| Summary: | 碩士 === 國立雲林科技大學 === 環境與安全工程系碩士班 === 97 === The contributions of biomass smoke to the ambient air in Taiwan are predominantly due to different harvest seasons burning of rice straw. This study focuses on particle-sized characteristics as well as the compositions of three anhydrosugars ( levoglucosan, mannosan, and galactosan ) and carbons derived from of different harvest seasons burning of rice straw, and on the estimations of biomass burning contribution in PM2.5 particles.
The results showed particle size distribution of anhydrosugars mainly in fine particles PM2.5 and PM>10, large particles; and PM2.5-10 the lower the concentration of coarse particles susceptible to environmental factors and the impact of atmospheric particles TSP concentration of total anhydrosugars was significantly less than non-harvest season, respectively, 3.8 and 3.5 times as high. In addition, the levoglucosan constituent accounts for over 90% in three anhydrosugars from harvest seasons. Seasonal effects of anhydrosugars particle size, the particle distribution of the winter harvest Levoglucosan to fine particles PM2.5 mainly ( TSP70% and above ), coarse particles (only TSP 3%) there is only a small amount; but summer, high humidity environment, fine particle aggregation role ( Particle Coagulation ) made from coarse particles increased the ratio of TSP 3% to 39%. And compare Levoglucosan/Mannosan (Levo/Mann) the ratio of PM2.5 particles in winter and summer, Levo/Mann ratio was 18.8 and 49.6, respectively, during the winter may be long-term retention of atmospheric particles in the atmosphere ( Aged Aerosol ) mixing particles of different combustion sources makes the ratio of decline in winter; summer ratio data with the chamber ( ~50 ) is similar to the summer more atmospheric deposition ( Fresh Aerosol ), it could be the summer of Levo/Mann ratio as the ratio of open burning characteristics. In this study, yet by Levoglucosan/OC ratio (%) assessment of biomass burning pollution incidents, the incident showed that if the burning of straw Levoglucosan/OC ratio of> 3%, so this can be regarded as the ratio of rice straw burning on the characteristics of pollution incidents. In addition, the study estimated that the rice straw burning particles contribute to the atmosphere than PM2.5 particles showed that winter and summer season rice harvest burning particles PM2.5 particles in the atmosphere contribution ratios of 14.09% and 18.77%, respectively, showing Taiwan open burning of rice in the region have a significant effect on air quality. In this study, size distribution of anhydrosugars of the discussion will help to resolve apparent effect on the rice season biomass burning atmospheric particle size distribution and the impact on air quality.
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