Table 1:
Air quality index (AQI) categories corresponding to PM2.5 concentration (10) and the PM2.5 concentrations reported in the previous studies
| AQI Categories | PM2.5 (μg m−3) [24-hours] | PM2.5 (μg m−3) of previous studies | AQI level of previous studies | Reference | |
|---|---|---|---|---|---|
| Good | 0–12 | Fitness centers | 0.9–43 | Unhealthy for sensitive groups | (2) |
| Moderate | 12.1–35.4 | 5–777 | Hazardous | (5) | |
| Unhealthy for sensitive groups | 35.5–55.4 | Gymnastics halls | 18–405 | Hazardous | (6) |
| Hazardous | 250.5–500.4 | School gyms | 17–95 | Hazardous | (7) |