| Summary: | 碩士 === 國立中山大學 === 海洋環境及工程學系研究所 === 94 === ABSTRACT
Taitung area was commonly seen as a particularly clean environment. But the air quality has diminished lately similar to that seen in some parts of the populated western area in Taiwan, with ozone (O3) concentration levels rising every year. Because ozone is a byproduct of photochemistry, its accumulation is not only related to the discharge of local pollutants such as nitrogen oxide compounds (NOx), volatile organic compounds (VOC) and the introduction of external pollutants, but also related to the meteorological conditions.
This research began with comparing the long-term trends of ozone concentration level and related pollutants in the Taitung area with those found in other survey stations spread in Taiwan. Through factor analysis, the relationship between air pollutants and meteorological parameters are analyzed. Finally, a screening of the events of abnormal ozone concentrations, followed with detailed analysis of the hourly data during these events and the discussion of the possible reasons for the comparatively poor air quality during these events and their correlations with seasons and meteorological conditions.
Analysis of the trends in monthly averaged concentration of ozone shows that the annual rate of change (AR) is increasing at all stations under this study, except the Guanyin station being -0.18%. Taitung station has relatively higher levels every spring (March - May) and fall (October – November); the annual rate of change is higher than other east area in Taiwan and the Hengchun station. These seasonal variation (SV) shows a progressively increasing north to south trend, Hengchun station being the highest and Taitung station being the second highest, indicates that concentrations of ozone are influenced by seasonal changes.
By using the method of factor analysis to analyze the relation among ozone concentrations, meteorological parameters and pollution parameters, resulted in a direct relationship to the wind speeds over the four seasons. The results show a negative relationship to the atmospheric pressure during summer. The ozone concentrations of the Taitung station show a direct relationship to the Hualian station, which indicates the north to south dispersion relationship. The Analysis of the abnormal event also shows that typhoons may be an important carrier for transporting external pollutants into the area.
|
|---|
