Table 2 Summary statistics of daily concentration of air pollutants and meteorological indices
Meteorological elements/air pollutants | April–June (N = 182 days) | July–August (N = 124 days) | September–November (N = 182 days) | December–March (N = 243 days) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Mean | SD | Maximum | Mean | SD | Maximum | Mean | SD | Maximum | Mean | SD | Maximum | |
Atmospheric pressure (hPa) | 1,008.2 | 5.6 | 1,022.8 | 1,005.9 | 5.4 | 1,015.1 | 1,011.7 | 6.4 | 1,024.6 | 1,013.9 | 5.5 | 1,025.1 |
Relative humidity (%) | 69.8 | 12.3 | 93.0 | 74.4 | 6.9 | 94.0 | 71.5 | 8.3 | 92.0 | 66.9 | 8.7 | 92.0 |
Temperature (°C) | 17.7 | 5.0 | 28.6 | 27.7 | 1.9 | 31.0 | 18.5 | 5.9 | 30.5 | 5.4 | 3.1 | 13.5 |
Wind speed (m/sec) | 2.7 | 0.8 | 5.8 | 2.6 | 0.8 | 7.5 | 2.4 | 0.9 | 7.7 | 2.7 | 0.9 | 5.8 |
Daylight hours (h) | 5.6 | 4.5 | 13.4 | 6.5 | 3.9 | 12.9 | 5.4 | 3.7 | 12.2 | 5.2 | 3.2 | 11.3 |
NO2 (ppb) | 12.5 | 4.8 | 27.8 | 8.6 | 2.6 | 16.8 | 10.7 | 4.2 | 23.6 | 12.9 | 5.9 | 40.1 |
Ozone (ppb) | 36.2 | 11.0 | 62.4 | 22.5 | 10.6 | 58.3 | 21.5 | 8.4 | 46.7 | 23.0 | 9.0 | 46.6 |
SPM (μg/m3) | 27.3 | 11.6 | 99.2 | 24.0 | 8.1 | 46.3 | 18.7 | 8.4 | 47.4 | 17.2 | 11.0 | 132.4 |
PM2.5 (μg/m3) | 22.5 | 12.7 | 81.3 | 21.3 | 9.8 | 43.1 | 19.8 | 12.6 | 69.5 | 21.1 | 11.2 | 73.6 |
PM10 (μg/m3) | 41.0 | 29.8 | 289.1 | 34.2 | 12.4 | 60.3 | 32.6 | 21.9 | 206.4 | 29.5 | 15.0 | 103.1 |
OBC (μg/m3) | 0.5 | 0.3 | 1.6 | 0.5 | 0.3 | 1.4 | 0.5 | 0.3 | 1.7 | 0.5 | 0.4 | 2.8 |