Table 2.
Mean relative substance distribution within each cluster.
| Cluster type | Lead substance | N (Germany) | N (Spain) | N (Italy) | Period and time of day | α-Pinene | β-Myrcene | β-Pinene | Δ3-Carene | Isoprene | 1,8-Cineole/cis- β-Ocimene | Limonene | p-Cymene |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | α : β-Pinene ratio > 4 | 0 | 5 | 4 | DrDay | 54.3% | 16.8% | 9.2% | 0.0% | 7.4% | 1.6% | 6.4% | 4.3% |
| 0 | 8 | 7 | DrNight | 45.9% | 26.4% | 12.8% | 0.0% | 3.5% | 0.0% | 7.1% | 4.4% | ||
| 0 | 5 | 2 | RwDay | 59.3% | 13.0% | 10.1% | 0.0% | 2.9% | 1.9% | 9.0% | 3.8% | ||
| 0 | 6 | 2 | RwNight | 64.2% | 12.2% | 8.9% | 0.1% | 1.3% | 0.0% | 9.5% | 3.9% | ||
| 2 | β-Myrcene | 0 | 5 | 4 | DrDay | 31.3% | 42.8% | 6.9% | 2.4% | 7.7% | 0.0% | 6.6% | 3.6% |
| 0 | 2 | 1 | DrNight | 7.7% | 74.9% | 1.2% | 8.3% | 1.0% | 0.0% | 5.4% | 1.6% | ||
| 1 | 3 | 4 | RwDay | 28.1% | 46.1% | 7.0% | 3.6% | 2.5% | 0.7% | 9.7% | 2.4% | ||
| 1 | 4 | 6 | RwNight | 31.5% | 44.1% | 9.1% | 2.6% | 1.0% | 0.0% | 8.8% | 3.0% | ||
| 3 | α : β-Pinene ratio ~ 1 | 1 | 2 | 3 | DrDay | 32.1% | 11.4% | 33.8% | 3.1% | 6.0% | 0.0% | 8.8% | 4.8% |
| 0 | 2 | 3 | DrNight | 75.3% | 4.8% | 13.1% | 0.0% | 4.9% | 0.0% | 0.0% | 4.8% | ||
| 1 | 4 | 4 | RwDay | 37.1% | 12.9% | 35.1% | 1.8% | 1.8% | 0.5% | 6.1% | 4.6% | ||
| 1 | 2 | 2 | RwNight | 39.4% | 8.7% | 37.1% | 3.4% | 0.7% | 0.2% | 7.1% | 3.4% | ||
| 4 | Δ3-Carene | 11 | 0 | 1 | DrDay | 29.2% | 6.9% | 7.3% | 33.1% | 15.6% | 0.0% | 1.2% | 7.1% |
| 12 | 0 | 1 | DrNight | 32.3% | 3.9% | 4.6% | 45.4% | 9.9% | 0.0% | 0.8% | 6.5% | ||
| 10 | 0 | 2 | RwDay | 28.6% | 8.2% | 5.4% | 39.4% | 6.7% | 0.4% | 5.1% | 6.2% | ||
| 10 | 0 | 2 | RwNight | 29.5% | 8.8% | 4.1% | 46.0% | 2.8% | 0.1% | 4.8% | 4.9% |
Clusters were derived from a PAM cluster analysis based on relative emissions from sample period drought (Dr) and after rewetting (Rw) at both times (Day and Night).