Table 3 Ambient air quality standards for substances that may be utilized in solar radiation management
| Substance | U.S Environmental Protection Agency | European Environmental Agency | World Health Organization | |||
|---|---|---|---|---|---|---|
| Limit (μg/m3) | Averaging period | Limit (μg/m3) | Averaging period | Limit (μg/m3) | Averaging period | |
| Sulfuric acid | - | - | - | - | - | - |
| Sulfur dioxide | 196.5 | 1 h | 350 | 1 h | 20 | 24 h |
| 125 | 24 h | 500 | 10 min | |||
| Hydrogen sulfide | - | - | - | - | - | - |
| Carbonyl sulfide | - | - | - | - | - | - |
| Nanoparticles | - | - | - | - | - | - |
| PM2.5 | 12 | 1 year | 25 | 1 year | 10 | 1 year |
| 35 | 24 h | -- | -- | 25 | 24 h | |