| Typicality: | 0.480 |
| Saliency: | 0.388 |
| for long-term observations | 5 | purpose |
| with pollution at its peak | 4 | temporal |
| by the mid-1980s | 2 | temporal |
| scientist → recognize → the need | 11 |
| scientist → see → the need | 10 |
| scientist → realize → the need | 3 |
| scientist → recognized → the need | 3 |
| negative | neutral | positive |
| 0.091 | 0.589 | 0.320 |
| Raw frequency | 27 |
| Normalized frequency | 0.388 |
| Modifier score | 0.700 |
| Perplexity | 140.619 |