Table 1.
Descriptive statistics of variables used in developing the LUR model for 1990–2009.
| Variable | No. of spatiotemporal pointsa | Mean ± SD | Minimum | Maximum |
|---|---|---|---|---|
| 8-hr O3 concentration (ppb) | 29,685 | 31.2 ± 13.1 | 0.0 | 104.0 |
| 8-hr temperature (°C) | 29,685 | 19.1 ± 5.3 | –3.5 | 33.9 |
| Precipitation (mm/day) | 29,685 | 3.0 ± 7.1 | 0.0 | 123.8 |
| Road density (km/πkm2) | 39 | 6.4 ± 7.9 | 0.0 | 25.4 |
| Rescaled latitude (km) | 39 | 114.6 ± 134.6 | 0 | 583.3 |
| aWe used 29,685 of 118,560 possible station-days (limited by temperature and precipitation variables). | ||||