Table 1.
O:C ratios of the aqSOA measured for SPC2011 and of the OA factors (including the aqSOA) for Bologna2013, together with literature values of laboratory aqSOA and cloud water samples
| OA type | O:C (AA) | O:C (AI) | Site | Notes | Source |
| Fog water | 0.53 (0.08) | 0.68 (0.08) | SPC | Fall 2011 | This study |
| aqSOA event 1 | 0.61 (0.09) | 0.83 (0.10) | SPC | Fall 2011 | |
| aqSOA event 2 | 0.61 (0.09) | 0.84 (0.10) | SPC | Fall 2011 | |
| aqSOA event 3 | 0.61 (0.09) | 0.83 (0.10) | SPC | Fall 2011 | |
| aqSOA event 9 | 0.62 (0.09) | 0.82 (0.10) | SPC | Fall 2011 | |
| HOA | 0.08 (0.01) | 0.10 (0.01) | Bologna | Winter 2013 | This study |
| BBOA | 0.26 (0.04) | 0.33 (0.04) | Bologna | Winter 2013 | |
| OOA1 or aqSOA | 0.57 (0.09) | 0.81 (0.10) | Bologna | Winter 2013 | |
| OOA2 | 0.44 (0.07) | 0.56 (0.07) | Bologna | Winter 2013 | |
| OOA3 | 0.66 (0.10) | 0.83 (0.10) | Bologna | Winter 2013 | |
| Low-volatility cloud water organics | 0.52–0.59 | Whistler | Ambient | Lee et al. (20) | |
| Gas-phase SOA | 0.3–0.4 | Chamber | Aiken et al. (57) | ||
| Glyoxal aqSOA | 1–1.8 | Chamber | Lee et al. (14) | ||
| Phenols aqSOA | 0.85–1.23 | Chamber | Yu et al. (13) | ||
| Phenols aqSOA | 0.8–1.06 | Chamber | Sun et al. (16) |
The elemental ratios are estimated by the AMS organic mass spectra using the Aiken ambient (AA) (57), and the ambient improved (AI) (58) methods. Uncertainty is reported between brackets. The AA method is known to underestimate O:C, whereas the AI method reproduces the O:C ratio of complex organic mixture within 10%. However, because most of the literature studies use the AA method, we report the O:C ratios calculated using both the AA and the AI parameterizations.