Polycyclic aromatic hydrocarbon emission from straw burning and the influence of combustion parameters

A simulated burning experiment was conducted in a tubular furnace system to examine the emission of polycyclic aromatic hydrocarbons (PAHs) from the burning of rice and bean straw, and the influence of combustion parameters was investigated. Total emission amounts of 16 PAHs (Sigma PAHs) from the burning of rice and bean straw ranged from 9.29 to 23.6 mu g g(-1) and from 3.13 to 49.9 mu g g(-1), respectively, which increased with the increase of temperatures from 200 to 700 degrees C. The contribution of combustion to individual PAH yields was about 80.6-100%, which was generally increased with the increase of burning temperature. Moisture content in straw had a negative effect on PAH formation, especially on PAHs with low molecular weight. Sigma PAHs emission amounts decreased by 78.2% for bean straw with a Moisture content of 30% in comparison with that for dried straw. In addition, PAH emission amounts increased with the increase of O-2 content in supplied air and then decreased, which showed a maximum emission at O-2 content of 40%. The source fingerprint of PAHs in emission from Straw burning was established, which showed that naphthalene accounted for 35.0 +/- 7.4% of Sigma PAHs. Based on the experimental data, emission amounts of Sigma PAHs from the burning of rice and bean straw were estimated to be 320-357 and 32.5-76.0 tons to ambient air per year in China, respectively. (C) 2008 Elsevier Ltd. All rights reserved.