Table 2.
Summary statistics of daily concentrations of air pollutants and meteorological indices
| Air pollutants and meteorological indices | 2011 | 2012 | 2013 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| January | February | March | January | February | March | January | February | March | |
| PM2.5 (μg/m3) | 13.9 | 26.9 | 20.9 | 19.9 | 24.2 | 26.7 | 24.1 | 25.3 | 37.2 |
| PM10 (μg/m3) | 19.6 | 39.1 | 33.0 | 26.0 | 30.8 | 36.5 | 31.8 | 33.7 | 59.9 |
| OBC (μg/m3) | 0.4 | 0.7 | 0.4 | 0.4 | 0.4 | 0.4 | 0.5 | 0.4 | 0.8 |
| NO2 (ppb) | 15.9 | 13.4 | 11.8 | 11.3 | 12.0 | 14.2 | 12.6 | 12.1 | 14.5 |
| Ozone (ppb) | 20.7 | 26.4 | 32.5 | 19.9 | 23.0 | 26.8 | 23.6 | 27.7 | 30.6 |
| Atmospheric pressure (hPa) | 1,014.5 | 1,014.8 | 1,013.7 | 1,015.6 | 1,014.7 | 1,012.6 | 1,016.8 | 1,016.5 | 1,011.7 |
| Relative humidity (%) | 64 | 68 | 65 | 67 | 67 | 68 | 68 | 69 | 67 |
| Temperature (°C) | 2.4 | 5.8 | 6.5 | 4.1 | 3.7 | 7.8 | 3.5 | 4.6 | 9.0 |
| Wind speed (m/s) | 2.8 | 2.3 | 2.5 | 2.5 | 2.7 | 2.8 | 2.5 | 2.4 | 2.7 |
| Daylight (h) | 6.3 | 5.5 | 6.0 | 4.6 | 4.6 | 4.4 | 5.4 | 4.7 | 5.7 |
NO 2 nitrogen dioxide, OBC optical black carbon, PM particulate matter