Table 1.
Characteristics of the burn pit smoke
| Variable | Plywood | Cardboard | Plastic | Mixture | Mixture/diesel | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Smolder | Flame | Smolder | Flame | Smolder | Flame | Smolder | Flame | Smolder | Flame | |
| MCEa | 0.68 | 0.94 | 0.72 | 0.98 | 0.78 | 0.93 | 0.78 | 0.97 | 0.74 | 0.97 |
| CO (g/kg)b | 250.6 | 74.5 | 223.6 | 25.5 | 202.1 | 101.9 | 191.5 | 33.9 | 195.0 | 36.2 |
| CO2 (g/kg)b | 818.2 | 1674.1 | 898.7 | 1547.8 | 1166.3 | 2315.7 | 1022.6 | 1891.9 | 860.2 | 1873.8 |
| PM (g/kg)b | 148.3 | 2.6 | 81.6 | 0.4 | 242.3 | 34.9 | 149.4 | 1.3 | 186.1 | 2.2 |
| CH4 (g/kg)b | 16.4 | 5.6 | 9.6 | 0.8 | 5.3 | 7.5 | 4.8 | 0.7 | 6.7 | 1.7 |
| VOCs (g/kg)b | 48.0 | 27.0 | 26.0 | 4.0 | 544 | 136.0 | 127.0 | 17.0 | 164.0 | 29.0 |
| NOx (g/kg)c | 1.5 | 3.8 | 0.4 | 2.9 | 0.2 | 2.4 | 0.4 | 3.9 | 0.3 | 2.9 |
| OC (% of PM mass) | 45.5 | 45.5 | 41.3 | 36.1 | 64.3 | 68.8 | 55.5 | 48.4 | 58.4 | 60.0 |
| EC (% of PM mas) | 0.4 | 0.4 | 0.4 | 1.6 | 0.1 | 5.6 | 0.2 | 5.6 | 0.1 | 2.3 |
| EOM (% of PM mass) | 64 | 59 | 61 | 38 | 71 | 39 | 70 | 49 | 71 | 65 |
| PM Size (µm)d | 1.5 [1.5] | 0.3 [1.1] | 1.0 [1.2] | 0.3 [1.1] | 1.3 [1.4] | 2.8 [2.0] | 1.5 [1.4] | 0.3 [1.2] | 1.6 [1.3] | 2.2 [2.0] |
aModified combustion efficiency (MCE) = ΔCO2/(ΔCO2 + ΔCO)
bEmission factor (EF) t (g/kg) = (fuel carbon fraction x mass of carbon emitted as t x molecular weight t × 1000) / (molecular weight carbon x total mass of carbon)
cEmission factor (EF) NOx (g/kg) = (mass of NOx / total mass of carbon emitted) x (mass of carbon in the fuel / total mass of fuel)
dMass median aerodynamic diameter (MMAD) of PM; values in brackets represent the geometric standard deviation