Abstract
The air quality in south-east Asia have been influenced by the emissions of agricultural residue burning. Not only air quality but also human health are also at risk of the chemical and physical properties of aerosols. Rice straw is the main crop in south-east Asia. Therefore, this study was designed to get more comprehensive understanding of size-segregated chemical characterization of aerosols emitted from rice straw burning (0.43-10μm). In addition, the three water contents of unburned rice straw were the operating factor with Tem. and Humi. Chamber in this study (<10%, 40%, and 90%). Eleven rice straw combustions and the sixteen large chamber experiments from forth Fire Laboratory at Missoula Experiments were conducted. The burning condition of all experiments were classified to flaming phase with modified combustion efficiency values. The emission factors of water-soluble ions, anhydrosugars, water-soluble organic carbon, and trace heavy metals were calculated. The levoglucosan, mannosan, galactosan were measured and levoglucosan occupied the most amount of these three anhydrosugars. The dominant species from rice straw burning were Cl-, K+, NO3-, and SO42-. The correlations of some specific ions (Cl-/K+, K+/NO3-, and NH4+/SO42-) were very good especially Cl- and K+ (above 0.937). The water contents of rice straw conditioned under three relatively humidity had no significantly influence on the size distributions of WSOC, anhydrosugars, and trace heavy metals. However, the size distribution of some anions and cations were affected by the different water contents. The heavy metals, Pb and Cd, were different from the origin of rice straw (Taiwan and China) and distributed in the fine mode. The emissions of wheat straw burning, rice straw burning, and grass burning were different in portions of ions from one another.