,800 |
| Toluene | 5,200 | 22,000 | 5,200,000 | 44,000,000 |
| Xylenes | 100 | 440 | 100,000 | 880,000 |
| Naphthalene | 0.072 | 0.36 | 72 | 720 |
| C5-C8 aliphatics | 630 | 880 | 630,000 | 1,760,000 |
| C9-C18 aliphatics | 100 | 150 | 100,000 | 300,000 |
| C9-C16 aromatics | 100 | 150 | 100,000 | 300,000 |
1 Based on target cancer risk of 10−6 (benzene, ethylbenzene, naphthalene) or noncancer Hazard Quotient of 1.0 (toluene, xylenes and carbon range compounds); 2 Based on indoor air-soil vapor (subslab) attenuation factors of 0.001 for residential structures and 0.0005 for commercial/industrial structures (after [8]; for example only).