Table 1. Average mass concentration levels of PM2.5 chemical elements in Changsha city (ng/m3).
| Indicators | Average value | Standard deviation | Minimum | Maximum | Percentiles (P) | ||
| 25 | 50 | 75 | |||||
| Na | 107.78 | 44.26 | 58.07 | 332.41 | 81.29 | 96.43 | 119.65 |
| Mg | 168.25 | 109.51 | 70.57 | 839.72 | 120.00 | 138.65 | 175.82 |
| Al | 833.55 | 380.31 | 425.83 | 2763.00 | 642.29 | 739.38 | 882.94 |
| Si | 1940.61 | 1158.14 | 759.44 | 9528.38 | 1430.57 | 1702.69 | 2095.75 |
| P | 12.19 | 5.78 | 1.80 | 45.55 | 9.08 | 11.20 | 13.27 |
| S | 3780.55 | 1525.23 | 966.14 | 9425.91 | 2763.43 | 3753.23 | 4415.92 |
| K | 1997.57 | 1695.27 | 296.39 | 11273.27 | 900.14 | 1546.74 | 2610.00 |
| Ca | 568.06 | 221.62 | 385.44 | 1638.62 | 438.02 | 483.09 | 612.40 |
| Ti | 34.53 | 18.73 | 13.05 | 145.10 | 23.49 | 30.84 | 38.83 |
| Fe | 462.51 | 222.12 | 181.63 | 1723.37 | 340.41 | 412.09 | 506.90 |
| Mn | 65.79 | 65.23 | 7.58 | 318.61 | 24.78 | 35.03 | 94.90 |
| Ni | 40.72 | 18.62 | 9.04 | 100.95 | 30.50 | 39.80 | 47.73 |
| Cu | 29.68 | 14.25 | 6.38 | 73.63 | 20.92 | 28.21 | 37.94 |
| Zn | 324.33 | 178.03 | 86.27 | 915.87 | 223.00 | 270.47 | 368.41 |
| Pb | 56.67 | 24.70 | 15.84 | 140.77 | 41.10 | 51.18 | 66.23 |
| V | 27.66 | 13.77 | 4.29 | 73.87 | 16.51 | 26.05 | 34.85 |
| Cr | 20.69 | 7.05 | 7.58 | 45.02 | 15.86 | 20.41 | 25.49 |
| As | 11.91 | 6.41 | 1.62 | 30.95 | 7.40 | 10.79 | 14.34 |
Al, aluminium; As, arsenic; Ca, calcium; Cr, chromium; Cu, copper; Fe, iron; K, potassium; Mg, magnesium; Mn, manganese; Na, Sodium; Ni, nickel; P, phosphorus; Pb, lead; S, sulfur; Si, silicon; Ti, titanium; V, vanadium; Zn, zinc.