Table 2. Levels of dust and air pollutants and meteorological observations during the study period.
Days | Mean | SD | 25th percentile | Median | 75th percentile | |
Dust extinction coefficients (/km) | ||||||
Hokkaido | 1199 | 0.012 | 0.014 | 0.003 | 0.008 | 0.015 |
Miyagi | 873 | 0.011 | 0.016 | 0.003 | 0.006 | 0.012 |
Ibaraki | 1333 | 0.017 | 0.014 | 0.007 | 0.016 | 0.025 |
Niigata | 529 | 0.021 | 0.026 | 0.008 | 0.015 | 0.025 |
Toyama | 1122 | 0.015 | 0.022 | 0.005 | 0.010 | 0.017 |
Shimane | 1159 | 0.032 | 0.035 | 0.016 | 0.024 | 0.036 |
Nagasaki | 1103 | 0.018 | 0.024 | 0.005 | 0.011 | 0.022 |
Spherical extinction coefficients (/km) | ||||||
Hokkaido | 1199 | 0.087 | 0.077 | 0.036 | 0.068 | 0.115 |
Miyagi | 870 | 0.074 | 0.107 | 0.014 | 0.039 | 0.085 |
Ibaraki | 1333 | 0.120 | 0.097 | 0.050 | 0.095 | 0.162 |
Niigata | 529 | 0.133 | 0.095 | 0.051 | 0.122 | 0.199 |
Toyama | 1122 | 0.059 | 0.061 | 0.016 | 0.045 | 0.083 |
Shimane | 1159 | 0.112 | 0.077 | 0.056 | 0.097 | 0.152 |
Nagasaki | 1103 | 0.086 | 0.071 | 0.038 | 0.069 | 0.115 |
SPM (µg/m3) | ||||||
Hokkaido | 1461 | 14.4 | 6.6 | 10.1 | 12.6 | 16.6 |
Miyagi | 1461 | 21.2 | 11.4 | 13.2 | 18.4 | 26.4 |
Ibaraki | 1461 | 23.8 | 12.7 | 14.7 | 20.7 | 29.7 |
Niigata | 1461 | 22.2 | 11.5 | 13.9 | 19.8 | 27.5 |
Toyama | 1461 | 19.9 | 11.6 | 11.4 | 16.9 | 25.4 |
Shimane | 1461 | 23.5 | 13.4 | 14.3 | 20.5 | 29.2 |
Nagasaki | 1461 | 28.7 | 14.7 | 18.6 | 24.9 | 34.7 |
NO2 (ppb) | ||||||
Hokkaido | 1461 | 11.4 | 4.8 | 7.9 | 10.3 | 14.0 |
Miyagi | 1461 | 13.3 | 4.8 | 9.9 | 12.5 | 16.2 |
Ibaraki | 1461 | 12.2 | 4.7 | 8.8 | 11.2 | 14.9 |
Niigata | 1461 | 10.5 | 4.3 | 7.5 | 9.9 | 12.6 |
Toyama | 1461 | 11.5 | 4.3 | 8.5 | 10.9 | 14.0 |
Shimane | 1461 | 6.4 | 2.5 | 4.6 | 6.0 | 7.7 |
Nagasaki | 1461 | 11.3 | 3.9 | 8.5 | 10.9 | 14.0 |
SO2 (ppb) | ||||||
Hokkaido | 1461 | 3.1 | 0.7 | 2.6 | 3.1 | 3.5 |
Miyagi | 1461 | 1.0 | 0.5 | 0.7 | 0.9 | 1.2 |
Ibaraki | 1461 | 3.4 | 1.0 | 2.7 | 3.3 | 3.9 |
Niigata | 1461 | 2.0 | 0.8 | 1.5 | 1.9 | 2.4 |
Toyama | 1461 | 1.8 | 0.7 | 1.4 | 1.7 | 2.2 |
Shimane | 1461 | 1.4 | 1.2 | 0.7 | 1.1 | 1.7 |
Nagasaki | 1461 | 3.3 | 1.1 | 2.5 | 3.1 | 3.9 |
Ox (ppb) | ||||||
Hokkaido | 1461 | 38.2 | 9.5 | 31.9 | 36.7 | 43.8 |
Miyagi | 1461 | 44.1 | 12.0 | 36.5 | 42.4 | 50.9 |
Ibaraki | 1461 | 49.4 | 16.0 | 38.7 | 46.1 | 57.0 |
Niigata | 1461 | 48.5 | 12.0 | 40.4 | 46.4 | 55.2 |
Toyama | 1461 | 51.7 | 13.5 | 41.8 | 49.6 | 60.4 |
Shimane | 1461 | 50.8 | 13.5 | 41.3 | 48.3 | 59.2 |
Nagasaki | 1461 | 47.5 | 15.1 | 38.2 | 46.2 | 57.6 |
Temperature Average (°C) | ||||||
Hokkaido | 1461 | 9.3 | 9.5 | 0.5 | 9.6 | 18.0 |
Miyagi | 1461 | 12.6 | 8.2 | 5.0 | 12.9 | 19.5 |
Ibaraki | 1461 | 14.0 | 8.0 | 6.6 | 14.4 | 20.9 |
Niigata | 1461 | 14.1 | 8.6 | 6.2 | 14.1 | 21.8 |
Toyama | 1461 | 14.5 | 8.8 | 6.7 | 14.9 | 22.0 |
Shimane | 1461 | 15.2 | 8.3 | 7.8 | 15.4 | 22.2 |
Nagasaki | 1461 | 17.6 | 7.8 | 11.0 | 18.0 | 24.6 |
Temperature Max (°C) | ||||||
Hokkaido | 1461 | 13.2 | 10.4 | 3.3 | 14.0 | 22.5 |
Miyagi | 1461 | 16.6 | 8.4 | 9.3 | 17.4 | 23.3 |
Ibaraki | 1461 | 18.9 | 7.7 | 12.2 | 19.2 | 25.1 |
Niigata | 1461 | 17.8 | 9.0 | 9.8 | 18.4 | 25.5 |
Toyama | 1461 | 19.0 | 9.3 | 10.9 | 19.9 | 26.5 |
Shimane | 1461 | 19.8 | 8.7 | 12.3 | 20.6 | 26.8 |
Nagasaki | 1461 | 21.4 | 7.9 | 14.7 | 22.1 | 28.1 |
Temperature Min (°C) | ||||||
Hokkaido | 1461 | 5.8 | 9.4 | −2.6 | 5.4 | 14.2 |
Miyagi | 1461 | 9.2 | 8.5 | 1.0 | 8.8 | 16.9 |
Ibaraki | 1461 | 9.7 | 8.9 | 1.4 | 9.8 | 17.7 |
Niigata | 1461 | 10.9 | 8.6 | 2.9 | 10.6 | 19.0 |
Toyama | 1461 | 10.7 | 8.6 | 2.6 | 10.3 | 18.8 |
Shimane | 1461 | 11.5 | 8.5 | 4.1 | 10.9 | 19.1 |
Nagasaki | 1461 | 14.2 | 8.1 | 6.8 | 14.1 | 21.8 |
Humidity (%) | ||||||
Hokkaido | 1461 | 68.0 | 10.0 | 62 | 68 | 75 |
Miyagi | 1461 | 72.6 | 13.2 | 63 | 73 | 83 |
Ibaraki | 1461 | 72.6 | 12.1 | 65 | 75 | 82 |
Niigata | 1461 | 69.5 | 8.9 | 64 | 70 | 76 |
Toyama | 1461 | 78.6 | 10.2 | 73 | 79 | 86 |
Shimane | 1461 | 73.9 | 8.9 | 69 | 74 | 80 |
Nagasaki | 1461 | 67.2 | 11.6 | 59 | 67 | 76 |
SD, standard deviation; SPM, suspended particulate matter.