Table 1.
Pollutant standard and guideline concentrations for various exposure periods.
| Pollutant | 1-hr average (acute) | 8-hr average (acute) | Annual average (chronic) | Standard (reference) |
|---|---|---|---|---|
| NO2 | 180 ppb (339 μg/m3) | NA | 30 ppb (57 μg/m3) | CAAQS (CARB 2010) |
| 100 ppb (188 μg/m3) | NA | 53 ppb (100 μg/m3) | NAAQS (U.S. EPA 2012b) | |
| CO | 20 ppm (23 mg/m3) | 9 ppm (10 mg/m3) | NA | CAAQS (CARB 2010) |
| 35 ppm (40 mg/m3) | 9 ppm (10 mg/m3) | NA | NAAQS (U.S. EPA 2012b) | |
| HCHO | 45 ppb (55 μg/m3) | 7.3 ppb (9 μg/m3) | 7.3 ppb (9 μg/m3) | Non-cancer REL (OEHHA 2007) |
| Abbreviations: CAAQS, California Ambient Air Quality Standard; CARB, California Air Resources Board; NA, not available; NAAQS, National Ambient Air Quality Standard; OEHHA, California’s Office of Environmental Health Hazard Assessment; REL, reference exposure level. | ||||