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Grades of pollen count [32].
| Grades | Allergenic description | Pollen of woody plant (grains/1000 mm2) | Herbaceous pollen (grains/1000 mm2) | Incidence rate (%/‰) |
|---|---|---|---|---|
| 1 | low | ≤100 | ≤50 | P < 1 |
| 2 | lower | 101–250 | 51–100 | 1 ≤ P < 2 |
| 3 | moderate | 251–400 | 101–150 | 2 ≤ P < 3 |
| 4 | higher | 401–800 | 151–300 | 3 ≤ P < 6 |
| 5 | high | >800 | >300 | P > 6 |
