臺灣南部都市能見度長期變化及短期大氣氣膠化學組成與粒徑分布

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Title:	臺灣南部都市能見度長期變化及短期大氣氣膠化學組成與粒徑分布 Long-term Trend of Urban Visibility and Short-term Chemical Composition of Size-fractional Aerosol in Southern Taiwan Airborne particulate matters are an important component of ambient air because of its significant effects on air quality, human health, regional visibility, and global climate change. High particulate matters are an important factor that causes low visibility. In this study, I investigated the relationships between visibility and PM2.5 concentration in the Tainan metropolitan area, southern Taiwan, from 2010 to 2018. The annual average PM2.5 concentration decreased from 37.0±19.4 μg/m3 in 2010 to 22.4±11.8 μg/m3 in 2018, while the annual average visibility increased from 8.53±4.56 km to 15.8±10.3 km in 2018. The 9-year annual average visibility was exponentially increased with the decreased annual average PM2.5 mass concentrations, expressing as Vis=587.2PM2.5-1.21 (where the unit in Vis is km and in PM2.5 is μg/m3, r value= -0.860). From 2010 to 2018, the visibility of the four seasons was the best in summer, with an average of 15.1±7.54 km, while the PM2.5 concentration in summer was the lowest, averaging only 15.5±7.88 μg/m3. The worst visibility was in the winter, with an average of only 6.62±6.18 km, while winter PM2.5 was the highest concentration, with an average of 40.5±16.9 μg/m3. Season visibility was also negatively correlated with PM2.5 concentration, expressing as Vis=157.9PM2.5-0.860 (r value= -0.866). The increasing trend in visibility is significantly related to the decreased concentration in PM2.5. The size distributions and concentrations of inorganic species during the Moon Festival such as nss-SO42- (2.9889±0.0300 μg/m3), NH4+ (0.9275±0.1131 μg/m3), K+ (0.5624±0.6594 μg/m3), Ca2+ (0.2971±0.3588 μg/m3), and Mg2+ (0.1856±0.2428 μg/m3), respectively;and were similarly peak concentrations of these species occurred at 0.56 μm in the droplet mode during Moon Festival, as a result, the chemical compositions that mention above were the main aerosol compositions that affects visibility.
Authors:	Wongrat, Chayanis
Contributors:	環境工程與科學系蔡瀛逸
Keywords:	長程傳輸 PM2.5 能見度減少化學成分 Long-term trend PM2.5 Visibility impairment Chemical compositions
Date:	2020
Issue Date:	2022-10-21 10:33:28 (UTC+8)
Relation:	電子全文公開日期：2023-12-31 學年度：108， 95頁
Appears in Collections:	[Dept. of Environmental Engineering and Science (including master's program)] Dissertations and Theses

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