Table 2.
Descriptive statistics on annual-average weather conditions and ambient air pollution in all counties (N = 2844) of Chinese Mainland during the study period (2013–2019).
| Mean ± SD | Minimum | Percentile |
Maximum | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| P1 | P2.5 | P25 | P50 | P75 | P97.5 | P99 | ||||
| Weather condition | ||||||||||
| Temperature (°C) | 13.7 ± 10.2 | −19.8 | −14.1 | −9.2 | 6.6 | 14.8 | 22.1 | 28.7 | 29.6 | 31.2 |
| Relative humidity (%) | 66.7 ± 16.6 | 19.3 | 25.2 | 29.8 | 55.6 | 70.1 | 79.9 | 90.3 | 92.3 | 95.2 |
| Air pollutants (μg/m3) | ||||||||||
| PM2.5 | 51.1 ± 40.4 | 4.8 | 7.3 | 9.4 | 24.1 | 39.3 | 64.4 | 164.0 | 207.0 | 323.1 |
| O3a | 80.7 ± 44.7 | 3.7 | 7.9 | 12.4 | 47.6 | 74.1 | 107.0 | 186.0 | 207.0 | 244.2 |
| NO2 | 33.5 ± 19.9 | 2.5 | 4.8 | 6.7 | 18.4 | 29.3 | 44.5 | 82.5 | 94.3 | 120.0 |
| CO | 1.0 ± 0.6 | 0.1 | 0.2 | 0.3 | 0.7 | 0.9 | 1.2 | 2.6 | 3.2 | 4.5 |
| SO2 | 21.0 ± 22.9 | 1.5 | 2.1 | 2.8 | 7.9 | 13.6 | 24.8 | 89.3 | 126.0 | 206.6 |
Abbreviations: SD, standard deviation; PM2.5, fine particulate matter, particles with aerodynamic diameters less than or equal to 2.5 μm; O3, ozone; NO2, nitrogen dioxide; CO, carbon monoxide; SO2, sulfur dioxide.
a
O3: Maximum daily 8-h.