Pooled estimates for the increase in mortality associated with an increase of 10μg·m-3 in nitrogen dioxide (NO2; average of lags 0 and 1 of the 1-h maxima of NO2) for different choices of the number of degrees of freedom used for seasonality control
| Model | |||
| Degrees of freedom | Fixed effects | Random effects | |
| Total mortality | -25% | 0.34 (0.29–0.39) | 0.33 (0.24–0.42) |
| Baseline mode# | 0.30 (0.25–0.35) | 0.30 (0.22–0.38) | |
| +25% | 0.27 (0.22–0.32) | 0.27 (0.19–0.36) | |
| CVD mortality | -25% | 0.45 (0.37–0.52) | 0.43 (0.32–0.55) |
| Baseline model# | 0.41 (0.34–0.49) | 0.40 (0.29–0.52) | |
| +25% | 0.37 (0.30–0.45) | 0.37 (0.25, 0.49) | |
| Respiratory mortality | -25% | 0.40 (0.23–0.57) | 0.44 (0.24–0.65) |
| Baseline model# | 0.34 (0.17–0.51) | 0.38 (0.17–0.58) | |
| +25% | 0.31 (0.13–0.48) | 0.33 (0.13–0.52) | |
Data are presented as percentage increase (95% confidence interval). CVD: cardiovascular disease. #: i.e. minimising the absolute value of the sum of the partial autocorrelations of the final model's residuals from lags 3 to 30.