Coefficients of correlation between hourly measured concentrations of PM7 and NO2, photochemical oxidants (Ox), temperature, and relative humidity
| Variable | Range of correlation coefficients* | |
|---|---|---|
| Warmer months (April–September) | Colder months (October–March) | |
| *Ranges of correlation coefficient for all 13 areas studied, 1990–94. | ||
| †Defined under the Japanese Air Quality Standard as any particles collected with an upper 100% cut-off point of 10 μm aerodynamic diameter. The 50% cut-off diameter for the particles is assumed to be approximately 7 μm (PM7). | ||
| ‡Photochemical oxidants. | ||
| PM7† and NO2 | 0.46 to 0.63 | 0.42 to 0.79 |
| PM7† and Ox‡ | −0.14 to 0.20 | −0.36 to −0.14 |
| PM7† and temperature | −0.09 to 0.28 | 0.04 to 0.28 |
| PM7† and relative humidity | −0.11 to 0.15 | 0.01 to 0.34 |