Formula
$$ m_\text{BC} = m_\text{PM} \cdot f_\text{BC} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $m_\text{BC}$ | Annual black-carbon mass | t | result |
| $m_\text{PM}$ | Annual PM mass | t | PM calc |
| $f_\text{BC}$ | BC fraction of PM by engine type | - | IMO PPR working docs |
BC fractions
| Engine | $f_\text{BC}$ |
|---|---|
| Slow-speed diesel | 0.45 |
| Medium-speed diesel | 0.35 |
| High-speed diesel | 0.25 |
| LNG dual-fuel | 0.10 |
GWP20 ≈ 460 makes BC a disproportionately potent short-lived forcer.
Sources
- IMO PPR Sub-Committee.
- IPCC AR6.