碩士 / 嘉南藥理科技大學 / 環境工程與科學系碩士班 / 96 / The spatial and temporal chemical compositions, characteristics, formation, sources, and particle distribution of aerosols in suburban Tainan in southern Taiwan during the Mid-Autumn Festival period, the fall moderate air quality period, and a high pollution loading (PM episode) period, and in the atmosphere of the remote Tseng-Wen Reservoir region are compared with the background information obtained in Alishan region.
The order of magnitude for gaseous pollutants in the atmosphere of the remote Tseng-Wen Reservoir region and of the fall moderate air quality period in the Tainan suburban region is NH3>SO2>HNO3>HNO2>HCl>oxalic acid. Meanwhile, during the Mid-Autumn Festival period, HCl concentration is higher than HNO3 concentration; during both the Mid-Autumn Festival period and the moderate air quality period, the daytime oxalic acid concentration is relatively higher. During the PM episode, both daytime and nighttime oxalic concentrations are high, indicating that there are more sources of oxalic acid during these periods. In Tseng-Wen Reservoir region, however, the order of magnitude for the daily average concentrations in PM2.5 is SO42->NH4+>NO3. During the Mid-Autumn Festival period, concentrations of inorganic salts in PM2.5 are higher during nighttime than daytime; the order of magnitude is SO42->NO3->Na+. Moreover, during the same period, the daytime and nighttime Na+ concentrations are higher than those for the moderate air quality period. Thus, in addition to sea salts, barbecuing activities also contribute to air pollution. Additionally, during the Mid-Autumn Festival period, the correlation coefficient between Cl- and K+ is 0.76 indicating that in additional to firecrackers, barbecuing also contributes to atmospheric pollution.
The order of magnitude for PM2.5 dicarboxylic acid concentrations in the atmosphere in the remote Tseng-Wen Reservoir and those during both the moderate air quality period and the PM episode in the Tainan suburban region is oxalic acid>succinic acid>glutaric acid; the daytime concentrations are higher than the nighttime concentrations. During the Mid-Autumn Festival period, the glutaric acid concentration is higher than the succinic acid concentration; the daytime concentration is 1.4 times whereas the nighttime concentration is 1.8 times those during the moderate air quality period, indicating that there are more sources of glutaric acid precursors during the nighttime period. The correlation coefficient between Na+ and glutaric acid is 0.72 revealing that glutaric acid originates from human activities during the Mid-Autumn Festival period. Additionally, the correlation coefficient between glutaric acid and succinic is 0.72 whereas both the correlations between succinic acid and oxalic acid, and between malonic acid and oxalic acid are low being only 0.49 and 0.27, respectively. This proves that the oxalic acid in the remote region originates from the local bio-emission.
The concentration distribution of inorganic salt concentration in the atmosphere of the Tseng-Wen Reservoir region is a droplet mode between 0.54 and 2.5 μm, and the nuclei mode is at 10 nm at which the primary aerosol forms. The NO3- particulate shows a single-peak distribution whereas tendencies of coarse mode formation for Na+ and succinic acid are the same, indicating that sea spray contributes to the pollution at both locations. However, the Na+ and Cl- concentrations at the peak of the concentration distribution are higher for Tainan suburban region than Tseng-Wen Reservoir region. During the Mid-Autumn Festival period, ratios of Na+ and Cl- concentrations in Tainan suburban region to those in Tseng-Wen Reservoir region are 8.63 and 5.46, respectively. Thus, there are more contributions from sea spray in Tainan suburban region during the Mid-Autumn Festival period than in Tseng-Wen Reservoir region. During the same period, the coarse mode aerosol glutaric acid, succinic acid and malonic acid in Tainan suburban region are 36.09, 10.41 and 14.49 times, respectively, those in Tseng-Wen Reservoir region. This also indicates the consequences of human activities on atmospheric pollution. The mass median aerodynamic diameter (MMAD) of oxalic acid in Tainan suburban region during the Mid-Autumn Festival period is 0.63 μm, which is smaller than 0.78 μm for oxalic acid during the fall moderate air quality period. Thus, the oxalic acid originating from special burning activities is distributed in the relative smaller particle size. The MMAD of oxalic in Alisan region is 0.83 μm, which is greater than 0.73 μm for that in Tseng-Wen Reservoir region. The average relative humidity in Alisan region is 88.5% that is higher than 74.5% in Tseng-Wen Reservoir region. Although the MMAD of oxalic acid in the Alisan region exists in the droplet mode of the cloud condensation similar to that in Tseng-Wen Reservoir region, the above observation shows that the increasing hydroscopic characteristics is more obvious for aerosols in the background Alishan region.
| Identifer | oai:union.ndltd.org:TW/096CNUP5515018 |
| Date | January 2008 |
| Creators | Yu-Chien Ma, 馬玉芊 |
| Contributors | Ying-I Tsai, 蔡瀛逸 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 122 |
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