Table 3.
Average mass concentrations of PM2.5 species during the sampling period at the four sites
| CAU | SZ | QZ | YC | |
|---|---|---|---|---|
| Mean ± SD | Mean ± SD | Mean ± SD | Mean ± SD | |
| PM2.5 (μg m−3) | 159.40 ± 95.76 | 141.50 ± 105.89 | 153.85 ± 101.53 | 141.78 ± 68.38 |
| NO3 − (μg m−3) | 19.23 ± 18.98 | 16.26 ± 19.28 | 16.01 ± 15.95 | 18.09 ± 15.13 |
| SO4 2− (μg m−3) | 18.61 ± 17.92 | 15.21 ± 14.80 | 20.08 ± 16.06 | 24.52 ± 14.66 |
| NH4 + (μg m−3) | 10.78 ± 10.26 | 9.67 ± 9.54 | 10.49 ± 8.31 | 12.25 ± 7.02 |
| Cl− (μg m−3) | 3.74 ± 4.82 | 2.28 ± 2.70 | 3.52 ± 4.36 | 2.42 ± 2.81 |
| Ca2+ (μg m−3) | 2.64 ± 1.98 | 1.82 ± 1.72 | 1.60 ± 1.59 | 1.25 ± 1.06 |
| Na+ (μg m−3) | 0.93 ± 0.87 | 0.84 ± 0.73 | 0.71 ± 0.69 | 0.70 ± 0.69 |
| K+ (μg m−3) | 1.32 ± 1.24 | 1.21 ± 1.16 | 1.73 ± 1.24 | 2.04 ± 1.43 |
| Mg2+ (μg m−3) | 0.32 ± 0.27 | 0.26 ± 0.18 | 0.23 ± 0.23 | 0.24 ± 0.26 |
| F− (μg m−3) | 0.26 ± 0.26 | 0.18 ± 0.19 | 0.21 ± 0.24 | 0.27 ± 0.26 |
| Sum of ionic species (μg m−3) | 58.84 ± 48.88 | 47.73 ± 43.78 | 55.31 ± 41.95 | 61.97 ± 35.63 |
| Secondary inorganic aerosol (μg m−3) | 48.6 ± 44.9 | 41.2 ± 40.8 | 46.6 ± 37.2 | 54.9 ± 33.1 |
| WSII (%)a | 0.35 ± 0.18 | 0.34 ± 0.17 | 0.35 ± 0.15 | 0.44 ± 0.15 |
| SIA (%)b | 0.29 ± 0.17 | 0.29 ± 0.16 | 0.30 ± 0.14 | 0.39 ± 0.15 |
aProportion of water-soluble inorganic ions in PM2.5
bProportion of secondary inorganic ions in PM2.5