Table 3.
Descriptive statistics of air quality 1.
| AQI Categories, Days (%) | |
| Excellent (AQI = 0–50) | 11,680 (31.3) |
| Good (AQI = 50–100) | 19,088 (51.1) |
| Lightly polluted (AQI = 100–150) | 6155 (16.5) |
| Moderately and heavily polluted (AQI > 150) | 438 (1.2) |
| PM2.5 Levels, Days (%) | |
| 0–35 µg/m3 | 18,594 (49.8) |
| 35–75 µg/m3 | 16,485 (44.1) |
| 75–115 µg/m3 | 2112 (5.7) |
| >115 µg/m3 | 170 (0.5) |
| PM10 Levels, Days (%) | |
| 0–50 µg/m3 | 13,087 (35.0) |
| 50–150 µg/m3 | 23,630 (63.2) |
| 150–250 µg/m3 | 626 (1.7) |
| >250 µg/m3 | 18 (0.0) |
| O3 Levels, Days (%) | |
| 0–160 µg/m3 | 23,960 (64.1) |
| 160–200 µg/m3 | 7716 (20.7) |
| 200–300 µg/m3 | 5423 (14.5) |
| >300 µg/m3 | 262 (0.7) |
1 The classification of AQI and concentrations of air pollutants are according to the Ambient Air Quality Standards in China.