| Cities with ≤100 days exceeding limits set for PM10 or ozone | Cities with >100 days exceeding limits set for PM10 or ozone | |
|---|---|---|
| Density of population (coefficient of regression β1) | 0.25 (p < 0.05) | 0.85 (p < 0.001) |
| F | 4.457 (p < 0.05) | 17.168 (p < 0.001) |
| R2 | 11.9% | 49% |
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