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PM2.5 concentration thresholds based on the WHO Global Air Quality Guidelines
| Risk classification | PM2.5 concentration (μg/m3) | Increased mortality rate (%) | |
|---|---|---|---|
| Safe | No/minor risk | ≤5 | Baseline |
| Unsafe | Low | 5–10 | 4 |
| Moderate | 10–15 | 8 | |
| High | 15–25 | 16 | |
| Very high | 25–35 | 24 | |
| Hazardous | >35 | >24 | |
Concentration thresholds and estimated mortality rates are based on the WHO Global Air Quality Guidelines3, which provide details on estimation methods.
