Effects of Moisture Content and Burning Period on Concentration of Smoke Particles and Particle-Bound Polycyclic Aromatic Hydrocarbons from Rubber-Wood Combustion

Physical and chemical characteristics of particles from rubber-wood combustion in a natural rubber sheet smoking process were studied. Experimental parameters include wood moisture content and wood-burning period. The size distribution of smoke particles was measured by using an 8-stage Andersen air sampler. Total smoke particle concentration was determined by collecting particles using a modified high volume sampler. Polycyclic Aromatic Hydrocarbons (PAHs) were extracted with Benzene-Ethanol by using ultrasonic technique and analyzed by HPLC/UV detection. Results show that the size distribution of smoke particles is single-mode in which the mass median aerodynamic diameter (MMAD) is 0.68 mu m and the average smoke concentration is 15.806 mg/m(3). This is equivalent to a mass emission to workplace of 4.33 kg/month/room. The smoke particle concentration and associated PAH concentration clearly depend on the wood moisture content and burning period. The highest PAH concentration and smoke particle concentrations were found to be 60.59 to 118.06 mu g/m(3) and 23.35 to 47.54 mg/m(3), respectively, for a wood moisture content of 37.4 to 73.6% d.b. (dry basis) at the initial period. Smoke particle-bound PAHs are dominated by 4-6 ring PAH compounds that contribute to more than 60% of the total PAHs.