Table 2.
Species | Emission index ranges (g kg−1)a | Source |
---|---|---|
Soot | 0.025 (0.01–0.1)b | Fuel carbon |
H2SO4 | 0.04 (0.01–0.1)c | Fuel sulphur SO2 + OH, SO2 + O |
HNO2d | 0.08–0.8 | Fuel- and air-nitrogen passed through combustor, NO + OH |
HNO3d | 0.003–0.3 | Fuel- and air-nitrogen passed through combustor, NO2 + OH |
OH | 0.1–0.5e | Combustion |
Low volatility hydrocarbons | ≈0.01–0.02f | Fuel carbon |
Volatile aerosol particles | 0.0065–0.05g | Condensable gases |
Equivalent emission index.
Modern engines have a soot emission index of about 0.01 g soot kg−1 fuel.
For a mean fuel sulphur content of 400 μg g−1 and a measured efficiency ɛ = 0.033 for fuel sulphur conversion to H2SO4. Commonly used fuel sulphur content values range from 10 to 1000 μg g−1 (upper limit 3000 μg g−1).
Condensable only in very cold, lower stratosphere (see text). (T ≤ 200 K).
Inferred from measurements with chemical plume models.
Inferred from measurements (see text) and from Kärcher et al. (2000). Very uncertain.
Taking 1016–1017 volatile particles (diameter 5 nm) and assuming a specific weight of 1 g cm−3. Very uncertain.