Table 3.
RMSE and R2 values for the 10-fold spatial cross-validation training set (90% of the data) and the 10% left-out testing set for both the 2008–2016 and 2008–2018 ensemble models.
| 2008–2016 Ensemble Model Training RMSE (µg/m3) (and R2) | 2008–2016 Ensemble Model Testing RMSE (µg/m3) (and R2) | 2008–2018 Ensemble Model Training RMSE (µg/m3) (and R2) | 2008–2018 Ensemble Model Testing RMSE (µg/m3) (and R2) | |
|---|---|---|---|---|
| By PM2.5 Level (µg/m3) | ||||
| Below 35 | 3.346 (0.682) | 3.905 (0.575) | 4.201 (0.523) | 4.151 (0.522) |
| Below 60 | 3.664 (0.714) | 4.179 (0.612) | 4.651 (0.568) | 4.499 (0.569) |
| Below 150 | 4.010 (0.720) | 4.526 (0.621) | 5.154 (0.615) | 5.009 (0.612) |
| Below 300 | 4.319 (0.706) | 4.646 (0.631) | 5.635 (0.626) | 5.376 (0.641) |
| Below 500 | 4.618 (0.690) | 5.247 (0.603) | 6.044 (0.618) | 6.118 (0.616) |
| Below 1000 | 5.061 (0.659) | 5.420 (0.589) | 6.576 (0.598) | 6.599 (0.593) |
| By Year | ||||
| 2008 | 4.037 (0.787) | 4.818 (0.689) | 4.920 (0.680) | 4.903 (0.661) |
| 2009 | 3.755 (0.744) | 4.416 (0.637) | 4.603 (0.614) | 4.611 (0.602) |
| 2010 | 3.537 (0.707) | 3.834 (0.634) | 4.372 (0.559) | 4.013 (0.579) |
| 2011 | 4.016 (0.723) | 4.264 (0.642) | 4.840 (0.598) | 4.396 (0.615) |
| 2012 | 5.459 (0.684) | 8.006 (0.504) | 6.180 (0.581) | 8.456 (0.449) |
| 2013 | 4.990 (0.683) | 5.927 (0.588) | 5.836 (0.562) | 6.022 (0.576) |
| 2014 | 4.816 (0.668) | 5.175 (0.572) | 5.728 (0.530) | 5.359 (0.540) |
| 2015 | 5.881 (0.667) | 5.107 (0.687) | 6.723 (0.571) | 5.423 (0.645) |
| 2016 | 7.239 (0.449) | 5.296 (0.520) | 7.794 (0.370) | 5.627 (0.454) |
| 2017 | N/A | N/A | 9.348 (0.684) | 8.868 (0.669) |
| 2018 | N/A | N/A | 8.553 (0.687) | 10.435 (0.619) |
| By State | ||||
| Arizona | 3.139 (0.614) | 4.094 (0.374) | 3.795 (0.469) | 3.894 (0.418) |
| California | 4.753 (0.719) | 4.026 (0.756) | 6.577 (0.632) | 5.197 (0.724) |
| Colorado | 5.940 (0.499) | 3.539 (0.472) | 9.143 (0.351) | 3.758 (0.432) |
| Idaho | 7.016 (0.663) | 11.539 (0.546) | 7.789 (0.605) | 10.034 (0.607) |
| Montana | 5.428 (0.648) | 5.192 (0.593) | 7.642 (0.636) | 7.183 (0.595) |
| Nevada | 3.639 (0.679) | 3.630 (0.634) | 4.273 (0.497) | 3.809 (0.568) |
| New Mexico | 3.628 (0.536) | 9.732 (0.028) | 3.732 (0.388) | 10.823 (0.006) |
| Oregon | 5.239 (0.597) | 10.063 (0.362) | 8.441 (0.612) | 12.081 (0.436) |
| Utah | 4.667 (0.638) | 4.979 (0.647) | 5.223 (0.495) | 4.584 (0.665) |
| Washington | 5.642 (0.583) | 4.409 (0.586) | 6.814 (0.529) | 8.412 (0.515) |
| Wyoming | 6.983 (0.516) | 3.859 (0.531) | 6.405 (0.418) | 3.839 (0.465) |
| By Season | ||||
| Fall | 5.960 (0.598) | 6.465 (0.520) | 7.896 (0.599) | 8.505 (0.561) |
| Spring | 3.168 (0.611) | 3.227 (0.561) | 3.871 (0.444) | 3.293 (0.543) |
| Summer | 5.745 (0.635) | 5.760 (0.571) | 7.771 (0.605) | 7.629 (0.591) |
| Winter | 4.682 (0.767) | 5.632 (0.658) | 5.787 (0.639) | 5.620 (0.650) |