| currently | 10 | temporal |
| to refine the technology | 8 | purpose |
| at the u.s. epa | 6 | temporal |
| research → be → underway | 79 |
| research → be under → way | 20 |
| negative | neutral | positive |
| 0.091 | 0.666 | 0.243 |
| Raw frequency | 99 |
| Normalized frequency | 0.700 |
| Modifier score | 0.750 |
| Perplexity | 81.619 |