Table 2.
Summary of the LUR model for O3 concentrations in the region of study (1990–2009).a
| Fixed effect | Coefficient | SE | Effect sizec |
|---|---|---|---|
| Constant | 39.530 | 1.577 | — |
| Temperature ≤ 18ºCb | 0.218 | 0.021 | 39.461 |
| Temperature > 18ºCb | 2.139 | 0.019 | — |
| Precipitation | –0.010 | 0.001 | –1.238 |
| Day of the year | –0.107 | 0.001 | 16.371 |
| Year | –0.165 | 0.018 | 3.315 |
| Road density ≤ 15 km/πkm2b | –0.255 | 0.098 | –14.995 |
| Road density > 15 km/πkm2b | –1.074 | 0.219 | — |
| Latitude ≤ 50 kmb | –0.123 | 0.038 | 1.687 |
| Latitude > 50 kmb | 0.003 | 0.003 | — |
| aFor the random effect, the SD of intercept is 2.464 (95% CI: 1.915, 3.170); the SD of residuals of mixed model is 8.904. bVariables modeled as linear spline functions to account for nonlinear relations with O3. cThe effect size was calculated by βiViMax – βiViMin for non-splined variables, and by βiLowerViSpline – βiLowerViMin + βiUpper(ViMax – ViSpline), where ViSpline is the value of the knot of the variable of interest, βiLower the coefficient for values lower than the knot value, and βiUpper the coefficient for values greater than the knot value. | |||