Table 2 Summary statistics of PM2.5 total mass and chemical species and weather factors during March–June 2014–2016
City/Variables | #days | Median (IQR) | Min | Max | Percent PM2.5 mass |
|---|---|---|---|---|---|
Nagasaki (Mar–June) | |||||
  PM2.5 (μg/m3) | 205 | 16.2 (11.5) | 0.9 | 73.3 | – |
  OC (μg/m3) | 205 | 2.9 (2.0) | 0.7 | 20.6 | 18.1 |
  EC (μg/m3) | 205 | 0.4 (0.2) | < 0.01 | 3.5 | 2.5 |
  Nitrate (μg/m3) | 205 | 0.8 (1.0) | 0.1 | 9.4 | 6.8 |
  Sulfate (μg/m3) | 205 | 1.1 (1.9) | 0.0 | 8.0 | 9.9 |
  Ammonium (μg/m3) | 205 | 0.4 (0.8) | 0.0 | 7.8 | 4.4 |
  Mean temperature (°C) | 366 | 17.5 (4.7)a | 3.2 | 26.2 | – |
  Relative humidity (%) | 366 | 73.3 (13.3)a | 37.0 | 99.0 | – |
Isahaya (Mar–May) | |||||
  PM2.5 (μg/m3) | 183 | 17.7 (9.8) | 3.1 | 58.0 | – |
  OC (μg/m3) | 183 | 2.6 (1.8) | 0.7 | 9.4 | 15.4 |
  EC (μg/m3) | 183 | 1.0 (0.8) | 0.3 | 8.9 | 6.4 |
  Nitrate (μg/m3) | 183 | 0.5 (1.1) | < 0.01 | 10.0 | 5.2 |
  Sulfate (μg/m3) | 183 | 5.1 (3.6) | 1.2 | 17.0 | 29.9 |
  Ammonium (μg/m3) | 183 | 2.2 (1.7) | 0.4 | 8.1 | 13.0 |
  Mean temperature (°C) | 276 | 15.9 (4.3)a | 3.2 | 23.3 | – |
  Relative humidity (%) | 276 | 69.7 (12.3)a | 37.0 | 96.0 | – |