Table 5. SO2 2019 model performance statistics.
The Prophet model forecasted 2019 values on an hourly basis, which was compared to actual values over a 5 day, 15 day, 1 month, and 1 year period. Units for MSE, RMSE, and MAE are ppm. The MAE was on average 0.00124 ppm away from the actual value after 5 days and as the time increased away from the known values, the error increased.
| Time | MSE | RMSE | MAE | Coverage |
|---|---|---|---|---|
| 5 Days | 7.39 × 10−6 | 2.70 × 10−3 | 1.24 × 10−3 | 94.5% |
| 15 Days | 1.03 × 10−5 | 3.20 × 10−3 | 1.37 × 10−3 | 92.1% |
| 1 Month | 1.06 × 10−5 | 3.24 × 10−3 | 1.40 × 10−3 | 91.5% |
| 6 Months | 1.57 × 10−5 | 3.93 × 10−3 | 2.00 × 10−3 | 86.6% |
| 1 Year | 1.92 × 10−5 | 4.34 × 10−3 | 2.41 × 10−3 | 84.7% |